discolored decks

EIVEN WHEN coated with the best Llrof protective finishes, wood decks will eventually succumb to the ravages of weathering and need to be refinished. Proper cleaning and restoration is an essential first step in refinishing decks.

The sources of discoloration of wood decks include:

(1) dirt and other foreign materials such as tree sap, bird droppings, grease, etc.;

(2) fungi discolorations from mildew, mold, decay and sapstain growth;

(3) algae, moss and lichen growth;

(4) nail and other iron stains;

(5) tannins and other extractives from the wood;

(6) graying of the wood due to surface decomposition by sunlight and moisturel cleansers containing ammonia since the resulting chemical reaction can form a potentially dangerous gas.

(7) fading/decomposition of weathered coatings.

In addition to being unsightly, these discolorations and the agents that cause them can significantly interfere with the performance of subsequently applied coatings. So, their removal is important from a performance as well as an aesthetic standpoint.

Until about 10 years ago there were few, if any, deck restorers on the market. Most coatings manufacturers recommended that decks and other exposed wood surfaces be cleaned before refinishing. The usual recommended cleaners were household products such as detergents for dirt removal and liquid bleach for mildew removal.

In the last decade, products began appearing that were specifically designed to clean and restore weathered wood surfaces such as decks and siding. Today, there are three general types of deck cleaners and restorers available: chlorine bleaches, oxygen bleaches, and oxalic acid-based formulas.

When

Used On

wood decks, chlorine-based bleached products can do more harm than good

Household cleaners and bleaches can be effective to some extent but they have their limitations. Also, since they are not usually designed for deck cleaning applications, they can present some handling problems to do-it-yourselfers and contractors. For example, liquid household bleach should not be mixed or used directly with ammonia or anv detersents or

Chlorine-based bleaches commonly incorporate sodium hypochlorite, calcium hypochlorite (both used in laundry detergents), or dichloroisocyanurate (a swimming pool additive). These chemicals are effective against mildew, but do little to remove dirt or other surface deposits (which is why bleach alone does not get clothes clean). When used on wood decks, chlorine-based bleached products can do more harm than good. They can result in the wood having a whitish, unnatural tone due to the bleaching out of natural components or a fuzzing of the wood's surface due to the loosening of small fibers during the cleaning process. Moreover, if not rinsed properly, the chlorine salt residues can result in sunlight prematurely graying the wood.

Oxygen-type bleaches are usually based on disodium peroxydicarbonate, commonly known as sodium percarbonate, a powder present in some color-safe fabric bleaches. When added to water, it forms hydrogen peroxide-a common oxygen bleach-and sodium carbonate (soda ash). Hydrogen peroxide is commonly used as a disinfectant and a stripper for hair coloring. On wood, it is effective in removing mildew stains and the weathered gray residue from ultraviolet (sunlight) degradation. The sodium carbonate acts as a builtin detergent removing dirt and other deposits. Sodium percarbonate-based cleaners, therefore, are effective in removing dirt, mildew and weathered gray residues. Once treated, the wood returns to its original natural appearance.

Certain wood species such as cedar and redwood contain natural reddish brown resins known as tannins. Water can extract these resins from within the wood and deposit them on the surface, leaving brown or black discolorations. Tannins can also react with iron present in fasteners or nails, resulting in blue-black stains. Neither chlorine nor oxygen bleaches are effective against tannin or iron stains. Oxalic acid, on the other hand, solubilizes tannins and iron stains and renders them colorless.

Thus, oxalic acid-based products are used on redwood or cedar, even though they are not as effective against mildew. Some homeowners and contractors will treat redwood and cedar with a sodium percarbonate or chlorine-based cleaner and, if tannin staining is apparent, follow it up with an oxalic acid-based product. Concentrated oxalic acid is toxic and should be handled with care.

So-"tim"r. in order to resrore a wood deck and prepare it for refinishing, the previous finish-or what's left of it-must be removed. Most deck cleaners and restorers are ineffective in removing paints or stains. This can be accomplished by chemical or mechanical means.

Chemical paint strippers are fairly potent and require care in use (avoid skin/eye contact, wear protective clothing, etc.). Depending on the formula, strippers will remove varnishes, oil-based stains or latex stains and paints. Residual amounts of the strip- pers should be thoroughly rinsed from the wood before any product is reapplied since residual traces of caustic salts can interfere with subsequently applied coatings.

Mechanical methods for cleaning and restoring the surface of wood decks include planing, sanding, and power washing. Planing removes the outer surface of the wood face exposing fresh, new wood. Planing is very effective but limited in usage since boards must be removed from the structure and passed through a planer. Since planing removes the outer veneer of wood, it also results in a change in physical dimensions of each board.

Sanding is effective as a mechanical means of removing unwanted coats of previously applied finishes, but may damage the wood surface. On redwood and cedar, sanding often results in an excessive amount of tannin resin bleeding.

Contractors typically prefer power washing. Power washers direct a high pressure jet of water at the wood surface to remove dirt, mildew, algae, gray weathered residue, and prior coatings. Often, contractors treat the surface with a chemical cleaner. then follow up with a power wash,/rinse.

Power washers provide retailers with a good opportunity for add-on sale or rental items. First-time users should be cautioned since excessive pressure can damage wood deck surfaces, as well as windows. doors and siding. As a result, many d-i-yers prefer to stick to chemically based means of cleaning and restoring their decks.

Failure to remove dirt. mildew and weathered residues is also an open invitation for early failure of subsequently applied coatings. Care should be taken to thoroughly rinse all cleanerlrestorer products from the wood. In addition, many coatings require dry surfaces prior to application, so contractors and homeowners should allow adequate time for the wood to dry before applying a finish.

Most decks contain some vertical components such as rails and spindles, and these require the same degree of cleaning and restoring as do the horizontal planks which make up most of the deck surface. Products designed to clean horizontal surfaces will generally work on vertical facings, as well. The only limitation for some of these products is a tendency to run off vertical components before the active ingredients Can fully function. Some cleaners/restorers/ strippers feature thickening agents that help the liquids cling better ro vertical surfaces, improving performance by increasing the contact time between the active ingredients and the surface being treated.

Remember, proper cleaning and surface preparation is essential to successful refinishing of weathered decks.

- This article is based on "Cleaners & Restorers for Wood Decks & Siding" by the Joint Coatings/Forest Products Committee.

Rrrrt:ns

Jones Lumber & Supply, Inc., Prairie Grove, Ar., has closed after 42years in business

West Building Materials is spending $l million remodeling its Clarksdale, Ms., store, expanding the unit from 16,000 to 34,000 sq. ft.; Scott Gayle, new store mgr.

Home Depot opens new stores March t2 in Vero Beach and Marathon, Fl.; March 19 in Lake Wales, Fl., and Odessa, Tx.; March 25 in Rock Hill, S.C., and April 2 in Florence, Ky.

Home Depot has begun constnrction of a 115,000-sq. ft. store in Winchester, Va.; plans stores in Allen and Plano, Tx.; is negotiating for sites in McKinney, Tx., and Seminole, Fl., which would uproot elderly mobile home residents; is rethinking acquisition of proprty in Pinellas Park, Fl., after detecting contaminated soil, and is battling South Venice, Fl., city officials and residents over a planned location

Lawe's Cos. opened superstores in South Fort Myers, Fl. (store mgr. John Scarcella); Jacksonville, N.C. (store mgr. George Blalock); Hattiesburg, Ms. (store mgr. Gary Smith); Lexington, Ky., and Hurst, Lewisville, Carrollton and Sugar Land, Tx. (store mgr. Mark Eakes), and replacement stores in Somerset, Ky. (store mgr. Morris Washburn), and Goldsboro, N.C. (store mgr. Steve Kirby, co-mgrs. Brian King and Ronnie Hill)

Lowe's plans openings in South Fort Worth, Garland and Rockwall, Tx., in mid-1998; is building new locations in Franklin, Tn., and on 16 acres in Madison, Al., and is constructing 150,000-sq. ft. replacement stores in Owensboro, Ky.; Asheville, N.C., and on 14 acres in Dothan, Al. ... the company applied for a rezoning in Fayetteville, Ga., to allow a 160,000-sq. ft. store ... burglars recently broke into Lowe's Athens, Tn., store and stole two cordless phones and three answering machines ... two gunman fled the Baton Rouge, La., store after an employee was unable to open a safe

Potters Shopping Center will open a 7,000-sq. ft. satellite home center this summer in Fairfield Glades, Tn.

W*ormlrrns/ftlmu mcru Rns

MacMillan Bloedel is closing seven of its 30 DCs, including Tampa, Fl., and St. Louis, Mo., and upgrading its Pine Hill, Al., plywood plant

Walker Holdings, /nc., El Paso, Tx., has purchased International Trading G roup - Millw o rk D iv is ion, El Paso; ITG will operate as a division af Tre-PoI International under general mgr. Jim Vanden Berghe, who is joined in sales by George Myers; Evert Dykhuis, exEmpire Distributors, is new to Walker Holdings as director of mktg....

Trus Joist MacMillan has relocated its Norcross, Ga., office to Duluth, Ga.

Kemper Pressure Treated Forest Products, Electric Mills, Ms., has been acquired by L.D. McFarland Co.,Tacoma, Wa., and renamed Electic Mills Pressure Treating ... McFarland has also begun leasing a Broken Bow, Ok., treating plant from Thomason Lumber &Timber Co.

MW Supply & Distribution has relocated its Dallas, Tx., facility to Grand Prairie, Tx.

Weyerhaeuser Co. has sold 60,000 acres of timberland in Pushmataha County, Ok., to the

Hancock TImber Resource Group, bringing the investment firm's holdings in the state to 260,000 acres...

Overhead. Door has relocated its Clearwater, Fl., location to a larger facility

Marine Construction, Inc., North Palm Beach, Fl., has dissolved Pressure Treated Lumber and created a new firm, MiIIenniwnVnyl & Plastic, Inc.

Kentuckt Veneer Co.. Manchester, Ky., has been acquired by Columbia Forest Products, Portland, Or.; the poplar veneer facility is similar to CFP's Craigsville, W.V., plant ...

Universal Forest Products has acquired the assets of Great Northern Wood Preserving Co., Lodi, Oh., including a treating plant on 48 acres, for $1.3 million

Celotex Corp,, Tampa, Fl., is phasing out three-tab strip shingles to concentrate on the premium laminated shingle market; plants in Goldsboro, N.C.; Memphis, Tn.; Camden, Ar.; Houston, Tx., and Perth Amboy, N.J., will be closed by mid-March

Jacuzzi brand maker U.S. Industries agreed to pay $765 million in stock and assumed debt for plumbing and bath products manufacturer Zurn Industries Inc., Dallas, Tx.

Crest Metal Doors, Inc., San Antonio, Tx., has acquired Acore Door Co., Qnincy, Mi.

Anniversaries: Columbia Lumber & Manufacturing Co., Columbia, S.C., 100th Nationnl H ardwood Lumber As sociation, Memphis, Tn., 100th Coulbourn Lumber Co., Inc., Windsor, N.C.,70th ...

Housing starts in Jan. (latest figs.) remained steady at a seasonally adjusted annual rate of 1.534 million single-family construction rose 7% to 1,196 million units, while multi-family with 5+ units dropped 2l7o ... permits climbed 4Vo to 1.534 million ... (Please tum to p. 23)