Building green isn’t actually all that complicated. In fact, when it comes to building decks, it’s mostly common sense. Many of the following tips are about using and wasting less material, which economy dictates as a goal anyway.
The decks in the photos in this article are part of a larger project my company is building — planned to be the first LEED Platinum house (see sidebar, page 56) in British Columbia. Here are five keys to a greener deck, in no particular order.
Minimal Material Use and Minimal Waste Minimize the amount of material used and the waste from construction. Like many professional deck builders, I have a tendency to want to overbuild things, but it’s unnecessary and it requires extra material.
Also consider spans and the size of members. One’s first thought might be to save material by using smaller joists. However, sometimes increasing their size lets you increase their span and eliminate posts and beams, thereby saving lumber overall. Not only does this save time and materials, but the fewer footings there are to be dug, the better, if you ask me (Figure 1).
Another way to conserve material, which most of us already do, is to plan the decking layout and pattern so we can purchase board lengths that minimize offcuts and waste.
Longevity and Continued Integrity When building a deck, we should consider it a permanent structure and part of the home, not something that will need to be replaced in five or 10 years. Building it to last many years more than that is not difficult. And the longer a deck lasts, the better, as the less often a deck needs to be rebuilt or replaced, the fewer materials are used. (Decks do require maintenance, but that’s a conversation with the homeowner — more on this later in the article.)
It rains eight months of the year in my location, so standing and pooling water and moisture traps are serious business (Figure 2). A very important aspect of deck longevity is the attachment at the house. It’s crucial that the integrity of the home be maintained by properly wrapping and flashing this area and by leaving an airspace or drainage plane, if possible. I’m aware of two products for creating a space at this connection: the Deck Ledger Spacer by Go Ahead Deck Me (866/583-0939, goaheaddeckme.com) and the Deck2Wall spacer by Decks Unlimited (888/577-2237, deck2wallspacer.com).
A few simple details will help prevent water from soaking in. Minimize horizontal surface areas; for example, chamfer the tops of rails and posts (Figure 3) and use 2-bys on edge instead of on the flat in your designs. Also, avoid having end grain meet a horizontal surface whenever possible and seal the end grain thoroughly. For this, I use two liberal coats of Timber Pro UV (Timber Pro Coatings; 888/888-6095, timberprocoatings.com). Another good idea is to use post bases with stand-offs, as I find post bottoms are vulnerable and one of the first places to go (Figure 4). Finally, it isn’t always possible, but wherever two pieces meet parallel, it’s nice to have at least a small airspace in between for drainage and drying.
Sustainable, Recycled, and Local Products Use local and sustainable lumber. Along with lumber, other materials should be produced as locally as possible. Not only is this good for local businesses, but the less transportation required to get your products to your destination, the less impact on the environment there is. The cedar in this deck was harvested in British Columbia.
Buying environmentally certified lumber is one way to ensure that your wood was harvested in a sustainable manner. Unfortunately, certified lumber in decking materials may be hard, if not impossible, to come by in some areas. If you can find it, FSC-certified lumber is the LEED standard (Figure 5, page 58). The FSC (Forest Stewardship Council, fsc.org) requires strict chain-of-custody records to document the lumber’s source. Another organization that certifies lumber is SFI (Sustainable Forestry Initiative, sfiprogram.org).
No matter which materials you choose, you will be making some sort of compromise. Materials with recycled content, such as composite decking, can be a responsible choice, as can all-plastic materials that promise exceptional lifespan. Two such products I prefer are TimberTech composite decking (800/307-7780, timbertech.com) and Azek PVC trim (877/275-2935, azek.com). TimberTech products contain a decent amount of recycled content, and it’s possible to get LEED points for using them.
I haven’t found any claims about Azek using recycled content, and I don’t believe that it does. Azek is made from PVC, and PVC production is not thought to be exactly environmentally friendly. In fact, there’s a lot of debate about the greenness of anything PVC. However, I think that because of its longevity, PVC trim can be considered a green product. Another of the many good choices for decking is thermally modified wood — several manufacturers use heat to modify wood so that it’s rot resistant (they often treat underutilized and abundant species with this method). Distribution is still spotty, though.
Treating, Staining, Sealing Keeping water and sun from damaging wood decking is important to its longevity. Although opinions vary, I believe it’s common sense that water-based finishes are greener than oil-based ones. I prefer Timber Pro UV (Figure 6). It is made with natural oils and is considered green and sustainable enough that its use can generate two to three LEED credits.
Our second biggest battle (the first being against moisture) is against the sun and its constant barrage of UV rays attacking our decks. Deck stains without some pigment in them are not nearly as effective at blocking UV and don’t last as long. Semi-transparent stains are a good choice for a number of reasons: They can effectively block UV rays, they allow you to see the natural beauty of the wood, and they usually don’t need to be reapplied as often as a transparent stain.
Maintenance The final key to a longer-lasting deck is proper and timely maintenance. Our job typically is done once the deck is built, but we should at least educate our customers about maintenance. Something else to consider is selling a scheduled maintenance package with the deck. Another option is keeping track of your customers and calling or writing when it’s about time to restain the deck. This can be just a reminder, or you can offer your services to do it.
If you address maintenance with your customers — and put into practice the other points in this article in the design and construction of your decks — you will be doing your part as an environmentally responsible builder.
Ryan Winchester owns Winchester Decks in Vancouver, British Columbia.