How do you maintain wooden doors and windows for maximum lifespan?
Tips & maintenance · Maintenance
MaintenanceMaintaining wooden doors and windows
Wood rot in a window almost always starts in the same three places. If you know them, you can keep a window frame going for decades with a few hours' work a year.
- Bottom sill first
- Sealant joints are the weak spot
- Touch up before it is bare
Where it always starts
Rot develops where water sits or quietly gets in. With windows and doors, those are almost always the same places.
The bottom sill is number one. All the water runs there, and it stands still when the drainage is blocked or too flat. Look especially at the corners, where the sill meets the stile: that is a joint that cracks open and lets water through.
Number two is the sealant joints around the glass. Sealant ages, shrinks and comes loose, and the water that then runs behind it cannot get out again. A window can look perfectly fine from outside while it is already soft under the glazing bead.
Number three is the bottom edge of a door: the one surface almost nobody paints, because you have to take the door off its hinges to do it. Untreated wood at the bottom of an exterior door soaks up moisture like a sponge — and that is exactly where you see nothing of it.
Push a screwdriver or an awl into the wood of the bottom sill and the corners. If it goes in a few millimetres without resistance, there is already decay under the paint. Do this every spring at five points per window — it takes two minutes.
- Inspection
- every spring, after the winter
- Most vulnerable
- bottom sill, corner joints, sealant joints
- Door
- paint the bottom edge too at every recoat
- Touching up
- as soon as the coating turns dull or shows hairline cracks
- Full repaint
- sheltered: every seven to ten years
- Facing south and west
- more often: every three to four years
- Hinges and locks
- lubricate and tighten every year
To be fair: maintaining exterior joinery is work you only notice when you do not do it. That is exactly why it gets put off until the paint comes loose — and by then touching up is no longer an option; it means sanding back completely or having it repaired. The bill for three years of delay is many times the effort you saved.
The year round
| When | What | Why |
|---|---|---|
| Spring | check everything: sills, corners, sealant joints | the damage has happened over the winter |
| Spring | probe test at the vulnerable points | decay sits under the coating before you see it |
| Spring | clean with mild soap | dirt holds moisture against the wood |
| Summer | touch up and paint | dry weather, and the coating cures well |
| Autumn | lubricate hinges, tighten locks | before the season when everything sticks |
| Autumn | clear the drainage | blocked sills let water stand |
| Winter | wipe off condensation | persistent condensation on the bottom sill is damage in the making |
In pictures · Touching up locally
Schematic drawing.
Touching up locally
- Remove loose paintScrape off whatever is coming loose, until the remaining coating is firmly attached everywhere. Whatever you leave will be back next year.
- Assess what lies underneathIf the wood is soft, paint is no longer enough. Cut away the affected part down to sound wood.
- FillSmall holes with a two-component wood repair filler, slightly overfilled because it shrinks. Large or load-bearing parts you have a joiner splice in with new wood.
- Sand and remove the dustSand flat and feather the edges of the old coating, so the transition does not stay visible.
- PrimeAlways prime bare wood, and the end grain twice — that is where the wood absorbs the most.
- Two top coatsThin, with a light sanding in between. And on a window: take the sealant joint a few millimetres onto the glass, so no water can get behind it.
What makes a wooden front door secure
Mass in the leaf
A solid door is considerably harder to force than a door with a light infill. On a front door, that is no luxury.
The lock and the strike plate
A good lock in a weak strike plate is not a good lock. The strike plate screws must go through the frame stile and grip the masonry.
Multi-point locking
A lock that bolts at three points spreads the force over the full height of the door. That is the most worthwhile improvement to an existing door.
Glass in the door
Laminated safety glass does not break out. Ordinary glass next to a cylinder is an invitation.
Hinges on the inside
If the hinges are on the outside, use hinge bolts or security pins so the door cannot be lifted off its hinges.
Maintenance is security
Rotten wood around a strike plate stops nothing, however good the lock is.
Frequently asked questions about maintaining doors and windows
How often should I paint wooden windows?
A full repaint every seven to ten years for sheltered joinery, every three to four years facing south and west. Touch up every year, as soon as you see hairline cracks.
Where does wood rot usually start?
On the bottom sill, in the corner joints between sill and stile, and behind sealant joints around the glass that have come loose. On a door: at the bottom edge.
How do I know if there is rot under the paint?
Probe the vulnerable points with a screwdriver. If it goes into the wood without resistance, there is decay under the coating.
Can I touch up locally or does everything have to come off?
As long as the surrounding wood is hard and the old coating is firmly attached, you can touch up locally. If the coating comes loose over large areas, sanding back is the only way.
Does the bottom edge of a door need painting too?
Yes, and it is almost always skipped because you have to take the door off its hinges. Untreated wood at the bottom of an exterior door soaks up moisture and rots from below.
What do I do about a door that sticks in winter?
Wait first: wood swells with moisture and often shrinks back by itself. If you plane it down in winter, you will have a gap in summer.
More maintenance
Decking, furniture and façades each need their own rhythm. It is all together in the tips section.
Have a question about your project? Just ask — we're happy to help.
Photos via Wikimedia Commons: Old paint being scraped off a wooden window frame — David E. Lucas, Public domain · Wooden workshop window with peeling paint on stiles and glazing bars — Roman Eisele, CC BY-SA 4.0
The Wood Guide
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- Maintaining a wooden worktop
- Giving your picnic table a makeover
- Maintaining wooden decking
- Maintaining a wooden pergola
- Maintaining a wooden house
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