Insulation tight to the roof deck i e.
Insulation for flat roof regulations.
Building regulations for insulating a roof.
A ventilation gap usually 50mm should be provided between the top of the insulation and underside of the roof covering to allow the air to flow across.
These are expressed as a u value which needs to be achieved.
U value of a flat roof to comply with part l of the building regulations 2010 all roofs to rooms except those in unheated buildings should be thermally insulated to a maximum u value of of 0 18 w m k.
While expensive the best insulation is polyiso rigid foam.
Building regulations standards set the levels of thermal insulation required when carrying out building work either for new build or refurbishment projects.
A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value.
You can expect to pay about 55 100 sq ft.
The limiting u value the maximise u value which cannot be exceeded required under current building regulations for the roof is 0 20w m.
Heat rises and therefore the building regulations requirements for heat loss through roofs are more stringent than those for walls.
The required u value will depend on the location of the project england scotland or wales type of building domestic or non domestic and the application floor wall or roof.
Possible locations for insulation within the roof assembly as addressed by ibc include.
Continuous insulation zones ashrae 90 1 ashrae 189 1 igcc ibc iecc 2004 2007 2010 2013 2016 2009 2011 2014 2012 2015 2009 2012 2015 0 25 1 15 20 2 15 20 25 3 15 20 25 4 15 20 302535 5 15 20 302535 6 15 20 3035 7 15 20 3540 25 8 20 3540 25 minimum r value non residential above roof deck.
Insulation on the floor of the attic figure 1.
Understanding building regulations relating to insulation blog posted on 26th september 2019 whether you are involved in a new build or a refurbishment project there are a certain set of standards for thermal insulation which need to be adhered to according to building regulations.
If moisture is a major concern you can also install xps rigid insulation which offers superior moisture resistance.
It is top quality and the most cost effective product for your flat roof.
At least 100mm of rigid board insulation must be positioned on top of the vapour control layer the vapour control layer stops any moisture within the building contaminating the insulation.
There must be a slope of 1 80 part h of the building regulations regarding drainage state that water should drain to one or two edges waterproofing should extend up the adjacent walls at least.
A qualified roofing contractor will be able to advise on this but here are some of the main guidelines.
One of the main benefits you will receive from installing a warm flat roof is condensation will not become an issue because of the positioning of the insulation.
