Building a Deck

What should we do to make sure we get the best performance
from stain on our new deck?


written by Bill Swanston, Benjamin Moore ~ photo courtesy of Labco Wood Products Ltd.

Ah, summer time and the living is easy. Only after the deck is done properly. If you are considering building a deck this year, reading this article could save you many hours in the years to come. Most people believe that because the wood is new, there is no prep work needed before staining or painting. Fact is unless the new wood is properly prepared, any finish you put on the deck will not give you maximum performance.

New wood as it comes from the lumber mill has been sawn and planed with high speed equipment. As the wood is finished the heat and pressure from the blades compressed the wood fiber on the surface which gives the wood a shiny appearance. This is “mill glaze”. Stains and paints will not properly penetrate the surface of the wood as long as there is mill glaze. Another concern is that although the wood is kiln dried, there may be an excessive amount of moisture in the wood. However back to mill glaze.

Prior to applying any coating to the wood the mill glaze must be removed. For this you have three options. Leave the wood out for two to three months so the rain and sun can get at it. Option two is to sand the lumber with the grain with 80 grit sand paper. The sand paper will cut into the surface removing the mill glaze and also any loose wood fibers and slivers. The third option is a chemical solution such as Bio Wash Wood Prep which we have at the store. Now that you have all the lumber prepped, no mill glaze is present, we now can look at staining or painting if preferred.

Moores Alkyd Solid Colour Deck Stain is our product of choice for spruce and pine. This will cover the wood entirely. If you are using cedar or want the grain or texture of the wood to show then use Moores Semi-Transparent Deck Stain. Remember there are six sides to every board. For solid colour stain, give all the lumber one coat of stain before assembly. If possible, do a second coat of stain on the side that is down and the edges of each board. Assemble the deck and then give the top side of the boards a second coat of stain. In the case of semi-transparent stain, do not stain the top side of the deck boards until assembly. Semi-transparent stain will hide more of the grain in the wood with repetitive coats. Brushing stain on to the boards is the most effective method for stain application since stain performs best if it is worked in to the fiber of the wood.

Some things to avoid when constructing a deck:

• never use a vapour barrier beneath a deck. The use of black plastic to keep weeds down will prevent water from draining away from beneath the deck. High humidity will cause stain to peel and wood to rot prematurely. Landscaping mesh is a preferred product in place of plastic.
  
• never skirt in a deck with solid material as this will reduce cross ventilation under the deck again resulting in a high humidity build up. If you want a skirt around the deck to keep out children and pets, use an open lattice which is also available from your local lumber supply store.
  
• when putting down the deck floor, make sure the boards are right side up. All kiln dried lumber will be slightly warped or “crowned”. By making sure the crown is up, you will prevent the board from cupping, thus holding unwanted moisture on the surface of the deck.
  
• never put a silicone based sealer on the deck as a temporary measure. The life span of such sealers is short, does little to protect the deck from harmful ultra violet rays and will also prevent stain from staying on the boards.
  
• never assume that “treated lumber” doesn’t need a coating. It is true that the wood will not rot for a good number of years but it will warp, check and split if it isn’t protected with a coating of quality stain.