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Project Report, Spring 2008:
My Vintage Green Cottage, Part 2 - Vintage Green Windows in a 1920s Style Second Unit

Last issue (see "My Vintage Green Cottage, Part 1") we began exploring the green features of an on-going second unit project by discussing its solar water heater. The small scale of this project (320 SF) and the availability of an earnest and underpaid (make that "volunteer!" - ed.) workforce make this house an ideal laboratory for green building. We want to spread the word that green building is not wed to a particular architectural style - it's good practice and practical for all homes, even those with vintage charm. Accordingly, we are detailing the various green features of this cottage in upcoming issues. In this issue, we'll discuss how salvaged single pane windows were retrofitted for energy efficiency - a convenient segue to "Deconstruction" and "Vintage Green Windows - Just Add Weatherstripping."

As you'll see in "Vintage Green Windows - Just Add Weatherstripping," the energy savings from double pane windows are mainly due to infiltration (air leakage) reduction. For this project we wanted an authentic vintage look at a lower cost, and we sought to match the existing primary residence's single pane original windows. After hunting around at various architectural salvage and deconstruction companies, we found 1920s Craftsman-style double-hung windows and two matching Craftsman-era stained glass windows. Knowing that infiltration is a major source of energy loss in older wooden windows, we were determined to address it in this project.

The solution, simply put, is weatherstripping. This, along with restoration and repainting, should hopefully provide another 80 years of good service from these windows. The weatherstripping products we used are from Pemko, but other suppliers exist, including Resource Conservation Technology.

Aside from the "standard" window restoration processes (disassembly, sash cord replacement, paint stripping, reglazing and repainting) it is necessary to cut slots around three sides of each window sash to accommodate the weatherstripping. For this project a table saw was used with a fence-height extension - a router is another option (there are also dedicated weatherstripping tools available.) After the sashes have been slotted, it's a matter of reassembling the window with weatherstripping around the perimeter of the sashes. There is weatherstripping available for the junction where the sashes meet, but we chose to rely on the sash lock to hold the sashes tight together.

Though it's not technically necessary to run the side weatherstripping the entire height of the window jamb, we feel it looks and operates better than with partial height pieces. The biggest difficult here is cutting an oval hole to fit around the sash cord pulley. We found that the best way to work with this weatherstripping is to use a 2x4 with a slot cut in it and the weatherstripping inserted, which exposes the back side of it and holds it steady. Working from the back side of the weatherstripping, a 1-1/8" bi-metal hole saw was used to cut a circular hole at the top and bottom of each sash pulley opening. The holes are then joined by cutting the weatherstripping with a cold chisel and tinsnips.

Sash Weatherstripping (Lower)

Sash Weatherstripping (Upper)

Once the outer (upper) sash is reinserted into the jamb, its side weatherstripping is stapled to the jamb. For zinc coated weatherstripping, we use galvanized staples. For bronze weatherstripping, we use stainless steel staples to reduce the chance of galvanic corrosion.

After the upper sash has been installed, the parting beads are reinserted and the lower (inner) sash is installed in a similar fashion, followed by the upper and lower horizontal weatherstripping.

If the weatherstripping has been installed correctly, the action of the windows is smooth and solid, and the infamous drafts are eliminated. Once the interior of the house is completed, we'll do a "blower door" test to verify the efficacy of our weatherstripping, but that's a topic for a future issue.

The green building topics "Deconstruction" and "Vintage Green Windows - Just Add Weatherstripping" will explore the issues and tradeoffs of double vs. single pane windows further, but for more "how to" information on wooden window restoration and weatherstripping, consult these references:

Bay Area companies which service old windows and fabricate replacement sashes include:

  • Wooden Window, 849 29th St., Oakland, 510-893-1157 or 415-357-1370
  • Novato Glass, 1020 Reichert Ave., Novato, 415-897-5117
  • DK Screens - Repairs or replaces wood screens for windows and doors (408) 294-2307
  • Hobel Woodworking - Wood sash windows, also furniture, cabinetry, architectural woodwork 414 Umbarger Road, Unit D, San Jose, CA 95111 - (408) 224-5000
  • Out Of The Woods - Custom wood sash windows & doors 138 E. Lake St., Salinas, CA 93901 - (831) 424-9049
  • Restoration Windows - Wooden window restoration - (415) 572-8700
  • Sheets Enterprises - General & Electrical contractor, specializes in doors and windows, custom cabinets and mill work 24 Sutter St., San Jose, CA 95110 - (408) 292-1132
  • The Old House General 707-579-1672 Window Restoration and Wood Window Balance Repair Services in Napa, Sonoma, Marin and Humbolt Counties Only. Window Restoration, Wood Sash Repair using Old Growth Materials, Window Balance Restoration, Wood Restoration and Conservation, Weatherstripping, Window Hardware, Glazing, Vintage and Period Glass, Paint Stripping and Removal.

Voice/Fax: 415-258-4501

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