Decks and costs

What a Deck or Deck Cover Costs in Thurston County (2026)

The Olympia figures you will find online date from 2021

Search for what a deck costs in Olympia and you land on a page quoting $18 to $21 per square foot for pressure treated and $34 to $36 for composite.

Check the date on that page. It was published in December 2021.

Labor is a big part of the reason. On current estimates it is roughly half or more of what a deck costs, and both labor and material prices have moved since 2021.

What a deck costs in 2026

Here is what three published sources say, side by side, so you can see how far apart they are. None of them is our quote, and no honest contractor can give you one from a blog post.

Most of the gap is about what each one includes. The Seattle estimate leaves out design, engineering and other extras, while the national guide is an installed range that includes the substructure. Kolmo also notes that Tacoma runs 5 to 10 percent lower on labor than Seattle.

For decking boards on their own, the same Seattle estimator uses about $4.50 per square foot for pressure treated, $9.50 to $13.50 for composite and about $18 for ipe.

That is the surface only. Useful for checking a quote that itemizes materials, and a poor basis for a budget on its own.

Where the money actually goes

Kolmo publishes a line-by-line estimate for a 20 by 20 foot composite deck in Seattle, and it shows the pattern well. Labor is the biggest single line.

Extras sit outside that total, including design and engineering at $800 to $2,500 when a deck needs an engineer's stamp.

Two lines deserve attention.

Railings can move the budget more than people expect. In the same estimate, 60 feet of pressure treated rail was $480 in materials, cable rail $3,720 and glass $5,700.

The ledger board and flashing is one of the smallest lines on the sheet, and it decides whether water gets in behind your siding. Not a place to save money in this climate.

What pushes the price up in Thurston County specifically

• Slope. A flat lot takes short posts and simple footings. A sloping lot takes taller posts, bigger footings and often engineering, and plenty of lots around Olympia are not flat.
• Height. A deck more than 30 inches above grade needs guards, and the taller it gets the bigger the posts, footings and stairs. All of that is real money.
• Soil and drainage. Wet ground means deeper or wider footings. Some lots need drainage handled before anything gets built.
• Trees. Douglas firs are wonderful until you have to work around the root protection zone of one, or pay to have limbs taken back.
• Access. If a mini excavator cannot get to the backyard, the footings get dug by hand and the labor line goes up.
• Hard surface limits. A new roof counts toward hard surface coverage, and depending on the code a deck can too. On a lot already near its cap this can force a design change.

What a deck cover costs

HomeGuide puts the cost to cover a deck at $10 to $60 per square foot, depending on the type of roof. On a 200 square foot deck that works out to roughly $2,000 to $12,000.

But that range hides an enormous difference in what you actually get.

Why the cheap covers do not work here

This is the part the national cost guides skip.

Shade sails and awnings are built to keep sun off a patio in a dry climate. Awning makers tell you to retract them in snow and high wind, and say they are not built to carry a snow load.

A pergola is an open lattice. Dappled shade, and no shelter from rain at all.

Now think about what you actually want a cover for in Olympia. You are not escaping the sun in August.

You are trying to use the deck in October, and in February. That means rain, and sometimes snow sitting on the roof.

There is a middle path. A louvered pergola with closing slats gives shade when open and sheds rain when closed.

It costs more than a fixed pergola. And when shut it is still a solid roof, which matters for permits. It is not a way around the structural question.

The permit cost nobody puts in the quote

Permit fees are not a flat price. Olympia works out building permit and plan review fees from the International Code Council valuation data, under OMC 4.36.010.

It then adds a technology fee of 4.1 percent to permit and plan review fees.

The fee scales with the value of the work, so a covered deck costs more to permit than an open one.

As a reference point, Seattle's 2026 permit and plan review fee on the 400 square foot composite deck above came to about $769. Olympia uses its own fee table, so expect a different figure. Add $800 to $2,500 if a structural engineer has to stamp the drawings.

A cover makes engineering more likely, because a roof brings snow load, wind uplift and, where it meets the house, a lateral load path.

Whether you need a permit at all changes the budget, so settle it before you commit to a design.

We wrote that up separately in our guide to deck and deck cover permits.

Comparing quotes without getting caught

• Check whether permits and plan review are in the number or excluded. This is the most common gap between two quotes that look similar.
• Check the footing spec. Two quotes with different footing sizes are not quoting the same deck.
• Check whether railings and stairs are included or sitting in an allowance.
• Ask whether ledger flashing and joist tape are included. They are small lines that decide how long the structure lasts.
• For a cover, ask what snow load it is designed for and get the answer in writing.
• Ask who pulls the permit. If the answer is you, that is a cost and a risk being handed back.
• Look the contractor up on the Washington L&I site. It takes thirty seconds and shows whether the bond and insurance are current.

Where to go from here

We build decks and covers across Olympia, Lacey, Tumwater and the rest of Thurston County, and we handle the permit work as part of the job rather than leaving it with you.

Tell us the site, roughly what size you have in mind and whether you want it covered, and we will give you a real number rather than a range.

Code requirements on this page were last checked on 7 October 2026. Codes change, so confirm current standards with your city or county before you apply.