Garage Door: Weatherstrip Rolls Needed

All versions

A garage door seal runs across the bottom or top and up both sides. This recipe adds the width and twice the height to get the inches of seal, converts to feet, adds waste for corners and cuts, and divides by the roll length to get whole rolls.

Quick formula: Width plus twice the height, in feet, times waste, divided by roll length:

=ROUND((B2+2*C2)/12,1)

A 192 x 84 inch door needs 30 feet of seal, which at 10% waste is 3 rolls of 15 feet.

Functions used (tap for the full reference guide):

ROUNDUP ROUND

The example

Three door sizes. Taller doors add seal on both sides, so height counts twice.

	A	B	C	D	E	F	G
1	Case	Width in	Height in	Waste %	Roll ft	Feet	Rolls
2	16 x 7 ft	192	84	10.0%	15	30.0	3
3	9 x 7 ft	108	84	10.0%	15	23.0	2
4	16 x 8 ft	192	96	10.0%	15	32.0	3

The formula

Perimeter on three sides, converted to feet and rolled up to whole rolls:

=ROUND((B2+2*C2)/12,1) // feet of seal; rolls = ROUNDUP(feet*(1+waste)/roll length,0)

How it works

Here is the logic, one piece at a time:

B2+2*C2 is the width plus two sides, in inches.
Dividing by 12 converts to feet.
(1+D2) adds waste for mitred corners and trimming.
Dividing by the roll length in E2 and rounding up gives whole rolls.

Use the same pattern for any seal that runs along the door's top and sides.

Try it: interactive demo

Interactive

Enter the door size, waste and roll length.

Door width (in)

Door height (in)

Waste percent

Roll length (ft)

Variations

Include the top seal separately

Add the width again for a separate top seal.

=ROUNDUP((2*B2+2*C2)/12*(1+D2)/E2,0)

Pull door size from a table

Look up width and height by standard door size name.

=ROUNDUP((VLOOKUP(Size,Doors,2,0)+2*VLOOKUP(Size,Doors,3,0))/12*(1+D2)/E2,0)

Pitfalls & errors

Bottom seals are often sold in lengths equal to the door width, not rolls; confirm the product form.

Mixing inches and feet gives answers off by a factor of twelve. Keep dimensions in inches and divide once.

Check the door for rubbing before you buy; a new seal can be thicker than the old.

Practice workbook

📊

Download the free Garage Door: Weatherstrip Rolls Needed practice workbook

Edit the yellow dimensions, waste and roll length; feet and rolls recalculate.

Frequently asked questions

Why twice the height?

There is a side seal on each side of the door, so the height is used twice.

Does this include the bottom seal?

Not as written. Use the Variations formula if you replace the top and bottom seals together.

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Function references: ROUNDUP ROUND