Also known as “household leprosy”, dry rot becomes a real scourge when it affects houses. This fungus mainly attacks buildings that are victims of humidity and its development is impressive. Fortunately, it can be treated in different ways.
What is dry rot?
Dry rot is a lignivorous type mushroom that comes from the forest. It is made up of cells that feed on organic molecules, in this case wet wood, which it devours until it completely decomposes. She particularly appreciates the cellulose found inside the wood as well as the lignin of the wood which constitutes its exterior. One of the main characteristics of this mushroom is certainly its growth rate. It is particularly rapid and affects the entire structure of a building, from the roof to the framework, including the floors, the lintels, up to the panelling, doors or stairs.
Dry rot also has a specific mode of development. The microscopic spores are found in the air and then come to attack the damp wood. Gradually, they grow into filaments known as hyphae which, in turn, form what is called the mycelium. It is he who is the most devastating since he attacks the woodwork until it is completely weakened. At its last stage of development, dry rot turns into a carpophore. This one looks like a pancake surrounded by a whitish halo with a slight rust-brown tint. Reproduction takes place at this stage.
Once it has attacked the wood, dry rot continues to develop until it destroys everything in its path. In the long term, it even reaches the healthy and dry parts thanks to the use of a water transport system. It is not uncommon for a healthy house located next to an infested building to be affected by dry rot.
Even if the criteria for the development of this fungus are no longer met, it does not disappear. It can stay on standby for a while. And as soon as the new conditions necessary for its development reappear, it attacks again.
Why does dry rot take over certain houses?
There are a number of factors that explain the development of dry rot in a home. First is humidity. To be able to survive, it needs at least 22° humidity. Its growth reaches an optimal stage from 35° of humidity. This fungus also needs darkness to grow. But he is not afraid of the light.
A lack of ventilation in the house also promotes its growth. The absence of air makes it possible to maintain the humidity level and the appropriate temperature for it, in the air. Like most fungi, dry rot also likes warm environments over 20°.
In summary, this fungus will be happy in humid, hot houses, which lack brightness and ventilation and whose air temperature is more or less high.
What risk and consequence in a house?
Apart from a few exotic species, dry rot attacks all types of wood. The latter displays a brown color. When left untreated, it crumbles and then breaks into many pieces. When wood is treated, cracking, blistering and warping occur. All wooden elements are affected such as stairs, furniture or floors. The structures are weakening and it becomes impossible to stay in the house. Worse, dry rot crosses ceilings and walls to touch bricks, cement joints and even electrical wires. Very dangerous factor: the fungus is a conductor of humidity. When water touches electrical wires, sparks may occur that could cause a fire.
You should know that it is quite difficult to detect the presence of this pest if you are not a real professional. Indeed, it tends to touch the interior of the wood more than its exterior. Unless there is a thorough diagnosis, it is therefore not easy to detect it.
How to prevent and treat dry rot?
Mode of prevention against dry rot
The first thing to do to prevent the appearance of this lignivorous fungus is to adopt good maintenance while paying attention to moisture concerns. Outdated water inlets, dilapidated sandstone toilets that tend to become permeable or even flat roofs with leaks deserve your full attention. Laundries, bathrooms, kitchens and other wet rooms must be optimally ventilated.
Avoid at all costs storing wood in the cellar. The insulation must be carefully checked as well as any water leaks. To fight against humidity, do not hesitate to install a humidity absorber. The good ventilation of the whole house is also the golden rule.
Be careful, to avoid the proliferation of the fungus, do not scratch the infected surface at the risk of spreading the spores everywhere. Never use certain products such as bleach or ammonia because dry rot particularly appreciates them.
Mode of treatment against dry rot
Among the solutions to fight against this fungus is the quilting of the walls. An operation carried out exclusively by a professional. After a diagnosis to detect dry rot and assess the extent of the damage, the specialist proceeds to a pricking by injections, sprays or brushing of the affected parts. He destroys the filaments with a blowtorch, changes the woodwork and sterilizes the masonry.
Injecting fungicide is also a solution like any other. The operation is carried out in depth or by superficial application. Floor, joints, wood, stairs, masonry… everything is treated.
Finally, if dry rot has really destroyed everything, demolition and reconstruction should be considered.
To prevent dry rot from attacking the house, making it uninhabitable, it is necessary to be reactive and to proceed quickly with the treatments. Experts can help you and provide all their expertise.
(Photos par Majavamm.jpg: Eppderivative work: Ak ccm (talk) — Majavamm.jpg, CC BY-SA 3.0)