Manthorpe Building Products has come up with the Joist Seal, which it claims combats air leakage around timber joists and I-beams.

Suitable for exterior and party walls, Joist Seal fits over the joist end before being built into the blockwork in the traditional way. During the drying out period when the joist shrinks, the seal is left intact. The product saves builders having to point timber joists with mastic, which is time-consuming and can lead to air leakages.

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