How to Repair a Crack in a Foundation

Even the sturdiest foundations tend to crack over time. Minor hairline cracks are usually no cause for alarm, but major cracks can be a red flag for the home’s structural integrity. Vertical foundation cracks can be indicative of poorly-prepared foundation footing while horizontal foundation cracks may be caused by vehicle traffic or earth loading.

It is recommended that all foundation cracks, whether vertical or horizontal, are screened by a structural engineer if they are larger than ¼ inch wide. Since these can be caused by settling foundation, the matter needs to be treated professionally. On the other hand, an excessive number of small cracks also need damage assessment by professionals who can determine the extent of the damage.

Homeowners can treat small foundation cracks themselves using vinyl concrete patches and follow the given steps. Large foundation cracks are best left to the experts.

Prepare for Patchwork

When the crack is wider than a hairline, make sure to clear out all loose material including dust, debris, and chipped concrete bits. If needed, slightly widen the crack to allow more room for the patch to adhere and prevent it from escaping out of the opening.

Equipment such as air compressors may also be used to blast out dust and particles from the crack.

Treat Hairline Cracks

foundation cracks verticalHairline cracks are easy to fill up with vinyl concrete patching. Prepare the patching compound as instructed and use a putty knife to work it into the opening and its edges. Apply the compound in several layers and press firmly after each layer to push the compound into the opening.

Concrete cracks can also be treated with a cement mixture if the opening is broad enough to permit sand. Prepare the mixture in a 1:3-part cement to sand ratio to yield a stiff mixture. In another container, blend a little bit of cement with water to get a paint-like consistency.

First, brush the inside of the opening using the thinner mixture, which acts as a primer. Follow the application with packing the stiff mixture into the opening and pressing firmly. Let sit in place for an hour and go over the treated area with a trowel to blend the patch with its surrounding surface.

Once the patching solution has cured, you may need to use sandpaper to smooth out the surface of the wall or floor.

Address Larger Cracks

foundation cracks verticalLarger concrete cracks can be treated in a number of ways. For instance, cracks which are slightly wider can be packed with concrete caulk. This can be done with the use of a caulking gun to push the concrete caulk into the length of the crack. Caulk not only fills up the entire space but also allows for foundational contraction and expansion in extreme weather conditions.

For foundation cracks wider than half an inch, foam backer rods can be used along with caulk. The rods are available in a range of diameters and lengths and are considered an ideal adjunct to patches since they prevent the patch compound from sinking deep into the crack as it ages and dries. Using a putty knife, push the flexible rod into the opening and fill with caulk or patching compound.

A third option is to use hydraulic cement to fill up the cracks. Follow instruction on package by mixing cement into water until consistent. First moisten crack with water sprayed from a bottle and then force the prepared mixture into the opening with a putty knife. Let sit for an hour or so before applying a second layer of the mixture over the opening. Take a trowel to smooth the patch.

Helpful Reminders

When engaging in foundation crack repair, it is always advised to use a product which gives a little since concrete tends to expand and shrink according to weather and temperature changes. As such, if the product is more elastic, cracks will demonstrate less likelihood of reappearing.

When preparing the dry patch powder, mix it with latex instead of water to give it more elasticity and adhesion. Plus, mix only a small amount at a time since most products dry fairly quickly.

Clean-up after patchwork should be quick to prevent materials from drying out on work tools and equipment.

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