Roof trusses play a very important part in the strength of a house, holding up the roofing materials that form the first line of defence against the elements. While made from strong timber and in ways that enhance that strength, there are problems that can affect roof trusses and cause them to weaken. So, what are the most common problems and how can you spot them?
Dry rot can be the stuff of nightmares if left unchecked as this is a type of fungus that can spread through thewood to metal and other building materials, even penetrating brickwork. It is probably one of the most destructive things that can affect the interior of a house and the roof trusses can be the place the infection starts.
The fungus known as dry rot is one of a number of species that thrive in dark, damp conditions such as under floors, behind timber panelling and in loft spaces. It requires higher than normal moisture levels so poor ventilation or issues with condensation are often behind the outbreak. Once the fungus gains a foothold, it can quickly spread to other building materials and cause serious damage.
When the fungus first appears, you can see off-white, felt like or cotton wool style sheets on brickwork and on timbers, often on roof trusses. Fungal strands about the thickness of a finger later grow and are lemon yellow where exposed to light. Mushroom-like fruiting bodies appear and these can grow on painted on plastered areas and release brick red spores that can coat everything. Timber affected by dry rot will crumble when you touch it.
Wet rot sounds more serious but is actually the lesser of the two conditions. Wet rot requires higher moisture levels than dry rot so is less common. Usually, a structural defect causes the condition such as a roof leaking or rising damp from a failed damp proof course.
Wet rot is one of three different fungi that has slightly different signs to spot. Pore fungus is the most common to affect wood and causes it to shrink and rift into cubical sections. It has white, flexible strands and sometimes fern-like growths.
Woodworm is another general term used for the infestation of wood by an insect that feeds on it. This was once commonly seen in furniture and other wood features but modern treatments have meant it is less common. It can still appear in the structural parts of a house and can lead to significant damage if it is left unchecked.
There are different signs for the different beetles and insects that might be involved but some common signs include bore dust, gritty sawdust that is left by the creature’s passage through the wood and clean, pale, exit holes where the insects have entered and exited the wood. They also cause fissures and cracks in the wood in some cases. Damp and humid conditions are needed for them to survive and they often infest newly seasoned green timber.