Landscape Architecture

What Material Should I Use for My Deck?

There are a lot of types of wood decks to choose from. How do you know which might be the right one for you? This post covers your main options for building a wood deck and explores the pros and cons of the different wood choices.

Leslie Batten

April 19, 2018

Wood Decks

Do I want a wood deck? Or something that looks like wood, but is low-maintenance? What other materials are there? What types of wood decks are available?

We get these questions all the time, which is exciting for us because decks span across our services. They are literally the threshold that connects the indoors with the outdoors, uniting architecture and interiors with landscape architecture. Decks are also an important part of enjoying glorious Pacific Northwest summers, providing space for outdoor entertaining and relaxing. What they are made out of will help create the desired atmosphere and also determine how much effort you’ll need to invest in order to maintain your new deck. Here are our thoughts on how to determine what decking material is best for you and your setting.

First, let’s be clear on what we mean by a deck. In most cases, we’re talking about an elevated structure, often 18” or more above the ground that (more often than not) physically connects to the house. They are usually open to the weather. There are many exceptions, but most commonly, decks are made out of wood and consist of posts, framing, and planks. (It’s not a balcony or a patio, those each deserve their own blog posts.)

In the Pacific Northwest, decking materials require an extra level of scrutiny. Long months of continuous rain and near-constant cloud cover are agents of mold, moss, rot, and algae. Sun also plays a role, with UV light stripping color and breaking down the molecular structure of the wood. These climate conditions, combined with busy lives, mean that many people are interested in low-maintenance and long-lasting materials – a tall order, but it is possible!

While most people immediately think of wood or composite decking, there are other materials such as metal, stone, and precast concrete. Over the next several blog posts on materials, we will present a general overview of each. But, keep in mind that site conditions play a major role in the suitability of any material, as do what your intentions are for how you use the deck. Be sure to discuss materials with your landscape designer to make sure you are selecting the best material for your home and location.

Types of Wood Decks

We’ll begin this series with wood decking materials. This includes the most common wood types and a couple of new products on the market that are modified or engineered wood types.

Cedar

Most often, this is locally sourced in the Pacific Northwest, including British Columbia.
This is the traditional deck material in the Pacific Northwest — a classic look, and long-lasting.
Cedar is a softwood that has natural resins that make it rot resistant and that repel insects. It doesn’t require toxic preservatives.
Due to its softness, it is easier to damage cedar with scratches or denting than it is for harder woods or wood products.
It is long-lasting, with a lifespan of up to 25 years, with care every 2-3 years.
The wood is stable, not prone to warping, cupping or twisting, and is easy to work with.
A good coat of oil stain will maintain the rich cedar color, or you can let it naturally turn silver.
Higher quality cedar planks include: tight knot and clear. Tight knot cedar has fewer and smaller knots without any holes. Clear cedar is knot free, and has a nice vertical grain. Both of these look great and are longer lasting. The cost of the material is offset by its longevity.

Juniper

Locally sourced in Oregon, restoration juniper is harvested to prevent loss of grassland habitat.
Juniper is a softwood with natural resins that make it rot resistant and that repel insects. It does not require toxic preservatives.
The wood is slightly harder than cedar, but if installed incorrectly, it may warp.
Due to its very rot-resistant nature, juniper is commonly used for raised garden beds. It will last 25 years in contact with soil.
Staining it will maintain the crème color, or you can let it naturally turn silver. For stain application, follow manufacturer recommendations.
Knots are unavoidable in juniper – good for those who like the added character.
Since the trees are smaller when they are harvested, board sizes are generally limited to 8" in width and 10' in length.
Natural variability in the wood requires you to include 10% overage to make sure you get boards that lack large knots or piths.
Many contractors are unfamiliar with this material. They will need to understand how best to work with it to achieve a quality installation.
Costs are 30% more than cedar for decking and trim material, but posts are half the price of tight knot cedar. Longevity offsets the initial cost.

Tropical Hardwoods

This can be a blog post in itself. But, generally speaking, tropical hardwoods are popular because of their rich color and longevity.
We strongly recommend that you only select Forest Stewardship Council (FSC) certified products, especially when shopping for tropical hardwoods. This ensures it’s harvested in a sustainable method, and specifically, to prevent rainforest destruction.
These woods typically offer rich, warm-colored wood with a tight grain that resembles mahogany, but is extremely dense and heavy, with very high scratch resistance.
These dense hardwoods are naturally rot and insect repellent and don’t require toxic preservatives.
They are long-lasting, up to 50 years and more with little maintenance.
Tropical hardwoods are more labor-intensive to install. They require pre-drilling and the use of stainless steel fasteners to withstand the high tannins in the wood. It will dull cutting tools. If you get a lower grade of wood that is cupped or warped, you will not be able to straighten or correct those problems — the boards will literally rip the fasteners out of the framing.
You can use a hardwood stain to preserve the warm color, or let it naturally silver.

Thermory

This is an engineered wood, made from White Ash that was damaged from the emerald ash borer on the east coast, or harvested from managed secondary growth forests in Eastern Europe.
During the manufacturing process, the wood is heated and steamed to burn off cellulose (cell contents that are subject to rot or attract insects). But, the wood remains porous, so it's recommended to apply a sealer every few years.
White Ash is a hardwood with straight grain. The treatment process gives it a warm, toasted brown color similar to walnut. The boards are knot-free and have excellent wood grain character.
It is not as hard as ipe (a tropical hardwood), but it is very close, and thus scratch and damage resistant.
Themory is long-lasting, up to 25 years.
It is designed for easy installation with clips and JEM jointing system, which minimizes waste by 5% or less.
You can apply an oil stain to it, or let it naturally turn silver.
This is a new product on the Pacific Northwest market, and so far our firm has only one deck installed with this material. We’re keeping a close eye on it to see how it ages and what the maintenance requirements are over time.

Kebony

This is an engineered wood made from either Scot’s Pine or Monterey Pine. The wood is impregnated with furfuryl alcohol and then heated to transform the alcohol into a polymer that stiffens the cells, resulting in a hardwood that is completely sealed.
Monterey Pine is used for a clear grain and Scot’s Pine is used for a character grade that has knots and grain pattern. The treatment process gives both types of wood a warm, toasted brown color, similar to walnut.
Kebony is long-lasting, up to 25 years and more with minimal maintenance.
This wood product is a step down from ipe or Thermory in terms of hardness and scratch resistance, but more durable than cedar.
It is designed for easy installation with hidden fasteners such as the Lumber Loc, or Terrace Clip.
You can apply an oil stain, or let it naturally turn silver.
We have yet to see this installed in the Pacific Northwest, and are curious about it as a long-term deck product.

While the maintenance component often scares people away from choosing wood for decks, there are numerous benefits of wood that deserve consideration. Sometimes, a few hours of elbow grease results in a better investment over the long term.