Whether you’re building a brand new home, extending a room, or want to renovate an older building, the floor is one of the most important things to consider.

You want your floor to be safe, secure, and stable for many years. Especially if you have heavy furniture or a lack of interior walls, you’ll need to plan your floor supports accordingly.

This article will compare and contrast the two most common types of floor supports: trusses and joists. We will highlight their advantages and disadvantages across a range of relevant categories. Ultimately, we’ll help you decide which support is right for your home ahead of construction time.

Floor Truss vs Floor Joist

What is a floor truss?

The job of a floor truss is to help keep the floor firmly in place. They are similar in design to bridges in that they have a flat top and bottom chord and a series of interconnected components that look like triangles.

Like the bridge, a floor truss is anchored on either end (usually to exterior walls) and can support heavy weights across its entire length.

Floor trusses are high-quality and custom-made, meaning that your architects and carpenter will measure and design the support system relevant to your rooms. They can be made in various materials, including wood, metal, or composite.

What is a floor joist?

A floor joist is a horizontal support structure that helps distribute the weight of a room, including the walls, furniture, flooring, and people inside, and helps frame an open space.

Joists are evenly distributed parallel to each other, underneath a plywood subfloor, often between two load-bearing walls. They are made from sawed logs and come as pure or engineered timber.

Floor joists are mass-produced in various standard sizes and grades that will fit the majority of homes. You can visit your local hardware store and buy them off the shelf.

Which is Better?

Now that we know the background of each support, it’s time to compare and contrast them. We’ve used various industry criteria to highlight the benefits of trusses and joists, picking a clear winner in each category.

1. Load bearing capacity: Winner – Floor truss

The load-bearing capacity means the maximum weight the truss or joist can carry. The higher the capacity, the better the support performs.

Floor trusses are the clear winner in this category because they come in four different bearing conditions – bottom chord bearing, bottom chord trimmable ends, top chord bearing, and mid-block bearing. This level of choice ensures you can adequately match floor heights.

Floor joists, on the other hand, only come in one load-bearing variation – bottom chord bearing. This can significantly limit their suitability in your home, especially if heavy-duty furniture like a pool table, hot tub, etc., needs support in the room.

2. Installing utilities: Winner – Floor truss

Especially if you are building a new home or extending a room, installing your utilities is one of the most important (and overlooked) things. We’re talking plumbing, electrical wires, ducts, radiant heating systems, and more.

Yet again, there is a clear winner in this department – trusses. Trusses create horizontal space when laid, making twisting and fitting cables and pipes easy throughout the supports.

This, in turn, can speed up the work of electricians and plumbers because they won’t have to drill or manipulate anything to install utilities. It also futureproofs your room – if you need to repair any system, you can access them easily with trusses.

Unfortunately, floor joists don’t offer the same flexibility. Because they are wide beams, your contractor might have to drill holes throughout the spaces to accommodate their work.

There’s also the chance that mistakes can be made where drilled holes don’t line up. Too many holes in a joist can dramatically reduce strength and load-bearing capacity. It also means you might have to buy replacement joists to compensate for human error.

3. Cost: Winner – Tied

Price can be challenging with floor supports because homeowners often forget to include labor and time spent installing when calculating the final cost.

On the one hand, we can focus on the price per square foot of the material. On raw materials alone, floor joists are a much cheaper material to use, averaging about 15% cheaper than floor trusses can cost.

This is because joists are generic, mass-produced, and quickly found in most, if not all, hardware stores. Floor trusses are custom-made, so you must absorb the added design and production costs.

Although floor truss systems are more expensive, they can help save you money in the long run. As we’ve said, electricians and plumbers love to work around trusses because they’re easy to lay pipes and cables around, and there’s little room for error during installation.

While trusses may cost more initially, you could save on hourly labor costs for subsequent repair work for your electricians and plumbers, including in the future. In our view, they are a worthy investment.

Therefore, we feel that both these types of floor supports are tied, and you should be influenced by what you can afford at the moment of construction.

4. Support requirements: Winner – Floor Truss

An important thing to consider when laying your flooring is figuring out if the beams underneath require their own supports to stay in place. Some might need to be near a bearing wall to anchor to.

The clear winner here is floor trusses because they do not require the installation of intermittent supports. This means they are excellent support for open rooms without any interior walls, giving you freedom in designing the room to your exact needs.

In contrast, floor joists need beams and posts laid throughout the room to be anchored. Depending on the room’s design, floor joists may be virtually impossible to lay down – even if you wanted them! Because they need a wall or beam, floor joists are useful for flooring smaller spans of about 10 to 15ft.

5. Fire safety: Winner – Floor joist

Fire safety is a significant concern for every homeowner. And how safe your home is can be influenced by whether you have floor trusses or floor joists in place.

One of the critical advantages of floor joists is that they fair better during a house fire. Firefighters say that a joist typically has a longer burning time than a truss, meaning it will not cave in as quickly when exposed to extremely high temperatures.

That said, the industry recommendation is that if you live in a hot climate where fires are a common concern, you may not want to use wood material in your home’s construction, instead opting for cinderblocks or concrete. You may also be able to clad or reinforce your support beams with fire retardant material to boost their safety, giving you some peace of mind in the time ahead.

6. Noise: Winner- Floor Truss

There’s nothing more annoying than setting down your floorboards or floor tiles, saying goodbye to your contractors, and realizing then that your floors are squeaking. Or there’s an audible “bounce” as you walk across your room.

Noise from floor supports can be a crucial thing to consider, especially when talking about multi-story homes. Floor trusses are the easy winner here because they are known for eliminating bounce.

Trusses stay rigid and stiff throughout their lifetime. You can rely on them to hold their furniture form, even when supporting heavy furniture like pool tables, hot tubs, etc.

On the other hand, floor joists are known to suffer from shrinkage as they dry out. If they warp, a space is created between the floor and the subfloor. When the floor and subfloor clash, a squeaky bounce is made in the room.

Conclusion

We believe floor trusses offer more benefits to support your new floor than floor joists. Yes, a truss is more challenging to install and can initially cost you more per foot, but it offers unmatched strength, durability, and support.

Also, a truss can make installing HVAC systems much easier, especially if you need to repair these systems in the future.

While joists are cheaper and easier to install, they cannot support as much weight as their rivals. And because they’re awkward for builders, plumbers and electricians, they can prolong installation and add to your labor costs.

If you still have a question about the differences between a floor truss and a floor joist, please leave a common.

In short, remember:

• Floor trusses don’t require intermediate support, whereas floor joists need a nearby beam or post to anchor to.
• Floor trusses have a higher load-bearing capacity, which can support heavier weights than joists.
• Remember – despite being more expensive, trusses might save you money if you hire an electrician or plumber to install utilities around your home.