Insulating Existing Concrete Flat Roof

The insulation is below the deck but above the plasterboard.

Insulating existing concrete flat roof.

Refurbishing an existing timber joisted flat roof which has no insulation. I ve built a timber frame to support a new plasterboard ceiling below the existing one. How to insulate a flat roof. With a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same.

Insulation material is placed on top of the roof rather than in between the ceiling and the decking. Roof types the various types of roofs found on homes sheds garages and other buildings fall into one of the following categories. The existing ceiling is sound but provides no insulation. Cold roof a very bad idea.

This is then covered with a further weatherproofing layer. To insulate a flat roof with a concrete deck we recommend a warm deck construction method where the vapour control layer is sandwiched between the concrete deck and a layer of rigid pir insulation boards. Both these variants require different approaches to insulation which will be covered in this guide. This method eliminates the need for ventilation and the risk of condensation whilst providing superior thermal performance to cold deck.

To produce a hot roof rigid insulation is fitted outside above the weatherproofing. There is only a small gap between this ceiling and a concrete roof cold roof felt covered. Here we share the most common mistakes people make when installing flat roofing insulation. The type that is right for your flat roof insulation job depends upon the state of the roof expert opinion on the best type and your budget.

Green roofs a green sedum or grass roof can also be put onto a flat roof provided it can take the weight. There are many different types and installation methods out there along with a lot misinformation about which products offer the greatest energy savings. This is used for refurbishment e g. Gable roofs hip roofs intersecting roofs butterfly roofs mansard.

Insulation is placed in between the joists underneath the roof surface above. With an inverted warm roof construction put ballast usually graded pebbles or concrete paving slabs on top of the insulation in order to keep the insulation down in the event of wind. A cold flat roof is one where the insulation is between or between and below the roof joists. Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation.