Warm Flat Roof Insulation Depth

13 july 2017 kingspan insulation uk.

Warm flat roof insulation depth.

However some in the industry would consider up to 15 o as their definition of a flat roof. It should be of the maximum available thickness. A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value. When building a flat roof it is vital that a degree of falls is built into the construction to ensure rainwater run off.

As only a few years ago the recommended depth of insulation was 200mm and before that it was as low. The target should be to achieve a u value of 0 25w m2k or better. If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of the tiles or slates with an 80mm board running across the rafters. Roofing insulation is one of the most important and misunderstood building components.

Energy efficiency grants are currently available for cold loft roof insulation. 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. There are two types of flat roof. They increase in depth by a small amount each one say 1 8.

There are many different types and installation methods out there along with a lot misinformation about which products offer the greatest energy savings. The sheets are laid at 90deg to the firrings. Tony1851 30 aug 2012. A cold roof can be cheaper as ridged warm roof insulation tends to be more expensive a warm roof is sometimes the only option when it is difficult to get the required cross ventilation rigid.

In this case ventilation is required and the roof can still become wet with condensation which may cause materials to decay. To achieve this add 100 to 160mm of insulation above the structural deck dependant upon insulant conductivity. Cold roofs and warm roofs. The definition of a flat roof according to bs 6229 is having a pitch less than 10 o to the horizontal.

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. Ventilation is required for these roofs. With a warm roof the usual process is to split the insulation into two layers. The typical u value of an existing uninsulated flat roof is 1 5w m2k.

Here we share the most common mistakes people make when installing flat roofing insulation. Cold roofs have the waterproof layer placed directly onto the roof deck and the insulation inside the roof just above the ceiling.