Damage can occur in timberwork at the base of older roof structures, typically as a result of fungal, rot or insect attack. This can be due to water penetrating through leaks in the roof, often as a result of inadequate maintenance.
Damage needs to be corrected, and when large sections of timber are being replaced, various types of joints are used – as shown in the model – depending on, for example, whether the structures (and therefore the joints) are visible or concealed.
There is a current requirement that a subroof solution be chosen when replacing roof coverings. The model shows a solution using a fixed subroof, which is the safest and most durable. The model also shows the principles for correctly insulating the roof.