Good external ventilation is also essential to minimize the risk of condensation in a cold roof.
Sarnafil cold roof ventilation.
Roof spaces must have ventilation openings on two opposite sides.
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.
Some of britain s best known buildings feature sika sarnafil roofs and it is the system of choice for applications in education commerce retail leisure travel and many other sectors.
Without ventilation there is a risk of condensation forming on the underside of the roof deck.
You only need ventilation in a cold roof.
Sika s experience would be to avoid cold roof design where possible.
This should ideally be in the form of soffit vents to the underside of the fascia boards but as many flat roofs were built without soffits it is often in the form of unsightly mushroom vents on top of the roof or soffit vents incorrectly fitted in to the fascia boards.
Cold roofs have the principal insulation below the structural deck and are recommended only for small or domestic roof areas where it is possible to provide cross ventilation above the insulation.
Berkshire uses sika sarnafil s single ply membrane system on its roofs terraces and balconies.
Sarnafil g 476 20 pds 0913 repl 0812 1 4 product data sheet sarnafil g 476 20 polymeric loose laid and concealed membrane for roof waterproofing product description sarnafil g 476 20 is a multi layer synthetic roof waterproofing membrane.
In a cold roof construction the sarnafil membrane is installed directly to the structural decking usually timber with firrings to fall.
Sarnafil cold roof ventilation in a cold roof construction the sarnafil membrane is installed directly to the structural decking usually timber with firrings to fall.
Insulation is laid below the roof deck typically between the rafters.
2011 code of practice for control of condensation in buildings stipulates that there should be a.
2018 recommends warm deck roofing designs wherever vertical space permits.
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.
Without ventilation there is a risk that condensation will form on the underside of the roof deck.
Since the 1960 s the performance and longevity of sika sarnafil roofs has been demonstrated in.
An open cross ventilation space is required above the insulation to prevent condensation occurring in the insulation layer and compromising the integrity of the roof.
The design of cold roofs usually occurs when external abutment height provision is problematic thus making a warm roof not achievable.
Cold roofs by the way are not recommended for high humidity areas see the blog on how to insulate roofs of swimming pools saunas and high humidity areas.
Ventilation for cold roofs.
