Author: Bob Yapp
Title of Treatment: Dutchman Stile & Rail Repairs- Test Window #W2
Class of Treatment: [ ] Maintain, [ ] Stabilize, [ x] Repair, [ ] Upgrade, [ ] Exception
Type of Treatment: [ ] Traditional, [x] Modern
Condition to be Treated:
The sashes were approximately 1" narrower in width than the jamb they came out of. The jambs were out of square from settling of the building over time.
In order for the upper and lower sashes to work properly in the existing jamb, new wood needed to be added to each side of each sash. Added wood pieces are jointed to the sash tightly, sash rope ploughs match the original. This was all done in the field with no shop equipment.
Typical Procedure :
1. Determined the sashes were too narrow to work properly in the existing jamb by 1". The sashes were constructed pine. Determined that the structure had settled and so the bottom and head of the jamb were slightly out of square with no immediate way to square the jamb.
2. Measured the thickness of the sash and determined they were 1-3/8" thick.
3. Cut one strip of salvaged pine to 1-1/2" wide x height of the sashes plus 1/4" x 3" thick. Jointed one edge square and flat. Cut a 1/2" strip off the jointed edge. Repeated on the same piece of wood three more times to create four pieces.
4. Filled the sash cord ploughs and knot hole with dutchman method and salvaged pine, hand planed flush with the sides of all four sashes.
5. Using an electric hand plane, jointed the sides of each sash flat and square to the face of the sashes.
6. Using a waterproof, one part, polymer glue the jointed strips were glued and clamped to each side of both sashes and allowed to cure overnight.
7. Using an electric hand plane, jointed the sides of each sash flat and square to the face of the sashes so the added pine strips on each side measured 7/16" thick which left each sash with a standard 1/8" in the side to side play between sashes and jamb.
8. Using a block plane, trimmed the added strips flush with the face of each sash. Using a dovetail saw cut the added strips flush with the bottom and top of each stile.
9. Using a router with a fence guide and a 1/2" straight, carbide router bit, re-ploughed the sash cord grooves to match the width and depth of the original grooves.
10. Using a Forster bit, re-drill the sash cord knot hole to match original knot hole in depth and upward angle.
11. Using salvaged pine, added wood to the bottom rail of the lower sash and top rail of the upper sash to take make up for out of square jambs. The pieces were added the same way as the add-ons for the stiles. One difference is that the pine rail add-ons were only glued to the rails and not glued to the ends of the stiles on either sash to allow for contraction and expansion between the stiles and rails.
12. Fit the sashes into the openings with 1/8" play side-to-side & up and down with the meeting/check rails coming together properly.
• Salvaged pine stock
• Waterproof, one part, polymer glue
Quality of Results:
Tightly jointed add-on wood pieces that cannot be detected when primed and painted. The rail add-ons are not glued to the ends of the stiles. Sash rope ploughs are clean and uniform as well as the knot hole drilling. The angle cuts on the rails done to compensate for the out of square jambs fit snugly to the bottom and head of the jamb.
Add-on wood pieces are jointed well but attached with galvanized finish nails instead of glued only. Some gaps in the jointing are seen and filled with either boiled linseed based glazing putty or architectural grade epoxy. The rail add-ons are not glued to the ends of the stiles. Sash rope ploughs are adequate but a bit rough as well as the knot hole drilling. The angle cuts to compensate for the out of square jambs create a visual where the sashes appear to fit properly in the jambs.
Add-on wood strips are sloppily attached with non-waterproof glue with lots of gaps. The rail add-ons are sloppily attached and fastened to the ends of the stiles. Sashes appear to not fit because there there are gaps.
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