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.
Roof insulation uk regulations.
Building regulations does not determine which material must be used but it stipulates what qualities it must posses.
Currently uk building regulations stipulate that a minimum depth of 270mm is required to adequately protect your home and keep it properly insulated.
Building regulations standards set the levels of thermal insulation required when carrying out building work either for new build or refurbishment projects.
Walls are defined by regulation 2 3 of the building regulations 2010 as being thermal elements.
Making significant changes to thermal elements walls roofs or floors would normally require building regulations approval and require the thermal insulation of the element to be upgraded to a reasonable standard.
A qualified roofing contractor will be able to advise on this but here are some of the main guidelines.
No ventilation is required for these types of roofs.
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.
This is just under a third of a metre which may seem like quite a lot to you.
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.
Building regulations for insulating a roof.
The actual regulations require that loft insulation should be at least 270 mm thick and must have good thermal properties.
7 2 d11 a ventilation of main roof spaces pitched roofs with insulation at ceiling level should always be ventilated to the outside air to minimise the risk of ventilation.
Cold deck this is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof.
If you are installing loft insulation as part of a roof renovation project where more than 25 per cent of the roof is being renewed then the level of insulation should meet the standards required by building regulations approved documents.
Care should be taken not to block any ventilation at the edges eaves.
Insulation and thermal elements.