Cold Deck Flat Roof Insulation

Where insulation depth is restricted by the flat roof construction it may be necessary to install the roof insulation between and below the joists to create a cold deck structure.

Cold deck flat roof insulation.

Cold roofs by the way are not recommended for high humidity areas see the blog on how to insulate roofs of. In this way the roof itself is kept cold. The solution warm deck insulation. The insulation is below the deck but above the plasterboard.

Cold deck flat roof the thickness of insulation required will vary depending on the material you decide to use and the manufacturer s specification. Refurbishing an existing timber joisted flat roof which has no insulation. As for insulating below the joists an insulating laminate insulation bonded to plasterboard such as celotex pl4000 or a separate rigid pir insulation board finished with a separate sheet of plasterboard can be securely fixed to the joists to provide an internal finish to the roof. A cold roof has the insulation placed below the structural deck which thus remains cold.

Warm roof insulation ensures the entire roof structure is insulated meaning a warm deck roof is more energy efficient than a cold roof. This is used for refurbishment e g. Alternatively battens can be secured to the underside of the. The layer of insulation is essentially placed outside of the roof.

The breakdown warm roof vs cold roof a cold flat roof insulation requires more work taking off old boards and replacing them and the roof surface. Fortunately these days there is a better form of insulation available for your flat roof. This method of insulation can also be used to upgrade the thermal performance of an existing roof without affecting the waterproofing system. Saint gobain insulation uk manufacture and supply glass mineral wool slabs and rolls along with rigid polyisocyanurate pir boards that can be considered suitable for a wide range of applications across flat roofs whether you re looking to insulate at joist level or above the roof deck in your flat roof construction.

This video shows the key features of a flat roof cold deck construction and how to draw the details to a scale of 1 10. This system is called warm deck insulation and eradicates the condensation and venting issues associated with the cold deck system. A ventilation gap usually 50mm should be provided between the top of the insulation and underside of the roof covering to allow the air to flow across. This construction relies on a vapour control layer working effectively and in tandem with a continuous ventilated airspace to disperse the water vapour to atmosphere before it reaches the cold deck and condenses.

A cold roof is where all of the insulation is placed either between and under or completely under the joists or deck. No insulation is on top. A cold flat roof is one where the insulation is between or between and below the roof joists.