Deck 102

Deck Building Materials

Since a deck is always exposed to weather it's sensible to select the most durable materials you can afford. Your payoff is reduced maintenance and repairs.

Redwood

The premier choice for decking lumber in the judgment of many is redwood with it's natural resistance to decay and wood destroying insects. Redwood is also easy to saw and sand. Grown only in California, redwood carries a higher price and is less availability than pressure treated lumber in most of the US. Nor can it span as great a distance as wood like fir or southern pine.

Cedar

While cedar is not as strong as redwood, cedar is more widely available east of the Mississippi.Cedar is grade into two appearance grades, knotty and clear. These may be further divided into three categories, good, better, best. Clear is considered to be number 1 grade lumber, all others considered to be number 2 grade lumber.

Pressure Treated Lumber

In most parts of the country, chemically treated pine it the practical choice for decks. Treated lumber is generally stronger than redwood and cedar, and lasts longer in contact with the ground. The term "pressure treated" describes the process by which chemical preservatives are forced into the cell walls to saturate the lumber. (brushed on or dipped coatings don't penetrate as deeply) The copper in the preservative leaves a distinctive green tone on the lumber. (TIP) Use pressure treated lumber for framing. Then apply deck boards and railings and trim of cedar or redwood)

Precautions for Pressure Treated Wood

Please follow these precautions from the Environmental Protection Agency when you work with pressure treated lumber. 1) Dispose of treated wood by ordinary trash collection or burial. Treated wood should not be burned in open fires,stoves,fireplaces, or residential boilers because toxic chemicals may be produced as part of the smoke and ashes. Treated wood from commercial or industrial use may be burned only in a commercial, industrial incinerators or boilers in accordance with state and federal regulations. 2) Avoid frequent or prolonged inhalation of saw dust from treated wood. When sawing or machining treated wood always wear a dust mask. When ever possible, these operations should be performed outdoors to avoid accumulations of airborne saw dust from treated wood. 3) When power sawing and machining, always wear goggles to protect your eyes. 4) After working with the wood and before eating,drinking or using tobacco products, wash exposed areas thoroughly. 5) If preservatives or saw dust accumulate on clothes, launder before reuse. Wash work clothes separately from other household clothing.

Composite Decking

50% Wood, 50% Plastic, composite decking promises a maintenance free deck surface. Sold under the brand name Trex by Mobil, you'll find this material in increasingly broad supply. Usually, its priced between pressure treated and redwood. You can cut,nail and screw it similarly to wood, but observe the manufacturers directions. Denser and more flexible wood, Trex is not intended or approved for structural components like joists, posts or beams. Use Trex for decking and railings only. Set joists on 16 inch centers for proper support.

Lumber Grades

Lumber is classified by its species, strength and exterior appearance. Unfortunately, many species have different grading systems. Generally you will pay a lot more for clear lumber that has no knots.

How To Order Lumber

Lumber yards may seem pretty intimidating to the uninitiated. Lumber is generally priced by the linear foot, though larger quantities may be priced by the board foot. One board foot is one square foot of lumber, 1" thick. All milled lumber has a nominal and an actual set of dimensions. For example, a 2 by 4 measures 1½" x 3½". The difference used to be the shrinking and the milling after the log was rough sawn. Today lumber is milled more precisely and the smaller dimensions are the standard.

Concrete

Concrete is a mixture of cement, sand and carefully sized gravel, formulated to form a void free mix. Cement based products do not dry. They cure by chemical reaction when the cement mixes with water. When mixing concrete, the proper amount of water is critical. Too much water and the concrete will be weakened by the voids left behind by the extra water. Too little water and the mix will be difficult to work with. Try to keep concrete moist for at least a few days after it is poured. The chemical reaction continues as long as the mix contains water. Rapidly dried concrete will not attain its full strength. Wrap newly poured concrete with a wet burlap or plastic sheeting.

Flashing

Sheet metal flashing of either aluminum or galvanized steel is the best protection you can provide for a ledger. If you can't find a stock flashing to fit your work, you can have it made up by a sheet metal shop or bend it yourself, using boards to get a crisp angle. Aluminum, sold by the roll in various widths, is far easier to bend than steel.

Selecting Caulks

Modern caulks provide years of protection from the elements. Silicone caulks are highly flexible and adhere well to all woods but cedar and redwood. Because silicone is hard to tool or paint it makes a good choice for anything that won't be seen. Acrylic caulks, often referred to as latex, are easily painted, easy to tool with a wet finger or rag, and easily washed off with soap and water before they cure. But they don't stretch or cling as well as butyl and silicone caulks. Butyl caulks are long lasting, but very sticky, and a mess to clean. They work best where they won't be seen. For example, behind exterior trim.

Updated:02/17/09 01:24 PM