Drilling patterns

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Best practice drilling patterns

From COSYTHERM WHITE WOOL CAVITY WALL INSULATION Agrément Certificate No 01/3789

7.3 Injection holes are drilled in a diamond pattern at approximately 1.35 m centres. The topmost injection holes should not be more than 350 mm below the upper edge of the cavity and not more than 1.0 m apart. The bottom row of holes should start approximately 800 mm above the dpc level.

From the BBA cosytherm certificate -  recommended drilling pattern.

The bottom holes are 0.9m above the ground level where the damp proof course but in places it's even higher being 0.8m from the bottom of the incomplete render (which is not the damp proof course).


The horizontal interval between holes is consistently around 1.16m rather than 1.35m as specified

The vertical distance between holes is 0.64m rather than  1.35m


Summary

Although there will inevitably some variation in drilling patterns to match brick/mortar boundries and to work around features such as chimneys. This installation falls short of the BAA certificate recommendation.

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