Celotex Isover

Insulation for Masonry Overcladding

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These types of wall typically comprise an outer skin of masonry and an inner skin of lightweight steel frame (SFS) construction, although depending on building height the inner skin can also be of timber-framed or cross-laminated timber (CLT) construction. The SFS is typically filled with a mineral wool roll or slab, then finished internally with plasterboard and externally with a sheathing board to provide protection from the elements. Additionally, membranes such as a Vapour Control Layer (VCL), Air and Vapour Control Layer (AVCL) or a breather membrane may also be specified.

The insulation between the SFS alone is usually not enough to comply with Building Regulation thermal requirements, so additional insulation can be installed against the sheathing board and fixed in place with a brick channel & tie restraint system. Between the outer face of the sheathing insulation and the masonry outer leaf a minimum 50mm residual cavity is maintained.

The sheathing insulation is typically a stone mineral wool slab, such as Isover Polterm Max Plus and Isover Steel Frame Infill Batt can be installed into the SFS zone.

The building detail is for illustrative purposes only. It does not constitute advice and should not be relied upon.

Insulation products to consider
Product Name Thickness Range Sizes Lambda BBA
ISOVER Polterm Max Plus 50-200mm Width 600mm, Length 1200mm 0.035 W/m.K Tick Icon
ISOVER Steel Frame Infill Batt 50-100mm Width 600mm, Length 1200mm 0.036 W/m.K Tick Icon