How to fix wood rot

Given an adequate supply of moisture and air, most species of timber will succumb to rot, which is actually a form of fungal attack. Rot can cause extensive, irreversible damage to timber, and by the time you see the physical evidence of spongy, damaged wood that falls apart in your hand, the problem is well established.

Attack of the spores
You can’t protect timber against airborne fungal spores and when wood starts to rot, the problem is usually well ahead of what you can actually see. What you can control is the availability of moisture, but the rotted timber needs to be cut out and replaced, or treated with poison or preservative.
Replacement can be expensive and difficult, especially in complex items of joinery, such as timber windows. It makes sense to try to stop the rot and repair what’s there. Earl’s Wood Hardener is a wood consolidant containing acrylic and urethane adhesives. These easily penetrate the timber and bind to the fibres to give them structural integrity and block the uptake of moisture, which causes the rot to become inactive. It’s suitable for rotting windows, cladding and weatherboards, outdoor furniture and fencing, but not for restoring structural timber.

How to fix a window frame

Gather your supplies
- Earl’s Wood Hardener
- Two-part filler such as Pro-build

Step 1
Scrape away flaky paint and remove the really loose timber. Let wood dry out completely; the hardener won’t penetrate moist timber. Ideally, wait until after a long dry spell or a few days of sun.

Step 2
If you’re ready but there’s a little morning surface dew on the timber, use a hair dryer or heat gun to evaporate the moisture from the wood.

Step 3

Drill a series of holes into sound timber beside and in rotted areas to help hardener penetrate deep into the wood. Make holes about 3mm in diameter to allow the air out as the fluid penetrates. Drill at a downward angle on vertical surfaces, and only drill part way into the timber so the fluid will be held inside the wood to penetrate deeply.

Step 4
Apply the hardener and then let it soak into and saturate the timber. The adhesives in the product will solidify around the fibres and stabilise the timber. For best results several applications of wood hardener may be needed. While the product does not contain toxic fungicides, the adhesives prevent water penetrating the timber and, without moisture, rot will not occur.

Step 5
Allow to dry and harden for 24 hours, then fill holes with a two-part filler to reshape the timber. Sand and prime, ready for painting.