Preventing wood rot: keep your woodwork healthy

Wood rot is one of the most expensive forms of overdue maintenance, and it almost always starts out of sight. A hairline crack in the paint, an open joint at the sill or a sealant edge coming loose is enough to let water in. Especially in the Zaanstreek with its wooden houses and in the open polders around Oostzaan, where wind and rain have free rein, it pays to catch it early. That way you prevent a small repair from growing into a replacement frame.

1. How wood rot develops

Wood starts to rot when it stays damp for a long time. Fungi then break down the wood fibres, making the wood soft and brittle. An intact paint layer keeps water out, but as soon as there is a small crack, moisture creeps in. It struggles to get out again, because the paint on the outside prevents it from drying. So the wood stays wet inside while the outside still looks reasonable.

That is why wood rot is often further advanced than you think. A small patch of flaking paint can indicate that the wood underneath has been damp for some time. How to recognise the first signs is explained in detail under recognising wood rot in window frames.

2. The weak spots of your home

Water always seeks the lowest point and stays where it cannot drain away. The places where wood rot most often starts are:

• sills of doors and windows, where rainwater collects
• corner joints of frames, where the wood can move
• glazing beads and sealant joints around the glass
• fascias and bargeboards beneath a leaking gutter

With the typical Zaanse wooden houses, the wooden boards on the outside wall add to that. Overlapping boards have joints and end grain where moisture easily soaks in. How this plays out in the Zaanstreek can be read on the page about exterior painting in Zaandam.

3. What you can check yourself

You do not need to be a professional to spot wood rot early. Walk around your house once a year, ideally in spring. Look for cracks, flaking and discolouration in the paint, and gently press suspicious spots with your thumb or a screwdriver. If the wood feels soft or springy, something is wrong.

Keep the gutters clean too, so rainwater does not overflow down the fascias. Wash window frames now and then with lukewarm water and a mild cleaner: dirt holds moisture and makes paint age faster. If you want to keep track of this clearly, use a maintenance schedule for painting work.

4. Painting on time

The best protection against wood rot is a paint layer that stays intact. Exterior painting therefore needs a regular cycle, depending on the exposure, the type of wood and the paint. Woodwork facing south or west gets more sun and rain than woodwork on a sheltered north side and is therefore due more often. What a reasonable interval is can be read in how often exterior painting is needed.

If you wait too long, the job grows: instead of sanding and two coats of gloss, wood has to be repaired first. In the polders around Oostzaan, where the wind sweeps across the open land, paint wears faster than in a sheltered street. More on this under exterior painting in Oostzaan. Oranje Kwast works exclusively with premium brands such as Sigma, Sikkens and Wijzonol, which are made to protect for years.

5. When it goes wrong anyway

If you discover wood rot, do not wait until the next paint job. The sooner it is tackled, the smaller the repair. With early-stage rot, the affected wood is milled away down to sound timber, treated and filled with a two-component wood filler. Primer and topcoat follow, so the repaired part is just as well protected as the rest.

If a large part of the frame is affected, a new piece of wood can be spliced in. A national market indication of the costs can be found under what wood rot repair costs. At Oranje Kwast, wood rot repair is priced to measure after the free advice session, once our painter has inspected the damage himself. The price depends on the extent and is excluding VAT, with a minimum of €300 per job.

In practice this topic belongs with wood rot and window frame repair and exterior painting. There you can read about the approach and the options, or request a free, no-obligation quote straight away.

Further reading: Exterior painting in Purmerend, How much does a painter cost per hour?, VAT on painting work: 9% or 21%?.

Frequently asked questions