Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.
When properly installed, joist hangers can keep your floors and decks secure and in good condition. While structural nails are typically used to fasten joist hangers, you may be wondering if screws can be used instead.
You can use screws explicitly made for joist hangers. However, avoid using any other types of screws as they cannot support joist loads and are not designed to withstand shear force.
While screws made specifically for joist hanger support are an option, there are other types of attachments used. We’ll take a look at some of the other options and discuss why some work well while others don’t.
Before we get into the details of connectors, let’s take a look at what joist hangers are to begin with and what specific purpose they serve.
What are Joist Hangers and what are they used for?
Joist hangers are used as structural support for wood joists on floors, ceilings, decks, and other such applications. They are typically U-shaped and come in various sizes and shapes.
Joist hangers are designed so that they wrap around three sides of a joist and have multiple holes so they can be attached
Because joist hangers are galvanized, the ideal types of fasteners are galvanized metal to avoid corrosion. Nails work well as long as they are sized correctly, but manufacturer-specified specialty screws can also work.
Consult the Manufacturer’s Guidelines
It’s best to use the specific types of fasteners that are specified by the joist hanger manufacturer. The right types of fasteners will ensure your floor retains the required performance standards.
Joist hangers play essential roles in the stability of floors, roofs, and ceiling. Therefore, manufacturers test every aspect of joist hangers to ensure the products meet the required standards. Be sure to consult the manufacturer’s guidelines when installing joist hangers to ensure you use the right type of fastener.
Deck Screws and Joist Hangers
Avoid using standard deck screws to install joist hangers. Although the deck screws have strong holding power, they are vulnerable to breaking when under shear stress.
Stress occurs when the shank of the fastener or screw moves back and forth. Screws are subjected to stress when joist hangers sway due to winds, seismic activity, or soil settlement.
Standard deck screws are usually made of hardened steel that can snap under stress. Instead of using standard deck screws to install hangers, consider using specialty screws.
The use of roofing nails as structural attachments for joist hangers is not uncommon, however, it should be avoided. Roofing nails are not made to withstand the structural forces that are required for joist hanger connectors.
What’s more, chances are high that the use of these nails would fail a building inspection. Over time, these types of nails do not hold up well and structural damage is likely to occur. Avoid them.
Joist Hanger Fastener Options
Joist hangers should be installed with hot-dip galvanized structural nails whenever possible. 16d and 10d nails are usually recommended for most applications.
For exterior joist installation projects, nails need to be corrosion resistant. It is generally a good practice to use them on interior installations as well. Hot-dip galvanized nails can work for this purpose.
Keep in mind that you’ll also want to use joist hangers that are made for outdoor use if the application is exterior. You can usually identify exterior joist hangers by the “z” symbol they have at the end of the model number.
Some manufacturers produce specialty nails that they recommend for installing their joist hangers. These types of nails usually feature thicker shanks than standard nails to withstand significant amounts of stress.
One of the benefits of using specialty nails is they pass through joist hanger nail holes without catching. Standard nails may not fit joist hanger nail holes.
Avoid these Joist Hanger Installation Mistakes
There are some common mistakes that people make when installing joist hangers. Avoid these mistakes to ensure your joist hanger is installed correctly.
Wrong Sized Joist Hanger
Many people make this mistake when they purchase joist hangers that are much smaller than the joists they are hanging. Be sure to buy joist hangers with the right dimensions for the joist you want to hang.
If you are unsure, measure the joist width and depth before purchasing the joist hanger. If you have engineering drawings or specifications to work from, consult those prior to making your purchase.
Not Filling all the Nail Holes
It is vital to secure the joist hanger completely. This can be done by inserting nails through each of the nail holes in the joist hanger.
Filling all the nail holes in the joist hanger helps to ensure it meets load capacity ratings. This is a crucial step to complete regardless of the number of joist hangers you need to hang.
Re-using Joist Hangers
Avoid re-using joist hangers even if they look like they are still in good shape. Reusing joist hangers undermines the integrity of your deck or floor.
Keep in mind that these are structural devices. While some materials can be recycled and re-used, you should avoid doing so with joist hangers.
Cutting or Reshaping Joist Hangers
Sometimes joist connections do not fit the standard configuration that joist hangers are intended for. You should avoid modifying the joist hanger by cutting it or reshaping it. Doing so will affect their structural integrity.
Instead, you should look for joist hangers that are shaped and specifically designed for such connections. Keep in mind that joist hangers come in various shapes, so you should have no problem finding the right type for the intended application.
Screws for Related Connectors
You may encounter different types of connectors when working with joist hangers including:
- Tie straps
- Post cap saddles
- Post base brackets
Many manufacturers recommend screws for some of these connectors, especially post cap and post base saddles. As always, be sure to consult your joist hanger manufacturer’s guidelines for specific instructions.
While you can use screws that are specifically created to support joist hangers, you should avoid using any other type of screw as it will not meet the shear force requirements for structural support.
Improper use of joist installation materials leads to a poorly installed floor system that is incapable of managing loads and performing as required.
Always consult the specifications of the joist hanger manufacturer and, if you have them, the engineering drawings that should specify the types of materials to use for proper installation.
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