ContractorHandbook

Siding for a 1,500 Square Foot House

Siding needed

17.4 squares

160 ft perimeter, 9 ft walls, two 30 ft gables at 6/12, 12 windows, 2 doors, 12% waste.

It does not stop at a number.

When the figures look right, the siding material list downloads as a real PDF with your business details on it, built inside your own browser. Nothing you type is uploaded anywhere.

wall length, ftheightgable = width x rise / 2net area with waste / 100 = squares
Siding is quoted in squares of a hundred square feet, and the gable is the piece people leave out. Openings only come off at half, because the cut piece around a window is rarely long enough to use anywhere else.

How that number is worked out

These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.

  • Wall perimeter160 ft
  • Wall height to the eave9 ft
  • Gable ends2 each
  • Gable width30 ft
  • Roof pitch, rise per 12 in6 /12
  • Windows12 each
  • Doors2 each
  • Outside corners4 each
  • Waste allowance12 %

Siding needed17.4 squares

Wall area1,440 sq ft
Gable area225 sq ft2 gables at 6/12
Openings deducted at half111 sq ftof 222 sq ft total
Net area1,554 sq ft
With 12% waste1,740 sq ft
Squares17.4
Vinyl cartons at 2 squares9
Starter strip160 ft
J channel228 ftaround windows and doors

The material list this produces

Siding, cartons at 2 squares9
Starter strip, ft160
J channel, ft228
Outside corner posts, 10 ft4
Undersill trim, ft160
House wrap, sq ft1,665
Siding nails, lb5

Roof pitch compared

Pitch only moves the gable triangles, but it moves them fast. Going from 4/12 to 12/12 triples the gable area on the same house, which is about three extra squares of siding on a 30 foot wide elevation and closer to six on a 40 foot one.

Roof pitchSiding neededGable area
4/1216.6 squares150 sq ft
6/1217.4 squares225 sq ft
8/1218.2 squares300 sq ft
10/1219.1 squares375 sq ft
12/1219.9 squares450 sq ft

What else matters here

Seventeen point four squares, which is nine cartons of vinyl at two squares each. The walls are 1,440 square feet of that and the two gables add 225, so the gables alone are more than two squares that get left out of a guess.

Openings come off at half: twelve windows and two doors is 222 square feet of opening, deducted as 111. Net area is 1,554, and 12 percent waste takes it to 1,740.

Perimeter is the number to measure carefully, not floor area. A 1,500 square foot house can have a 160 foot perimeter if it is a simple rectangle or well over 200 if it has bump outs, and the siding follows the perimeter, not the square footage.

What this calculator assumes

  • A gable is a triangle, so its area is the width squared times the pitch divided by 48. Two gables on a 30 foot wide house at 6/12 add about 225 square feet, which is more than two squares of siding that people routinely forget.
  • Openings are deducted at half, not in full. You still cut siding around a window and the offcut is usually scrap, so the trade rule is to take off half the opening and leave anything under 10 square feet in.
  • 12 percent waste is normal for vinyl on a straightforward house. Lap siding, a cut up elevation or a staggered shake course runs higher.
  • A carton of vinyl siding covers two squares, 200 square feet. Fiber cement and wood lap are sold by the piece, so use the square figure and convert at your supplier's coverage.

Questions people ask

How many squares of siding for a 1,500 square foot house?

About 17.4 squares, or nine cartons of vinyl, for a single story with a 160 foot perimeter, nine foot walls and two 6/12 gables. The gables and the perimeter shape move that figure more than the floor area does.

How do you calculate gable area?

Width squared times the pitch divided by 48. A 30 foot wide gable at 6/12 is 30 times 30 times 6 divided by 48, which is 112.5 square feet each, 225 for a pair. That shortcut is the triangle area formula with the rise already substituted out, so you never have to measure the height of the peak.

Do you subtract windows and doors from siding?

At half, not in full. You still cut siding around every opening and the offcut usually cannot be used anywhere else, so the trade rule is to take off half the opening area and leave anything under about 10 square feet in the number entirely.

Different numbers?

The siding calculator takes any dimensions you like and hands back the same list.

Other common sizes