Insulating Above A Groundbearing Slab

“…when installed with a screed is ideal for underfloor heating…”

Putting floor insulation on top of a slab shields the slab’s thermal mass from the building envelope which makes the building easier to heat.

Such floor insulation is ideal to use in insulation of UK buildings that are not always heated. This type of insulation works with buildings made of masonry and timber and if installed with a screed works well with underfloor heating.

Ballytherm insulation boards  are made following specifications for boards that fit this type of construction. These boards are high density as well as water resistant. And, since they have a low thermal conductivity it reduces the need for maximum thickness in insulation UK when laid under a floor during construction.

The necessary thickness of the Ballytherm Insulation can be worked out from the following Table 5.

Table 5 - floor insulation

Further Advice & Information

For more information about Ballytherm products, technical advice, or guidance on the suitability of our products for your project, contact us at 0800 644 6900,, email us at or use our contact form.

Floor Insulation

Design Guidance