Building regulations state that a ventilation gap of at least 50mm must be in place between the insulation and the underside of the flat roof deck.
How to build a cold flat roof.
A note to consider before construction.
These roofs are mostly flat but usually have a bit of a slope.
Flat roof construction can come in the form of a warm roof or cold roof depending on the requirement of the owner and architect as they relate to the building regulations regarding heat loss and insulation.
As the name suggests a pyramid roof is a roof in the shape of a pyramid and is designed for a square building.
From there the flat roof system you choose will determine the materials you apply.
This arrangement allows the deck to become cold.
In a cold roof construction the sarnafil membrane is installed directly to the structural decking usually timber with firrings to fall.
Consider geography budget and use for the roof to determine the best option.
For that reason cold flat roof construction needs to keep in mind the need for unblocked airflow.
Hip and pyramid roofs.
Types of flat roof construction warm and cold flat roofs.
The 3 most common materials used for flat roof construction.
There must be an adequate void minimum 50mm between the deck and the insulation traditionally mineral wool to allow free movement of air and to prevent moisture vapour being transmitted from the building outwards where it could condensate in the roof.
If insulation is installed below the flat roof deck this is called a cold roof.
In a cold weather such roofs are inherently prone to condensation which can cause material decay and deterioration.
There are several methods and materials for the design of the exterior surface of a warm or cold flat roof.