Deck Staining Cost Calculator

A price per square foot tells you almost nothing because two contractors can quote wildly different rates for identical work, and because the same rate covers wildly different amounts of work. Two things break it: which surface it is measured against, and what is already on the deck.

The denominator is the whole argument

A contractor quotes $4.19 a square foot. Another quotes $1.88. They may be charging the same money for the same work.

The first is pricing against the deck floor — 192 sq ft, the number on the plan. The second is pricing against the 428.5 sq ft actually being coated, because the railing, its balusters and the stairs all take stain. Both arrive at $805.

Two decks with identical floor area are not the same job. Put 40 feet of balustered railing on one and leave the other open, and the second is less than half the work — 192 sq ft against 428.5 sq ft. A floor-area quote either carries the railing in a fudge factor or is about to be surprised by it, and the surprise is not usually resolved in your favour.

Ask any quote which surface it is priced against. If the answer is the floor, ask what happens to the price when they see the railing.

Prep is the other half, and it is not a multiplier on the same work

Refinishing a deck is two jobs quoted as one — taking the old finish off, then putting the new one on — and the first is the one that moves the price. Cleaning a sound deck and stripping a failing solid stain are different jobs, not the same job at a higher rate. One is a wash and a rinse; the other is chemical stripping, then sanding, then getting back to bare wood before anything can go on. On this deck the hired price runs from $557 for bare new wood to $1,551 for a solid stain that has to come off — near enough triple, for a surface that has not changed size. Those are estimates.

The DIY cost barely moves across that range, $342 to $619, because stripper and a hired sander are the only things you have to buy that you would not otherwise. What changes is the hours: 7.1 hours of prep on a weathered deck becomes 13.3 on one being stripped.

Which produces a result worth stating plainly. The worse the condition, the better DIY looks on paper — about $10 an hour on bare new wood against $31 on a stripping job, both from estimated rates and estimated hours. That is exactly backwards from where a first-timer should be attempting it.

To price a staining job, this calculator works out the surface first and applies money to it second.

surface = floor + rails + balusters + stairs (+ underside)
labour = surface × rate × prep factor × regional labour
DIY = stain + supplies + any hire

The surface comes from the Deck Stain Calculator, not from a second calculation here. Both pages read one engine, so a gallon count on that page and a cost on this one always describe the same deck.

The labour rate is $1.45 a square foot of coated surface at national average, with a $350 minimum job charge — our estimate, not a published rate, because nobody publishes one. The prep factor runs from ×0.6 to ×2.2, and the optional postcode field below the result swaps the national multipliers for regional ones. It never gates anything: the numbers above it are already right at national average.

Supplies are bought in whole containers, which is why a small deck's supply line looks disproportionate — one bottle of cleaner covers 200 sq ft whether you need it or not. On this deck supplies come to $198 against $184 of stain, and they are the line every DIY estimate on the internet leaves out.

A 16 × 12 ft deck, weathered and grey, with 40 ft of balustered railing and 4 steps, has 428.5 sq ft of coated surface. That is the number both columns are priced against.

Doing it yourself: $382. $184 of stain and $198 of cleaner, brightener, brushes, rollers and masking. No hire, because a weathered deck needs neither a sander nor a sprayer at this size.

Hiring it out: $805. 428.5 sq ft at $1.45 a square foot, unchanged by the ×1.0 prep factor a weathered deck carries, plus the finish the contractor supplies. An estimate, as everything in that column is.

The gap is $423, and it costs 24.3 hours — 7.1 of prep and 17.1 of application, both estimates. Priced on the floor alone the same job would have read $226 and $442, which is the quote a floor-area calculator hands you and the one that gets revised upward when somebody looks at the railing.

Region moves the hired column and barely touches the other. The same deck in Greater Boston and southern New England is $1,045 hired against $428 yourself: lumber and stain are close to national commodities, and labour is emphatically not.

You should do it yourself if you can find the hours and the deck is in reasonable condition, and you should not if it needs stripping and you have never done it. The figures below are the argument, both ways.

What the saving is actually worth

The saving is $423 and it costs 24.3 hours, which is about $17 an hour on our figures — both the labour rate and the hours behind it are estimates, so treat the magnitude as meaningful and the decimal as noise. Add the 4 days the deck is unusable after you finish.

Then be careful what you compare it to, because the opportunity cost is not what it looks like. That figure is tax-free, and these are weekend hours that were never billable in the first place: somebody earning $40 an hour at work is not losing $40 an hour by staining their deck, because those hours were not for sale. It runs the other way too — if you would otherwise spend the weekend doing something you actually want to do, you are paying more than that for it, not less.

What you are actually buying from a contractor

You are buying prep and equipment, not skill with a brush. A crew owns the floor or orbital sander and the airless sprayer you would be hiring at $75 and $65 a day. A two-person crew sprays and back-brushes together — one laying the finish on, one working it into the wood before it skins — and is finished in two days rather than across three weekends waiting for weather.

They are also carrying the risk of the weather window. A coat that goes on before rain has to come off again, and a homeowner who has taken a Saturday off is far more likely to start anyway than a crew who can come back on Tuesday.

When DIY is the wrong answer

Hire it out if the existing finish is failing or peeling, if the deck is elevated, if you cannot keep it dry through the cure window, or if you need it usable next weekend. A first stripping job is the worst possible place to learn, and it is the one the numbers make look most attractive.

Stripping also produces waste, and that waste is regulated in some jurisdictions. It is a cost we could not price and have deliberately left out of the figures above rather than invent — but it never appears in a DIY estimate and it is already buried inside a professional quote. Check what your municipality requires before you open a tin of finish stripper.

What a bad DIY job costs to fix

A finish that did not bond has to come off before anything else will go on, which puts you in the most expensive row on the list: $1,551 hired, or 30.5 hours of your own if you go again. The common causes are all avoidable — coating wood that was still wet, skipping the brightener, or working in direct sun so the finish skinned before it penetrated.

That is the real asymmetry in this decision. A professional job that goes wrong is the contractor's problem; a DIY job that goes wrong costs you the materials, the weekend and the strip.

A staining quote should say which surface it is priced against, what prep it covers, and whether the finish is included. Most are supply-and-apply, which is why the hired column here carries the material line — on this deck that is $184 of a $805 job.

A labour-only quote is not the cheaper one it appears to be. It is the same quote with the finish moved into your column, and it hands you the product decision — which is the decision that sets how long the job lasts, not the one that sets what it costs today.

Get two written quotes. Our labour rate is a survey estimate and the regional multiplier is a broad one, so the figures on this page are for judging whether a quote is in the right country — not for arguing a contractor down to them.