Lesson 3 of 3

The second deck
is the expensive one.

A deck is priced by the square foot and paid for by the year. The bid shows what the first deck costs. This page is about what the deck costs per year you can walk out on it, sealing schedule included, and it is written for the person funding the build as much as the person building it.

Run Your Numbers (615) 792-5156

The math the bid leaves out

Three costs that never make the spreadsheet.

The schedule. A treated deck wants to be washed and sealed or stained every two to three years to keep water out of the checks and the color even. That is a weekend and a few buckets, or a check to someone with a sprayer, every couple of years for the life of the deck. A capped composite deck is built so the surface never takes a finish; the makers' care guides call for soap and water. Neither number is on the bid.

The year it happens. Treated decking that has been sealed on schedule commonly gets pulled and replaced somewhere in its second or third decade, and the boards that come up go to the dump. A capped composite surface on a sound frame is warranted for 25 to 50 years by the makers we sell. One of those replacements lands on your watch, or it does not, and that depends on how long you own the house.

The frame under both. Both decks sit on treated lumber. A frame built right, Ground Contact joists, tape, and a flashed ledger, outlives either surface. A frame built cheap takes the expensive deck down with it, and the boards have to come up to fix it.

The question is not which deck is cheaper. It is what each deck costs per year you get to use it.

How to use this page

Bring two quotes. We do not put prices on the site.

Get a quote for the deck you are being told to buy and one for the deck you would rather stand on. Enter the installed price per square foot for each, the deck size, and how long you expect to own the house. Then enter the service life you believe for each surface, and what you will spend per year keeping it up: sealer and labor for treated, a wash for composite, in your own dollars. If a replacement means tearing out and hauling off the old boards, enter that too.

The calculator counts a replacement whenever a surface's life runs out inside your hold, charges the tear-out with it, adds the yearly upkeep for every year of the hold, and credits the unused life of whichever surface is still good when you sell. The result is what each deck costs over the hold, and per year of service.

It does not know which decks you are comparing. It only knows arithmetic.

Cost Over Time

Two decks, one house, your numbers.

Nothing you type here is sent anywhere. It runs in your browser.

The house

Deck size, in square feet

Years you will own it

Tear-out and haul-off, per square foot (at replacement)

Deck A (the cheaper quote)

Installed price per square foot

Service life you believe, years

Upkeep per year, dollars (sealing, staining, washing)

Deck B (the better quote)

Installed price per square foot

Service life you believe, years

Upkeep per year, dollars

A place to start: treated decking sealed every two to three years commonly serves 15 to 25 years; capped composite carries 25 to 50 year material warranties from the makers we sell. For upkeep, price one sealing job and divide by the years between jobs. Pick numbers you would defend to a buyer.

Over 15 years

Deck A, day one: –
Deck A, upkeep over the hold: –
Deck A, replacements during the hold: –
Deck A, cost over the hold (net of unused life): –
Deck A, per year of service: –
Deck B, day one: –
Deck B, upkeep over the hold: –
Deck B, replacements during the hold: –
Deck B, cost over the hold (net of unused life): –
Deck B, per year of service: –
Difference on the bid: –
Difference over the hold: –

Fill in both quotes, both service lives, and both upkeep numbers to see the comparison.

Cost over the hold = first deck, plus upkeep for every year of the hold, plus each replacement (new deck plus tear-out) that falls inside the hold, minus the value of the life left in the last deck when you sell (priced at that deck's installed cost). Per year of service = installed cost divided by service life, plus one year of upkeep.

Before You Price a Deck

Know what you are standing on.

Three short reads on composite and treated decks. Written for the builder who has to answer to the money, and for the money.

Lesson 1 What you are paying for The board, its cap, the frame under it, the clip, and the rail. Six things that separate a deck that lasts from one that looks the same on the truck. Each one you can check on a sample. Read it → Lesson 2 Read the spec sheet The fade number, proration table, transfer window, code report, and the tag on the end of a treated board. What "50-year" means once you read the table. Read it → Lesson 3 The second deck is the expensive one A deck is priced by the square foot and paid for by the year. Run your own two quotes, with the sealing schedule, against the years you will own the house. You are here

Frequently Asked

Deck cost over time, answered.

How often does a pressure-treated deck need to be stained or sealed?

Every two to three years is the common schedule for a water-repellent sealer or a semi-transparent stain on a treated deck in a wet, sunny climate like Middle Tennessee, sooner on the south and west sides and on stairs. New treated lumber usually needs to dry for a season before it takes a finish, unless it was kiln dried after treatment. The job is a wash, a dry day or two, and a coat. Skipping it does not fail the wood, which the treatment protects, but it lets water into the checks and greys the color. Put your own number for that job, in dollars per year, into the calculator.

How long does a treated deck last compared with a composite deck?

The treated frame under both is the same wood, so start there: a Ground Contact frame that is flashed, taped, and kept dry is a decades-long frame, and one that is not is a 15-to-20-year frame. On the surface, treated decking that is sealed on schedule commonly serves 15 to 25 years before boards check, cup, and get replaced; capped composite carries 25-to-50-year material warranties and the makers built the cap so that the surface does not need a finish at all. Pick the life you would defend to a buyer and enter it.

Does a composite deck add resale value?

It removes an objection more than it adds a number. A buyer walking a grey, checked treated deck sees a project; the same buyer on a capped composite deck sees a finished space. Whether that shows up in the sale price depends on the house and the market. What is certain is the transfer window: the composite warranties Midway sells transfer once, within five years of purchase. If you are building to sell inside five years, that is a real line in the listing.

Is it worth putting a cheap frame under an expensive deck?

No, and it is the most common way to waste money on a deck. A 50-year board on a frame that rots at year 18 is an 18-year deck, and replacing the frame means taking up the boards. The frame is a small share of the total: Ground Contact joists and beams, joist tape, a flashed ledger, and end-cut treatment add little on the day of the build. Ask for the frame as line items on the quote and spend there first.

Stop By the Desk

Let’s talk it through in person.

Bring your plans or just your questions. We’ll get you squared away.
119 Cumberland St, Ashland City. The coffee’s on.

Get Directions (615) 792-5156

The second deckis the expensive one.