Restoring Wood Window Sash and Frames

PART 1–GENERAL

1.01 SUMMARY

1. This procedure includes guidance on restoring the appearance of wood window sash and frames and preserving the wood. This includes removing the existing paint by hand, removing deteriorated glazing compound, treating weathered wood surfaces with wood preservative, reglazing as needed, priming and repainting.
2. The choice to fully restore wood windows can be an expensive investment, but the choice will likely reduce future maintenance costs and extend the life of the original windows.
3. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:
   1. Safety Precautions
   2. Historic Structures Precautions
   3. Submittals
   4. Quality Assurance
   5. Delivery, Storage and Handling
   6. Project/Site Conditions
   7. Sequencing and Scheduling
   8. General Protection (Surface and Surrounding)

These guidelines should be reviewed prior to performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO).

PART 2–PRODUCTS

2.01 MANUFACTURERS

1. Sarco Putty Company
2. The Sherwin Williams Co.
3. Benjamin Moore

2.02 MATERIALS

NOTE:  As the state of coatings technology is in a constant state of flux, it is vital that proper research into product manufacturers be made. What used to be viewed to as the individual components primer and stain are now referred to as a coating system and are usually specified together for reasons concerning performance. We must adhere to a certain set of guides and carefully follow instructions to get the best coating system performance and maintain the manufacturer’s warranty. Therefore, it has become vitally important on special portions of a project to utilize products which are found within the catalog of a single manufacturer, allowing us to attain traceable and warrantable results.  In any case, we must understand the existing coatings on the surface to be refinished. If a surface is treated as if it was coated with varnish and it turns out to be shellac, polyurethane, or a natural rubbed wax finish, damage that could have been avoided may occur. Extreme caution is advised, and testing on hidden areas of a finished surface is advised.  As time goes on and the materials used on our projects change because of scientific studies, it is important to realize that we once thought lead, mercury, PCB’s and asbestos were safe products for everyday use. It is possible that some chemical we use today might be placed in the category of less-than-desirable materials in the future. When considering any coating project, it is incumbent upon the planner of the project to make sure they are fully aware of the history of previous materials used on a particular surface, understand the properties of adhesion and reactivity that may be exhibited between differing chemical compounds involved, and be prepared to fully record the coating materials they choose to use in the future. An area that is protected, such as a painted space behind a baseboard or a piece of trim where the original coatings might be seen in the future, should be carefully protected, recorded and remain undisturbed so that those layers can be studied in the future when new technology might lead to a better understanding of its qualities.

1. 80 to 120 grit sandpaper
2. Primer chosen for compatibility with the coating system (see introductory paragraphs to this section, above). The individual manufacturer will specify coating thicknesses, drying times under particular environmental conditions (temperature, humidity, direct sunlight, etc), and these details must be adhered to without fail.
3. Pure steam-distilled turpentine. For the usage specified below (E), turpentine is preferred over mineral spirits, despite its higher cost.
4. Boiled Linseed Oil. (This is a prepared product and does not need to be heated in the field). Users are cautioned that most latex-based products in use today will not perform well when they come in contact with fresh Linseed Oil. Utilize this product only when using more traditional coatings such as Alkyd-or thinner-based primers and paints, and always adhere to the manufacturer’s guidelines. Allow sufficient drying time before applying any coating to a surface treated with Linseed Oil.
5. Wood Preservative: A mixed solution consisting of 60% boiled linseed oil and 40% turpentine. NOTE: WITH WOOD THAT IS VISIBLY DRYED-OUT AND DISPLAYS OPEN SPLITS IN ITS SURFACE, A GREATER PERCENTAGE OF LINSEED OIL IS ADVISABLE (such as 70% Linseed, 30% Turpentine).
6. Caulking Compound (a durable, flexible caulk that bonds well with the chosen coating system and the components it will come in contact with, such as DAP RELY-ON Latex Caulk).
7. Glazing Compound such as “Sarco Multi-Glaze Type M Glazing Compound”, or approved equal.
8. Top coat (paint) chosen for compatibility with the desired coating system.

2.03 EQUIPMENT

1. Hand-held sheet Orbital Sanders (NO ROTARY DISK SANDERS or BELT SANDERS)
2. Stiff bristle brushes
3. Paint brushes
4. Putty knife
5. Triangular scraper
6. Appropriate personal protective equipment such as a NIOSH /OSHA rated dust mask certified for use with the materials present, gloves, eye protection, etc.

PART 3–EXECUTION

3.01 EXAMINATION

1. Verification of Conditions: Determine the type of wood used and understand its properties. Pine for instance is much softer than oak. Therefore, special care should be taken on the pine elements so as not to damage or obscure any detail.

3.02 ERECTION, INSTALLATION, APPLICATION

1. Remove paint from sash, frame, and sill by hand.
   1. Carefully sand the surface by hand using 80 to 120 grit sandpaper. Hand-held orbital sanders may be used on large, flat surfaces, but disk or belt-sanders should be avoided. Follow the grain of the wood, and be sure not to remove details or profiles on edging. NOTE: THIS EQUIPMENT SHOULD BE USED BY EXPERIENCED OPERATORS ONLY. For alternative methods in removing paint from wood features, see 06400-07-R and 06400-09-R.
      CAUTION: PAINT ON OLDER SURFACES MAY CONTAIN LEAD. FOLLOW EPA REGULATIONS AND SAFETY GUIDELINES INCLUDING THOSE REQUIRED FOR THE IDENTIFICATION, REMOVAL AND DISPOSAL OF LEAD-BASED PAINT.
   2. Reset all exposed nail heads and treat with a rust- inhibiting primer that is compatible with the chosen coating system. If utilizing an Alkyd-based primer, the product Penatrol may be added to aid in preventing the oxidation of old nail heads.
2. Remove deteriorated glazing compound and glazing.
   CAUTION: PUTTY ON OLDER SURFACES MAY CONTAIN LEAD OR ASBESTOS. FOLLOW EPA REGULATIONS AND SAFETY GUIDELINES INCLUDING THOSE REQUIRED FOR THE IDENTIFICATION, REMOVAL AND DISPOSAL OF THESE MATERIALS.
3. Brush apply the chosen, compatible wood preservative to all bare wood surfaces.
4. Caulk seam cracks and crevices in the surface with the caulking compound. Depending on the caulk chosen, time may have to be allowed to allow for preservative drying time.
5. Sand smooth the transitions between muntin/mullion and any original glazing that remains.
6. Replace glazing and apply the glazing compound smooth and evenly to the surface.
7. Apply final coats of paint to match the desired color and thickness. If glazing compound is exposed it should also be coated once it has dried.

END