Should I Sister a Floor Joist?

Some homeowners are skilled enough with wood working that they will attempt to DIY projects involving it. Therefore, when a crawl space floor joist is somehow damaged, they won’t hesitate to try and fix it themselves. A common solution to floor joist failure is sistering a joist. It’s relatively simple and can be done by many, even those with limited experience with crawl spaces. 
 
However, sistering a floor joist isn’t always the solution. Often, DIY solutions are a band aid on the problem instead of a permanent fix. 

• The Problem with Sistering a Floor Joist  

Sistering a floor joist involves attaching a second piece of wood to the failing floor joist. The idea is that the damaged joist can be reinforced with a healthy piece of wood. The joist itself lacks strength, so the “sister” joist aids it in holding up the floor. There are two problems with this and it’s that, while a healthy piece of wood can provide some reinforcement, it’s not a solution that will last long. If your floor is sagging because of wood rot and you don’t waterproof your foundation, then the healthy joist will soon get infected as well. 
 
Not to mention, while a piece of wood can provide temporary reinforcement, it cannot even out your floor. Your floor will still be uneven after sistering a joist because there is no way to exert upwards pressure on the floor with the wood alone. Sistering a joist is fine for a quick fix as you wait on foundation repairs, but if you care about the long-term health of your crawl space, you’ll need another solution.  

• What To Do Instead 

Instead of sistering a floor joist, contact your local foundation repair experts as fast as you can. The more the floor sags, the more likely it is that the floorboards get damaged or that someone gets hurt. Walking on an uneven floor is a safety risk, so evening out the floor should be a priority. Also, sistering a floor joist might not help you solve the issue because the problem could lie in the concrete posts or walls instead of the joists. 
 
There are certain solutions that are specially designed to repair joists permanently, and sistering a joist is not one of them. A foundation expert can bring you better, more cost-effective solutions, so consider calling a professional if your floor is sagging.