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Wood Rot: How To Detect And Diagnose Dry Rot And Wet Rot

Detect And Diagnose Dry Rot And Wet Rot
Wood rot is the cancer of the housing industry. It can creep in silently and throw your infrastructure into disarray. When left untreated, it can erode load-bearing frames and leave structural defects for homeowners to contend with. The consequences of untreated wood rot can be costly and cause headaches. Not least, rotting wood attracts allergens which, in turn, can worsen asthma, rhinitis, and skin conditions. At its worse, rotting wood rolls out the red carpet for Stachybotrys, commonly as black mould, which can affect your health. The good news is, in many cases it is possible to detect, diagnose and treat wood rot and this article delves into how to do that.

What Exactly Is Wood Rot?

Wood rot happens when fungi proliferate and consume wood. While every fungus has its own unique effects, there are two main types of wood rot: dry rot and wet rot. Here, we’ll explore the differences between dry rot and wet rot.

Dry Rot

If you’re asking yourself, ‘What is dry rot?’ look no further. Dry rot fungus is the most hazardous rot of the bunch. It is caused by a fungus called serpula lacrymans— a species that can grow in environments with only 20% moisture content. Because it doesn’t need much moisture to proliferate, it’s easy to miss in its early stages. It targets the components that give wood its robustness, so its long-term effects are irreversible. When dry rot strikes, it can strike hard, at it’s worst being known to spread across a building’s surfaces and penetrating every room. Left untreated dry rot can cause your beams can degrade, ultimately causing your entire building to collapse.

Wet Rot

Wet rot is the most common form of fungal decay. There are several kinds of fungus behind it, but coniophora puteana (cellar fungus) is the most frequent offender. It thrives in untreated wood that has a moisture content of between 30 and 50%. It tends to be localised before it matures and it doesn’t grow into your masonry, so early manifestations are easy to treat. Once wet rot has passed its initial stage, though, it causes serious structural problems, so this isn’t a problem to tag onto the end of your to-do list. Left to thrive, fungi will attack your load-bearing structures, so they need an urgent approach. Address a wet rot infestation early and you will eradicate it without complications.


Detecting wood rot involves knowing what to look for and, importantly, what to smell for. If you’re not sure, call in the experts to help you detect a problem. An expert nose will track down wood rot long before it becomes visible, just from the smell.

How to Detect Dry Rot

‘What does dry rot look like?’ is a common question for property owners. Dry rot is often called ‘brown rot’ due to its dark, earthy hue.

What to look for: Initially, dry rot makes itself known through large splits in your wooden structures. It evolves into a subtle white pattern before blossoming. Once fully grown, dry rot has a soft, fleshy body with yellow, orange, and lilac elements. Its spores look like red dust. Initially, dry rot wood decays in concentrated patches, but it ultimately develops a large mushroom-like body. On walls and masonry, dry rot develops as a white, chalky texture that evolves into a more severe cuboidal effect. A late-stage infestation mars the texture of your paint, eventually causing your wall to crumble.

What to smell for: Dry rot smells like soil—an odour that grows more intense as it spreads. You’ll also detect a musty, damp scent.
Early signs of infestation include:
  • A cubical fracture along the grain of your timber
  • Wood shrinkage
  • A musty scent that resembles soil
  • Discolouration, darkening
  • Cracking paint that crumbles under light pressure.
Dry rot doesn’t need much moisture, so it can be difficult to detect during the early stages of its lifecycle. If you know what to look for, however, you’ll catch it in time to correct it. At the first sign of wood shrinkage and darkening, you should get a comprehensive assessment of moisture intrusion. If you eliminate rising damp and leaks soon enough, damage reversal will be cheap and easy. Secondary measures will protect against regrowth.

How to Detect Wet Rot

Wet rot can proliferate in damp, dark places like basements, crawl spaces, and attics.

What to look for: You can spot wet rot early by its dark brown stain. You might also notice longitudinal cracks and a chalky surface. As the fungus germinates, it darkens and grows, ultimately giving your wood a crumbling texture. Paint can disguise wet rot, so pay attention to any cracks or caving in your coatings.

What to smell for: Wet rot gives off a damp, musty smell.

Early signs of infestation include:
  • Darkened wood with a spongy texture
  • Cracks that crumble under light pressure
  • White, cotton-textured layers that yellow in direct sunlight
  • Shrunken timber
  • A musty scent.

Treatment Options

As with any home treatment solution, the appropriate treatment and cost to treat will depend on the scale and severity of the problem. Treatment options differ depending on whether you have dry rot or wet rot. Read on to explore treatment options for both.

How To Treat Dry Rot

Contrary to what its name suggests, dry rot cannot grow without moisture, so the first step to eradication is finding the cause of moisture intrusion, but a few other steps are equally important:

1) Remove the Affected Wood

If your dry rot has penetrated the surface of your timber, it’s best to remove it entirely. This is a delicate process, so it’s best handled by a professional.

2) Treat Your New Timber

Once you’ve eradicated your rot, you’ll need to take preventative action against future problems. Applying a fungicide as your wood dries will help it to penetrate the surface.

3) Kill Existing Fungus

If your wood hasn’t lost its structure yet, a simple borate treatment might clear your infestation without requiring structural changes. Spraying it across your infected wood is an efficient early cure. Glycol is another low-toxin treatment that won’t damage your timber.

4) Fix Water Intrusion

A wood treatment can be a powerful fungicidal aide, but without a cure for your moisture intrusion, your effects won’t last. You’ll need to repair leaks and rising damp. That’s best handled by a professional who can also advise on any insulation and structural repairs that might be required.

How to Treat Wet Rot

Treating wet rot as a localised problem will help prevent any repeat infestations in the future.

1) Find and Eliminate the Cause

Wet rot is usually caused by roof defects, plumbing leakage, blocked gutters, and even failing insulation. A wood rot pro will also fix rising damp and condensation so that you never have to think of fungal infestations again.

2) Kill Existing Fungus

If you’ve caught your wet rot early enough, it might only need a chemical cure. A fungicide treatment is a pocket-friendly option.

3) Remove and Replace Affected Timber

Wood is a porous substance, so it’s difficult to eradicate rot without removing the entire structure. Wet rot also wears away the strength of your wood, so it may not be fit for its role anymore.

4) Isolate the Moisture Source

If you’re short on funds, you might get away with isolating your wet rot from your moisture source before treating it with a fungicide. This is far from a comprehensive cure, though, so you’ll need to watch the area closely in the coming months.

We’re Experts At Treating Dry Rot And Wet Rot

Wood rot is a demanding problem that requires a holistic solution. At Dower Datech, we use our specialist knowledge of damp and timber to treat wood rot from every angle. We address it right where it begins: the point of your water intrusion. Once we’ve eliminated the cause, we perform preventative treatments so that you can leave rot where it belongs: The past. Get your free quote today.

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