SR37 The effect of timber moisture content on construction adhesives (2007)

An experimental programme was carried out to determine whether high moisture contents in wall framing timber affected the performance of adhesives used to fix wall linings.

A range of construction adhesives (three water-based and two solvent-based) were used to prepare shear test specimens using timber at moisture contents of either 15% or 25% by weight. After curing for 4 weeks at either 65% RH or 95% RH, the specimens were tested in shear.

To simulate drying of the timber after lining out, one set of specimens was prepared using timber at a moisture content of 25%, cured, then conditioned back to a moisture content approaching 15% by weight.

The differences in behaviour of the adhesives and the likely effect on performance of high moisture content timber are discussed.