Can I use loft insulation between rafters?

Author: Mandy Hackett V  |  Last update: Friday, April 18, 2025

Yes, you can use loft insulation between rafters.

Where not to put loft insulation?

One important thing to remember is that insulation should never be pushed right into the eaves because it will interfere with airflow. If you're going for a warm loft then you'll need much more insulation to be able to cover the underside of the roof along with the gable and party walls.

What is the best insulation to use between rafters?

Easiest and most cost-effective thing to use is the fiberglass rolls. R-40 is recommended for ceilings. It is recommended to also finish the walls and/or ceiling afterwards with drywall as the paper on the insulation is a fire hazard.

Should you insulate between rafters or joists?

In unfinished attic spaces, insulate between and over the floor joists to seal off living spaces below. If the air distribution is in the attic space, then consider insulating the rafters to move the distribution into the conditioned space.

Can you put batt insulation between rafters?

Placing Insulation: Place the insulation between the rafters. For fiberglass batts, ensure the paper side faces down if you mainly heat your home. If you mainly cool your home, the paper side should face up. Pressing Firmly: Press the insulation firmly into place but avoid compressing it.

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Can you use loft insulation in rafters?

Can you use loft insulation between rafters? Yes, you can use loft insulation between rafters.

Is it OK to double up insulation?

As a general guideline, it's advisable to install double layers of thermal insulation throughout your house. Nevertheless, this may not be feasible in all areas due to space limitations. Typically, it's not practical to add two layers of insulation within the walls of your home.

Can you insulate between rafters on warm roof?

In some warm roof designs, the insulation is fitted both above and between the rafters. This method can be chosen for a number of reasons.

Should loft insulation be in between joists?

Insulating between the joists of your loft will keep your house warmer, but make the roof space above colder. This means pipes and water tanks in the loft space could be more likely to freeze, so you will need to insulate them.

What is the best insulation for attic rafters?

Fiberglass batt is considered to be the best insulation for attics. Compared to other insulation materials, it is the cheapest and easiest to install.

Can I insulate the underside of my roof?

If you go with a hybrid assembly, Kohta recommends using fibrous insulation on the underside. You could use open-cell spray foam there, but cellulose or fiberglass would be much less expensive and do the job just as well when installed properly.

What is the air gap for loft insulation?

You'll need to start laying with a minimum gap of 25mm between the eaves and the insulation to ensure a suitable air gap. Maintain this gap along two opposite sides of the loft.

Can I put ROCKWOOL between rafters?

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.

Should I remove old loft insulation before laying new?

Should I remove old loft insulation before laying new? Older insulation material will typically need to be removed before adding new insulation. However, in some cases the material may be in good condition, meaning you can simply top up the existing insulation material for a fraction of the cost of a full replacement.

Can you use too much loft insulation?

One way that excessive loft insulation can cause dampness is by blocking ventilation. Proper ventilation is necessary to allow moisture to escape from the building. If insulation is installed too thickly or packed too tightly into the loft, it can block air flow and prevent moisture from escaping.

Do you need membrane under loft insulation?

A vapour barrier is a damp-proof membrane used to create a perfect seal between the surface you want to insulate and the rest of the loft. This should prevent condensation from the home rising into the roof which would end up degrading the insulating materials.

Should you insulate between rafters in a loft?

Insulating between rafters can help to improve the energy efficiency of your home or building by reducing heat loss through the roof. This can lead to lower energy bills and a more comfortable living or working environment.

Should loft insulation be pushed up to the eaves?

Remember that insulation should never be placed right into the eaves, as this will impact ventilation.

Do you need 2 layers of insulation in attic?

You should install two layers of insulation in your attic; wood joists must be covered to allow the air to move. The first layer will sit between the joists, and the second layer will run perpendicular over the joists. The first layer should have the facing against the drywall to act as a vapor barrier.

Do you need an air gap between roof and insulation?

Yes, an air gap between the roof and insulation is needed, especially for traditional materials like fibreglass, mineral wool, and foil insulation.

Is it better to insulate rafters or ceiling?

Since insulation is not water-resistant, insulating your ceiling will give you better protection for your money. The insulation in your ceiling is less likely to suffer damage from unidentified leaks. When a roof leak develops, you'll find it more easily, which means you can have it repaired sooner.

How do you keep insulation between rafters?

Install a metal insulation support: Take a single metal insulation support, and while gripping both ends of the wire, bend it slightly. Carefully place it between two studs or rafters with insulation and slowly release the wire's ends to wedge it between the wood.

Can you add too much attic insulation?

Too much insulation will leave humidity and moisture to accumulate in your attic space. This can lead to mold growth on your walls and insulation. There might also be water damage to the support beams in your home's roof.

Is there a big difference between R13 and R19 insulation?

R19 Insulation offers superior thermal insulation compared to R13. With a typical thickness of 6.25 inches, R19 fiberglass is designed for use in 2x6 wall cavities, making them suitable for colder climates where higher thermal resistance is necessary.

Is 2 inches of insulation enough?

The recommended thickness for attics is typically 12-16 inches. Spray foam insulation: As discussed earlier, the recommended spray foam insulation thickness can vary depending on factors like climate and location. For attics, a thickness of 2-4 inches is usually sufficient.

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