Wood Rotting: Dry vs Wet and How to Treat Them

Wood rot can be a problem in any home, with older properties or unheated spaces being particularly suspectable.

Wood decay is normally caused by fungi and other microorganisms, which can grow on wood surfaces in humid and moist conditions. Different types of wood have their own level of rot resistance; in general, hardwoods such as mahogany and teak tend to decompose slowly from fungal decay, while softwoods such as pine and spruce are highly susceptible. In most Irish homes, a roof's rafters and trusses are usually made from softwood.

Similarly, different kinds of rot affect different woods: Both dry rot and wet rot can attack the same type of wood for different reasons. With the proper knowledge about spotting the signs of damp and dry rotting on wood, you can call a professional company to address the problem before this rot destroys a property's roof.

What is Wood Rot?

Rotting is the process by which organic materials decompose when exposed to water, oxygen, and certain types of microorganisms. Wood rot is no differnent in this regard. As a natural material, wood can begin to decay. This process is quickened if the wood is exposed to moisture or wood-decaying fungi or mould.

Both dry rot and wet rot are caused by fungi, bacteria, or a combination of both.

Dry Rot

Dry rot is caused by wood-decaying fungi that excrete large amounts of spores that land on other wood and create infections when released into the air. Dark spores are common on the surface of dry rot and are generally not visible on wet rot. As mentioned, a softwood like pine – which is found in most Irish homes – is particularly susceptible to the decaying effects of dry rot. Fungal spores penetrate deep into the wood and cause decay. Unlike wet rot, dry rot happens when moisture is absent in the wood. As a result, it occurs primarily in the outer layers of wood, where moisture content is lower.

Wet Rot

Wet rot happens when fungi or bacteria grow inside wet wood, causing it to break down. The difference between wet and dry rot is in the level of moisture present in the wood and surrounding air. Wet rot happens in spaces that have a high moisture content or in places that are poorly ventilated; in Ireland, wet rot is prevalent in attics.

Differences Between Dry and Wet Rot

Dry rot and wet rot are different in many ways, including the conditions in which they are most likely to grow, the types of wood they affect, and the level of damage they cause. However, they also share a few traits, including that they are both types of wood rot caused by fungi and bacteria. Dry rot is likely to occur in already dry wood and is often found in wooden beams and joists that are not exposed to moisture-rich conditions. On the other hand, wet rot usually occurs in wood with a high moisture percentage and is stored in a moisture-rich environment.

How to Spot Wood Rot?

While both types of rot are easy to spot in some instances, in others, it may not be so easy to tell if your wood is decaying. Suppose you suspect that your wood is rotting. In that case, there are a few signs to look out for, including discolouration, cracking, and an unpleasant smell. Decaying wood will often have a dark spot where the rot has entered the wood. Suppose you see any signs of discolouration on your wood. In that case, it is essential to act quickly—discolouration often means more extensive damage is happening inside the wood. In many cases, wood rot can spread to other pieces of wood, particularly if there is a crack or gap. It's essential to remember that rotting wood is a symptom of a more significant problem: excessive moisture is present in the property.

What Causes Wood Rot?

Wood rot is caused by fungi and bacteria that are present in almost all wooden structures. The presence of these microorganisms is usually not a cause for concern. Still, certain conditions can cause them to flourish and spread to other pieces of wood. To prevent wood rot from growing in your home, you must take steps to control the level of moisture in the environment.

How to Treat Wood Rot?

Implementing dry rot treatments and wet rot treatments is important because wood that is already rotting can cause further damage and lead to expensive repairs. In addition, wood rot can be a health hazard, mainly if it is in a visible area of your home. The best treatment for wood rot is prevention.

Allied Damp Solutions offer an extensive range of damp-proofing solutions and ventilation options that optimise moisture levels in a home. Dampproofing not only helps prevent wood rot, but it can also address issues like recurring mould growth. Mould is unsightly and can also be detrimental to human health. Individuals with pre-existing respiratory problems are particularly vulnerable to the ill-health effects of mould growth.


Wood rot can be a problem in any home with older properties or unheated spaces. That being said, even the newest builds can still have moisture problems. With the proper knowledge about spotting the signs of wet and dry rotting on wood, you can have an expert company like Allied Damp solutions begin the process of damp-proofing your home. Our expert team are available for consultations and property assessments today.



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