Question10
10. What thickness of Crown DriTherm Cavity Slab (full
fill application) is required in a masonry cavity wall consisting
of a brick outer leaf and a 7 N/mm2 block inner leaf to achieve the
0.35W/m²K U-value to meet the Building Regulations?
To calculate U- values you need to know the thermal
conductivities and thicknesses of all the components of a
structure. It is the conductivity of the block, not its compressive
strength that is needed for the calculation. In the absence of this
information, a cavity wall of this construction with 12.50mm
plasterboard on dabs to the inner face of the block, a thickness of
85mm Crown DriTherm Cavity Slab will achieve a U-value equal or
better than 0.35W/m²K.