How to Treat Woodworm, Dry Rot and Wet Rot

Woodworm, dry rot and wet rot can all seriously impact the structural integrity of your home. Conditions like this can even affect its value if you want to sell up.

If you suspect that your home is being menaced by these threats, immediate action is key. Once you notice the first signs of attack, it’s time to spring into gear, rectify and damage and get rid of its cause.

Timber is one of the central materials used for house building. A great deal of homes are timber-framed. In the bulk of houses, the floors, doors, roof framing, window frames and baseboards are all made of timber.

Since wood is everywhere in houses, any attacks on timber by woodworm, dry rot or wet rot should be viewed seriously. Unless checked rapidly, they can gravely weaken the stability of your building.

We will look first at what is behind these attacks on your timber then we’ll show you how to treat woodworm, dry rot and wet rot.


Woodworm is the collective name for a variety of wood-boring insects. Their larvae feed on timber.


There are 3 main types of this wood-boring beetle:

  • Common Furniture Beetle (Anobium puntatum)
  • House Longhorn (Hylotrupes bajulus)
  • Death Watch Beetle (Xestobium rufovillosum)

As the name suggests, the first of these is by far the most prevalent. The other two are far more selective. The house longhorn is only interested in the end grain of softwood. The death watch beetle will attack nothing but old hardwood. The common furniture beetle is not choosy and will happily devour any timber at all.

Not only does the common furniture beetle attack wood indiscriminately, it does the most damage. Most houses suffer from this insect encroaching to some extent.

While varieties of woodworm vary, the method of treatment remains constant.

Unfortunately, you only notice woodworm once some damage has been done.

The common furniture beetle lays its eggs in the cracks of unpolished wood. When the larvae emerge from the eggs, they tunnel into the wood. This is a process that lasts perhaps 3 years. The finale is the adult beetle coming out of the wood. It’s these exit holes that form the first signs of the presence of woodworm.

Dry Rot

Dry rot is a grievous form of timber attack.

Dry rot

It’s caused by a fungus (Merulius lacrymans) that spreads easily through porous materials. It lives on the moisture within the hollow parts and holes of the grain of timber.

This fungus will only develop when conditions are ideal. Dry rots thrive in damp and poorly-ventilated areas. Any hollow floors, cellars or gaps behind baseboards are perfect for the fungus to flourish.

When this fungus attacks the timber, it will become rather dry and crumbly.

Wet Rot

Another type of fungus growth, wet rot is nowhere near as difficult to pinpoint and deal with as dry rot.

Wet rot occurs when timber is in contact with wet or damp surroundings.

Wet rot

If wet rot is treated in a timely fashion, any damage can be kept to a strict minimum.

General Treatment of Woodworm, Dry Rot and Wet Rot

When it comes to dry rot and wet rot, the correct treatment is considerably different. It pays to be able to differentiate the two.

Dry rot breaks out in damp and still areas with inadequate ventilation.

Wet rot develops where timber has been in contact with the moisture created by leaking pipes, water tanks or where insufficient damp proofing has been carried out.

Dry rot is not often seen in newer houses due to improved techniques and superior damp proofing.

While both dry rot and wet rot are fungus attacks, with dry rot is it only caused by one particular type of fungus. The growths it produces look like sheets of silver-gray with patches of brighter colors, often bright yellow or lilac.

How To Treat Dry Rot

Follow these simple steps to kiss goodbye to the havoc wreaked by dry rot…

  • Make sure you remove all affected timber along with any timber within a 5-foot radius of the damaged area. Burn any rotted timber as it can harm sound wood
  • Hack away any plaster surrounding the damaged area of timber to a distance of around 3 feet. Use a hammer and bolster
  • Clean up all surfaces thoroughly with a wire brush. Pay close attention to surface cement, brickwork, pipes and any adjoining timber. Vacuum up any dust and remove it from the house
  • Apply 2 coats of a proprietary fungicide to all the surfaces you have brushed clean
  • Replace the removed timber with dry, well-seasoned timber
  • Coat the new timber with fungicide. Make certain to stand the ends in a bucket so that the fungicide can really soak into the end grain

Equally as important as treatment is remedying the situation that allowed the dry rot to develop in the first place…

Insert airbricks into the walls in order to give ventilation a boost. Check the damp proofing course for any defects. Using a chemical damp course is often the quickest fix.

How To Treat Wet Rot

Wet rot is a lot simpler to treat than dry rot.

  • Once you have taken care of the initial cause of dampness and the timbers nicely dried out, it might not even be necessary to cut away the affected spot. The rot itself is not infectious. Wet rot only spreads in wet conditions so once that’s reversed, the problem disappears
  • If the timber has been seriously damaged then you will need to remove and replace this area
  • Use a strong, pointed tool like a bradawl to test the extent of the impairment.  If you can push the bradawl right into the timber then the rot has severely weakened the timber’s sub-structure. This means the rotted part will need to be cut away and replaced. Treat the replacement timbers with fungicidal fluid as above for dry rot
  • Leave in place any timber that is not badly affected

How To Treat Woodworm

The inbuilt problem with woodworm, as outlined above, is that the attack is only apparent when it’s effectively too late…

The exit holes as the adult beetle leaves the timber let you know that at least one generation of woodworm have ravaged the wood.

  • In the event of a mild attack, you can use proprietary woodworm fluid in the way we will describe below
  • With severe damage and larger holes, you’ll have little choice but to cut out and remove the timber

We will now give you some more specific advice about treating these problem attacks in various areas of the house.

Woodworm in Furniture

Luckily, your furniture is not at risk from wet rot or dry rot.

The bad news is that furniture certainly is susceptible to woodworm.

Firstly, make sure you have the right type of woodworm fluid. Some solutions will damage polished surfaces.

Brush your selected woodworm fluid on all unpainted surfaces. Inject the fluid into any exit holes so it penetrates the wood deeply. Pay close attention to bottoms of furniture and bases of closets or cupboards.

When treating doors or shelves, be sure to dust properly before you start the treatment.

Leave all timber to dry naturally for a few days then wipe with a dry cloth.

Woodworm and Dry Rot in Mouldings

If your baseboards and picture rails come under attack from woodworm, just remove them, treat and replace.

Take the moulding from its fixing, coat the surface and end grain as well as any fixing plugs. As before, leave to dry and wipe away any unabsorbed fluid with a dry cloth.

Refix and repaint the moulding and you’re good to go.

With dry rot, you’ll need to remove and burn the timber.

Woodworm and Wet Rot in Doors and Windowsills

These timbers are particularly prone to wet rot as they are exposed to the elements.

Regularly paint the door sill to stop wet rot from occurring in the first place.

Treat with fungicide or woodworm fluid depending on the nature of the attack.

Damage to Structural Timbers

Whether it’s an outbreak of woodworm, wet rot or dry rot, any damage to structural timbers needs drastic action. It can be quite disrupting even trying to analyze the nature of the problem.

Wet rot here is perhaps the least troublesome. Weakened wood will need replacing while with a minor case of wet rot you can just strengthen the timber.

Ground floor timbers are most as risk.

With a full-blown case of woodworm, you’ll need to remove and replace any boards. Treat any lesser cases in situ.

With the threat of infection from dry rot, always remove and destroy any structural timbers to prevent this.

Damage to Floorboards

Dealing with damaged floorboards is straightforward: remove and replace them.

Treat any adjacent boards with the appropriate preservative even if they look sound.


We hope you have found this look at how to treat woodworm, dry rot and wet rot to be useful.

Please feel free to get in touch if you have any queries or feedback. We are always delighted to hear from our readers.

4 thoughts on “How to Treat Woodworm, Dry Rot and Wet Rot

  1. Obviously, rot is hazardous for the wood, but I’m curious whether it’s hazardous for the health of people as well. Can it make you sick? :/

  2. Hello

    Thanks for this nice article. I’d like to know whether manufacturers treat furniture from woodworms, wet rot, and dry rot before they sell it to people. Thanks again.



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