Wall Sealer & Coating Cost Calculator

Work out how many gallons of masonry sealer a wall needs from its area, coats and coverage — then cost it at the price per gallon you enter, plus labor.

Planning estimate: this is a planning estimate from the numbers you enter and standard reference quantities — not a bid or a contract. Get itemized written quotes from licensed contractors and confirm measurements before you commit.

Calculator

linear ft
Total length of wall being coated.
ft
Height of wall to coat — area is perimeter × height.
Masonry sealers often want two coats on porous block.
sq ft/gal
From the product label — roughly 100 sq ft/gal/coat on masonry is typical.
$/gal
The sealer price from your supplier.
$
Optional labor line if you are not applying it yourself.
Sealer needed10 gallons
Wall area960 sq ft (120 LF × 8 ft)
Sealer cost$400.00 (× $40.00/gal)
Labor (yours)$0.00
Estimated total$400.00

A 960 sq ft wall at 1 coat(s) and 100 sq ft/gal needs 10 gallons ≈ $400.00 with labor. Interior coatings resist damp — they are not a fix for active water pressure.

A masonry waterproofing sealer or coating is the lightest, most DIY-friendly way to resist damp on a basement wall. The cost comes down to how much product you need, which is a coverage problem: figure the wall area, multiply by the number of coats, and divide by the coverage on the product label to get gallons.

Coverage and coats are the two levers people forget. Porous block drinks the first coat, so many products specify two coats and a lower square-foot-per-gallon rate on masonry than on smooth surfaces. Both are user inputs here so the estimate matches the exact product you buy.

Formula

wall_area = perimeter × height

gallons = ceil(wall_area × coats ÷ coverage)

total = gallons × price_per_gal + labor

Gallons are rounded up to whole cans. Coverage comes from the product label and coats from how many passes the wall needs. No price is stored — you enter $/gal.

Worked example

A 120 ft perimeter at 8 ft high is 120 × 8 = 960 sq ft. At one coat and 100 sq ft/gal:

960 × 1 ÷ 100 = 9.6, rounded up to 10 gallons.

At $40 per gallon, that is 10 × $40 = $400 of sealer (before labor). Switch to two coats and the gallons — and the cost — roughly double.

What a sealer can and cannot do

Interior sealers and coatings resist damp and vapor and can brighten a dry-ish wall, but they are not a fix for active water under pressure. If water is pushing through cracks or at the floor-wall joint, a coating will not hold it back — that calls for drainage (interior drain tile) or an exterior system, and possibly a look from a licensed engineer if the wall is moving or cracking. Round gallons up to whole cans, buy a little extra for touch-ups, and read the label: coverage on rough or thirsty block is often lower than on the datasheet, and two coats are common. This is a materials estimate for a benign coating job, not a health or moisture-remediation claim.

Frequently asked questions

How many gallons of sealer do I need?
Multiply wall area (perimeter times height) by the number of coats, divide by the coverage on the label, and round up to whole cans. A 960 sq ft wall at one coat and 100 sq ft/gal needs 10 gallons.
One coat or two?
Porous concrete block usually wants two coats, and many waterproofing sealers specify it. The coats selector lets you try both — two coats roughly doubles the gallons and the cost.
Will a sealer stop a leaking basement?
No. Coatings resist damp and vapor but not water under pressure. If water is actively coming through cracks or the floor joint, you need drainage or an exterior system, not just a coating.
What coverage number should I use?
Use the figure on your product’s label. Roughly 100 sq ft per gallon per coat is typical on masonry, but rough or very porous walls cover less — enter what the label says for the product you buy.

Related calculators

Basement Waterproofing CostEstimate basement waterproofing cost from your perimeter and the price per linear foot you enter, for interior drain tile, exterior membrane or sealant methods.Interior Drain Tile CostEstimate interior drain tile cost from your footing perimeter and the price per linear foot you enter, plus the installed sump pump price from your quote.Crawl Space Insulation CostEstimate crawl space wall insulation cost from your wall area and the price per square foot you enter for rigid board or spray foam at your target R-value.