New Extension Roof Insulation

Column a is for extensions where the existing dwelling s walls and roof u values are worse than 0 70 w m k in the walls and worse than 0 25 w m k in the ceiling.

New extension roof insulation.

For a new build property we recommend a target u value of 0 11 w m 2. Remember the roof is one place where you can easily upgrade the insulation and increase the energy efficiency of your home. If you are constructing a ventilated roof insulating between and under the rafters then there needs to be a 50 mm air gap between the insulation and the sarking felt to avoid condensation building up. Column b is for other extensions upgraded existing thermal elements non exempt conservatories and conversion of unheated buildings.

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. The roof covering is then laid over the ply. K for scottish homes. Choose feldco roofing for your brand new roof.

Cold deck the thickness of insulation required will vary depending on the material you decide to use and the manufacturer s specification. Hi i have a flat roof extension built in the 1970s. The extension will be 3 5x6x3 5m. K for properties in england and wales and 0 10 w m 2.

I will be building an extension to the rear of my property shortly and will be having a lean to roof with pitched roof inside with two sky lights. Whole roof will have a new breathable membrane. Celotex a 225mm solid brick wall will have a u value of around 1 7w m k and a 400mm stone wall about 1 4. Adding 50mm of rigid insulation will reduce the u value to around 0 4 while 50mm of mineral wool or natural insulation will reduce it to 0 5.

Due to a rewire i ve had to remove parts of the plasterboard ceiling and have found that there is no insulation in the roof i can see the roof deck and joists there is no vapour layer and the plasterboard is not foil backed. The gs5000 product is an insulation board and plasterboard in one image credit. 70 s chalet with 100 50 rafters at 410 centres. In a warm pitched roof it is important to ventilate above the insulation line to avoid condensation so ensure that fascia vents give access for cold air to circulate.

I need to reach 0 18 u value and minimise the depth of insulation as i will be left with a step between original and new slopes. Kingspan with a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same. New roof extension same construction. Whether you re doing a weekend fix or folding it into a bigger home renovation insulating your roof will pay off for years to come.