by Bob Yapp

Sash Removal and Restoration.

1. Be sure window opening to be worked on has a weather stripped storm window in place to protect the house from the weather. If not protect with ½” OSB board.

2. Remove all interior sash stop, parting stop, metal weather stripping & both window sashes from the opening and mark for location that can survive paint removal. Discard parting stop and keep interior stop. If new interior stop is to be installed, discard original interior stop. Save all screw and washers removed from interior stop for later re-use.
3. Remove sash cords from sash weights & leave weights in jamb pocket.
4. Carefully remove sash pulleys from jamb & all hardware. Safely store all hardware & screws.
5. Remove all paint, putty & non-original obstructions from the 4 surfaces of the wood jambs, all surfaces of the window sashes and the interior stop. DO NOT dry scrape jambs, stops or sashes. All paint removal from sashes and interior stops must either take place off-site or in an area on the subject property, outside the main house. Use a wet paint removal product or mist the jambs with water before carbide scraping the jambs. Do not use heat that exceeds 600 degrees to remove paint. Over 600 degrees causes lead paint fumes that are toxic and can burn the original wood. Dispose of all paint debris according to local regulations.

   [editor's note: Follow all LEAD SAFE WORK PRACTICES guidelines when removing or repairing historic windows. If you are unsure whether your windows have lead based paint always assume they DO. According to the EPA and HUD guidelines, heat guns set to a temperature below 1100 degrees are an acceptable tool.]

6. Remove all remnants of glazing putty and glass. If the glass is of no historical importance, break it out, our over a large garbage can. This should remove most of the glazing putty as the glass is broken. If the glass is of historical importance attempted to save as much original glass as possible for re-installation later. The average glass loss under this scenario is about 20%.
7. Repair individual window sashes, as needed. Clamp and re-pin sagging rails and stiles & utilize architectural epoxies. If rotted wood exists on the interior side of a sash and it will be finished naturally, it should have new wood that matches the original spliced in. If a sash is disassembled, DO NOT glue-up the mortise and tenon joints when re-assembling. Pinning the joints with two, a hot-dipped, galvanized finish nails that have been cut off shorter than the thickness of the sash and driven into the mortise and tenon joint, at opposing angles, if sufficient as long as the joint is clamped snuggly before pinning. Provide new parting and interior stop as needed to closely match originals.
8. Repair jambs as needed with wood or exterior architectural epoxies. If the jamb is to be natural, use exterior grade fillers that will take a stain.
9. Lightly sand to 120 grit, all wood jambs, sills, interior stops & window sashes. Prime the faces, top& bottom edges of the window sashes only and do not prime or paint the sides of the sash. Prime all, including the glazing bed with alkyd oil based primer.

   [editor's note: Sanding window components that were covered with lead based paint WILL release lead dust. RenovateDSM and the Des Moines Rehabbers Club do not recommend sanding wood jambs, sills, or trim. Stripped and repaired sashes may be sanded off site, provided the sanding tool has a HEPA vacuum attachment and all lead safe work practices are followed, including containment and protective personal equipment.]

10. Install all original & new glass into bed of acrylic-latex, siliconized caulking & secure with adequate glazing points. All new glass is to be double strength. Install new glazing putty so that putty, at glass, is in the same sight plane as interior molding edge of sash. The glazing putty that is to be used is Glazol by UGL. This professional grade putty skins over quickly and can be primed and painted within 24 hours of installation.
11. Prime glazing putty with alkyd, oil based primer. See Specification #109 for priming requirements.
12. Apply two topcoats of the Acrylic Latex paint to sashes, jambs & sills. Specification #109 for priming requirements.
13. Stain, if needed, and apply three coats of White or Amber Shellac to interior sash surface, interior stop and parting stop to match original woodwork finish for that room.

Install Restored Sash.

1. Make all sash pulleys functional. If any are missing replace with new or salvaged pulleys that match in size & shape. Clean the surface of the pulleys, sash lifts & interior stop screws/washers without removing patina, do not buff unless you can establish that the original finish was polished. If any interior stop screws/washers are missing, provide new ones that are aged to match original patina.

2. Install sash pulleys with original or new, aged screws.
3. Install upper sashes with original or new metal weather stripping By Dorbin Metal Strip Company (see attached supplier list) & new parting stop. Parting stop to be attached with 3 brass screws that are counter sunk instead of nailed. This makes it easier to pull the top sash for cleaning the exterior side of the glass. Install the bottom sash in the same manner.
4. Install all sashes use nylon sash cord.
5. Install refinished interior sash stop with original screws and washers.
6. Clean up the area and dispose of all debris off-site.

The text on this page is posted/adapted with permission of Bob Yapp. All material on this page remains Bob Yapp's intellectual property and as such is copyrighted. Any use of this material is prohibited unless permission is specifically granted by Bob Yapp.

Bob Yapp was raised in Des Moines and was an early Sherman Hill rehabber and Sherman Hill Association Board member. Bob is a furniture maker, old house restorer, author, teacher, preservation consultant & hosted the national PBS series “About Your House with Bob Yapp”. Bob lives in Hannibal, Missouri and can be reached at yapperman@msn.com. More detailed information is available on Bob's website, www.bobyapp.com which will be up and running March 1, 2009