Painting Frames, Sills and Casing

Remove old panes & putty, cut & clean glass, putty & paint.
Site Admin
Posts: 166
Joined: Thu Aug 29, 2013 8:21 pm
Location: Portland, Maine, USA

Painting Frames, Sills and Casing

Postby johnleeke » Wed Apr 23, 2014 4:44 pm

(update: 7/12/16 added sash track paint removal video; 6/20/12)

Basic overall procedure to refurbish windows:
(excerpt from )

1. Remove sashes from frame, install temporary weather panel
2. Move sashes to onsite or remote workshop
3. Remove heavy paint buildup from frame and sill
4. Repair sills, paint sills and frames
5. De-glaze (remove glass) sashes, remove paint, cleanup
6. Mill out stock for replacement sash parts
7. Cut & fit stock for each sash repair
8. Repair wood of sashes
9. Re-glaze and paint sashes
10. Move sashes back to site and distribute to window locations
11. Re-install sashes in frame and tune up for proper operation

Step 3.a. Remove heavy paint buildup from frame and sill

Remove heavy paint buildup from the sash channels (aka tracks).

Video: Removing paint from the window's sash channel using the steam paint removal method. 5 min.

Step 4.b. Paint Sills and Frames is detailed here.

Painting Frames

The only part of the window frame that needs painting or other protective treatments is what is exposed to view and to the weather. With typical double-hung windows this is usually the sill and the sash channels.

Treating Sash Channels (or Tracks)

The channel includes the wide flat surface of the vertical frame jambs and the adjacent surfaces of the stops and parting beads.

There are three functions to serve when finishing the surfaces of the jamb and sash channels:

-- keep liquid water out of the wood
-- let water vapor pass out of the wood
-- a slippery surface for the sash to slide on

Generally, sash channels should be left without paint or other coatings so the sashes can slide freely. If there are paint or other coatings the sash is more likely to stick, especially as coatings of paint build up over the years.

To lubricate the bare wood of the channels, rub with solid wax (beeswax, or paraffin (candle wax)), or brush on a mixture of beeswax dissolved in turpentine, or paraffin dissolved in mineral spirits. The wax also acts as a water-repellent protecting the wood from water and deterioration when it is applied as a liquid. Some liquid water-repellent preservative products may be suitable if they leave a slippery, not tacky, surface.

The lower half of the outer sash channel can be painted if the upper sash is fixed and does not slide down into the track.

If the bare wood of the channels must be colored do it with a stain. Thin down oil-based paint with turpentine or mineral spirits creating a stain and brush it on, then wipe off most of the stain with a rag leaving just a little for the color. Allow to dry thoroughly before installing the sash. Do not use "latex" or acrylic paint, which can remain tacky, or "blocky," causing the sash to stick or jam.

Sash track colors.
One practice that was common from about 1850 to 1940 was to make the inner track match the interior finish scheme, and make the outer track match the exterior finish scheme, and this was described in at least one trades manual from the era.

My own 1899 wood-framed house in Portland, Maine, was like this on the first floor that had a natural shellac finish on the interior woodwork and the interior sash track was shellacked. The exterior of the house was painted gray, and the outer sash tracks on the first floor have a gray wash-coat. (Wash-coat is similar to what we would call a stain today.) On the second floor, where the interior woodwork was painted brown, both the inner and outer sash tracks have a gray wash-coat, an indication that there really were not strict standards for sash track colors.

Painting Sills and Exterior Casings

The following assumes the wood is bare, clean and all wood repairs are done.

This is a 4-step procedure, essentially following best practice for most exterior woodwork painting:

- Pre-Treat
- Prime, oil-based linseed oil (slow dry), or oil-based alkyd resin primer (slow dry); and seal joints
- First Top Coat, 100% acrylic house paint, or oil-based alkyd resin house paint
- Second Top Coat


Apply a penetrating pre-treatment to the bare wood. There are two types, 1. Paintable water-repellent preservative, 2. consolidating oil-resin. Paintable water-repellent is suitable for sound wood surfaces. (if waxy paraffin type (Forest Products Lab's WRP Recipe, Thompson's WaterSeal, or similar) apply to all surfaces, if sticky oil or resin type do not apply to the inner surfaces of the stops that the sash run on (the narrow strip where the face of the sash rubs on as it slides up and down). Consolidating oil-resin treatment is suitable for gray weathered wood surfaces or surfaces that are somewhat "soft" or more porous than perfectly sound wood. The traditional recipe for this treatment is linseed oil and turpentine. I no longer use linseed oil because it is susceptible to mold and fungus attack. I now use a 50%-50% mix of mineral spirits and oil-based alkyd resin varnish or a proprietary product (Flood's Penetrol, or similar) Just to confuse us all, there are some combination products that may be suitable. (California's Storm Stain Penetrating Wood Stabilizer, or similar) Water-based products of both types MAY be suitable, but all my experience and this recommendation is for oil-based products.

Penetrol (made by Flood) is an oil-based product made of mineral spirits and alkyd resin that penetrates deeply into the wood surface. The mineral spirits evaporate leaving behind the resin that cures and consolidates loose fibers at, and just beneath, the wood surface. After 24-48 hours the treated surface is dry to the touch and ready for light sanding or direct application of paint primer. Penetrol is like a light varnish or like an alkyd resin oil-based paint without the pigment.

Storm Stain (made by California Paints) is a waterborne product that contains zinc napthanate and a very tiny amount of resins. Zinc napthanate is a preservative that limits mold, mildew and fungus. The resins help hold the zinc napthanate in the wood, but there is not enough resin to consolidate loose fibers at the surface of the wood. Storm Stain does not penetrate as deeply as oil-based pre-treatments because it is waterborne. After 24-48 hours the water has evaporated , the wood surface is dry, slightly tacky to the touch and ready for paint primer.


Apply oil-base alkyd primer by hand brushing.
Allow primer to dry thoroughly.
Apply caulking or sealants to the sill/jamb joints, and possibly to the jamb/exterior-stop-joint if necessary.
Sand surface lightly if there are any whiskers or nibs sticking up.
If any bare wood was exposed during sanding, dust off and clean the surface with a tack rag or vacuum, and apply another coat of primer.
To get good quality primer spend at least $25-35/gallon.

Top Coats

Apply two top coats by hand brushing. Use any good top quality paint you like. I often use 100% acrylic house paint, or oil-based alkyd resin enamel or house paint. To get good quality paint spend at least $45-55/gallon.

More to come...

Post your questions or comments.

Posts: 8
Joined: Fri Aug 15, 2014 2:55 pm

Re: Painting Frames, Sills and Casing

Postby golazo » Fri Aug 15, 2014 6:15 pm

Hi John, in a thread in Historic Home Works on painting sashes you mentioned the following: "9b. Prime. Do not prime the side edges of the sash that run in the tracks. Prime all surfaces of the entire sash with oil-based alkyd resin primer, except side edges and face margins. Prime the glazing rabbets if the pre-treatment was a water-repellent preservative. Do not prime the glazing rabbets if the pre-treatment was an oil-resin. This rule-of-thumb can be modified within following guidelines:

-- No priming or painting of the top edge of the upper sash because it usually doesn't need protection from moisture when the sash are single-hung or if double hung and the top sash is not operated
-- The top edge of the upper sash does need paint protection from the weather if it is a casement window
-- The bottom edge of the lower sash may need painting, especially if it had extensive deterioration due to moisture on the sill.

My question is about that last comment in bold; I plan to do an epoxy method for filling checks as mentioned in one of your videos on the subject, however, I thought I would then leave the bottom of the stile and bottom rail of bottom sash bare wood. Are you suggesting instead that the bottom of the sash be painted as well? Does this mean you recommend the top side of the sash (which comes in contact with the top jambs) be painted as well? This is the first time I'd heard of this from all of the info. you've given; at this point I am ready to 1 coat pre-treat (with Flood's Penetrol based on your rec.) >then> 2 coats prime with good alkyd primer >then> glaze with Sarco M >then> finally, two coats of quality latex paint. I plan on a modern waterborne.

Site Admin
Posts: 166
Joined: Thu Aug 29, 2013 8:21 pm
Location: Portland, Maine, USA

Re: Painting Frames, Sills and Casing

Postby johnleeke » Mon Aug 25, 2014 11:07 pm

If the bottom edge of the bottom rail and the bottom ends of the stiles are in good condition, then paint is not usually needed. If they have deteriorated due to excessive moisture (and the source of that moisture is likely to continue) then they may need repairs and painting is probably a good idea to prevent future deterioration.

Posts: 12
Joined: Fri May 30, 2014 9:53 am

Re: Painting Frames, Sills and Casing

Postby patrick » Sat May 23, 2015 6:38 am

John, any concerns about the perm ratings for alkyd primers? I thought the recommendation for using acrylic latex paint as topcoat was to promote breathability and transmission of water vapor out of the wood. Wouldn't an alkyd primer with a perm rating of less than 1 act very much like an alkyd topcoat, i.e. lock water in the wood? And if leaving the sides bare allows for all the drying required, is there any reason then for not using an alkyd topcoat? Hope I was clear with the question. Many thanks in advance...

Site Admin
Posts: 166
Joined: Thu Aug 29, 2013 8:21 pm
Location: Portland, Maine, USA

Re: Painting Frames, Sills and Casing

Postby johnleeke » Mon May 25, 2015 7:46 pm

Patrick, no I'm not too concerned about the perm rating for oil-base alkyd primers when using acrylic paints. It's true that the primer will tend to limit the passage of water vapor, but that is far outweighed by the benefits it provides, such as good adhesion of the whole paint film system. The oil-based alkyd (or linseed oil) primers always give an advantage on old wood.

Posts: 1
Joined: Tue Feb 26, 2019 2:06 am
Interests: Historic.home.owner,preservation.enthusiast,

Re: Painting Frames, Sills and Casing

Postby scottd » Sun Mar 10, 2019 10:17 pm

John, I do not understand your classification of California's "Storm Stain" as a "water-bourne" product. I have used many of their formulas for years on my pine clapboard siding, garden furniture, windows, including my favorite, the 200-30 lindseed oil stain. All their Storm Stain line will recommend mineral spirits clean-up and are most definitely oil based. Please explain your water-borne concept; is there something I am missing here?
BTW, after not being able to find their 200-30 Storm Stain last time I needed to restock, I called the company in Massachusetts, and was told it was no longer available and that the replacement product was now called 100-40. slightly different formula, but still oil based.

Site Admin
Posts: 166
Joined: Thu Aug 29, 2013 8:21 pm
Location: Portland, Maine, USA

Temporary Stabilization of Sills

Postby johnleeke » Mon Jul 22, 2019 2:20 pm

One project had limited funding and requirements to make the windows safer and stabilize the windows for future work. The wood sills had weather checks and a heavy paint buildup that was alligatored and ready to start flaking off. There was no money or time to set up for lead-safe work, strip the sills, fill the checks and repaint. We applied one quick coat of an elastomeric sealant. No lead-safe setup was need since we did not disturb the old paint at all. The coating encapsulated the lead paint making the sills safer. (the product was made by Global Encasement, Inc.)
Five years later we returned for more work. The coating easily peeled off each sill in one or two sheets taking 95% of the old paint buildup with it, right down to bare wood. The coating had kept rain off the sills and the wood was very dry and with very little prep was ready for repairs and painting. As an expedient stabilization this coating was an unqualified success.
I've used this method a couple of times since then with the same results.

As always, test and develop in small areas before proceeding with the work to assure you will get the expected results.

Elastomeric Sealants

Global Encasement Inc. makes several types:

ZINSSER® Peel Stop® Clear Binding Primer ... ng-primer/

Mad Dog Primer
Some of the Mad Dog primers may work in this treatment, but have not been tested.

Return to “Glaze & Paint Sashes”

Who is online

Users browsing this forum: No registered users and 2 guests