Flat Roof Insulation - Euro Energy Group

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Flat Roof Insulation

Flat roof insulation is different from pitched roof insulation because flat roofs don’t allow water to naturally run off.

How does flat roof insulation work?

In definition a flat roof is any roof with a pitch of less than 10 degrees and is very easily identified on the basis that in view it is horizontal.

Flat Roof Insulation is perfect for houses that do not have a loft or conventional roof space, also applicable to a rood that is pitched (slightly sloped to avoid rain water collecting). Flat Roof Insulation differs as the insulating material is placed on the top of the roof, rather than in between the ceiling and decking, making it a common improvement when roof coverings are being replaced entirely.

Insulating your Flat Roof has many benefits including lowering your energy bills by £100’s each year, regulating the temperature of your property and allowing you to quickly warm rooms as less heat escapes. A side-benefit is also an increased lifespan of your roof as the right level of protection will also strengthen roof structure.  


A flat roof property in its very design is flawed and susceptible to heat loss and a prone to leaking causing deterioration in the materials of the roof itself.

flat roof insulation

Benefits of flat roof insulation

The Flat Roof construction was popular from the 1950s to the 1970s, however, most flat roof construction did not prioritise insulation.

Without a loft space to insulate, it is extremely common that a flat roof has little or no insulation present. This meant homes were hard to heat during the winter and too hot in the summer months.

The main benefits of Flat Roof Insulation are: 

Flat Roof Insulation Fitting

flat roof insulation

Avoiding condensation

One of the main benefits you will receive from installing a warm flat roof is condensation will not become an issue because of the positioning of the insulation.

At least 100mm of rigid board insulation must be positioned on top of the vapour control layer (the vapour control layer stops any moisture within the building contaminating the insulation). The waterproofing system is then applied over the top of the insulation.

flat roof insulation

Installation process

  1. We first lay Plywood or OSB board across the timber joints that acts as a base
  2. Now we install the vapour control layer that reduces condensation and maintains structural integrity
  3. Insulation board is then laid over the vapour control layer and fixed in place
  4. A second layer of Plywood or OSB board is then placed over the insulation board
  5. Once the deck is fixed together we finally install a waterproof membrane to finish off the deck and protect it from the elements.
flat roof insulation

How long will it last

Insulation materials are generally quite tough and you can expect Flat Roof Insulation to last between 25 and 40 years.

Warm roof insulation will slowly degrade over time as it is exposed to the elements, however you shouldn’t be concerned as it will last equally as long as durable the waterproofing material that covers the roof.