Fabric Stapler & Roofing Staplers for Underlayment

Before the first shingle is ever nailed to the roof, the entire wooden deck must be wrapped in a waterproof barrier known as underlayment (synthetic felt or tar paper). If this thin barrier is not secured properly, a sudden gust of wind will rip it completely off the roof, leaving the bare plywood exposed to a sudden rainstorm. To secure thousands of square feet of underlayment rapidly, professional roofers rely on a heavy-duty fabric stapler.

Before you start stapling down your waterproofing membrane, you must know exactly how many rolls of underlayment to buy. Use our Free Roofing Calculator to calculate your exact roof surface area and generate a flawless material estimate in seconds.

Table of Contents

1. What is a Roofing Stapler?
2. The Danger of Standard Construction Staplers
3. The Industry Standard: Cap Staplers
4. Pneumatic vs Heavy Duty Hand Stapler
5. Conclusion: Protect the Membrane
6. Frequently Asked Questions

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What is a Roofing Stapler?

When laying down thin, tear-prone materials like tar paper, house wrap, or modern synthetic underlayment, a standard roofing nail is overkill and takes too long to install.

A roofing staple gun (or fabric stapler) is a specialized tool designed to shoot wide-crowned staples rapidly into the wooden roof deck. The staples feature a wide, flat top (the crown) that pins a large surface area of the thin fabric down against the wood, preventing the material from tearing loose in high winds.

The Danger of Standard Construction Staplers

If you walk into a hardware store and buy a standard upholstery stapler, a finish staple gun, or a basic heavy duty hand stapler (like a classic Arrow T50 squeeze-stapler), you will ruin your roof.

These standard construction staplers shoot incredibly thin wire staples with very narrow crowns. If you shoot a thin wire staple into synthetic underlayment, the sharp wire acts like a knife. The first time the wind blows, the underlayment will instantly tear itself straight through the thin wire staple, ripping off the roof. Furthermore, standard staples are rarely galvanized, meaning they will rust and degrade under your shingles.

You must use a wide crown stapler (where the top of the staple is at least 1/2 inch to 1 inch wide) to safely secure roofing membranes.

The Industry Standard: Cap Staplers

Today, building codes and shingle manufacturer warranties strictly require the use of a Cap Stapler (or Cap Nailer) for installing underlayment.

A cap stapler is a highly specialized pneumatic stapler for underlayment.

• It holds a coil of standard staples, but it also holds a massive roll of round, 1-inch plastic discs (the caps).
• When you pull the trigger, the gun automatically dispenses a plastic disc onto the roof, and simultaneously shoots a heavy-duty staple straight through the center of the plastic disc into the wood.
• The Result: The 1-inch plastic cap acts like a massive washer. It pins the synthetic underlayment down with incredible surface area, making it virtually impossible for the wind to tear the fabric. More importantly, the plastic cap completely seals the hole created by the staple, preventing rain from leaking through the underlayment.

Pneumatic vs Heavy Duty Hand Stapler

If you are choosing a tool to install underlayment, you have two primary options based on the scale of the job.

1. The Slap Stapler (Hammer Tacker): This is a heavy duty hand stapler that looks like a hammer. You literally slap it against the roof, and the momentum drives a staple into the wood. It is incredibly cheap, fast, and requires no air hoses. However, it cannot deploy plastic caps, meaning it does not meet modern building codes for severe weather zones, and the underlayment is highly prone to wind-tearing.
2. Pneumatic Cap Stapler (Air Stapler): This requires an air compressor and a hose. It is vastly more expensive, but it shoots the mandatory plastic caps. For professional roofers, a pneumatic cap stapler is the only acceptable tool for laying down underlayment quickly and legally.

Conclusion: Protect the Membrane

The underlayment is your home’s last line of defense against water if a shingle blows off in a storm. If you fasten that critical barrier using a cheap furniture stapler or narrow crown brads, the membrane will tear and leak immediately. By investing in a proper pneumatic cap stapler (or a high-quality medium crown stapler), you ensure the waterproofing stays pinned to the deck during the worst storms.

Once the underlayment is secured, you must cover it with shingles. Don’t guess how many bundles you need. Head over to our Free Roofing Calculator right now. By inputting your roof’s basic dimensions, our algorithm will calculate your exact square footage and generate a mathematically flawless estimate of all your roofing materials.

Related Guides

• Best Roofing Nailer: Top Rated Coil Guns
• DIY Shingle Roof: Materials Needed

Frequently Asked Questions

Can I use a siding staple gun on a roof?

No. A siding staple gun (often a medium crown 15 gauge staple gun) is designed to shoot incredibly long, heavy-duty staples (often 2 to 2 1/2 inches deep) to anchor thick vinyl or cedar siding into wall studs. This is massive overkill for thin roofing underlayment, and the deep staples will blow completely through the plywood roof decking, protruding dangerously into the attic below.

What size staples should I use for roof underlayment?

For synthetic roofing underlayment, you should use staples with at least a 1/2 inch to 1-inch wide crown, and the legs of the staple should be 3/8 inch or 5/8 inch long. This provides enough depth to anchor securely into 7/16-inch OSB roof decking without blowing completely through the wood into the attic space.

Do I have to use plastic caps?

It depends on your local building code and the manufacturer’s warranty. Many modern synthetic underlayment manufacturers (like RhinoRoof or Titanium) explicitly state in their warranty documents that the material must be installed using plastic cap staples or plastic cap nails. If you use a standard slap-stapler without caps, you void the warranty immediately.