When you have a crack in a basement wall, you need to determine whether the crack is in concrete, brick, drywall or plaster. The type of wall will determine exactly which type of crack repair you need to perform. With that knowledge, a few tools and a little elbow grease, you should be able to repair any minor crack in your basement. However, to be safe, make certain that you note just how big or major the crack is. If it is too large and seems to be getting bigger each week, you will want to leave this task up to the pros.
Repairing Basement Cracks in Concrete or Brick Walls
If you have a basement crack in your concrete or brick, you have a definite problem to deal with. Because these materials are so durable, lasting up to 100 years, anything bigger than a small crack represents soil movement or faulty design, which means the crack will likely only get bigger. However, the good news is that there are plenty of different types of crack repair products on the market that can repair these larger structural problems.
Types of Repair Products to Use
- Special Cements
- Expand as they dry
- Must undercut the crack with a chisel so that it looks like a dovetail joint when looked at from the side
- Add the cement and allow to dry completely
- Check your local home improvement store for this type of cement
- There are specialty glues or epoxies made to help adhere old concrete to new, as well as old concrete to old concrete and new to new
- These epoxies bond to the concrete and can withstand any chemicals in the concrete
- Some epoxy glues are very strong and can essentially weld concrete back together
- Most often these are best applied by those who have a lot of home improvement DIY experience, or by experienced professionals
- Brush on Compounds
- Not the best option for a cement crack, but if you have a small, hairline fracture this type of material can work as a simple repair job
- The most important thing here is to read the directions very carefully and follow them exactly
- Also make certain that you have properly prepared the surface. The wall needs to be very clean and a little moist
- As well, make certain you apply thin coats rather than thick coats, as the thick coats will have a tendency to pull away from the wall
- Polyurethane Foam Injection
- These foams are injected into the crack as a liquid
- After a few minutes the polyurethane reacts with the water in the crack and begins to foam, increasing the material to 30 times its liquid form
- As it expands, it fills the crack in a 360 degree direction
- The finished product is one that is watertight and forms a very strong bond with the concrete
- Many contractors believe this is the most superior form of crack repair because it is more than just a surface patch and can ensure that water doesn't make its way into the foundation
Plaster or Drywall Basement Wall Crack Repair
Thankfully for those with plaster or drywall, basement wall crack repair is a much more simple task. It only takes a few tools and simple applications. Typically a basement crack is going to be the result of a settling foundation, or perhaps a water leak. If it is a water leak you will want to consult a professional, as you may need to go behind the drywall or plaster to repair the foundation.
Here are a few important steps to following when repairing a plaster or drywall crack.
- Clear the crack of any debris with a utility knife
- If the crack is large, then cut into the crack just a little so the patching compound will have as much surface area as possible to bond to
- For plaster, hairline cracks can be filled with a plaster paste, which comes in powder form or a pre-mixed version, which is available from your local home improvement store
- Using a putty knife, slather on a little of the paste, after it dries, simply sand over the top of the area and then paint
- Drywall crack repair is a similar process, but the compound you use to repair the crack will be different (sometimes called joint compound or spackling putty)
- Drywall can handle a lot more sanding than plaster, so feel free to apply more than one coat, first to fill the hole, then to smooth it over
Reference Books for Basement Repairs
The following do-it-yourself books can guide you through your crack repairs.
- Smart Guide: Basements: Step-by-Step Projects, Editors of Creative Homeowner
- Remodeling a Basement (Build Like a Pro), by Roger German
- Basement Ideas That Work, by Peter Jeswald
Consult a Repair Professional
Keeping your basement in good shape is essential to home safety. Basement walls crack for a reason, so it's usually wiser to consult a professional about the problem in order to gage whether you need to hire someone to fix a crack or if you can safely take care of it yourself.