For the measurement of the drilling resistance method was chosen always one element of the
roof truss (freestanding column, the column by the wall, rafters, tie beam) and elements of visibly
affected area by decay – the area of water leaking.
The first measurement was performed at the freestanding column, which is shown in Figure 5 –
visibly infected with wood-destroying insects.
The centre of the cross section shows greater resistance of the wood than its edge parts which
are more affected by wood-destroying insects, which damages the timber progressively from the
edges toward the middle of the cross-section (see Fig 6).
Figure 6. Drilling resistance – the freestanding column
The second measurement was performed at the column standing by the wooden wall (see Figure
7). The result of the measurement shows significant decreases of wood practically the entire cross
section of the column (see Figure 7).
Figure 7. Drilling resistance – column by the wall
Another measurement was carried out on selected tie beam, which exhibited locally by
wood-destroying insects (see Figure 8).
Figure 8. Tie beam – wood-destroying insect damage
