Our U-value calculator allows you to create U-values for Solid walls, partially filled cavity walls and full filled cavity walls. Once you have produced your calculation you can email it to yourself or others and download related product information.
To use the U-value calculator, please register your details and login to the Specification Zone, which also includes other interactive tools such as our brick blending visualiser and flue estimator as well as news and updates.
What are U-value calculations
A U-value is a measure of heat loss in a building element such as a wall, floor or roof. It can also be referred to as an ‘overall heat transfer co-efficient’ and measures how well parts of a building transfer heat. This means that the higher the U-value, the worse the thermal performance of the building envelope. A low U-value usually indicates high levels of insulation. U-values are useful as a way of predicting the thermal performance of an entire building element rather than relying on the properties of individual materials.
Part L of the Building Regulations provides guidance on the maximum U-value allowed for each building element i.e. roofs, walls and floors. However, other factors such as building size, location and heating source that are taken into consideration in SAP calculations may require improved U-values.
As a result, calculating U-values at an early stage in the design process avoids expensive re-working later on in a project. It also allows the designer to test a project’s feasibility early on to ensure it is fit for purpose and will comply with the standards in place.
Forterra's online U-value calculator allows instant thermal assessments on a variety of masonry wall construction methods that use Forterra products. A report can then be emailed to you, giving a breakdown of your selections. This should be used for guidance purposes only. Once you have narrowed down your intended construction method we recommend contacting our Walling Solutions Technical Centre where an official U-value assessment can be obtained from a trained assessor.