ContractorHandbook

How Many Shingles for a 24x24 Garage Roof?

Roofing squares needed

6.7 squares

A 24 by 24 foot garage at a 4/12 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 length24 ft
  • Building width24 ft
  • Roof pitch, rise per 12 in4 /12
  • Waste allowance10 %
  • Ridge length, 0 if unknown24 ft

Roofing squares needed6.7 squares

Footprint area576 sq ft
Slope multiplier at 4/121.05 x
Actual roof surface607 sq ft
Squares before waste6.1
Squares with 10% waste6.7order to this number

The material list this produces

Shingles, bundles (3 per square)21
Synthetic underlayment, rolls (10 sq each)1
Starter strip, linear ft108
Ridge cap, linear ft24
Drip edge, linear ft96
Roofing nails, lb15

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
4/126.7 squares
6/127.1 squares
8/127.6 squares
10/128.2 squares
12/129 squares

What else matters here

A detached two car garage is the smallest roof most people ever order materials for, and at 4/12 the slope multiplier is only 1.054, so the footprint and the roof are within six percent of each other. This is the one case where the shortcut almost works.

Seven squares is 21 bundles, which fits on a pickup and does not need a delivery. It is also small enough that the minimum order rules start to bite: a single roll of synthetic underlayment covers ten squares, so you are buying more than you need and that is simply the price of a small roof.

Garages are where second layers live. If there is already one layer of shingles up there and the sheathing is sound, a lay over is legal in most jurisdictions and saves the tear off entirely. Check the local code, then check the deck, because a garage roof is also where soft sheathing hides.

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 24x24 garage?

About 21 bundles at a 4/12 pitch with ten percent waste, which is 6.7 squares.

How many squares is a 24x24 roof?

The footprint is 5.76 squares. At 4/12 the roof is 6.07 squares before waste and 6.7 after. At a steeper 8/12 it is 8 squares with waste.

Can I shingle a garage roof myself?

It is the most realistic roof to do yourself: low pitch, small area, simple shape, no second story. The parts that still need doing properly are the underlayment, the drip edge and the nailing pattern, all of which decide whether it lasts.

Different numbers?

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

Other common sizes