ContractorHandbook

How Many Shingles for a 1,100 Square Foot House?

Roofing squares needed

13.5 squares

A 1,100 square foot footprint, 44 by 25, 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 length44 ft
  • Building width25 ft
  • Roof pitch, rise per 12 in6 /12
  • Waste allowance10 %
  • Ridge length, 0 if unknown44 ft

Roofing squares needed13.5 squares

Footprint area1,100 sq ft
Slope multiplier at 6/121.12 x
Actual roof surface1,230 sq ft
Squares before waste12.3
Squares with 10% waste13.5order to this number

The material list this produces

Shingles, bundles (3 per square)41
Synthetic underlayment, rolls (10 sq each)2
Starter strip, linear ft156
Ridge cap, linear ft44
Drip edge, linear ft138
Roofing nails, lb30

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
4/1212.8 squares
6/1213.5 squares
8/1214.5 squares
10/1215.8 squares
12/1217.1 squares

What else matters here

Eleven hundred square feet of footprint at 6/12 is 1,230 square feet of roof, 13.5 squares with waste, forty one bundles.

The material list also calls for 156 linear feet of starter strip, and that is a line worth understanding rather than skipping. The first course at the eave has to be a starter, not a shingle turned around, because a starter has its adhesive strip along the bottom edge where the wind gets under the first course.

A field shingle has the adhesive higher up, so flipping one leaves the very edge of the roof unsealed, which is where blow offs start. The same applies along the rakes on many manufacturers' instructions, and a starter run is a wind warranty condition as well as a good idea. Buy the starter roll rather than cutting field shingles down, because the cut version puts the seal in the wrong place too.

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 1,100 sq ft house?

About 41 bundles at a 6/12 pitch with ten percent waste, which is 13.5 squares.

What is starter strip and do I need it?

A purpose made first course with its sealant along the bottom edge. It seals the very edge of the roof, where wind gets under the shingles, and it is a wind warranty condition for most manufacturers.

Can I use a shingle upside down as starter?

It was once common and it is no longer accepted. A flipped field shingle puts the adhesive strip in the wrong place, leaving the eave edge unsealed.

Different numbers?

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

Other common sizes