Editorial & Photography By: Dr. Christopher Cooper
In a previous article we tackled one of the most demanding projects on an old house – replacing wooden sills. We will continue this series showing a step-by-step restoration of very early window architraves.
Exterior window and door architraves are vital clues to the style period of the building. The original 1837 portion of Blenheim Farms house has a flat exterior architrave 4 ½” by 1” in dimension, replete with a fine ¼” bead framing the inner edge of the architrave (see Image 1). A handsome brick mould wraps the outer edge to fill the gap of brick and architrave. The rear of this round brick mould has been flattened with a small filet2 to allow the moulding to sit flush with the flat architrave (see Image 2).
All of these dimensions and moulding techniques bespeak the Georgian period and are a fine example of the same. This humble moulding can be found throughout our country, replete with brick mould(s) on masonry buildings or devoid of the brick mould, with a simple square outer edge on frame buildings (see Image 3a & 3b).
Left Image 3a | Right Image 3b
Several problems plague the architraves on Blenheim Farms House. To begin with, the paint film has been allowed to deteriorate to a point where the oil binder in the paint has long since evaporated and what is left are simply the pigments and lead in the guise of hard little coloured nubs (see Image 4). The areas devoid of a paint film have been severely damaged by paper wasps. These ferocious insects will literally chew exposed cellulose (wood fiber) to craft their nests, leaving deep furrows in millwork (see Image 5).
Another issue these architraves have is with the storm windows that have been attached. Large screws have been driven through the face of the storms and into the architraves. This practice of screwing storms in place is not recommended: it not only damages the architrave, but it can also cause the owner dread and reluctance when it comes time to remove the storms in the Spring (see Image 6).
Damp in summer months can build up between the principal window and the storm, which will eventually cause the principal window or storm to rot. A practical solution to securing the storms to the windows will be investigated in future issues.
Our project architraves make up the exterior stop for the upper sash (as do many exterior architraves). They extend past the frame to allow the upper sash to ride up and down in a channel or slot formed by the exterior architrave (see Image 7 note: blocking installed at a later date). After probing (with a scratch awl) the outer face of the architraves, I have come to the conclusion that they are sound and devoid of any rot. During the sill replacement illustrated in the article (A Sill Replacement) on Old Home Living, I was able to inspect the back of the architraves with a small video camera endoscope to ensure no rot was present. If you suspect rot is evident through probing (not everybody has an endoscope in their tool chest) I would recommend the removal of the architrave from the frame instead of an “in-situ” repair.
We removed the brick mould to restore the entire face of the architrave and the brick mould, which is inaccessible at the union of the moulding and the brick. The process of removing the entire architrave from its frame is the same, as follows.
A small amount of pressure at the end of the brick mould will create a space in which to slip a wooden shim (see Image 8). Wooden shims are sacrificial soft tools and are not damaging to the millwork you are endeavoring to retain. Tapping the shim will open a space above and below the shim, allowing subsequent shims to be placed above or below.
Once the whole of the length is shimmed, start at the beginning and drive another shim behind the shims which are already in place. The idea is that you will be gently pulling the moulding away from its nailing position below (see Image 9).
Remove the shims once a space of approximately ¼” is created between the brick mould and the architrave. A hack saw blade and holder are used to cut the nail between this space. Do not use an electric reciprocating saw. It may be fast; however, it can also be damaging in the wrong hands. Slow and easy wins the race, with little or no damage!
Lift the moulding off the architrave (see Image 10) and number the pieces on the back of the moulding, left, right, etc. A quick scraping of the holes left by the screws which held the storm windows, is followed up with the application of a two-part epoxy filler (see Image 11). After the epoxy has cured and been shaped and sanded, a generous coat of boiled linseed oil is painted over the architraves and the brick mould (see Image 12). This not only revitalizes the wood but it will also soften and bind the old paint surface making it easier to remove when dry. We allowed the linseed oil to dry for 48 hours and employed an infrared paint stripper and a flat carbide scraper to remove the old paint finish (see Image 13a & 13b).
The beads required special attention. With the aid of a readily available paint scraper and a rotary tool fitted with a grinding attachment, I crafted an inexpensive (under $5.00) hand scraper to the profile of the bead mould with a left and right profile (see Image 14a & 14b) and removed the built-up paint, being careful not to gouge the underlying wood.
After all the paint was removed, wasp damage was brushed with a liquid epoxy, allowed to cure, and followed up with a paste epoxy to fill the deep furrows left by the wasps (see Image 15). Keep in mind, however, that much of the character of these hand-made mouldings is created by the subtle hollows and rises of hand-planing, I would not recommend over filling with epoxy or a filler. We want to keep the character, not mask it!
After all the epoxy has had time to cure and has been carefully hand sanded, a coat of oil- based primer is used to seal the mouldings. Never use latex primer (see Image 16). Two coats of 100% acrylic latex paint were applied and the brick mould was reinstalled (the original nails removed). The joint at the brick moulds and the architraves were caulked with a bead of paintable latex caulking, and the paint finish touched up. A high quality caulking to blend into the colour of the mortar was used to caulk the joint between the brick and the brick mouldings. And remember to use backer-rod if the space is over ¼”.
The finished architraves and replaced sill have been painted to fit the new paint scheme of the house – Soldier Blue. Once the sashes are restored they will be painted Barn Red (see finished project Image 17a b &c).
The application of linseed oil aids in the removal of original linseed oil based paints. The linseed oil also treats and revitalizes old timber. I add a couple of tablespoons full of borate per liter of linseed oil to protect the linseed oil in becoming a food source for insects and microbial creatures.
When we removed the mortar around the architraves and the brick mould we discovered the original colour. As you can see by the arrows above (17b) the paint we chose before the work began matches the original paint left behind. The painter’s sloppiness nearly 200 years ago is a great find for us today!