Guide to
Repair Methods for Foundation Cracks
Repair Methods for Foundation Shrinkage Cracks
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Before repairing a foundation crack it is important to diagnose the cause of
the crack and its effects on the building structure. The significance of any foundation crack depends on the crack's cause, size, shape, pattern, location, foundation materials, extent of cracking, impact of the crack on the building, and possibly other factors as well. If there is an underlying ongoing problem causing foundation movement or damage, that problem needs to be corrected too. |
Suggestions for Repairing Concrete Foundation Shrinkage Cracks
Repairs to foundation cracks which are not traced to building movement, structural problems, site problems, or other conditions which require site or structural repairs may be attempted for cracked foundations and other cracked concrete structural elements using a variety of products and materials such as masonry repair epoxy or sealant products.
These products, some of which include even structural repair epoxies, might be used to seal against water leakage as well, and may be used for repairing certain cracks in concrete foundations following evaluation and advice from a foundation professional. An evaluation of the presence, absence, or condition of reinforcing steel in cracked concrete foundations should be a part of such an inspection.
Shrinkage cracks, which are not normally a structural defect in a building, may nonetheless need to be sealed against water entry. Common repair methods include chipping out the crack and applying a masonry patching compound to the surface, use of epoxies, or other sealants.
Water entry leaks at foundation cracks: Polyurethane foam sealant is used for foundation crack repairs to stop water entry. (Also find and correct outside water sources). See our article on Using Polyurethane Foam for Foundation Repairs for details on using this product to seal foundation cracks against leakage.
For various methods and products used to seal cracks in concrete floors or walls, see How to Seal Cracks in Concrete a description of various products and methods used to seal or repair cracks in poured concrete walls, foundations, floors, & slabs.
Once any concrete cracks it is possible for water to leak into the building through the crack. There are several ways to repair a basement crack leak. An easy, quick, and effective measure to stop basement or crawl space water entry through a foundation crack is to perform an injection of polyurethane foam into the basement crack. [Also be sure to find and fix the sources of water outside.]
Water entry leaks at foundation cracks: Polyurethane foam sealant is used for foundation crack repairs to stop water entry. (Also find and correct outside water sources).
Cracks at Control Joints in Concrete explains how we prevent shrinkage cracks in poured concrete floors and walls
Repair Methods for Vertical Foundation Movement - Foundations, slabs, fireplaces, chimneys
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In the photos shown here, substantive cracks appeared and continued to increase in size in this poured concrete foundation used to support a modular home which had recently been completed. The cracks and foundation movement were probably due to a combination of: poorly prepared foundation footings, blasting on an adjacent building lot to prepare that site for new construction, and possibly omission of steel reinforcement in the poured wall. As movement appeared to be ongoing over more than a year, the builder might have repaired the foundation by supporting it from below using one of the methods listed at Vertical Foundation Movement Repairs.
- A detailed discussion and illustration of repair methods for foundation settlement or "vertical foundation movement" repair is provided at Vertical Foundation Movement Repairs where we explain and illustrate various methods to arrest foundation settlement, and where appropriate, to raise or level or reinforce settling or moving foundation walls or slabs.
Additional details provided at Vertical Foundation Movement Repairs include descriptions of grout pumping to stabilize soils or elevate slabs, slab jacking to stabilize or lift settled slabs over deeper unstable soils, the use of driven steel pins to stabilize settling foundation walls or footings, the use of helical piers or "screw piers" such as those provided by A.B. Chance to repair sinking foundations or to level floor slabs, and a similar use of friction piers such as those provided by Magnum piering - are driven piles which rely on soil friction against the sides of the pile. Since it's sometimes the only appropriate repair method for foundation damage, we also illustrate foundation reconstruction.
Repair Methods for Bulged Foundation Walls
- In a separate article at Bulged foundation Repairs we illustrate and describe several methods used to stiffen or reinforce bulging foundation walls against further movement.
 The motive for a decision to reinforce a building foundation rather than rebuild it can be easily understood by noticing the difference in cost between bolting a few vertical steel beams to a building or building a pilaster and the cost to add temporary support to the floors above, remove an existing foundation, and rebuild a new one in its place. However the decision to support or reinforce a foundation wall versus rebuilding it is often made by the wall itself. If the amount of bulge or bow is sufficiently severe the wall needs to be rebuilt. If the underlying source of wall damage cannot be reliably addressed without excavating outside to add drainage and perhaps water proofing, there is additional motivation to perform a more costly repair. The foundation bulge or lean repair methods listed below are shown roughly in order of their most common appearance in residential buildings. The sketch shown here describes application of a steel I-beam against a masonry block wall for reinforcement. More details are given below. |
Repair methods for bulged foundation walls are illustrated and discussed in detail at Bulged foundation Repairs where we describe the use of pilasters, reinforcing steel I-beams, foundation anchors, sister walls, steel cables, and even complete foundation wall reconstruction to deal with foundation wall bulging, cracks, leaning, or movement.
Horizontal foundation movement creep
- Steel pins for foundation creep repair or prevention: The wall may be
pinned to the surrounding soil or hillside. Pinning moving walls is a separate
engineering problem and involves a critical step in discovery of the various
components in movement (site drainage, footing condition, condition of
underlying soils, clay, or rock.
- Excavation and reconstruction for foundation creep movement Excavation and reconstruction, possibly with reinforcement over original design and with additional foundation and site drainage is often required
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