There are two types of flat roof.
Warm roof construction ventilation.
The need for roof space ventilation is eliminated or reduced.
Cold roofs have the waterproof layer placed directly onto the roof deck and the insulation inside the roof just above the ceiling.
In pitched roof construction thermal insulation can be placed horizontally at ceiling level cold roof.
Ventilated roofs remove moisture from roof cavities structural members sheathing and insulation.
The advantages of warm roof construction.
Approved document c2 requires that roofs be designed and constructed so that their structural and thermal performance are not adversely affected by interstitial condensation.
Introduction warm cold roofs this guidance offers guidance on the difference benefits between warm and cold roofs.
A properly insulated ventilated roof can help to control or prevent the formation of ice dams.
Where the insulation is placed above the structural deck warm deck and either above or below the waterproofing.
These roofs keep your home cooler during the hot summer months.
Understanding the roof construction of any new build or refurbishment is essential to determine what products are required for the job.
The ceiling space is on the warm side of the insulation.
Ventilation building regulations.
Cold roofs and warm roofs.
With the potential of additional living space a cathedral roof design or a conditioned roof void are rapidly becoming the preferred choice of pitched roof construction in the uk.
There is no need for additional ventilation.
Although there is a low risk of condensation with warm roof construction it is very difficult to seal all joints gaps and penetrations against all water vapour transmission.
Cold bridging occurs when there is a continuous path created through the insulation.
Eliminating traditional ventilation and the potential condensation risk associated with large voids of cool air make this the optimum pitched roof solution.
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.
Figure 2 warm roof construction.
Like a cold roof warm roof ventilation is required at high and low level to remove moisture laden air from the batten cavity and comply with approved document c and the.
Inclined along the line of rafters warm roof or positioned within the roof.
Because the sheathing is kept cooler roofing materials tend to have a longer life span.
Thermal bridging is largely eliminated as the insulation is continuous over the whole roof structure.
A warm roof construction allows heat to be conserved within a property without the need for a ventilation system.
Ventilation is required for these roofs.
A cold roof design is generally not recommended for new build roof applications due to the added requirement for roof void ventilation and the difficulties in preventing cold bridging through the system.
