There are typically two different ways to insulate a roof a warm roof and a cold roof.
Warm pitched roof build up.
They can be built up from profiled metal decks as the insulation selected would provide enough rigidity to span the open sections of such decks.
With the potential of additional living space a cathedral roof design or a conditioned roof void are rapidly becoming the preferred choice of.
Insulating a pitched roof above the rafters is the common method chosen for new builds and re roofing existing detached buildings as it provides superior thermal performance for the building.
In this blog post we explore some of the options available.
Warm roof in a warm roof construction the principal thermal insulation layer is located above the structural decking resulting in the structural deck and support structure being at a temperature close to that of the interior of the building.
Ventilation and the potential condensation risk associated with large voids of cool air make this the optimum pitched roof solution.
Warm cold and inverted.
Firstly just to make it clear when we are talking about rafter level we mean the timbers that support the pitched roof.
Roofs with pitches of 10 to 20 are often called low pitched roofs and special considerations need to be made particularly on the overlap between tiles to avoid water being blown into the.
With the introduction of vapour permeable plastics underlays the need to create ventilated voids above inclined insulation and the requirement to ventilate cold roof lofts may be reduced.
Pitched or sloping roof.
There are a couple of different methods for constructing pitched style roofs.
This is more of a traditional manner in regards to cutting the timber while onsite and building up the roof by the use of rafters ridge boards joists and purlins among others.
Warm pitched roof ventilated and sealed.
A pitched or slanted roof has a terrain of at least 15 but it is often much more.
In areas of high snowfall then the roof pitch can be much greater to allow the snow to fall off the roof rather than settle and build up on the roof.
Insulating the roof above the rafters is known as warm roof insulation as the rafters are brought into the insulated envelope of the building.
There are three recognised designs of flat roof construction.
Flat roofs are usually made of variations of bitumen felt and function as durable long lasting roofs that are perfect for water run off in wet weather and protect wood and cement from potential build ups of damp and dry rot.
In building construction roof pitch is a numerical measure of the steepness of a roof.
A warm roof building will make the entire structure of the building warm in an attempt to avoid any cold bridging.
When insulating a pitched roof at rafter level there are a number of key design considerations which will affect the build up of the roof and the choice of insulation.
Rather than actively ventilating to the outside entrapped water vapour diffuses.