A U-value is a measure of thermal transmittance, or the amount of heat energy that moves through a floor, wall or roof, from the warm (heated) side to the cold side. It is the number of Watts per square metre of the construction, per degree of temperature difference between one side and the other ( W/m2K ) .

The quick, free and easy way to find out the insulation thickness and the U-value you need for your building project. The U-value Calculator covers all the main ways of building walls, flat roofs, pitched roofs and floors using Kingspan Insulation products. Celotex TB4025 is targeted at cut-to-fit applications between rafters or joists and enables users to achieve lower U-values with a single layer of insulation than has previously been possible. It is also appropriate for use in floors and walls. Login to the Celotex Members' Area for a range of specification tools, making specifying Celotex easy! Register to gain access to our comprehensive technical library which contains helpful specification tools, including the popular Celotex U-value Calculator, Thermal Bridging Models, BIM objects and much, much more. A U-value is a sum of the thermal resistances of the layers that make up an entire building element – for example, a roof, wall or floor. It also includes adjustments for any fixings or air gaps. A U-value value shows, in units of W/m²·K, the ability of an element to transmit heat from a warm space to a cold space in a building, and vice versa. Celotex Technical Centre: 01473 820850 celotex.co.uk Physical Properties Method GA4000 Compressive strength BS EN 826 ≥140kPa Dimensional stability BS EN 1604 DS(TH)8 Water vapour resistance BS EN 12086: Method B >150 MNs/g Thermal conductivity BS EN 12667 0.022 W/mK Surface spread of flame BS 476-7 Class 1 Typical U-values

U-values - Designing Buildings Wiki - Share your construction industry knowledge. U-values (sometimes referred to as heat transfer coefficients or thermal transmittances) are used to measure how effective elements of a building's fabric are as insulators. That is, how effective they are at preventing heat from transmitting between the inside and the outside of a building.

Celotex with lambda values as low as 0.021W/mK achieve better U-values and thinner solutions preventing heat loss and maximising thermal performance. With a premium range including ‘best in class’ product solutions for pitched and fl at roofs, walls and fl oors Celotex will continue to help meet the requirements of Building Regulations. SuperQuilt is proven to save cost, space, wastage & installation time compared to Rigid PIR Insula tion (Kingspan / Celotex) Require a U-value document for building control? Visit our free & easy to use Online U-value Calculator. Receive instant solutions in less than 60 seconds! Click Here to Use! import_contacts See Full Guide U-Value. Now you have your Rt value, the calculation is simple, one divided by the Rt. There you have your U-Value. Other helpful bits: Architecture.com U-Value guide BRE Guide to U-Values. One of our readers, Brian, has very kindly provided access to the U-Value calculations of a live project so that you can get a feel for what is involved.

The quick, free and easy way to find out the insulation thickness and the U-value you need for your building project. The U-value Calculator covers all the main ways of building walls, flat roofs, pitched roofs and floors using Kingspan Insulation products.

Celotex Technical Centre: 01473 820850 celotex.co.uk Physical Properties (*insulation only) Method GS5000 Compressive strength* BS EN 826 ≥120kPa Dimensional stability* BS EN 1604 DS(TH)8 Thermal conductivity* BS EN 12667 0.021W/mK Fire resistance BS EN 13501-1 Euroclass B-s1,d0 Typical U-values U-values will vary depending on application. 1980: In the U.S. in the 1980's Celotex Thermax insulating board was described by the Celotex Company (Jim Walters corporation, Tampa) as an insulating sheathing board with an R-value of 5.4 for a 3/4" thick board: higher R than its competitors at the time as it was compared with foam insulating board sold by Dow, WR Grade and Simplex