Alaskan Deck

Alaskan Deck

By Greg Stopher of  Stopher Construction  |  It’s nearly spring in Southeast Alaska and this time of year contractors are often asked, “What is the best decking material for the region?” Decking materials range from natural wood to manufactured composites made from recycled materials. When it comes to selection a lot of things need to be considered, including the homeowner’s preferences, maintenance, costs, and the general advantages and disadvantages of each material under the advisement of your contractor. Each material performs differently and can be used in multiple ways to obtain what the homeowner is trying to accomplish. I will explore composite, natural wood, treated wood, membrane, flashing and attachment details. 

A lot of composite decking materials are on the market now and all seem to have the same low maintenance claims. Many state they are resistant to mold and mildew, stains, scratches, splitting and impervious to water and insects. In the Alaskan climate all of these claims seem to hold true with the new generations of composite decking as long as they are cleaned and maintained regularly. Each composite decking material should be cleaned twice a year, usually spring and fall to maintain their great look and durability throughout the years. Although composite decks are mold and mildew resistant, this does not mean mold and mildew will not grow on the material. Mold and mildew will grow on the microfilm of the material and will eventually affect the composite itself if not cleaned regularly. A light detergent and a soft brush with a garden hose will easily clean the deck.

Composite decking can be fastened to the structure in multiple ways. Face fastening is the most common which is basically a fastener through the face of the material into the structure. Composites can also be fastened with hidden fasteners or clips. Hidden fasteners are fasteners that are placed on the side of the material and into the structure. Clips are used to grip the groove on the side of the composite (must be ordered with these grooves) and fastened to the structure. Spacing is key when using composite. You can find special spacing tools to create hidden fasteners or clip fasteners, making spacing nearly automatic. When face fastening a composite material I will use a carpenters pencil to space the decking which gives it about 3/8 inch spacing. When using a composite decking, the structure or deck joists need to be spaced less than when you are using a natural wood or treated wood decking, at about 12” on center which will add some material costs and labor costs.

Natural wood decking material has its benefits and drawbacks as well. Most natural woods used for decking like cedar, redwood, teak, and other exotic species have natural chemicals contained within the wood to deter rot, moisture, and insects. Wood materials like common lumber will have to be treated with a sealer or finish to be impervious to moisture. Although cedar has a natural chemical to deter rot, I always use a sealer or stain that is able to breathe so moisture that gets into the wood can escape. Cedar is a popular choice in Southeast Alaska because it can be harvested regionally and supplied locally which cuts down on transportation costs, environmental costs, and keeps people employed locally. Natural wood decks need to be cleaned, stained, and sealed regularly which takes a little more maintenance than the composite decking. The color of the stain can also be changed if you do not like the color or are going want to change the look. This is an important point to consider when comparing cedar to composite decking, as composite stays the same color throughout its life and cannot be changed without changing the composite entirely.

The fastening on natural wood decks can be done exactly like the composite decking either face fastened or hidden fastened. Both ways of fastening are the same as the composite decking, although the use of clips is not common with wood decking. Another advantage lumber has over composite wood is that it can span a greater distance between deck joists saving on structural materials and labor. But this can be offset by the fact that natural lumber may have warping, cupping, or crowning sometimes making it a challenge to work with.

Pressure treated and Sunwood (surface treated lumber) material is also a popular option. Neither pressure treated lumber or Sunwood receives stain or finish well, so what you see is what you get. It is possible to paint, but it can only be painted with the right preparation using a water based acrylic latex paint.

Membrane decks are the great idea in this climate especially a second story deck since the underside of the deck can be used as a covered patio or deck below. Membrane decks must be maintained and cleaned regularly to allow them to be in the weather for many years. There are other variations on membrane decks that incorporate concrete, concrete pavers, and other materials and all are good options for a deck on a second story.

I spoke of fastening systems above (face, hidden, and clip) but the fasteners themselves are as important as the fastening systems. Some fasteners are not compatible with pressure treated lumber and the chemicals in the lumber will eat or corrode many fasteners resulting in a failing deck. Stainless steel fasteners are recommended for pressure treated lumber. Stainless steel fasteners are also recommended for cedar because other fasteners tend to stain or discolor the cedar.

I have also used hot dipped galvanized and aluminum hidden fasteners to fasten cedar successfully. Composite decking has many composite-specific fasteners and though they’re compatible with composite, be sure to confirm the fasteners are compatible with the structure the deck will be fastened to, usually pressure treated lumber. The clip systems with the grooved composite decking I have found to work very well, although every joist should be clipped to eliminate squeaks and clicks.

The connection between the deck and the home is the most critical part of the system. Rain splashing up from the deck can greatly affect the structure of a home. The deck is usually fastened to a board hung off the home whether it’s a first story deck or second story deck. The board, also known as, a ledger should be held off the home with a ledger bracket. A common bracket for this application is the Stratton bracket which holds the ledger board ½ inch off the house to allow water to drain behind the deck. I still like to install an ice and water shield behind the siding that the brackets fasten through to eliminate any water that may find its way behind the siding.

Decks require regular maintenance. No matter what type of material you decide to use for your deck, whether a new deck or refurbishing an old, it will be important to develop a regular maintenance schedule. Clean your deck regularly, stain and finish it on a regular basis and you will have a deck to enjoy for many years to come.

Greg Stopher has over 16 years of experience in the construction field and earned a degree in Construction Technologies from the University of Alaska – Southeast. His company, Stopher Construction, LLC, is a general contracting company specializing in remodeling, custom finishes, additions and new home construction projects. He can be reached at 907-321-2350.