The Benefits of Insulating Your Warm Flat Roof

warm flat roof

What insulation for warm flat roof? There are many types of insulation available for flat roofs. Depending on the type of roof, the climate and the budget, the most popular types of insulation include foam board insulation, spray foam insulation, and polyiso insulation. Additionally, there are several reflective roof coatings that can help to reduce heat transfer and keep the roof cool. It is best to consult with a roofing contractor to determine the best insulation for your flat roof.

What insulation is best for a flat roof?

Roofing professionals underline the importance of selecting flat roof insulation with the suitable R-value. Polyisocyanurate (Polyiso) rigid foam is the most expensive and highly recommended insulation. Extruded Polystyrene (XPS) and Expanded Polystyrene (EPS) are other excellent choices (EPS).

Warm flat roof:

Is 50mm insulation enough for a warm roof?

You can use two 50mm sheets, however this is insufficient to meet current rules. You will not obtain the accurate ‘U Value,’ which represents heat resistance. In a nutshell, condensation could form on your roof (interstitial). A minimum of 120mm is recommended when using Celotex.

Can you put insulation under a warm roof?

The general advice we give is that you should always insulate between and above the rafters (warm roof) or between and under the rafters (cold roof).

How thick should insulation be on a warm flat roof?

What Thickness Insulation Do I Need for Flat Roofs? A flat roof with no insulation has a U-Value of about 1.5 W/m2K. When insulating one, you want to achieve a value of 0.25 W/m2K or less. To accomplish this, insulate your flat roof with insulation boards totaling roughly 150mm in thickness.

Does a warm flat roof need ventilation?

A heated flat roof does not normally necessitate ventilation. How much area do I need to leave for ventilation? To guarantee adequate ventilation, sufficient space must be provided to allow for air movement, reducing the possibility of condensation accumulating within the roof.

Vapour barrier & avoid heat:

Does a warm flat roof need a Vapour barrier?

A heated flat roof is the most common installation these days to keep your space warm, dry, and sheltered from the weather. This roof construction should also include a vital layer of protection known as the Vapour Barrier.

Where does the vapour barrier go on a warm flat roof?

A vapour control layer must be installed beneath the insulation to prevent moisture vapour from being driven into the insulation by thermal pressure from within the building. To completely enclose the insulation, waterproofing membranes are applied over it.

How do you deflect heat from a flat roof?

If you have the opportunity to replace your ceiling, installing a layer of foam insulation beneath it is perfect. This efficiently controlled heat and cold, keeping your building warm in the winter and cool in the summer.

How do you keep a warm flat cool?

Why then do flats get so hot?

Close the drapes and blinds.
Make use of an old fan.
Learn about ice bowls.
Close the doors to any rooms you aren’t utilizing.
Choose cold food.
Keeping windows open and closed.
Make good use of your freezer.


I hope this article was helpful to you. But what’s more helpful is professional roofing service at your beck and call.

LeakStop is a one-stop destination to meet your roofing-related requirements. We offer roof repair, replacement, maintenance and inspection services all over GVRD (Greater Vancouver Regional District).

We offer a free inspection to first-time clients. Connect with us TODAY at 1 866 777 0084 for immediate assistance!

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Derek Lindsay

Derek has been a part of the Roofing Industry for 20+ years. His experience in the field enables him to write insightful and informative content on Roofing and everything related to Roofing.