Foam Cavity Wall Insulation U Value

Polyurethane products are well known for their increased thermal efficiency which results in lower u values.

Foam cavity wall insulation u value.

U value calculator for cavity walls. Foamular 250 retards the transmission of water vapor and moisture in masonry walls. If you do and it consists of blown mineral fibre or polystyrene beads and you re still receiving high energy bills we recommend switching to expanding foam insulation. In this instance to achieve a u value of less than 0 2 w m 2 k you need to apply either internal or external wall insulation too although you will only need to apply 50mm of celotex either internally or externally to achieve this.

Building regulations now specify that walls must adhere to specific u value standards thermal transmittance so many properties already have cavity wall insulation. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. These can be supported with a detailed report. We provide u value calculations to show compliance with current building regulations standards and best practice.

For more information see our articles and how to videos below. U value ratings generally fall between 0 16 and 1 20. Usually white and very light. Users need to make a selection from each of the drop down boxes.

The easiest way of getting a u value calculation is by using our free online u value calculator. The u o factor for all frame walls is based on the r value of cavity insulation and the continuous insulation r value if used. It is designed for all users but specifically those who want to make an assessment of the u value achieved with various combinations of block and thermal insulation prior to finalising a wall design. The maximum u value you can achieve by retrofitting cavity wall insulation in any property older that 1975 is 0 5 w m 2 k since you are limited by the thickness of the cavity.

The entire wall is assumed to have structural sheathing. If the user does not enter a continuous insulation sheathing r value or enters a value of 0 0 the software assumes a sheathing r value of 0 83. The lower the u value the greater a product s resistance to heat flow and the better it s insulating value. Foamular 250 extruded polystyrene xps provides continuous insulation in insulated concrete sandwich panel walls in masonry unit cavity walls or when used with non penetrating surface mounted furring systems over masonry or concrete walls.

U values are expressed in units of w m2 k. For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3. When continuous foam insulation is specified 100 of the wall is assumed to be covered at the specified r value. The r value is the reciprocal of the conductivity of a material and is the measure of the capacity of a material to resist heat transfer.

We are able to provide contractors architects specifiers and homeowners u value calculations for their projects when using our products. Installing our cavity wall insulation product technitherm and using our spray foam product duratherm which both have a low thermal conductivity value of 0 025 w mk means you can achieve lower u values.