Insulation for Masonry Overcladding

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 (Isover Steel Frame Infill Batt can be considered), 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. The sheathing insulation is typically a stone mineral wool slab, such as Isover Polterm Max Plus. Between the outer face of the sheathing insulation and the masonry outer leaf, a minimum 50mm residual cavity is maintained.

Key Considerations

When using Isover products, you need to satisfy yourself that use of the product meets all relevant national Building Regulations and guidance as well as local, national and other applicable standards relevant for your construction or application, including requirements in relation to fire and applicable height restrictions. In addition to the product datasheet, please refer to the following product documents:

• BBA certificates - where applicable to the application
• Declarations of Performance
• Health & safety datasheets

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

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Insulation products

Product Name	Thickness Range	Sizes	Lambda
Isover Polterm Max Plus	50-200mm	Width 600mm, Length 1200mm	See datasheet
Isover Steel Frame Infill Batt	50-100mm	Width 600mm, Length 1200mm	0.036