When done right, decks and patios can extend your living space, bringing the indoors outside and the outside in.
The most frequent question I get asked about decks is whether the homeowner should use composite decking.
When I started building decks, about 60% of my customers were still using traditional cedar decking. Now, about 90% use composites. The biggest reasons are the ease of maintenance and the material’s long life.
Cedar decking has its upsides: It’s rot- and insect-resistant, renewable and locally abundant. When it’s new, cedar looks gorgeous and has a natural, organic feel. But to keep it looking nice, you have to stain or paint it every year or two. It will eventually need replacing, and cedar is soft, so it scratches if you have large dogs.
Composite decking is a terrific choice, especially in the rainy Pacific Northwest. Composites are made from PVC or from plastic and wood fibers that are compressed into boards. It will never rot, maintenance is almost zero and, in theory, it should last as long as your house. The decking cuts cleanly and you won’t get splinters.
There are around half a dozen manufacturers, but the two most established brands are Trex and TimberTech (which merged with Azek a few years ago). These companies have been around for years and will probably remain in business should you need warranty work.
The substructure and labor to install a composite deck is exactly the same as a cedar deck. The big downside is upfront cost: Expect your total materials cost to be about 30% higher. But you make that up over time by avoiding maintenance and with resale value.
Which option is the most eco-friendly is debatable. If the deck is never replaced, composites are generally considered the most environmentally sound. Wood can be sustainably harvested but it needs to be replaced every couple of decades. Trex uses recycled plastic and wood fibers, so it’s easier on the environment than PVC boards.
Two other wood options worth mentioning are bamboo and hardwoods. Bamboo is renewable, but is still relatively new and unproven in the Northwest. Hardwoods (such as ipe or ironwood) are beautiful, but are also the most expensive choice and require about 30% more time to install. Hardwoods are not easily renewable, and you must be careful how you source the wood.
Railings are another area that requires consideration. There are a handful of options, each with pros and cons.
A wood railing is the cheapest option. There are numerous style choices, but they all use cedar posts mounted to your substructure, with railing infill that spans between the posts. If you want to be creative or build a privacy screen, cedar is a good option.
Cable railing uses wood or metal posts with rows of stainless steel wire. The cable can appear almost invisible and looks great next to modern homes. Installation can be challenging (DIY builders, beware). Natural expansion and contraction makes it hard for the cable to keep its harp-like twang, so you’ll probably need to fiddle with tightening it. Also, kids love to climb them.
Hogwire railing has become very popular in recent years. It has a similar look to cable railing without many of the downsides. It uses rigid panels that are cut to fit between your posts and is held in place using compression or metal tracks. This is my favorite style of railing for both cost and durability.
Glass railing is a good option if you have a nice view or want to cut down on wind. High cost and having to clean the glass every time it rains are the major drawbacks.
All-metal and composite railings are also worth considering. Composite railings can match your decking. All-metal railings look great on modern or commercial structures. Both choices come with severe sticker shock, and the railing alone can cost more than the rest of the project combined. Few of my customers choose these options due to the price.
Doing it yourself
If you’re thinking of building a deck on your own, the good news is that decks aren’t rocket science.
If you feel comfortable around power tools and have a basic knowledge of construction terms and techniques, a deck is a straightforward project to cut your teeth on.
A big reason: The construction requirements (what size of boards to use, what spacing, how deep to dig your footings, etc.) are fairly well established and you can use existing span tables to plan your project. As long as you’re following your city’s code requirements, the building part isn’t terribly complicated.
Good places to start your research are Decks.com, a site sponsored by Trex, and Seattle’s Department of Construction Tip Sheet, which summarizes the permit requirements.
Hiring a contractor
It’s a good idea to be honest with yourself about your situation. If you lack the time or the skills to build a deck, it’s best to get a few bids from qualified contractors.
This is especially true if you have a tricky site or want to build or repair a large structure. Bad things can happen if you build a deck wrong, so vetting a good builder is critical.
Navigating the permit process can be complicated, so it’s usually worth hiring someone to get your plans approved.
If you expect to invest in another construction project down the road, a deck can be a good way to test-drive a builder. Deck builds usually take a week or two, and they’re fairly self-contained, so it’s a low-risk way to see if you like their work and if they bill fairly.
The permitting process
Getting a permit is one of the most dreaded aspects of building a deck, and probably the largest roadblock for homeowners.
The cost is calculated based on the estimated total cost of your project. City fees might be around $400 for a typical, modest deck in Seattle. But it can be much more, depending on the scope.
Fortunately, there are some exceptions and loopholes that can expedite or even eliminate the need for a permit. Here are some of the major factors to consider (note that these will vary from city to city).
The remodel rule: If your deck already exists, things are generally easier for you. As long as the substructure was built correctly and you’re only replacing the railing or your deck surface, you can typically avoid permits.
Likewise, if you already have a deck, it may be grandfathered in, even if it wouldn’t be allowed today. The city may allow you to remodel it, even if you can’t alter the footprint or basic design.
Setbacks and lot coverage: These two requirements can trip up a homeowner’s plans in a hurry.
A setback is a distance from your property line where you cannot build. Normally, you can’t put a structure within 25 feet of your rear line, 5 feet from the sides or 20 feet from the front of your lot.
The lot coverage is the total percentage of your lot that you can fill with structures. For most single-family homes in Seattle it’s 35%. When calculating the percentage, you must include outbuildings, decks taller than 36 inches and detached garages. Condos and townhomes are almost always maxed out on their coverage, so a new deck is often a non-starter.
You can apply for a variance, but it’s a gamble with your time and money.
The under-18-inches rule: If a deck will be low to the ground, you probably won’t need a permit. Decks surfaces less than 18 inches above the ground are considered a “patio” and not a deck, and they do not require a permit. In most cases, low decks are not subject to the lot coverage or setback requirements, so you could fill your yard with a low-lying deck without asking permission (although you should still follow best practices for construction to ensure safety).
The under-8-foot rule: If your deck surface is less than 8 feet off the ground, you usually qualify for an expedited permit called Subject to Field Inspection. You still have to submit plans, but the review process is faster.
The full review: If your deck surface is taller than 8 feet, or it’s a rooftop deck, you will go through the city’s full review process for new homes and major remodels. This can take months.
Environmentally critical areas: If your site is in an environmentally critical area, your plans will fall under additional scrutiny. You may not even know you’re in a critical zone. Examples include steep slopes, shoreline and being near a stream. Your review process will include extra site visits, and you will need to hire specialists such as survey crews and geotechnical engineers to prove that your site is adequate. This can be expensive and time consuming. Plus, there’s no guarantee you’ll eventually get approved.
Drawing plans yourself: Most deck permits do not require professionally drawn plans. If you’re willing to learn the city’s submission requirements, you can draw them up yourself.