Concrete Block Foundations: When to DIY and When to Call a Pro

Water causes most foundation problems. Poor drainage and seasonal soil expansion can damage a concrete block foundation, but the damage is not irreparable. Some small cracks and minor water problems have DIY repairs. On the other hand, professional experts should tackle ongoing problems and any larger cracks with either bracing or full reinforcement projects if the wall is displaced more than one inch.

DIY Concrete Block Foundation Fixes

Small cracks may be the result of harmless settling or natural concrete fractures. If there is no bulging or horizontal displacement, just seal the crack. Scrape away any rough mortar and make sure the walls are dry, then add mortar and concrete caulk.

Moisture in concrete block foundation walls or flooring may be a larger problem, but it may just point to grading problems. Make sure water flows away from the house. Secure gutters and extend downspouts to make sure rooftop rainwater drains at least five feet from the house. Also make sure soil drops away at least six inches in the first 10 feet from the home.

When to Call in the Pros

If the cracks and moisture return, it may be time to call a professional. Large cracks, bulges and tilting in concrete block foundations either need to be braced or excavated. Both are jobs for experts in sealing water problems, repairing cracks and shoring up foundations.

Shoring up a Foundation

A bulging or bowed wall in any winter climate is typically caused by the expansion of freezing soil. The middle of the wall may crack at the frost line. A poorly built mudsill can combine with lousy drainage to tilt the top of a wall inward. Finally, poor drainage can undermine the foundation and tip the bottom of the wall inward.

In any case, less than one inch of displacement can be cured with bracing by one of two main methods:

• Concrete block foundations can be reinforced with concrete and rebar. Experts can thread steel rebar into existing concrete blocks, then fill the blocks with new concrete for greater strength against water pressure. A block is also typically nailed to the joists to keep the top of the foundation walls from tipping inward.
• Otherwise, steel columns can be pushed against a concrete block foundation, then bolted to the joists and slab every three to four feet.

In either case, a licensed engineer must design the bracing.

Excavating and Plumbing a Foundation

More than one inch of displacement is typically a trigger for serious foundation work. The ground must be excavated around the foundation so the wall can be jacked back into place and plumbed. After replacing the mortar in any cracks and resetting the foundation wall, make sure the wall is coated with asphalt cement and plastic sheeting. To avoid future problems, repair and improve the drainage system before backfilling around the foundation.

Find professional help for concrete block foundation problems here. Get free quotes and find a contractor in your area.