How to Reinforce Ceiling Joists: How Much Weight Can They Hold?
The weight capacity of ceiling joists varies depending upon their design. A typical 2×6 ceiling joist weighs between 3 and 5 pounds.
If you want to make your home safer, it’s better if they are stronger than those rated at 3 or 4 pounds per square foot (psf). You can increase the strength of ceiling joists by using them with metal plates. However, there are other ways to strengthen ceiling joists.
If you have a large space in your house where you need to store items such as tools, books, furniture etc., then you might consider reinforcing ceiling joists with steel plate.
Steel plate is not only strong but also very easy to install. You just need some nails and screws and you’re done!
In addition to strengthening ceiling joists, you can also use them to create shelves. For example, you could add a shelf to the wall behind your sofa so that you don’t have to climb up into the attic anymore.
You can also put a bookcase under your bed.
You can see how sturdy and stable these shelving units are when compared with regular wood shelves!
You can also use metal plates to strengthen ceiling joists when you want to add additional support for an attic expansion. For example, if you plan to build an addition onto your home, then adding additional floor joists will give extra stability.
You could reinforce ceiling joists with steel plate so that they won’t collapse under the weight of the roofing shingle.
Metal plates will also increase the strength of your ceiling joists.
How to Reinforce 2×4 Ceiling Joists
Metal plates are easy to install and very affordable. You can reinforce a 2×4 ceiling joist by attaching metal plates to the bottom of it.
This process is extremely easy and you should be able to complete it within an hour or less.
Finally, if you have a free-standing garage, then be sure to reinforce ceiling joists with metal plates. Over time, your home may settle or shift due to soil conditions.
As a result, you could start noticing cracks in the walls and even the slabs. Of course, the garage is going to suffer from this settling too.
Even a car is heavy, so you certainly do not want the ceiling collapsing in on it!
If you do not install metal plates, then the weight of a car is more than enough to cause the ceiling joists to snap in half. This is something that you want to avoid at all costs.
Ceiling Joist Sistering
A sister beam is a wooden beam that spans between adjacent 2×4 roof joists to create a pathway for bridging (or blocking). This is a sistering beam to the ceiling joist.
Roof trusses are also sistered by blocking or bridging beams (or joists) to prevent them from twisting or bending too much.
Ceiling Joist Bridging
Blocking or bridging is the term used to describe wooden beams that go between ceiling joists to support the ends of the roof trusses.
Metal Plates for Ceiling Joists
Metal plates for ceiling joists are available in 16 and 24 inches wide types. You can pick these up at any sheet metal fabricating store.
You should also ensure that metal plates have the same coating on both sides to prevent them from rusting. Galvanizing is always a good choice, since it prevents oxidation from occurring.
If you look at a truss, you can see that is has a top chord and a bottom chord. These chords need extra support to prevent them from twisting or bending too much.
Reinforcing Ceiling Joists With Steel Plates
In some cases, you may want to reinforce ceiling joists further with steel metal plates.
When looking for metal plates, you’ll notice that there are many different types of metals to choose from. This isn’t something that most people think about, but there are several factors that you should consider before making a final decision.
Before you go running off to your local metal fabricating shop, you need to make sure that this is even necessary. If you installed metal plates on the bottom of each ceiling joist, then this might be overkill.
However, if you didn’t install metal plates on the bottom of your ceiling joists or if you just want to be extra safe, then it would be a good idea to add steel metal plates to the top of the ceiling joists as well.
First and foremost, you should always go with a metal that is coated because this prevents it from rusting. Galvanizing is the best method to prevent oxidation and coating metal plates with zinc is one of the most common methods for doing this.
Zinc coated metal will prevent any form of metal plate from rusting, which means that you’ll be able to use it for a very long time.
Secondly, you may want to consider using steel instead of galvanized metal. Galvanized metal tends to be a little bit more flexible than steel.
Now, this isn’t necessarily a bad thing, but it’s important that you understand the pros and cons between using steel and galvanized metal plates.
Galvanized metal is not as strong as steel, so it’s going to bend easier. This means that your ceiling joists are less likely to suffer any major damage from heavy objects resting on them if they’re made out of galvanized metal.
The extra weight that the trusses may have to endure can be a bit much for just the bottom chord of the trusses. Granted, they will have sistering blocking on top and bottom of them, but you still want to make sure that they are as strong as possible.
A lot of Framing carpenters like to sister joists and trusses with blocking or bridging which is short pieces of 2×4 lumber. Some professionals don’t sister joists with 2x material, but rather metal sistering plates (pictured below), which are also available at your local building materials supplier.
In any case, blocking or bridging is installed on the bottom of each truss and joist to add additional support. This makes a really big difference when it comes to preventing sagging or bowing in the floor system.
Now, you may be wondering why people would go through all of the trouble to sister joists and trusses if it’s possible to use metal plates instead. Well, it’s because metal plates are quite expensive and require a lot of extra work to install.
If you were building a small deck, then metal plates might be overkill. But, if you’re building a large deck or an entire house, then you should seriously consider using metal plates on each of the framing members.
In addition, metal plates serve other purposes than just preventing sagging joists and trusses. For example, metal plates provide a moisture or vapor barrier between the different layers of the floor structure, which in turn can prevent squeaks and creaks in your floor.
One thing you need to be aware of is that some metal plates are not 100% perfectly flat. Now, this may seem like a minor issue, but it can cause your floor to become uneven if not level.
If you’re building a large structure such as a house, then the small amount of unevenness in each plate probably won’t be enough to cause issues.
However, larger houses need a tremendous amount of framing work, and if your metal plates are not perfectly flat then this can result in floors that aren’t perfectly level.
Sources & references used in this article:
- Reinforced wooden wall (JG Ramirez – US Patent 5,531,054, 1996 – Google Patents)
- Reinforced building structure and method of constructing the same (JG Ramirez – US Patent 5,782,048, 1998 – Google Patents)
- Construction of reinforced-concrete-slab roofs for buildings (HDW James – US Patent 1,367,289, 1921 – Google Patents)
- Study on aseismic performance of integrated ceiling system and anti-fall measures of ceiling (Y Masuzawa, T Kanai, Y Hisada… – Proceedings of The …, 2017 – wcee.nicee.org)
- Non-combustible reinforced cementitious lightweight panels and metal frame system for roofing (TD Tonyan, JM Ullett, JE Reicherts – US Patent 7,841,148, 2010 – Google Patents)