KKV Labs

Free roofing calculator

Drip edge calculator

This drip edge calculator counts the pieces you need for the eaves and rakes, with the 2 inch overlap the IRC requires at every joint, waste for corners and cut offs, and the fasteners to hold it at 12 inches on center. Enter your edge lengths and order straight from the result.

ft

Every bottom edge, added up.

ft

Every sloped gable edge, measured along the slope.

ft

Drip edge is usually sold in 10 ft sticks.

in

The IRC minimum is 2 in (Florida asks for 3 in).

%

Corner miters, cut offs and damaged sticks.

in

The IRC maximum is 12 in on center.

Pieces of drip edge

2010 ft pieces

160 linear feet of eaves and rakes, with a 2 in overlap at every joint and 10% waste.

Eave pieces
11
Rake pieces
7
Waste pieces
2
Total pieces to order
20
Linear feet of material
200 ft
Fasteners
178

Chart

Drip edge pieces by length of edge

Number of 10 foot pieces for a run of eave or rake, at the IRC 2 inch overlap, at Florida's 3 inch overlap, and at 2 inches with 10% waste.

Drip edge pieces needed by length of edge
Edge length2 in overlap3 in overlap2 in + 10% waste
20 ft334
40 ft556
60 ft778
80 ft9910
100 ft111113
120 ft131315
150 ft161618
200 ft212124
250 ft262629
300 ft313135

Code notes

What the code says about drip edge

Where. The IRC (R905.2.8.5) calls for drip edge at the eaves and rake edges of asphalt shingle roofs.

How it sits. It has to reach at least 1/4 inch below the roof sheathing and run at least 2 inches back up onto the deck. Underlayment goes over it at the eaves and under it at the rakes.

Joints and fastening. Adjacent pieces overlap by at least 2 inches, and the drip edge is fastened to the deck no more than 12 inches apart.

Local changes. Florida asks for a 3 inch overlap and drip edge over the underlayment at the gables. Other states and towns amend the IRC too, so check the edition your building department enforces before you set the overlap and spacing above.

Questions

What roofers ask about this

How many pieces of drip edge do I need?
Add up the eaves and the rakes and divide by the length each piece really covers, which is the piece length less the overlap. With 10 foot pieces and a 2 inch overlap each extra piece adds 9 feet 10 inches, so 100 feet of eave takes 11 pieces and 60 feet of rake takes 7: 18 before waste and 20 with 10% waste.
Does drip edge go over or under the underlayment?
Under the IRC (R905.2.8.5) the underlayment goes over the drip edge at the eaves and under the drip edge at the rakes. So at the eave the drip edge goes down first; at the rake it goes on top. Florida's code also allows eave drip edge over the underlayment and requires it over at the gables.
How far apart should drip edge be nailed?
No more than 12 inches on center under the IRC, with roofing nails or the fasteners the code lists for shingles. The calculator adds one more fastener per piece so every piece end is held down.
How much should drip edge overlap?
At least 2 inches between adjacent pieces under the IRC. Florida's building code asks for 3 inches. Overlap in the direction water runs so the upper piece sits on top.
Is drip edge required by code?
The IRC requires drip edge at the eaves and rakes of asphalt shingle roofs, reaching at least 1/4 inch below the sheathing and at least 2 inches back onto the deck. Whether it applies to your job depends on the code edition your building department has adopted.

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