Leeds Clark, Inc. specializes in historic preservation with approximately 85% of revenues generated from wood and steel window restoration. No other firm has been established longer or participated in more projects than Leeds Clark, Inc., as it relates to preservation of historic windows. Below is a diagram of the anatomy of a double-hung window and the various steps taken by Leeds Clark, Inc., during historic wood window restoration and replacement:

Wood Window Restoration & Replacement

• Pull the sashes from jambs and number according to the opening. Number should be stamped into top or side of each sash to prevent mix-up of sashes. Marker pen ink will disappear when sashes are chemically stripped.

• Transport sashes to off-site shop facility for chemical dipping in neutral PH stripper for the removal of paint and glazing compound in a controlled environment. Follow all local, state, and federal laws concerning disposal of any hazardous waste.

• Cut and install OSB plywood to cover window openings during restoration work. Plywood should be installed from interior to butt against outside stop of upper sash track and secured to jamb using 1 ¼" drywall screws. Plywood should be cut into 60/40 length allowing upper piece to overlap lower piece to the exterior. This will prevent water infiltration at joint. Since plywood is located at the outer portion of jamb, rain water will drain to outer portion of wood sill and not penetrate interior of building. The lower section can be removed for natural light and ventilation at any time. This type of installation also allows daily removal and re-securing during frame preparation and rehabilitation.

• Remove brick molding from outside perimeter of jambs and stamp according to opening number. Chemically strip (abate) paint from molding at an on-site staging area or off-site at shop facilities. Remove any caulking or paint from perimeter masonry. Remove and dispose of parting stop from existing jamb. Parting stop should be double-wrapped in poly plastic and secured with duct tape prior to disposal.

• Strip (abate) paint from window jambs (on site) using neutral PH based chemical paint stripper such as B-4 (Gemini Coatings) or equivalent. Care should be taken to mask and contain all removed materials for proper disposal. Do not gouge or damage wood during process. Wipe all prepared surfaces with denatured alcohol after paint removal.

• Replace any jamb components where structural stability is in question using old growth lumber matching species and graining. Material should be seasoned old growth salvaged wood free of knots and checks. Samples of material used should be provided to architect prior to use for approval. All replacement components should be primed and end-grain sealed prior to installation.

• Epoxy all checks and voids in material where minor defects or surface deterioration exists such as sills, stool, and lower jamb areas where joinery connects to sill. Product shall be suitable two component epoxy such as Advanced Repair Technologies (Flex-tec HV).

• Prime all bare wood with approved latex wood primer and apply two finish coats of paint as specified by Architect.

• Re-install salvaged or new brick molding made from salvaged long leaf yellow pine which has been pre-primed and sealed on end grain.

• Caulk all wood to wood joints using Dap "Alex-Plus" siliconized acrylic latex sealant and exterior surround joints of brick molding and sill to masonry using a one-part urethane sealant such as Sonneborn NP-1.

• Sashes should be chemically stripped in dip tanks for removal of paint and glazing putty. Chemicals should be a neutral PH stripper such as liquid B-7 (Gemini Coatings) or equivalent.

• Salvage all historic glass for re-use in sashes.

• Replace missing sash components or mill replacement sashes where designated using vertical grain old growth lumber that is called for in the specifications. Wood should be seasoned and have a moisture content not to exceed 11% and be free of any knots or checks. Match historic profile of sash.

• Sand all sashes prior to application of primer. Seal all end grain of sash components with Type II wood glue prior to priming all surfaces of sash.

• Re-install historic glass in sashes and replace any broken or missing glass with 1/8" clear (DSB) annealed glass. Back-glaze units using a clear siliconized acrylic sealant such as Dap "Alex-Plus" or equivalent. Apply push points to seat glass against sealant and allow time for curing. Glaze window sashes using Dap 33 oil based glazing compound or equivalent. Allow glazing putty to cure prior to application of finish paint over glazing. Glazing trim (using the same lumber that is called for in the specifications) can be used in place of the glazing compound.

• Clean salvaged hardware including pulleys, lifts and locks. Provide new sash hardware where missing, matching the original as close as possible. Submittals must be approved by architect prior to installation.

• Install sashes in finished jambs. It will have been determined prior to installation as to whether the sashes are to be fixed in a closed position, fully operable, or have a fixed upper and operable lower.

• Install salvaged and new hardware upon completion of sash installation.

• Clean glass prior to acceptance by architect or owner.

• Complete any punch items submitted by architect or owner.