What Size Staples for Roofing Felt? (Answered)

When shingling a roof, one of the first questions that pop up in a homeowner’s or a builder’s mind is; “what size staples for roofing felt should be used?”

Likewise, whether staples or cap nails are ideal for fastening roofing felt is also commonly asked.

Roofing protects a roof against excessive moisture, acting as a barrier against any humidity, rain, or snow.

Homeowners who wish to secure their roofs against moisture, snow, and water leaks should install strong roofing felt, either with the help of staples or cap nails.

The question is, what size staples for roofing felt should be used? Let’s explore the answer below.

What Size Staples for Roofing Felt is Ideal?

Roofing felt, or roofing underlayment, protects your roof against extreme weather conditions such as snow and rainfall.

However, to securely fasten these underlayments, it is vital to use staples of the right size so that the strength and durability of roofing felt are not compromised.

A good choice for fastening a 30lb roofing felt is T50 staples made of stainless steel with a length of ½ inches.

Stainless steel and heavy-duty staples are essential for providing extra strength to the roof, especially in areas where there are extreme weather conditions, such as high winds or excessive snowfall.

The right size of T50 staples ensures the roofing felt is properly attached and protects against wind and water.

However, if the wrong size of T50 staples is used, the roofing underlayment will not stay in place, and high winds can forcefully uproot the roofing felt, causing damage to the roof and its interior surfaces.

On the other hand, roofing felt underlayment installed with T50 staples greater or smaller than ½ inches would not be able to protect the wood decks from harsh exposure to wind, causing destruction and uprooting.

How Many Staples Should Be Used for Fastening Roofing Felt?

When installing roofing felt for your roof, you should use 400 staples per square to attach roofing felt. You would also need four fasteners per shingle to secure the roof shingles.

A dual-capacity tack hammer is also recommended for stapling the roof felt, strengthening the staples more securely and strongly.

Why should You use T50 Staples for Roofing Felt?

For roofing felt installation, it is necessary to use stainless steel T50 staples of ½ inches in length for secure roofing felt. Here are some of the reasons you should be using T50 staples for roofing felt:

  • Widely used for heavy-duty applications, such as installing roofing underlayments and boards.
  • It is also used in other common stapling applications, such as installing house wraps, window fastenings, wood crafts, masonry, furniture upholstery, and DIY projects.
  • Made of stainless steel that ensures long-lasting strength and durability of roofing felt.
  • Have remarkable holding power for all roofing projects.
  • Staples are less costly than cap nails for roofing felt installation and offer more holding strength than the latter.
  • Staple guns are commonly used to install staples for roofing felt. These staple guns are easy to repair when they get jammed and are easy to replace as well.

Staples vs. Cap Nails for Installing Roofing Felt

While staples and cap nails are used to fasten roofing felt, the choice of which securing tool should be used depends on the roof’s slope.

Cap nails are steel and used for securing the roofing underlayments.

Many people prefer using cap nails to fasten the roofing felt because they deliver more waterproofing in case high winds remove the top layer of roof shingles.

They also reduce tearing and uprooting that might occur due to high winds. However, staples are recommended for securing roofing underlayments as they are easier to install and more secure than nails.

Moreover, staples also deliver more durability and strength for a long-lasting underlayment that can withstand extreme weather conditions.


For securing or fastening roofing felt, it is necessary to use staples of the right size and material. But what size staples for roofing felt are ideal?

The ideal length of staples for securing roofing felt is stainless steel T50 staples of ½ inches, as staples of these sizes are easy to install and deliver strength and durability to the roofing felt as protection against high winds and rain.