ContractorHandbook

How Many Shingles for a 1,400 Square Foot House?

Roofing squares needed

17.2 squares

A 1,400 square foot footprint, 40 by 35, at a 6/12 pitch with ten percent waste.

It does not stop at a number.

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

12 in of runrise, inrafter linefootprintroof surfacefootprint x slope multiplier / 100 = squares
A roof is always bigger than the house under it, and how much bigger is right angle geometry rather than an allowance. Square the rise, add 144, take the root, divide by 12, and that multiplier turns a footprint into real surface area before any waste is added.

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.

  • Building length40 ft
  • Building width35 ft
  • Roof pitch, rise per 12 in6 /12
  • Waste allowance10 %
  • Ridge length, 0 if unknown40 ft

Roofing squares needed17.2 squares

Footprint area1,400 sq ft
Slope multiplier at 6/121.12 x
Actual roof surface1,565 sq ft
Squares before waste15.7
Squares with 10% waste17.2order to this number

The material list this produces

Shingles, bundles (3 per square)52
Synthetic underlayment, rolls (10 sq each)2
Starter strip, linear ft168
Ridge cap, linear ft40
Drip edge, linear ft150
Roofing nails, lb38

Roof pitch compared

Pitch is the number most people guess at, and it is worth more shingles than any other input. Same house, five pitches.

Roof pitchRoofing squares needed
4/1216.2 squares
6/1217.2 squares
8/1218.5 squares
10/1220 squares
12/1221.8 squares

What else matters here

Fourteen hundred square feet of footprint at 6/12 is 1,565 square feet of roof, 17.2 squares with waste, fifty two bundles.

Ventilation is the part of a reroof that is not on the material list and decides how long the shingles last. The code rule is one square foot of net free vent area for every 150 square feet of attic floor, which drops to one in 300 when the vents are split roughly evenly between high and low and a vapor retarder is present. On a 1,400 square foot attic that is a little over nine square feet at 1:150 and under five at 1:300.

Balance matters more than the total. A ridge vent with no soffit intake cannot draw from outside, so it pulls conditioned air out of the house through every ceiling gap instead, which raises the heating bill and pushes moisture into the attic. Look at the soffits before adding any more exhaust, because painted over or insulation blocked soffit vents are the usual reason an attic runs hot with a ridge vent already installed.

What this calculator assumes

  • Footprint times the slope multiplier gives the actual roof surface. A 6/12 roof is 11.8 percent larger than the ground it covers, which is the number most people forget.
  • Three bundles per square is standard for both three tab and architectural shingles. Check your brand, a few premium lines run four.
  • Synthetic underlayment is figured at 10 squares per roll, starter and ridge cap at one linear foot per foot.

Questions people ask

How many bundles of shingles for a 1,400 sq ft house?

About 52 bundles at a 6/12 pitch with ten percent waste, which is 17.2 squares.

How much attic ventilation do I need?

One square foot of net free area per 150 square feet of attic floor, or per 300 when intake and exhaust are balanced high and low with a vapor retarder in place.

Why is my attic hot with a ridge vent installed?

Almost always blocked or missing soffit intake. Without intake the ridge vent draws air out of the house instead of through the attic.

Different numbers?

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

Other common sizes