Historic Preservation - Technical Procedures
Applying A Water-Repellent Preservative To Wood
Developed For Hspg (Nps - Sero)
Wood And Plastics
Applying A Water-Repellent Preservative To Wood
A. American Building Restoration Products, Inc. www.abrp.com
B Wolman Manufacturing, Division of Rustoleum Corporation http://www.rustoleum.com/product-catalog/consumer-brands/wolman/
NOTE: SIMPLE WATER REPELLENTS (WR), BY THEMSELVES, DO NOT PROVIDE ADEQUATE PROTECTION AGAINST DECAY AND ULTRAVIOLET DEGRADATION AND ARE NOT TO BE USED AS THE SOLE FINISH.
Be cautious in choosing the correct product as it is easy to purchase a WP when what you really desire is a WRP (the subject of this Technical Procedure). Read the label carefully, as the appearance of the phrase ���������mildew resistant��������� on a water repellent does not mean the product is a preservative.
It is very important to be aware how different manufacturer���������s repellents react to being top-coated with paints of varying chemical compositions (latex/oil/alkyd/etc.). Be sure to fully investigate manufacturer���������s datasheets and application guidelines before moving forward with any work.
A. Utilize commercial water-repellent preservative such as
- American Building Restoration Products, Inc "X-100 Natural Seal" (oil base)
- Wolman Brand ���������F&P������ Finish And Preservative��������� (oil base)
- Wolman Brand ���������Woodlife������ Classic��������� (water base)
- or approved equal
B. Home-made preservative based on the USDA Forest Products Laboratory formula (see TP 0631001S for guidance on preparation).
C. Household detergent (NO AMMONIA)
D. Household Bleach:
1. Other chemical or common names include Sodium Hypochlorite (NaOCl); Bleaching solution; Laundry bleach (such as 5% Chlorine products ���������Clorox��������� or ���������Javex���������); Solution of chlorinated soda.
2. Potential Hazards: CORROSIVE TO FLESH.
3. Available from chemical supply house, grocery store or supermarket, hardware store or janitorial supply distributor.
E. Clean, clear water
1. Use natural ���������china bristle��������� bristle paint brushes for oil/alkyd preservatives. Precondition by soaking in raw linseed oil for 24 hours. Use nylon ���������synthetic bristle��������� bristle brushes for applying latex ���������water based��������� preservatives. Do not use the same brush for both types of stain.
2. For thin, runny stains, foam pad applicators can be used.
3. Stiff natural bristle scrub brushes.
A. Surface Preparation: The surface should be free of all loose fibers, dust and grease before application of a WRP.
3.02 ERECTION, INSTALLATION, APPLICATION
A. Use one of the proprietary products listed above. For warranty purposes this is often a more desirable decision.
Prepare the Water-Repellent Preservative (USDA Forest Products Laboratory formula, See 06310-01-S for guidance).
NOTE: Depending on the manufacturer, on a smooth surface 1 gallon of WRP can be estimated at a coverage of approximately 250 SF. On a rough surface it will cover only 100 to 150 SF.
B. Dipping is the most effective means of treatment, especially for the ends of wood members. Brushing to the point of refusal (total saturation), is the next best method of treatment.
1. For treated lumber, dip freshly cut surfaces before installation, 10 seconds to 3 minutes.
2. For untreated lumber, dip, brush or spray with preservative. Pay particular attention to end grain and joints.
3. For wood shingles, dip before installation, with a second coat brushed onto the surface after installation.
4. On fixed surfaces, use a minimum of two successive coats.
5. For pieces that are removable, soak for 10 seconds to 3 minutes.
C. Allow adequate time to dry before repainting so that paint will adhere properly. Always follow the manufacturer's instructions.
1. In general, if the surfaces have been brush treated, 48 hours at 70 degrees F. is generally sufficient drying time.
2. Longer drying times will be required if it gets colder than 70 degrees F. at any time during this drying period.
3. Wood that has been dipped for 10 seconds will need a minimum of one week of similar, ideal drying time.
4. If work is being done late in the year, and it is too cold in the evenings for any paint film to dry properly (above 50 degrees F overnight), only apply a WRP and wait until spring to prime and paint over it.
D. In addition to adequate drying times, some WR/WRP's must be allowed to weather before painting. Follow the manufacturer's instructions, as the weathering time can vary from six months to two years.
A. Caulking joints is an important part of surface preparation. You should generally caulk after a WR or WRP has been applied, bujt be sure to check the manufacturers specifications for both the preservative and the caulk to insure compatibility and attin maximum performance.