How To Insulate An Attic Roof Rafters?

How To Insulate An Attic Roof Rafters
How To Insulate A Finished Attic

  1. Add outside insulation when replacing your roof.
  2. Drill holes between the rafters and studs to blow in insulation.
  3. Remove paneling or drywall from the walls and ceiling, apply insulation between the wall studs and rafters and cover new panels or drywall.

What is the best insulation between roof rafters?

What should i use to insulate between the rafters in my roof? My attic has been converted into two bedrooms, I have a normal staircase leading up to it. I have 4 hatches around the side walls. Inside these hatches I have noticed,due to the wind and chills, that there is no insulation whatsoever on the underside of my roof tiles.

  1. What should I be using to insulte this and what are the legal requirements and regs.
  2. Ie spacing for ventillation? Do i also need to board over whatever I use to insulate this area.Any help would be greatly appreciated as i have a roll of rockwool and was going to use this and hold it in with sheets of wood.

Is this wrong? i would like to add that the conversion was signed off and certificated but was done before myself and the previous owners lived there. It must be 15 years ago. Once i’ve used kingspan or celotex does this then require boarding over or plasterboarding? Best Answer Did you have building regulations in place, as this would have been stipulated, and all of the works including insulation would have been checked by bco.

  1. I think you will have to use Celotex or Kingspan, but make sure that no air flows are restricted.
  2. Best to check with bco as these works will need to be signed of, without certificate of compliance it could affect the sale of the house, should you sell it, as the rooms couldnt be classed as habitable.2012-01-27T10:10:01+00:00 Answered 27th Jan 2012 There is nothing wrong with that method in princaple is just very tricky, hard work and itchy !!!!! best material to use is 100mm ” kingspan” or ” celotex” foil backed insulation board, easily cut to size to fit between rafters.100mm based on 150mm rafters leaving 50mm air flow.

Regards Gary 2012-01-27T10:10:02+00:00 Answered 27th Jan 2012 You need 50mm airspace between felt and insulation. We use 100mm kingspan inbetween and 50mm fixed underneath 2012-01-27T10:10:01+00:00 Answered 27th Jan 2012 Ok what ever you do, do not insulate directly under the tiles,

  • No matter how well you try and do it you will cause a conflict of areas ( the area that should be warm and the area that should be cold ) your insulation should go above your loft ceiling down the walls and along the lower ceiling,
  • The area you are looking into ( although drafty ) is needed to keep your roof ventilated in the eves and up hopefully to the ridge,

It keeps it free from condensation and most types of rot ! 🙂 Now you asked what to use, Retro fitting to the walls you should use a 100 mm 4 ” “cavity battern ” like fiberglass but its cheap enough and slightly ridged, The floor level / ceiling to get it up to regs you now need as much as 300 mm 12″ thick of fibreglass ” earth wool ” and B and Q had it on offer for a unbelievable 3 £ per roll,

  1. Good luck hope this made sense,
  2. Thanks woody apex lofts barnsley 2012-01-27T10:10:01+00:00 Answered 27th Jan 2012 well its not covered by building regs now,but by the sounds of it niether is your loft or you wouldnt be having this problem,so yes insulate with that,it will stop the cold to a point,but not as good as celotex or kingspan 120mm thermo board,and of course rockwool is a lot cheaper 2012-01-27T10:10:02+00:00 Answered 27th Jan 2012 I would personally use celotex cut tightly in-between the rafters.

You need to leave a gap to the rear of the insulation between the membrane and the insulation to allow air to circulate around the roof space. You could then simply clad the area with plasterboard etc.

Make sure there are no huge gaps where the breeze is felt as there could be other problems that need to be addressed first. Hope this helpsChristiaan

2012-01-27T10:10:02+00:00 Answered 27th Jan 2012 I presume that as you are concerned about legal requirements and ventilation regs etc,that your loft conversion has been done officially and been signed off by building control.If so,the living space should be as insulated as well as it needs to be already.If it has not been done officially,i would get someone to come take a look at the structural side of things before you insulate anything as your conversion may not be safe or legal.2012-01-27T10:10:01+00:00 Answered 27th Jan 2012 : What should i use to insulate between the rafters in my roof?

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How do you insulate a pitched attic roof?

Pitched Roofs: The Basics – Traditionally, pitched roofs are insulated by nailing or attaching insulation boards to the floor of the attic space, keeping the cold air in the loft room, and preventing it from penetrating down into the rest of the property, unless a door is opened, or air sweeps through between the panels.

However, this is not an effective method of insulation long-term, and does not seal your property completely against cold wind or moisture in the air. It also leaves the loft space feeling so cold that it’s often left unused, or solely for storage purposes. The best way to insulate a pitched roof is to install the very latest insulation technology – which comes in the form of spray foam insulation,

This multi-purpose material is mixed with water, and blown directly onto the designated surface, using highly specialist equipment. In the case of pitched roofs on a home, the spray foam is applied directly onto the rafters of the roof, This keeps the heat in, and gives you back your attic space to use as you like.

What is the best insulation for an attic ceiling?

2. Blown-in Insulation – Also known as loose-fill insulation, blown-in insulation comes in tiny chunks packaged in large bags, and entails using a blowing machine to fill in necessary spaces. Fiberglass, cotton, and mineral wool can all work as loose-fill insulation material, but the far and away top choice for blown-in insulation is fiberglass.

Should you insulate the underside of your roof?

Insulate the pitched roof and exterior walls – You’ll also want to insulate the exterior walls and the underside of the attic’s roof. Otherwise, space will suck up a tremendous amount of heating and cooling energy throughout the year, because all of that energy goes right up and out of the roof.

Should I insulate the rafters in my attic?

Table of Contents:

  1. How Attic Insulation Benefits You and Your Roof
  2. The Types of Attic Insulation
  3. Cold Versus Warm Insulation
  4. How to Insulate an Attic
  5. Insulating an Attic With a Low-Pitched Roof
  6. Insulating a Roof Without an Attic
  7. Getting a Roof Replacement? Now is the Time To Update Your Insulation

Disclaimer: This basic guide to insulation is not meant to act as a substitute for a professional opinion. Homeowners should talk to experts and refer to their local building codes before they choose their insulation type and quality. Installation of insulation should be left to professionals.

  • Should you insulate your attic roof? Insulation is a wise choice to increase the energy efficiency of your home.
  • Quality insulation will make it more cost-effective to heat and cool your home, The Department of Energy’s estimates range from a 10% to 50% savings, depending on several factors.
  • However, attic insulation isn’t just about heating.

Proper attic insulation can also keep your roof in better condition by helping to prevent ice dams and condensation. How To Insulate An Attic Roof Rafters Your building codes may require you to have a certain quality of insulation. However, installing even better insulation is to your advantage and your roof’s advantage. Although, over-insulation can heat your shingles and shorten their life span. This is especially the case if your roof also lacks proper airflow.

  • Balancing the two needs, one for insulation and one for ventilation is critical.
  • Almost all building codes and all asphalt roofing manufacturers require proper ventilation of a roofing system, regardless of the form of insulation used.
  • Some forms will impact not only the life of your roof but the coverage your roofing manufacturer provides under your warranty.

You should read and understand your roofing warranty and the limitations it has relating to air flow and roofing insulation. Discover what you need to know about attic insulation and how it affects your roof.

Do you need to leave an air gap for insulation?

An error occurred. – Try watching this video on, or enable JavaScript if it is disabled in your browser. If you take a piece of foil and you pull it tight across the top of the skillet, a few inches away, and you put your hand on top of the foil, you’re going to feel almost NO heat coming off that skillet.

  1. The heat’s coming up, it’s hitting the foil, and it’s being reflected back.
  2. This is reflectivity.
  3. Radiant barrier foil has a 97% reflectivity, basically it’s only letting about 3% of that heat pass through.
  4. If you put the foil directly in/on the skillet and you put your hand several inches above it, now the foil is working off what’s called the emissivity quality.

This is the ability to prevent heat from releasing (ie. not emitting heat), and it’s basically the inverse of reflectivity. Foil has an emissivity of 0.03, or 3%. So you could pretty much keep your hand above that skillet all day long and your hand would never burn because the foil is just not emitting much heat.

If you were to take your hand and you put it down, directly on top of the foil, now you’ve eliminated that air gap, and now you’re back to conduction. That heat is gonna flow extremely efficiently from the skillet, through the foil, and in to your hand. These are the exact same principles that apply to installing a radiant barrier in any assembly.

You MUST have an air gap in order to get either the emissivity quality or the reflectivity quality that you’re looking for, otherwise the foil will not work as a radiant barrier. Typically we suggest you have an air gap between 1/2″ and 3/4″ for the radiant barrier to work.

Air gaps larger than this work well too – they promote ventilation on the foil and help keep the air dry and the air temps lower. Insulation is technically a solid with a lot of air in it therefore, it is NOT an air gap. You literally must have a VOID, nothing in the air gap except air itself. So if you are installing under a roof or in a wall, you must create an air gap.

It doesn’t matter which side the air gap is on, the foil will work the same whether it is using reflectivity or emissivity to block the heat transfer. In order for radiant heat to exist, you MUST have this air gap. If you don’t have this air gap, you CANNOT scientifically possibly have radiant heat because if you sandwich two products together and eliminate that air gap, you have conduction, or conductive heat.

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Can you insulate a roof from the inside?

Your Options For Roof Insulation – For traditional pitched roofs, sometimes called sloping roofs, you will be looking at three main options to insulate from the inside; installing solid insulation boards between the joists of your roof, installing fibreglass or mineral wool insulation batts within the joists, or installing spray foam insulation on your house roof.

Is Blocking between rafters necessary?

Rafter blocking is an essential part of the roof framing process in that the blocks provide a stop for ceiling insulation and a continuous surface for the roof sheathing to be edge nailed to. Each block is 2×4 or 2×6 depending on the size of the rafters, and is secured to the top plate.

Can I insulate my attic roof myself?

Working time: 3 to 5 days Total time: 2 to 3 days Skill level: Intermediate Project cost: $2,000 to $2,500

Compare Quotes From Top-rated Attic Installers Free, No-commitment Estimates One of the best ways to banish cold from your living space is to insulate the attic. Since heat rises, the attic is the logical place to install insulation. You can insulate your attic either by blowing in loose-fill cellulose insulation or by laying fiberglass batts between the ceiling joists.

How do I stop cold air from coming into my attic?

Thanks for signing up! – A welcome email is on its way. If you don’t see it, please check your junk folder. The next issue of NP Posted will soon be in your inbox. We encountered an issue signing you up. Please try again Your attic is a cold zone – that means that it should be the same temperature as the outside air.

By letting heat escape freely from your home into the attic, and having cool air from the outside meet in the middle you may have a problem. You’ll be able to tell if your attic is losing heat in the wintertime – take a look at your roof after a snowfall – are you seeing icicles and patches of melted snow? That’s a sign of heat loss.

There are companies that can collect heat loss data from entire neighbourhoods by flying overhead with thermographic imaging technology. If your city is covered, this is a great way to easily check how energy efficient your home is – and find ways to mitigate any heat loss.

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  2. R-Value R-Value refers to the capacity an insulating material has to resist heat flow.
  3. The higher R-Value, the better the material can insulate.
  4. Remember, just because one style of insulation is thicker than another, doesn’t mean that will be more effective for keeping your house warm.

Types of Insulation There are a lot of options for insulating your attic, each with their own pros and cons. When I insulate an attic, I aim for an R-Value of at least 60. That will help keep my house nice and warm in the winter, but cool during the summer.

  • Batt Insulation Typically made of fibreglass or mineral wool, batt insulation is made up of strips of material that fit between the ceiling joists to provide insulating power.
  • Batt insulation should be loose fitting – within the material is a lot of air that provides extra R-Value.
  • By compressing batt insulation you will actually be losing R-Value.

This advertisement has not loaded yet, but your article continues below. Foam Board Insulation Rigid panels of insulation are most commonly made from polystyrene or polyurethane. Foam board can be used on an attic hatch, but wouldn’t be used to insulate the entire space, generally being reserved for exterior wall sheathing or basement walls.

Blown-In Insulation The most common type of insulation you’ll find in attics. Small chunks of insulating material (typically fibreglass and cellulose) is blown into the attic space in smaller chunks. Like batt insulation, blown-in insulation should be fluffy. It will lose R-Value when it’s been compressed.

Sustainability and building for the future is something that I believe in, and the cellulose used in blown-in insulation is an environmentally friendly product. Adding blown-in insulation is a job that you will need to leave to the professionals. This advertisement has not loaded yet, but your article continues below.

  • Spray Foam Insulation A polyurethane foam is sprayed in the attic, which will fill cracks and gaps, forming a barrier.
  • There are two types of spray foam insulation: closed cell and open cell.
  • Open cell foam is permeable to moisture, but impermeable to air, while closed cell foam stops air and moisture.

Closed cell spray foam provides the highest R-Value, offering a value of up to 7 per inch. Installing a spray foam isn’t a do-it-yourself job. Amateurs tend to pile the insulation too high, blocking out the soffit (attic intake) vents, which cuts off all ventilation in the attic.

  • If you aren’t careful, this can lead to ice dams, which can cause major damage to a roof.
  • Ice Damming Ice damming is more likely to be an attic issue than one with your eavestroughs.
  • Too little insulation at the perimeter of the attic can result in heat loss coming in contact with cold air, creating condensation and freezing.
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One way to solve this issue is by using a closed cell spray foam just around the edges of the attic. Watch Mike Holmes in his series, Holmes Makes It Right, on HGTV. For more information, visit

What is the cheapest way to insulate a roof?

1. Fibreglass insulation – Glass wool is one of the most common insulation materials for roofs. It is lightweight, has a good insulation value and is quite cheap as well. Glass wool insulation is only possible if there is a roofing underlay. Moreover, the inside should always be finished with a vapour barrier.

Can you have too much insulation in your attic?

Mold in the Middle – It is possible to over-insulate your house so much that it can’t breathe. The whole point of home insulation is to tightly seal your home’s interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers.

Which is better attic insulation blown or rolled?

1. Efficient Process – First of all, using blown insulation vs. rolled insulation is a much more efficient process. Blown insulation does require a machine to be used, but a machine and some workers are easier to manage when you compare the rolled insulation process.

Is it better to insulate ceiling or roof?

If you are deciding between insulating the roof deck or the ceiling, Insulating your ceiling should be the priority. Not only is it easier but ceiling insulation is beneficial in a number of ways: Keeps the temperature in the building regulated. Saves on energy costs.

Should insulation touch the roof?

Preserve The Attic’s Airflow – How To Insulate An Attic Roof Rafters Courtesy Covering up the soffit vents with loose fill or batts, which can happen if you stuff insulation along the eaves, is a huge no-no. The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams, and the material will block that flow.

How do you tell if a roof is properly insulated?

Problem 2: Odd Temperatures – This test is a little more complicated. First off, you’ll need to open all of the inside doors for awhile and let the temperature of your home even out. Make sure the vents are open, too. Once you’ve done that, take a walk around and check for rooms that seem significantly warmer or colder than other areas.

While you’re at it, feel the ceiling and see if it seems strangely hot or cold in any area. If any rooms have odd temperature changes, there’s a good chance that the insulation in that area is poor and will need to be replaced. Note that ceilings aren’t the only areas where insulation can be poor. You may also be losing heat through the walls or even through poorly-insulated windows.

Be sure to check all areas of your home.

Why you shouldn’t spray foam your attic?

Open-cell spray foam on your roof: – The potential for open-cell spray foam to rot your roof is a hot topic of debate. Moisture from indoors can escape through open-cell foam and find the cold roof sheathing. From there, it accumulates and eventually rots the roof. Regardless of the climate, you should opt for closed-cell spray foam for roof insulation.

Does every rafter need a rafter vent?

Without rafter vents, air cannot properly circulate in your attic, trapping heat and moist air in the space. If you’ve noticed damages to your roof, you might want to look into your attic’s insulation. Rafter vents balance the temperature in your attic, preventing damaging ice dams from developing.

Can you put Rockwool in between rafters?

Pitched Roof Solutions ROCKWOOL offers a range of products for installation both between and over the rafters. Offering more than warmth, ROCKWOOL pitched roof insulation also delivers additional peace of mind through its additional advantages of sound protection and exceptional fire resistance. : Pitched Roof Solutions

What is the best insulation for a 2×6 ceiling?

Insulation for 2×6 Walls – Some newer homes may have walls built with 2×6 studs. Use R-19 or R-21 kraft-faced fiberglass insulation for two-by-six (2×6) walls. This combination ensures that the insulation is neither too loose nor too tightly packed within the walls.

Best Insulation for 2×4 and 2×6 Wall Studs
Insulation Type Thickness of Insulation Appropriate for This Wall Type
R-13 3 1/2 Inches (+/-) Two-by-four (2×4) stud walls
R-15 3 1/2 Inches (+/-) Two-by-four (2×4) stud walls
R-15 3 1/2 Inches (+/-) Two-by-four (2×4) stud walls with true 4-inch depth.
R-19 6 1/4 Inches (+/-) Two-by-six (2×6) stud walls
R-21 5 1/2 Inches (+/-) Two-by-six (2×6) stud walls

The Spruce / Jason Donnelly

What thickness roof insulation is best?

For example, the recommended thickness for loft insulation is 270 millimetres for glass wool, 250 millimetres for rock wool, and 220 millimetres for cellulose.

Is Blocking between rafters necessary?

Rafter blocking is an essential part of the roof framing process in that the blocks provide a stop for ceiling insulation and a continuous surface for the roof sheathing to be edge nailed to. Each block is 2×4 or 2×6 depending on the size of the rafters, and is secured to the top plate.