Where the ceiling below a cold pitched roof includes a vapour control layer the design should ensure adequate ventilation is provided to the habitable areas to prevent condensation problems in the home.
Warm or cold pitched roof.
Inclined along the line of rafters warm roof or positioned within the roof structure to form an insulated void room in roof which can result in warm and cold roof areas.
The object being to design out the possibility of warm moisture laden air coming into contact with a cold surface and condensing.
A cold roof is best when you re initially creating a flat roof and is cheaper than a warm roof but does provide an inferior thermal performance.
A warm roof construction allows heat to be conserved within a property without the need for a ventilation system.
In a cold roof the insulation is applied between the rafters but in a warm roof the insulation is applied on top of the existing roof surface.
A typical roof pitch in the uk for a traditional house will be 40 50 but at most it can go up to 70.
A warm roof construction has many benefits over a traditional cold roof essentially it is a breathable roof construction which allows moisture to escape which in turn prevents damp and any associated decay problems.
For condensation to form it would need cold too meet hot air but now its all hot air inside the building until the top of the warm roof insulation.
Answered 12th may 2018 like 1.
A warm roof is much more straightforward to install and provides a superior thermal performance and is therefore more costly.
Warm roof construction requires that the entire roof construction is encapsulated within the insulation envelope of the building to be kept warm.
As opposed to insulating between rafters the warm roof insulation is simply installed on top of the existing surface.
In pitched roof construction thermal insulation can be placed horizontally at ceiling level cold roof.
An architect makes the usual decision of the pitch.
The construction of a warm roof the insulation sits on top of the rafters.
Anything underneath the warm roof insulation is now part of the fabric of the building the same as the plywood or ceiling below it.
Cold deck roof a cold deck roof is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof.
Warm roof insulation tends to relate more to pitched roofs which feature as mentioned in the previous sentence a higher profile.
Namely the insulation layers.
Ventilation is required for these roofs.
You create a warm roof or a cold roof simply by applying the layers of the roof in a different order.