Since 1993Class A contractorFully insured
Mon–Fri 8–5Serving Loudoun, Fairfax, Prince William & Arlington

Wood sash repair · Northern Virginia

Wood Window Sash Repair

A rotted wood window sash can often be repaired when enough sound wood remains. We harden and fill localized rot, splice new wood and rebuild damaged sections, then reglaze, prime and paint as required. Sash restoration is almost always done at our shop. When the damage is beyond repair, we can supply a replacement wood sash or assess a new window.

  • Repair first
  • No pressure
  • Free, itemized estimate
Older white-painted wood windows on a rustic log-and-board exterior
Original wood windows are worth keeping. Older painted wood windows like these can often be repaired in place of replacement, keeping the character of the house.

What to look for

Signs of wood rot in a window

Rot starts where water sits: the bottom rail of the sash, the corners where the rails and stiles meet, and the sill. Look for:

A painted wood window frame corner with worn paint and debris

Soft wood.

Press a screwdriver into the wood. Sound wood resists. Rotted wood gives, feels spongy or crumbles.
Worn paint lets water into the wood. The corner of a painted wood window where the paint has worn thin. Once water gets past the paint, the wood underneath starts to soften.

Peeling or blistered paint,

especially on the bottom rail and sill.

Cracked or missing glazing putty

around the glass.

Dark stains, gray wood or open joints

at the sash corners.

A sash that sticks, sags or rattles

because the joints have loosened.

Catching rot early keeps the repair small. A soft spot on one corner is a quick fix. A bottom rail that's rotted through is a bigger job.

Understand the cause

What causes wood window rot

Wood rots when it stays wet. On windows, that almost always traces back to a few causes:

  • Failed paint. Paint is the wood's weather barrier. Once it cracks and peels, rain soaks straight in.
  • Failed glazing. Old glazing putty dries, cracks and falls out, letting water run behind the glass and into the sash.
  • Condensation. Moisture on the inside of the glass runs down and sits on the bottom rail and sill.
  • Water that can't drain, from a flat sill, a clogged drip edge or gaps in the caulk around the frame.

Fixing the cause is part of the repair.

A painted wood window sill with a worn finish and debris
Sills take the most water. A wood window sill with its finish worn away. Sills catch rain and condensation, which is why they're one of the first places rot shows up.
Close-up of a casement window sill with worn wood
Surface wear on a sill is repairable. A casement window sill with worn wood along the edge. Catching wear like this before it turns soft keeps the repair small.
A wood-framed casement window opened inside a room
Casement sashes can be repaired too. A wood casement window, open. Rot repair works on casement sashes as well as double-hung sashes.

Restoration at our shop

How we repair a rotted sash

  1. Inspect and measure.

    We assess the sash, sill and surrounding frame and measure any glass that needs replacing.
  2. Plan the shop work.

    Sash restoration is almost always performed at our shop, where the work can be carried out in suitable conditions.
  3. Remove and rebuild damaged wood.

    We harden and fill localized rot, splice in new wood or rebuild damaged sections according to their condition.
  4. Reglaze and finish.

    We reglaze where needed, then prime and paint the repaired sash. Broken or fogged glass can be replaced as part of the work.
  5. Refit and check.

    We confirm the repair and refitting arrangements for the particular window and clean up the work debris.

Wood-sash drop-offs at our Sterling shop are available Monday–Friday, 8 am–5 pm. Contact us to discuss your sash and the work needed.

Our work

Wood window sash details

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Your options

Rotted window sills and replacement wood sashes

We repair localized sill damage and replace complete wood sills when necessary. We can also supply new wood sashes when the existing sash is beyond repair and the surrounding frame is serviceable. These options let us assess each affected window instead of automatically recommending replacement of every window in the house.

Common questions

Frequently asked questions

Can a rotted wood sash be repaired?

Yes, when sufficient sound wood remains. We harden and fill localized rot, splice new wood or rebuild damaged sections, and reglaze, prime and paint as needed. This work is almost always performed at our shop.

Can you replace a whole wood sill or just the sash?

Yes. We replace complete wood sills and can supply replacement wood sashes. We assess the surrounding frame before recommending repair, a new sash or a replacement window.

Do you reglaze wood windows?

Yes. We reglaze single-pane wood windows and can include replacement of broken or fogged glass in the assessed sash work.

Do you repair sash cords and weights?

We consider cord-and-weight repairs case by case after identifying the system and condition.

How do I know if my wood window is rotted?

Press a screwdriver into the bottom rail, the corners and the sill. Sound wood resists the tip. Rotted wood feels soft or spongy, or crumbles.

What causes window sills to rot?

Water that sits on the wood. Peeling paint, cracked glazing, condensation running off the glass and sills that don't drain all let water soak in.

Is it worth restoring old wood windows?

Often, yes. Restoring a few affected sashes keeps the original wood profiles and the look of the house and can cost less than replacing all the windows. When the surrounding frames are rotted beyond repair, or many windows have several serious problems, compare restoration and replacement costs.

How much does wood window sash repair cost?

The main factors are the extent of rot and whether the glass needs replacing. Repairing a few affected sashes can be more economical than replacing every window in the house. Every estimate is itemized. Send photos of the damage for a free estimate.

Do you repair Andersen and Pella wood windows?

Yes. We repair wood windows from Andersen, Pella, Marvin, Weather Shield and other brands.

Andersen, Pella, Marvin and Weather Shield are trademarks of their respective owners.

Explore your options

Wood sash repair from American Screen & Glass

American Screen & Glass has repaired wood windows throughout Northern Virginia since 1993. We serve all of Northern Virginia, including Fairfax County, Loudoun County, Arlington County, Alexandria and parts of Prince William County.

Related services:

Repair first. No pressure. Send photos of the soft spots for a free, itemized estimate.