How Much Roofing Felt Do I Need for a 10×8 Shed?

Last updated: 2026-06-11 by Ted Sellers, Owner

How much roofing felt for a 10×8 shed? One 36-inch wide roll of #15 felt covers it — about 400 square feet of coverage with a 10% waste factor built in. One 36-inch-wide roll of #15 roofing felt is enough for a 10×8 shed. A standard #15 roll covers about 400 sq ft, and a 10×8 shed roof — even with a steep pitch — won’t exceed 130 sq ft of total roof area. You’ll use about a third of the roll and have plenty left over for a future repair or a second small project.

If you’ve got a flat shed roof instead of a pitched one, swap to one 50-pound roll of #30 felt for extra puncture resistance. The coverage is similar but the thicker felt holds up better when there’s no slope to shed water quickly.

I’m Ted Sellers from Sellers Roofing in Arden Hills, MN. I’ve shingled my share of detached garages, lawn-mower sheds, and chicken coops over 18 years in the field. The amount of felt is the easy part of a shed roof. What trips people up is overlap, fastening, and whether felt is even the right underlayment for a shed this small.

The math on a 10×8 shed roof

A 10×8 shed has 80 sq ft of footprint. The roof itself is bigger than 80 sq ft because of the pitch. For typical shed pitches:

Roof pitch	Pitch multiplier	Roof area (10×8 footprint)
Flat (1/12)	1.003	80 sq ft
3/12	1.031	82 sq ft
4/12	1.054	84 sq ft
6/12	1.118	89 sq ft
8/12	1.202	96 sq ft
10/12	1.302	104 sq ft
12/12	1.414	113 sq ft

Even a steep 12/12 gable roof on a 10×8 shed only needs 113 sq ft of coverage. That’s a fraction of what’s in a standard 400 sq ft roll of #15 felt.

For a gambrel shed (double-pitched, common for storage barns), add about 15% to the totals above. A 10×8 gambrel maxes out at around 130 sq ft.

How much felt is in a roll?

The two felt grades you’ll see at supply yards in the Twin Cities:

#15 felt (lighter, more common):

• Roll dimensions: 36” wide × 144 linear feet
• Coverage: 400 sq ft per roll
• Weight: about 30 lbs
• Best for: pitched shed roofs (4/12 and steeper)

#30 felt (heavier, more durable):

• Roll dimensions: 36” wide × 72 linear feet
• Coverage: 200 sq ft per roll
• Weight: about 50 lbs (often called “50-lb felt”)
• Best for: low-slope shed roofs (under 4/12) or shed floors that might see standing water

For a 10×8 shed, one roll of either is more than enough.

Overlap rules (this is the part people skip)

Felt isn’t installed edge-to-edge. The horizontal rows overlap, and the ends overlap, and skipping the overlap is how you get a leak the first time it rains hard.

Standard overlap pattern for shed felt:

• Horizontal overlap (between rows): 2 inches for #15 felt, 2–4 inches for #30
• End overlap (between rolls): 4 inches
• Hip and ridge overlap: 6 inches over the peak
• Eave overhang: 1 inch past the drip edge

Those overlaps eat into your coverage. A 400 sq ft roll of #15 effectively covers about 360 sq ft once you account for overlaps and trim. For a 10×8 shed, you’re still well inside one roll.

Step-by-step: felting a 10×8 shed roof

This is the order I use. It works for any pitched shed roof.

1. Start at the eaves. Run the first course of felt parallel to the lower edge, with a 1-inch overhang past the drip edge. This is the most critical row — water that gets past the shingles needs the felt to channel it off the roof, not into the soffit.

2. Staple every 12 inches. Roofing staples or 1-inch cap nails. Cap nails are better but staples are fine on a small shed. Drive them flush, not deep enough to tear the felt.

3. Overlap the next course by 2 inches. Snap a chalk line if you want it straight. On a 10×8 shed with one 36-inch roll of felt, you’ll have 3 horizontal courses to reach the ridge on most pitches.

4. End-lap is 4 inches. If you have to splice rolls horizontally (rare on a shed this small), the seam should fall 4 inches over the previous roll, with the upper roll on top.

5. At the ridge, lap one course 6 inches over the peak. This protects the seam between the two roof slopes. On a gambrel, do the same at each pitch break.

6. Trim flush at the rakes (gable ends). Leave a half-inch overhang for the drip edge to bend over.

A 10×8 shed roof takes about 30–45 minutes to felt by yourself, an hour if you’re working slowly.

When to use synthetic underlayment instead

Synthetic underlayment (brands like GAF FeltBuster, Owens Corning Deck Defense, Tyvek Protec) costs more per roll but is becoming standard on full-house roofs. For a shed, the cost-benefit usually favors felt.

Use synthetic if:

• Your shed is going to sit exposed (without shingles) for more than a week. Synthetic holds up to UV. Felt wrinkles and cracks in sun within 5–7 days.
• The shed roof is steep (10/12 or steeper) and you’ll be walking on it. Synthetic has better foot traction.
• You’re storing something expensive in the shed (lawn equipment, motorcycle) and want extra leak insurance.

Use felt if:

• You’re shingling within a few days of decking.
• You want the cheapest reliable option.
• The shed roof is a standard pitch and won’t get walked on much after install.

For 90% of 10×8 sheds, #15 felt is the right answer.

Common mistakes I see

A few things that come up when homeowners call me to look at a leaky shed roof:

1. Felt installed upside down. Felt has a smoother side (facing down toward the deck) and a rougher side (facing up toward the shingles). Reversing this can cause the shingles to slide on hot days.

2. No drip edge. Drip edge goes UNDER the felt at the eaves and OVER the felt at the rakes. Most shed kits skip drip edge entirely. Add it — about $20 in metal for a 10×8 shed.

3. Skipping the felt over OSB seams. If the shed decking is OSB or plywood, the felt has to bridge the joints. Seams in the decking should be at least 4 inches from any felt overlap so you don’t double up weak spots.

4. Using duct tape to patch tears. Use felt-specific tape or a small strip of felt with roof cement. Duct tape adhesive fails in heat.

What about ice and water shield?

Minnesota residential code requires ice and water shield on house roofs at all eaves and valleys. Sheds are exempt — they’re considered accessory structures. You don’t need ice and water shield on a shed in St. Paul, Minneapolis, or any Twin Cities suburb.

That said, if the shed is heated (a workshop with a wood stove, for example) or you’ve had ice damage on a previous shed roof, adding 2 feet of ice and water shield at the eaves costs about $30 and prevents a known failure point.

Frequently asked questions

How much felt paper do I need for a 10×8 shed?

One roll of #15 felt is enough. A standard #15 roll covers 400 sq ft, and a 10×8 shed roof has 80–130 sq ft of area depending on pitch. You’ll use about a third of the roll and can store the rest for future repairs.

Do I need #15 or #30 felt for a shed roof?

Use #15 felt for pitched shed roofs (4/12 and steeper) and #30 felt for low-slope shed roofs (under 4/12). #30 is heavier and more puncture-resistant, which matters when water sits on the roof longer before draining.

How much does a roll of roofing felt cost?

A 400 sq ft roll of #15 felt costs $30–45 at Twin Cities supply yards. A 200 sq ft roll of #30 felt costs $35–50. Synthetic underlayment (like FeltBuster or Tyvek Protec) runs $90–130 for a 1,000 sq ft roll.

Can I skip the felt on a shed roof?

You can, but you shouldn’t. Felt is the secondary water barrier under the shingles. Without it, any water that gets past the shingles (hail, ice dams, missed nail holes) hits the bare decking and rots the OSB. The $30 you save on felt costs you a new roof deck in 8–10 years.

How many staples do I need per roll of felt?

About 1 box (5,000 staples) is plenty for a shed-sized job. Use ⅞-inch crown roofing staples, every 12 inches along the rows, every 6 inches along the edges and overlaps. On a 10×8 shed, you’ll use 150–200 staples total.

Does felt go under or over the drip edge?

Felt goes OVER the drip edge at the eaves and UNDER the drip edge at the rakes. This is backwards from what most people guess. The pattern lets water drain off the roof instead of behind the fascia.

 

Related Sellers Roofing guides: Learn how much a bundle of shingles cover, how to estimate shingles in a square, whether you need roof turbines for attic ventilation, and explore our Twin Cities roofing services.