Free CT 1: Prehistoric History of Madhya Pradesh 10 Questions 10 Marks 7 Mins Concepts: The members which support the covering material of a steel roof truss are called purlins. Purlins are beams of light sections spanning between trusses carrying dead load of roof, live load and wind load.

Purlins transmit these loads to the trusses. Generally, the purlins are so spaced that they are supported over the top chord joints of the truss. Purlins may be angles, channels, I-sections, tube sections etc. They are placed in an inclined position over the main rafters (top chord) of the trusses. To avoid bending in top chord, it is theoretically desirable to place purlins at panel points however; they are placed at very closed intervals for economic point of view.

A strut is a structural component of a roof truss and designed to resist longitudinal compression. ( Reference – Design Of Steel Structure By S.K Duggal (Page-485) Last updated on Sep 29, 2022 MPPSC AE Revised Selection List Out! This is for advt no 05/2020.

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The MPPSC will release a new notification for the MPPSC AE 2022 too. With Degree in Engineering as the basic educational qualification, it is a great opportunity for various job seekers.

What supports the roof of a house?

Common rafter – Rafters are normally made from wood or metal, and they run from one end of the roof to the other to form the main framework, meeting at the apex. They support the covering and insulation for the roof.

What is the name for the horizontal member at the top of a truss?

History – Timber roof truss example The top members of a truss are known generically as the top chord, bottom members as the bottom chord, and the interior members as webs. In historic carpentry the top chords are often called rafters, and the bottom chord is often referred to as a tie beam,

What are roof members called?

Different Parts of a Roof Structure There are many different parts of a roof, as well as different types of roofs, including gable, flat, and mansard. For the most part, though, a typical roof structure will consist of the following parts. First is the frame of the roof structure.

The truss is the “skeleton” of a roof, made of a series of parallel beams. The rafters are the supporting beams that run from the apex to the bottom of a roof, holding up the truss. Eaves are the edges of a roof, typically overhanging the vertical exterior walls of a building. They consist of fascia, soffits, and drip edges.

Then there is the finishing layer on top of the roof. The sheathing consists of boarding—either plywood or particle board—that is laid on top of the truss. It adds structural integrity to the frame and provides a base for the underlayment and shingles.

• Underlayment is a waterproof seal that is often made of felt and lays over the sheathing.
• Flashing, meanwhile, is a metal strip that forms a watertight seal between the roof shingles and other materials, like a chimney or vent.
• Last but not least are the shingles, which can be made of asphalt, clay, wood, metal, or something else entirely.

This top, finishing layer provides waterproofing and a neat appearance. Whether you want to DIY your own roof or are a roofing contractor in the business of building roofs for residential and commercial structures, is your source for the materials you need to get the job done.

Our locally and family owned business has been in the construction field for over 12 years, helping homeowners, builders, and contractors find the materials they need at low prices. You can find siding, tools, fasteners, and more from well-known and respected brands like TAMKO and Atlas Roofing. We are located in North Atlanta and we proudly serve all of the greater Atlanta area.

Contact us today to begin building a superior roof that will look great and last for decades, all thanks to affordable, high-quality materials. : Different Parts of a Roof Structure

How is a roof supported?

Is Your Roof Properly Supported? – When roofing a home, there are two roof framing systems used—rafters and trusses. Rafters and trusses provide the roof support for your home. It’s crucial that whichever your home uses, it is in proper working condition to provide the necessary support for your homes structure.

Roofs that are framed with rafters use individual rafters, which is just sawn lumber members, that are spaced at about 24 inches on center and go from the exterior walls to the ridge or into the sides of the main hip rafters. Commonly referred to stick-framing, this roofing style consists of two-by-sixes.

But, because of the use of this small size, they don’t span very far and need to be braced near mid-span. In most roofing structures, the roof-bracing system carries the majority of the weight of the roof. Because of this, it’s crucial that the roof braces rest on the load-bearing walls and not the most convenient interior room partition wall.

While this seems standard, many framers often support the roof bracing system on the closest wall, which leads to floor sag and other complicated issues in the structure. Along the peak of the roof is a ridge board that is used as a bearing-plate for the opposing rafters. And while the ridge board does not provide any structural support, it is required that it be tall enough to be placed in full contact with the cut face of the mating rafter and that opposing rafters align directly with one another.

These requirements are vital to the structural integrity of the home. When the ridge board is not structurally sound, the roof rafters should be lapped alongside and connected to the underlying ceiling joists at the exterior wall plate. And, the ceiling joists that extend across the home must be properly lapped and connected to create a tension-tie across the home.

1. If these standard practices are lacking, the roof ridge will sag and the exterior walls will begin to lean outward.
2. Roof systems framed with trusses use pre-engineered, light-gage-plate-connected sawn lumber members fabricated according to a proprietary engineering design.
3. The benefits of trusses include its ability to withstand structural load requirements and difficult roof framing configurations.

Trusses are able to transfer all of their load to the outer bearing points, thus, they do not need any support from interior room partition walls. However, truss-framed roofs can still create floor sag and other issues. When trusses are excessively long, they become flimsy and fragile.

Which of the following roofs are sloping roof?

Building Construction Questions and Answers – Types of Roofs This set of Building Construction Multiple Choice Questions & Answers (MCQs) focuses on “Types of Roofs”.1. Which of the following is not a category of roofs? a) Pitched roofs b) Flat roofs c) Aligned roofs d) Curved roofs View Answer Answer: c Explanation: Roofs are classified into three categories.

1. These are pitched roofs, flat roofs and curved roofs.
2. Pitched roofs are also known as sloping roofs and flat roofs are also known as terraced roofs.2.
3. Which roofs are preferred in areas having heavy rainfall? a) Pitched roofs b) Flat roofs c) Terraced roofs d) Curved roofs View Answer Answer: a Explanation: Pitched roofs are preferred in areas having heavy rainfall.

They have a sloping top surface which allows the rain or snow to slide off. Buildings having limited width can usually be covered by pitched roofs satisfactorily.3. Which roofs are used in hot regions? a) Pitched roofs b) Flat roofs c) Sloping roofs d) Curved roofs View Answer Answer: b Explanation: Flat roofs are used in hot regions or in the areas having moderate rainfall and no snowfall.

They are used for the buildings in plain areas. Note: Join free Sanfoundry classes at or 4. Which roofs are more preferred for public buildings like libraries and theatres? a) Pitched roofs b) Flat roofs c) Sloping roofs d) Curved roofs View Answer Answer: d Explanation: Curved roofs are more preferred for public buildings like libraries and theatres.

Their top surface is curved. These roofs provide architectural effects. They include cylindrical shells and shell domes.5. Which of the following roofs slopes in two directions? a) Lean-to-roof b) Gable roof c) Hip roof d) Mansard roof View Answer Answer: b Explanation: Gable roof slopes in two directions.

• These two slopes meet at the apex line.
• Hip roofs and mansard roofs slope in four directions while lean-to-roof slopes in one direction only.
• Take Now! 6.
• Pitch is expressed as a ratio of _ a) Span to ridge b) Ridge to span c) Rise to span d) Span to rise View Answer Answer: c Explanation: Pitch is expressed as a ratio of rise to span.

Span is the distance between the supports of an arch or beam. Rise is the vertical distance measured between the wall plate and the top of the ridge.7. The hip is formed by the intersection of two sloping roof surfaces making an external angle less than 180°.

• A) True b) False View Answer Answer: b Explanation: Hip is formed by the intersection of two sloping roof surfaces making an external angle more than 180° while a valley is the reverse of a hip.
• It is formed by the intersection of two roof surfaces making an external angle less than 180°.8.
• The apex line of a pitched roof is known as _ a) Purlin b) Ridge c) Hip d) Valley View Answer Answer: b Explanation: The apex line of a pitched roof is known as the ridge.

Horizontal wooden members are provided at the apex of a roof truss in the form of beams. These are known as ridge pieces or ridge beams.9. _ is known as the lower edge of an inclined roof surface. a) Eaves b) Ridge c) Plate d) Purlin View Answer Answer: a Explanation: Eaves is known as the lower edge of an inclined roof surface.

• The rainwater slides off from the roof surface from the eaves.10.
• Sloping triangles are formed in _ a) Gambrel roof b) Gable roof c) Hip roof d) Mansard roof View Answer Answer: b Explanation: Sloping triangles are formed in the hip roof at the end faces while in the mansard roof, sloping ends are obtained.

Mansard roof also slopes in four directions just like hip roof but the difference is that in mansard roof, each slope has a break. At the end of the hip roof, the sloped triangular surface formed is known as the hipped end. Sanfoundry Global Education & Learning Series – Building Construction.

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What is pitched roof covering?

What is Pitched Roof? Parts and Types of Pitched Roof – Civil Engineering Saumik Mallik A pitched roof is a roof comprising a sloping surface or surfaces with an angle of usually over 20 degrees. It is a bi-fold, bi-planer roof with a ridge at its highest point. To be more specific – a pitched roof requires a pitch of more than 10 degrees or a roof with two slopes that meet at a central ridge.

What are the 5 members of a roof truss?

What are the different types of roof trusses? A consists of top chords, bottom chords, internal web members and steel connector plates at all junctions to connect the timbers together and the combination of timber and plates support the roof loadings throughout the truss and down into the load bearing supports below.

• Timber roof trusses can be used to frame a wide range of roofs, both cold and warm, and a wide range of super structures including timber, masonry and steel frame.
• There’s a variety of different roof trusses and they vary in terms of their shape, size and use and it can be overwhelming trying to work out which type you need for your project.

As a roof truss manufacturer, we want to help make it clear what the most popular different types of roof trusses are and what they are typically used for. We design all types of roof trusses, some examples are fink trusses, attic trusses, scissor trusses, raised tie trusses and mono trusses to Glulam feature trusses, oak feature trusses and kerto feature trusses. Standard Fink Trusses: these are most common type of truss used for the majority of new build houses across the UK and mostly by national housebuilders. These can be used as roof trusses for garages, extensions and self builds too. Attic Trusses (standard overhang, cantilevered eaves and stubbed eaves): Attic trusses are used when a habitable space is required within a roof zone. The trusses are designed as attic style with larger timber sections to support additional loadings to allow people to live within the truss zone. Scissor Trusses: these are used primarily as a feature over living rooms or master bedrooms. The bottom chord members are pitched to create a sloping ceiling. The appearance is similar to scissors, hence their name. Mono Trusses : these are sloped in one direction and often used in porches and to form roofs with hip ends but can also be used to form new build roofs. Raised Tie Trusses: These are used to create a part sloping ceiling within a room. These sloping ceilings are ideal for adding Velux windows. Although these are the most popular types of roof trusses we design and supply, we can manufacture to a different shape based on customers’ requirements. Cold roof trusses vs warm roof trusses: Cold roof trusses are most commonly used in new build houses. These are our standard fink trusses and the loft insulation is laid directly above the ceiling. They are called ‘cold’ trusses because the area above the loft insulation leaves a large cold space in the roof zone.

• A warm roof truss, also referred to as an attic truss is where people live so the insulation on the truss is placed within the sloping top chord of the truss so there is a minimal void space above the insulation and the outside environment, hence the term ‘warm’ roof truss.
• Rafters vs Trusses: There’s often some confusion between trussed rafters and roof trusses and we want to try and provide some clarity about the differences.

Rafters need to be cut and constructed on site whereas a truss is a fully designed structure meant to be lifted and installed onto the roof. Rafters require more labour costs and time, whereas trusses are manufactured offsite ready to be installed when they reach the site.

We often get asked what the standard size and pitch of a truss is as many people think they are an off the shelf product. They are not. Each roof truss we supply is designed for the building they are being used for, so they are completely unique. As well as roof trusses, we design and manufacture a range of high quality timber engineering products including and You can request instant, competitive pricing for the roof trusses and joists you need using our function.

If you require help with a more complex roof truss solution, please get in touch and our design team will be happy to assist you with your enquiry. : What are the different types of roof trusses?

What is the name of the sloping framing member for the roof?

A rafter is one of a series of sloped structural members such as wooden beams that extend from the ridge or hip to the wall plate, downslope perimeter or eave, and that are designed to support the roof shingles, roof deck and its associated loads. A pair of rafters is called a couple.

What are the support beams in a roof called?

What is a Roof Rafter? – You may be wondering, “What is a rafter?” If so, you’ve come to the right place. We specialize in rafters and pretty much all things roofing! A rafter is defined as one of a series of sloped structural pieces (typically wooden beams) that extend from the hip or ridge to eave, wall plate, or downslope perimeter.

Common rafter Plumb cut Ridge board Collar tie Birdsmouth cut Tail cut Ceiling joist Double top plates Wall stud

Rafter boards that create the slope of the roof are typically wider than ones used to create trusses. While 2x4s are most common in trusses, 2x8s, 2x10s, and 2x12s are most common in rafters. In a finished space, insulation is placed between the rafter boards and drywall.

What is truss member?

Octet truss – Truss members are made up of all equivalent equilateral triangles. The minimum composition is two regular tetrahedrons along with an octahedron. They fill up three dimensional space in a variety of configurations.

What are strut members?

A strut is structural member that is being pushed from opposite ends. It is said that a strut ‘resists compression.’ A tie is a structural member that is being pulled from opposite ends. It is said that a tie ‘works in tension.’ Columns are vertical, structural members of a structure.

What is the structural member of a roof system called?

Roofing Elements Defined – 1.Trusses Trusses are the backbone of a roof system. Usually built from wood, this framed structure is comprised of triangle shaped joints, which provide a roof with stability and a rigid structure to support the roofing system.

A framed truss provides the strength and overall shape of a home or commercial building’s roof. The durability and strength of a truss will hold up to heavy amounts of snow and rain.2. Roof Deck This is the layer of material used to cover the trusses, and is then treated with weatherproof layers or insulation prior to receiving a layer of tile or shingles.

The roof deck acts as the link that unites all of the roofing components together. The roof deck can be made of plywood, OSB sheathing, wood tongue and groove, corrugated metal, or a variety of high-quality materials that a professional roofer may recommend.3.

• Underlayment The underlayment is an essential piece of the roofing system, as it keeps water and other forms of moisture from penetrating the roof.
• Shedding water is the primary function of this roofing component.
• With high winds and heavy rain, a roof must have a high-quality underlayment to defend against the elements.4.

Flashing Flashing is sheet metal or another rigid pliable material used to waterproof a roof system’s various joints and valleys and keep moisture from leaking in. All vents, jacks, and fireplaces that penetrate the roof should have a flashing layer.5.

Drainage All roofing systems should have shapes and sloped features to drain water off of the roof. Having the ability to shed water will keep a roof system functioning for many years.6. Ventilation A roof breathes in cool fresh air and also will exhale warm, moist air as part of a healthy functioning roof system.

A series of vents, pipes, and screened openings are used to allow air to flow in and out of a roof’s attic space. A qualified roofing contractor can explain all of the building codes and requirements for a home or commercial building’s ventilation system.7.

Which walls support the roof?

Load-bearing walls, sometimes called simply ‘bearing walls,’ support the weight of the floor or roof structure above them. They are designed to transfer the weight from the roof, through the floors and down to the foundation.

What supports a roof load?

Mastering Roof Inspections: Roof Framing, Part 1 by Kenton Shepard and Nick Gromicko, CMI® The purpose of the series “Mastering Roof Inspections” is to teach home inspectors, as well as insurance and roofing professionals, how to recognize proper and improper conditions while inspecting steep-slope, residential roofs. This series covers roof framing, roofing materials, the attic, and the conditions that affect the roofing materials and components, including wind and hail.

1. We won’t go into attic inspection too deeply since this series of articles from Mastering Roof Inspections is primarily about roofing defect recognition, but you should have an understanding of the two main, basic roof structure systems: conventional roof framing and roof trusses.
2. You’ll be evaluating the roof framing from inside the attic space, but we have an advantage in technology.

Let’s strip away the roof and wall coverings of a home and identify some of the more common roof framing members. We’ll start with a conventionally framed roof in which individual roof-framing members are cut and assembled on-site. CONVENTIONAL ROOFS

• Conventional Roof Framing
• Common Rafters
• Rafters which rest on the outside walls at the bottom and connect to the ridge at the top are called “common rafters” (highlighted here in yellow).

Rafters on opposite sides of the ridge should be installed directly opposite each other in pairs – although, if you see a few that don’t align, it’s really not a defect. Rafters sometimes have to be moved a little to accommodate components of other home systems. The illustration above shows a rafter moved to accommodate a combustion vent. If you see many rafters that don’t align, you may comment on this, but in existing homes, refrain from calling it a defect unless you see failure. In newer homes, many rafters which don’t oppose usually indicate poor-quality framing. It’s an indication that you should look carefully for other problems in the roof framing.

• Rafters are typically installed on 24-inch centers.
• If you see rafters installed on centers greater than 24 inches, look for signs of failure, such as sagging of the rafters.
• If you see sagging rafters, recommend stabilization by a qualified contractor.
• Stabilization typically involves installation of a purlin system.

Hips Hip roofs have “hip rafters” which are oriented diagonally to the ridge and outside walls. Hip rafters are simply called “hips,” and are shown here as brown. Hips rest on an outside corner at the bottom and connect to the ridge at the peak. Rafters which rest on the exterior walls at the bottom and connect to a hip at the top are called “hip jacks,” shown here as purple. Valleys Where ridges change direction, an inside corner is created, which is spanned by a “valley rafter” or simply “valley,” shown here as green. Valleys are also oriented diagonally to the ridge and exterior walls. Valleys rest on top of the walls at the inside corner at the bottom, and connect to the ridge at the top.

• Rafters which connect to the valley at their bottoms and connect to the ridge at the top are called “valley jacks,” shown here as light blue.
• Conventional Ridge The illustration shows a conventional ridge (colored orange).
• In homes with conventional ridges, the rafters support the weight of the roof and transmit the roof load down through the walls to the foundation and, finally, to the soil.

The route taken by the weight of the roof through the framing members to the soil is called the “load path.” The purpose of the ridge is to provide an easy method for connecting rafters at the peak of the roof, and to provide better nailing at the peak. Older homes may have no ridge at all. That was a common building practice at one point in various parts of North America, and it’s not a defect as long as the rafters oppose each other. Engineered lumber used for roof framing has very specific requirements for connections, and discussing them here exceeds the scope of this series. In homes with flat ceilings and an attic space, the bottoms of opposing rafters should be fastened together with ceiling joists, which form “rafter ties.” When rafters have been installed perpendicular to the ceiling joists, rafter ties typically rest on top of the ceiling joists. Collar ties connect the upper ends of opposing rafters. They should be installed on every other rafter in the upper third of the roof. Their purpose is to prevent uplift. Whether or not they should be installed is an engineering call. They aren’t always required so the lack of them is not a defect, but when you see them, they should be installed correctly.

1. Here, you can see collar ties installed in the upper third of the roof, and rafter ties installed down low and spliced over a wall.
2. Purlin Systems
3. You can also see the purlin system.

Purlin systems are designed to reduce the distance that rafters have to span. They consist of strongbacks nailed to the undersides of the rafters and supported by diagonal braces. The bottoms of purlin braces should rest on top of a bearing wall. Braces that rest on ceiling joists or which somehow pass the roof load to the ceiling below are defective installations.

1. If you see braces which rest on ceiling joists, look for a sag in the ceiling.
2. Braces are typically installed every other rafter and should be at an angle no steeper than 45°.
3. Here’s a purlin system installed in the garage of an older home.
4. With no central wall to carry the braces, they bear on a strongback that rests on the ceiling joists.

There was no sagging, so there was no comment in the inspection report. Purlin systems have been built in many ways – some better than others. Modern building codes call for strongbacks to be of equal or greater dimension than the rafter dimension, but most purlin strongbacks you’ll see will not meet this requirement.

If you know that the home was required to meet this code when it was built, call it a defect; otherwise, limit your inspection to looking for signs of failure, such as sagging or broken rafters and broken components. Also, look for improper installations, such as braces resting on ceiling joists, braces but no strongback, and too few braces.

In older homes in some areas, it’s common to find no strongbacks. It’s a quality issue unless the roof is sagging; then, it’s a structural issue and you should recommend stabilization by a qualified contractor. The term “purlin” has several different meanings depending on what part of North America you’re in, what part of the roof you’re talking about, and the background of the person you’re discussing it with, so don’t be surprised if someone tries to correct you.

Structural Ridge Homes with vaulted ceilings usually don’t have rafter ties to keep the walls from spreading and the ridge from sagging, so they use a structural ridge. In a home with a structural ridge, the ridge consists of a beam strong enough to support the roof load without sagging. Overframe When you’re inside an attic, you may see a condition in which the ridge and a few jack rafters from one roof section are framed on top of an existing roof.

This is called an “overframe” and it’s quite common in certain areas. Built correctly, it’s structurally sound. You’ll often see a section of roof sheathing removed to provide a passageway between attic spaces. If you can’t enter a portion of the attic, recommend that it be inspected by a qualified inspector after access is provided.

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What is a fully supported roof?

Commercial – We commit ourselves to providing the most economical service available. We are not tied into any one supplier or system which means value engineering is always available. Our partnering mentality is ideal for those who wish us to become involved from an early stage, which can often result in cost reduction of other trades such as steelwork, masonry, etc.

We have extensive experience of working within a range of sectors. Fully Supported Traditional metal roofing and cladding generally describes the covering of a roof with metal sheeting such as aluminium, steel, copper and zinc roofing and cladding where the limitations to the metals structural strength mean it is unable to span distances unsupported and is therefor fully supported by the substrate construction below.

This highly skilled craft is the cornerstone of our company. Longworth is one of the founding members (and one of the largest companies) in the Federation of Traditional Metal Roofing Contractors ( FTMRC ), which has been growing rapidly since we joined in 1999.

Fully supported by a continuous insulated or ventilated substrate. Available in a wide range of materials such as stainless or coated steel, aluminium, copper and zinc. Available with different jointing techniques such as standing seams, batten rolls or welts (depending on pitch and location or aesthetical requirement). A very traditional looking system used for architectural buildings, installed by craftsmen, formed on-site using hand tools. Guaranteed with a long lifespan (usually over 50 years). Maintenance-free.

Which type of houses have sloping roofs?

In the hilly areas, houses with sloping roofs are preferred so that snow and water may slip down. Besides, stones are easily available there than sand. Hence stones are mostly used to build houses in these areas. Even the roofs are made up of slate stone.

How many types of sloping roofs are there?

Basic Civil Engineering Questions and Answers – Roof Types

• This set of Basic Civil Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Roof Types”.
• 1. Roof may be broadly classified into: a) 2 b) 3 c) 5 d) 6
• View Answer

Answer: b Explanation: The three types are sloping roofs, flat roofs and shell roofs. They can be used according to the place of construction and requirements.

2. 2. The lowest edge of the sloping surface of roof is called: a) Ridge b) Rafters c) Pitch d) Eves
3. View Answer

Answer: d Explanation: Ridge is the apex line of a sloping roof. Rafters are wooden members extending from ridge to eves. Pitch is the inclination of the sloping roof to horizontal.3. _ Roof has four sloping sides with zero vertical roof lines. a) Gable b) Gambrel c) Hip d) Shed View Answer Answer: c Explanation: Hip roof is difficult to construct compared to flat and gable roof because these have complicated truss and rafter structure.4.

1. The figure below represents a _ roof.
2. A) Butterfly b) Bat c) Prismatic d) Conoid View Answer Answer: a Explanation: It is type of shell roof.
3. The two sides are shaped like wings of a butterfly, hence the name.
4. It is not commonly used because it does not provide drainage facility.5.
5. Ridge piece in a sloping roof is usually a: a) Metal b) Wood c) Polymer d) PVC View Answer Answer: b Explanation: Ridge piece runs horizontally at the apex.

Rafters are then affixed on to this. It is usually a wooden piece or board.6. How many types of sloping roofs are available? a) 2 b) 10 c) 5 d) 6 View Answer Answer: d Explanation: There are 6 types of sloping roofs available. They are steel sloping roofs, lean-to-roofs, couple roofs, couple close roofs, collar beam roofs and trussed roofs.7.

Timber trusses can be built for long spans. a) True b) False View Answer Answer: b Explanation: Steel trusses are mostly used for longer spans. These are easy to fabricate, install and maintain. They have higher resistance to fire, corrosion (painting) etc.8. A finishing coat with _ ratio is provided in Punjab terrace roofs.

a) 1:4 b) 1:2 c) 4:1 d) 2:1 View Answer Answer: c Explanation: The finishing coat primarily consists of cow dung and cement mixed together. They are taken in 4:1 ratio, that is 4 parts cow dung to 1 part cement.9. Which of the below roof types can be used for a span of 4.5 m? a) Couple close roof b) Lean-to-roof c) Couple roof d) Collar beam roof View Answer Answer: a Explanation: Lean-to-roof is usually employed for a span of 2.5m.

Couple roof is provided where a span of 3.5m is required. Collar beam roof can be used up to the span of 4-6m.10. A gable roof slopes in _ direction. a) 1 b) 3 c) 2 d) 4 View Answer Answer: c Explanation: A gable roof slopes in two directions in such a way that the end formed by the intersection of slopes is a sloped triangle.

It is commonly used in houses, workshops, etc.11. How many layers of flat tiles are placed in Madras terrace roofs? a) 2 b) 4 c) 0 d) 3 View Answer Answer: d Explanation: In Madras terrace roof, firstly wooden joists are placed over steel joists or walls.

Then, a course of well burnt bricks is placed in the lime mortar, followed by a layer of brick bat concrete. Then 3 layers of flat tiles in the lime mortar (1:2) is provided and the roof is finished with 3 coats of plaster.12. Which of the below is the type of folded plate roof? a) Prismatic b) Cylindrical c) Corrugated shell d) Ellipsoidal View Answer Answer: a Explanation: Folded plate roofs may be defined as slabs with folds.

These folds reduce bending moment and shear force considerably. Cylindrical, Corrugated shell and Ellipsoidal are types of shell roofs. Sanfoundry Global Education & Learning Series – Basic Civil Engineering. To practice all areas of Basic Civil Engineering,,

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What is the best roof slope?

Proper roof slope can be an important consideration when designing high-performance roof systems. Minimum and maximum roof slope limits vary based on specific roof system and project types. Following is a review of code requirements and NRCA’s roof slope guidelines, as well as some additional factors designers should consider.

Code requirements Building codes generally provide prescriptive minimum roof slope requirements for various roof system types. For example, the International Building Code, ® 2018 Edition (IBC ® 2018) prescribes a 1/4:12 minimum roof slope for asphalt built-up, polymer-modified bitumen, thermoset and thermoplastic single-ply, and liquid-applied membranes in new construction.

This 1/4:12 minimum roof slope requirement also applies to spray polyurethane foam (SPF) roof systems in new construction. For metal panel roof systems with nonsoldered seams with applied lap sealant, IBC 2018 prescribes a 1/2:12 minimum roof slope. For standing-seam metal roof panel systems, a 1/4:12 minimum roof slope is prescribed.

For steep-slope roof systems, IBC 2018 provides for a 1:12 minimum roof slope for mineral-surfaced roof roll roofing; 2:12 minimum roof slope for asphalt shingles, photovoltaic (PV) shingles and building-integrated PV; 2 1/2:12 minimum roof slope for clay and concrete tile; 3:12 minimum roof slope for metal roof panels with nonsoldered seams without applied lap sealant, metal shingles and wood shingles; and 4:12 minimum roof slope for slate and wood shakes.

The International Residential Code, ® 2018 Edition (IRC ® 2018) prescribes minimum roof slopes similar to those of IBC 2018 except IRC 2018 indicates a 3:12 minimum roof slope for wood shakes. In cases of roof system replacement and re-cover of existing low-slope roof systems, IBC 2018 and IRC 2018 waive the codes’ 1/4:12 minimum slope requirement and apply a performance-based, positive roof drainage minimum requirement.

Both codes define the term positive roof drainage as: “The drainage condition in which consideration has been made for all loading deflections on the roof deck and additional slope has been provided to ensure drainage of the roof within 48 hours of precipitation.” Although building codes do not directly prescribe maximum allowable roof slopes, fire classifications—which are required by code—often do include maximum roof slope limitations.

For example, some EPDM membrane assemblies have maximum roof slope limitations as low as 1/2:12. Some TPO membrane assemblies also have relatively low maximum roof slope limitations. PVC membrane assemblies generally have higher maximum roof slope limitations; some are unlimited.

Steep-slope assemblies generally do not have maximum roof slope limitations. Designers should refer to manufacturers’ specific roof assembly fire classifications for maximum roof slope limitations. Individual manufacturers can be consulted for their fire classifications, which are roof assembly-configuration specific.

This information also is accessible via UL’s online classifications directory at www.ul.com or FM Approvals’ RoofNav application at www.roofnav.com, NRCA’s guidelines NRCA ‘s guidelines for minimum roof slope are provided in the roof system-specific sections of The NRCA Roofing Manual,

NRCA recommends membrane, liquid-applied and SPF roof systems be sloped to provide positive roof drainage. Additionally, for new construction, a roof system should meet building code requirements for minimum roof slope. For metal panel roof systems, NRCA recommends slopes of 1/2:12 or more for structural panel systems and 3:12 or more for architectural panel systems.

For asphalt shingle, clay and concrete tile, metal shingle, slate and wood shake and shingle roof systems, NRCA recommends slopes of 4:12 or more. NRCA ‘s recommended minimum roof slope guidelines for steep-slope roof systems generally are greater (at steeper inclines) than those in the building code.

Although the code’s values represent minimum requirements in the context of minimum legal requirements for construction, NRCA ‘s recommendations are best practice guidelines. Additional considerations Designers also should consider the following project-specific conditions. For steep-slope roofs where two roof areas of equal slope intersect to form a valley, the resulting valley slope is less than that of the two adjacent roof surfaces.

For example, where roofs with a 4:12 slope intersect at a valley, the valley’s actual slope is only about 3:12. To accommodate this, designers should consider greater than the minimum recommended roof slope for steep-slope roof designs with valleys or other complex geometries.

Also, steep-slope roof areas with long rafter lengths experience greater amounts of water runoff than roof areas with short rafter lengths. To better accommodate this water runoff, designers should consider roof slopes greater than the minimum recommended slope. For low-slope roofs where a tapered insulation cricket or saddle creates a valley, the valley’s slope will be less than that of the cricket or saddle.

Some ponding water along cricket and saddle valleys typically will occur and should be anticipated. Additional information regarding roof slope and project-specific design considerations is provided in The NRCA Roofing Manual, Mark S. Graham is NRCA’s vice president of technical services.

What holds a roof in place?

Common roof framing elements – Below is a list of common roof framing elements:

FRAMING ELEMENT	Description
Barge board	Barge boards are found on homes with a gabled roof. Their function is similar to that of a fascia board – however it runs parallel to the rafters, on an angle at the skillion end of a gable. A barge board disguises the rafters closest to the end of of a gable roof.
Ceiling joist	Ceiling joists are the lengths of timber or metal that the ceiling is attached to.
Collar tie	Collar ties are elements that are fitted between rafters to prevent them from spreading apart.
Fascia board	A fascia board is attached across the end of the rafters to disguise them.
Hanging beam	Hanging beams sit at a right angle directly above ceiling joists. They are attached to the ceiling joists by metal hoops or brackets. Their main purpose is to support the joists and allow for shorter joists to be installed.
Hip rafter	A hip rafter extends from the wall plate to the ridge in the angle of a hip roof.
Purlin	A purlin is a horizontal piece of timber or metal which supports the roof’s rafters or decking and helps to prevent your roof from sagging.
Rafter	Rafters are sloped beams that run from the roof’s ridge to the eaves. They provide the support for the external roofing material.
Ridge beam	Ridge beams are long, rectangular, rigid pieces of wood, metal or stone which are placed horizontally along the ridge of the roof.
Roofing batten	Roofing battens run across or down a roof (sometimes both) to provide a fixing point for roofing cladding materials such as tiles or shingles.
Soffit bearer	Soffit bearers sit between the wall and the fascia, providing a base for the soffit lining to be fixed to.
Struts and props	Struts and props are vertical elements which support and transfer the load from the purlins to the strutting beams.
Strutting beam	Strutting beams support the roof members where there are no load bearing wall studs available. They transfer the load of the roof to load bearing walls. Strutting beams should only support roof loads, and not be used as ceiling joists.
Top plate	A top plate is nailed to the top of wall studs. This is the plate that the roofing elements sit on, and effectively the meeting point of the walls and the roof structure. It supports the roof load and helps transfer it down load bearing walls and into the foundations.
Truss	A truss is a piece of framework using triangular shapes. Roof trusses are generally fabricated offsite, reducing price and speeding up the construction of your roof frame. Roof trusses provide support for the roof deck, the framing and counteract wind load.
Valley rafter	A valley rafter extends diagonally at a 45° angle from the inside corner of two intersecting wall plates up to the ridge of the roof.

How is a roof attached to a house?

Rafter roof construction – A basic rafter roof is made up of rafters which rest on horizontally placed plates at the top of each wall. The top ends of these rafters typically meet at a ridge beam, however in some cases they can butt directly to another rafter, forming a couple (pair of rafters).

Depending on the material used to cover the roof, either horizontal purlins, laths or battens are attached to the rafters. In other cases, boards made from oriented strand or plywood from the roof deck are used in order to support the roof covering. Tie beams, which sometimes also double as ceiling joists, are usually connected to the bottom ends of opposite rafters which prevents them from forcing the walls apart by spreading.

Collar beams or ties may be fixed at a higher level by roofing contractors to add further strength.

What keeps a roof from falling over?

Rafter ties prevent spreading – Located in the bottom third of the roof structure, rafter ties effectively resist the horizontal forces caused by gravity loads that would otherwise cause the roof to pancake, pushing the sidewalls out. Rafter ties (or ceiling joists acting as rafter ties) are required by code unless the house is designed so that the walls or a structural ridge beam carries the full load of the roof.

If you are framing a cathedral ceiling, there are a couple ways to deal with the need for rafter ties. You can possibly remove them altogether of you include posts in the gable walls to support a structural ridge. If this isn’t an option, the next best thing would be to space several large rafter ties out, using either attractive timbers–as you would see in a traditional timber frame–or wrapping them in order to make them architectural elements in the space.

You may need to add reinforcement to the top plates of the walls in order to compensate for the wide spacing of this type of rafter tie; again, consult an engineer to make sure this is feasible and that you get the details right. Installed in the top third of the roof structure, collar ties prevent separation of the roof at the ridge due to wind uplift.

What supports a roof load?

Mastering Roof Inspections: Roof Framing, Part 1 by Kenton Shepard and Nick Gromicko, CMI® The purpose of the series “Mastering Roof Inspections” is to teach home inspectors, as well as insurance and roofing professionals, how to recognize proper and improper conditions while inspecting steep-slope, residential roofs. This series covers roof framing, roofing materials, the attic, and the conditions that affect the roofing materials and components, including wind and hail.

• We won’t go into attic inspection too deeply since this series of articles from Mastering Roof Inspections is primarily about roofing defect recognition, but you should have an understanding of the two main, basic roof structure systems: conventional roof framing and roof trusses.
• You’ll be evaluating the roof framing from inside the attic space, but we have an advantage in technology.

Let’s strip away the roof and wall coverings of a home and identify some of the more common roof framing members. We’ll start with a conventionally framed roof in which individual roof-framing members are cut and assembled on-site. CONVENTIONAL ROOFS

• Conventional Roof Framing
• Common Rafters
• Rafters which rest on the outside walls at the bottom and connect to the ridge at the top are called “common rafters” (highlighted here in yellow).

Rafters on opposite sides of the ridge should be installed directly opposite each other in pairs – although, if you see a few that don’t align, it’s really not a defect. Rafters sometimes have to be moved a little to accommodate components of other home systems. The illustration above shows a rafter moved to accommodate a combustion vent. If you see many rafters that don’t align, you may comment on this, but in existing homes, refrain from calling it a defect unless you see failure. In newer homes, many rafters which don’t oppose usually indicate poor-quality framing. It’s an indication that you should look carefully for other problems in the roof framing.

1. Rafters are typically installed on 24-inch centers.
2. If you see rafters installed on centers greater than 24 inches, look for signs of failure, such as sagging of the rafters.
3. If you see sagging rafters, recommend stabilization by a qualified contractor.
4. Stabilization typically involves installation of a purlin system.

Hips Hip roofs have “hip rafters” which are oriented diagonally to the ridge and outside walls. Hip rafters are simply called “hips,” and are shown here as brown. Hips rest on an outside corner at the bottom and connect to the ridge at the peak. Rafters which rest on the exterior walls at the bottom and connect to a hip at the top are called “hip jacks,” shown here as purple. Valleys Where ridges change direction, an inside corner is created, which is spanned by a “valley rafter” or simply “valley,” shown here as green. Valleys are also oriented diagonally to the ridge and exterior walls. Valleys rest on top of the walls at the inside corner at the bottom, and connect to the ridge at the top.

Rafters which connect to the valley at their bottoms and connect to the ridge at the top are called “valley jacks,” shown here as light blue. Conventional Ridge The illustration shows a conventional ridge (colored orange). In homes with conventional ridges, the rafters support the weight of the roof and transmit the roof load down through the walls to the foundation and, finally, to the soil.

The route taken by the weight of the roof through the framing members to the soil is called the “load path.” The purpose of the ridge is to provide an easy method for connecting rafters at the peak of the roof, and to provide better nailing at the peak. Older homes may have no ridge at all. That was a common building practice at one point in various parts of North America, and it’s not a defect as long as the rafters oppose each other. Engineered lumber used for roof framing has very specific requirements for connections, and discussing them here exceeds the scope of this series. In homes with flat ceilings and an attic space, the bottoms of opposing rafters should be fastened together with ceiling joists, which form “rafter ties.” When rafters have been installed perpendicular to the ceiling joists, rafter ties typically rest on top of the ceiling joists. Collar ties connect the upper ends of opposing rafters. They should be installed on every other rafter in the upper third of the roof. Their purpose is to prevent uplift. Whether or not they should be installed is an engineering call. They aren’t always required so the lack of them is not a defect, but when you see them, they should be installed correctly.

1. Here, you can see collar ties installed in the upper third of the roof, and rafter ties installed down low and spliced over a wall.
2. Purlin Systems
3. You can also see the purlin system.

Purlin systems are designed to reduce the distance that rafters have to span. They consist of strongbacks nailed to the undersides of the rafters and supported by diagonal braces. The bottoms of purlin braces should rest on top of a bearing wall. Braces that rest on ceiling joists or which somehow pass the roof load to the ceiling below are defective installations.

• If you see braces which rest on ceiling joists, look for a sag in the ceiling.
• Braces are typically installed every other rafter and should be at an angle no steeper than 45°.
• Here’s a purlin system installed in the garage of an older home.
• With no central wall to carry the braces, they bear on a strongback that rests on the ceiling joists.

There was no sagging, so there was no comment in the inspection report. Purlin systems have been built in many ways – some better than others. Modern building codes call for strongbacks to be of equal or greater dimension than the rafter dimension, but most purlin strongbacks you’ll see will not meet this requirement.

If you know that the home was required to meet this code when it was built, call it a defect; otherwise, limit your inspection to looking for signs of failure, such as sagging or broken rafters and broken components. Also, look for improper installations, such as braces resting on ceiling joists, braces but no strongback, and too few braces.

In older homes in some areas, it’s common to find no strongbacks. It’s a quality issue unless the roof is sagging; then, it’s a structural issue and you should recommend stabilization by a qualified contractor. The term “purlin” has several different meanings depending on what part of North America you’re in, what part of the roof you’re talking about, and the background of the person you’re discussing it with, so don’t be surprised if someone tries to correct you.

Structural Ridge Homes with vaulted ceilings usually don’t have rafter ties to keep the walls from spreading and the ridge from sagging, so they use a structural ridge. In a home with a structural ridge, the ridge consists of a beam strong enough to support the roof load without sagging. Overframe When you’re inside an attic, you may see a condition in which the ridge and a few jack rafters from one roof section are framed on top of an existing roof.

This is called an “overframe” and it’s quite common in certain areas. Built correctly, it’s structurally sound. You’ll often see a section of roof sheathing removed to provide a passageway between attic spaces. If you can’t enter a portion of the attic, recommend that it be inspected by a qualified inspector after access is provided.

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: Mastering Roof Inspections: Roof Framing, Part 1