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Kooltherm K107 Pitched Roof Board
Premium performance pitched roof insulation board
Dormer Cheek and Dormer Roof Constructions
A dormer can add architectural interest to a building, maximising natural light whilst also creating additional headroom, making the loft space usable.
Whether you are building a new property, completing a dormer extension or upgrading your existing dormer, there are a number of dormer insulation solutions available.
On this page you will find:
- Our dormer roof and dormer cheek (side wall of a dormer) insulation options
- A comparison of the different solutions we offer so you can select the right product for your project - scroll down the page for a full comparison table
- Useful links to help with your project, including our U-value calculator.
If you are a homeowner don't forget to take a look at our Homeowner Hub where you can find a wealth of advice and support for your project!
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Dormer insulation support
Our Dormer Insulation Solutions
The table below shows the different options available. Note the lower the thermal conductivity, the better the thermal performance. Selecting better thermal performing products may mean you can use a thinner board. This can be benefecial in dormers where you want to maximise space and the amount of daylight entering the building.
Product | Application | Thermal conductivity |
|---|---|---|
Dormer cheeks | 0.019 W/mK | |
Dormer cheeks | 0.022 W/mK | |
Pitched dormer roofs | 0.019 W/mK | |
Pitched dormer roofs | 0.022 W/mK | |
Flat dormer roofs waterproofed with partially bonded torch applied multi-layer bituminous waterproofing | 0.024 - 0.027 W/mK | |
Flat dormer roofs waterproofed with mechanically fixed single-ply waterproofing | 0.022 W/mK | |
Flat dormer roofs waterproofed with fully adhered single-ply, partially bonded built-up felt, mastic asphalt and cold liquid applied waterproofing | 0.024 - 0.027 W/mK |
Page updated: 24/06/2025