How you insulate a roof will depend on the type of roof you want to install insulation into. For example, a pitched roof may require something more sturdy than perhaps a pitched roof.


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Insulating a roof

There are many different roofs and as such each roof is in need of different types of insulation to ensure the insulation performance is top quality. Not only is it great for soundproofing, heating and cooling, but insulating a roof can also help you reduce energy bill costs for your property.

It’s found that most heat is lost through the roof; especially in an property that is uninsulated. So incorporating roof insulation can help you in the long run with a quick and easy installation.

Insulating a conservatory roof

A conservatory roof can be insulated in a few different ways. Although how you choose to insulate it will depend on budget and what you want to get out of the insulation. The most popular way of insulating a conservatory roof is by replacing the existing roof altogether and installing an insulating material. This could be anything from PIR insulation board to breather membrane or even polycarbonate roofing.

If you would like to know more about conservatory roof insulation or conservatory insulation in general, you can check out our guide here.

Insulating a pitched roof

There are multiple insulation materials you can use for pitched roofs. However, the first thing to note is that acoustic insulation slabs are exclusive to pitched roofs and cavity walls. Which makes it a perfect solution if you want to focus on soundproofing.

It’s also worth nothing there is a minimum required U-value of 0.18 W/m²k for pitched roof refurbishment. So make sure that you choose products with the thermal conductivity in mind.

Materials you can typically insulate a pitched roof with include:

There is also a choice of whether to insulate a roof using the warm roof insulation method or cold roof insulation method. Though typically a warm roof is easier and more budget-friendly.

Cold roofs on the other hand have been admired for their affordability. However, if a cold roof cannot be installed because the loft is being used for a living space, installing warm roof/loft insulation can be more appropriate.

You can find out more about warm roofs and cold roofs here.

Note: Installing a warm loft is a big task, so make sure to call in a professional for accurate installation.

You can find out more about how to install loft insulation, here.

Insulating a dormer roof

A dormer roof can be insulated in a number of different ways, including:

Rigid insulation is a common choice when it comes to insulating a dormer roof, producing a thermal conductivity between 0.020 W/m k and 0.023 w/m k. How this is done is typically with 150mm of a thick insulation between the rafters, with a 50mm air gap to reduce the risk of cold bridging.

Celotex is just one example of insulation used in dormer cheeks. To find out more about Celotex dormer cheek insulation and how to install it, check out ‘How to install Celotex insulation boards‘.

Spray foam is a material that has been fairly new to homes as insulation in recent years, but is greatly admired for it’s benefits. It has one of the highest r-values of insulation products. R-value measures the effectiveness materials have when preventing a conductive heat flow. As such, higher r-value means better thermal insulation. You can find out more about r-values here.

Spray foam is considered quite easy to apply, reaching more difficult areas without the need of an air gap. As a bonus, this material can help prevent leaks in future. For this material, it can be expected to have a thermal conductivity between 0.032 W/m k and 0.037 W/m k.

Note: spray foam insulation can be a costly solution. So make sure you’re happy with this budget-wise before moving forward.

The other option is mineral wool insulation that offers a thermal conductivity between 0.040 W/m k and 0.044 W/m k. You can find out more about mineral wool insulation here.


If you would like to find out insulating a flat roof or other insulation projects, check them out via Help and Advice guides or via “Shop by Project” for support. 

You can also check out our ‘Insulation buyer’s guide‘ for more information about different insulation available for a wide variety of insulation projects. 

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