PSI - Issue 81

Andrii Pavluk et al. / Procedia Structural Integrity 81 (2026) 198–204

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roofing material above the duct outlet also occurs. Thus, avoiding such defects is essential. a) b) c)

Fig. 9. Technological defects (ventilation ducts discharged into the attic space) (a, b, c).

Finally, the study also included a summary of defect types identified in roofs of different service life categories as well as the frequency of their occurrence (Table 1).

Table 1. Frequency of occurrence of identified defects and damages in roofs with different service lives

The name of the defect

Service life of up to 10 years, %

Service life from 10 to 50 years, %

Service life from 50 to 100 years, %

Moist or periodically wetted timber Changes in the natural colour of the timber Unacceptable deformations of structural elements Damage caused by wood-boring insects

8

30 70 47 50

86

31

100

8 0 8 0

0

71 14

Timber fungal infestation Technological defects Shrinkage-induced cracking

3

47

0

100

100

100

Timber decay (rot)

0

7

57

Corrosion of metal components at structural joints Charring (resulting from fire exposure)

85

100

100

0

7

14

The diagrams of the research results are presented in Figs. 10 – 12. In design and construction practice, there is a common stereotype regarding the durability of timber structures. Many specialists in the field consider wood to be a material with limited longevity. However, our studies of timber structural elements demonstrate the opposite. With proper operation and maintenance of timber roof structures, their service life can significantly exceed the design expectations.

Fig. 10. Frequency of defects in roofs with a service life of up to 10 years