The object of the work is to check the general properties of a glued laminated beam after treatment of the members composing it by means of commercial insecticidal and fungicidal formulations in clear solvent under the most common conditions of manufacture. The species used have been spruce, redwood and Douglas fir in planed boards of 80 cm long, 14 cm wide and 20 mm thickness at about 12% moisture content, glued after treatment with a commercial glue of the resorcinol-formaldehyde type at the rate of 6 laminates to make one experimental beam. The treatment products have been 4 in number, commercialized and readily available on the French market. These products will be called A-B-C-D. They all belong to the organochlorine type in solution in an organic solvent, the other material and solvents being allowed to be different. In general, the boards used were composite cut and comprised essentially of heartwood, the proportion of sapwood at the edge being often of little importance. A preliminary initial measurement of the absorption of the preservative product by each board was made by weighing. The following tests have been persued after gluing. Resistance to delamination - Resistance to shearing in compression and percentage of adhesion. The biological tests have been carried out by exposing newly hatched larvae of the house longhorn beetle on the external zones of beams (sappy zones for the species with sapwood distinct and susceptible to attack). The first results scrutinized permit us to think that with the weak amounts used the mechanical properties of the beams will remain satisfactory. After observation of the behaviour of the newly hatched 1arvae, chemical quantitative analyses are going to be undertaken in order to establish the threshold of effectiveness of the four products.

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