So any timber joists that are used need to be strong enough to support this weight.
Timber cold flat roof construction.
In the warm flat roof construction there is insulation packed into every possible space where air can flow.
In a cold roof construction the sarnafil membrane is installed directly to the structural decking usually timber with firrings to fall.
One of the most essential considerations in a cold deck flat roof construction is the requirement for adequate ventilation in the form of a ventilated cavity of at least 50mm between the underside of the timber deck and the roof insulation below.
Old asbestos roofs are often replaced with flat roofs.
As you may imagine there is a fair amount of weight involved here in terms of boards felt etc.
Hopefully this video will help explain the difference between cold flat roof construction and warm flat roof construction this videos show detailed drawings.
This is used for refurbishment e g.
Sizes of joists needed for flat roof construction.
This ventilation is necessary to prevent condensation from forming below the roof deck which can.
The insulation is below the deck but above the plasterboard.
The major difference between the warm flat roof and the cold flat roof has to do with the air flow between the roofing timbers known as joists that help to hold up the roof.