How Much Does Poured Con­crete Foun­da­tion Crack Repair Cost?

May 14, 2014 • By Matthew Stock.

Res­i­den­tial foun­da­tions are typ­i­cal­ly con­struct­ed in one of two ways. Both start with a poured con­crete foot­ing to help sup­port the foun­da­tion walls and dis­trib­ute the weight of the structure.

Cur­rent­ly, the most com­mon approach is to con­struct a sys­tem of forms on top of the foot­ings and pour walls of con­crete to form a mono­lith­ic foundation.

In some parts of the coun­try, a mason­ry foun­da­tion is built on top of the foot­ings, most often of con­crete blocks, also known as ​“cin­der” blocks or CMUs (con­crete mason­ry units.) In the past and occa­sion­al­ly for spe­cial­ized con­struc­tion, bricks or stones might be used.

Either foun­da­tion, prop­er­ly built, will do a fine job of sup­port­ing the struc­ture and con­tain­ing a base­ment or crawl space. Both, how­ev­er, are prone to crack­ing when the foun­da­tion sinks or set­tles or when over-sat­u­rat­ed soil out­side the foun­da­tion cre­ates lat­er­al pres­sure that push­es the walls inward.

The cracks that ensue may be struc­tur­al or non-struc­tur­al. When struc­tur­al cracks occur it is not so much a mat­ter of repair­ing the crack as it is sta­bi­liz­ing the entire wall or rais­ing and sta­bi­liz­ing the foun­da­tion and these repairs can cost thou­sands of dol­lars. Non-struc­tur­al cracks seep water into the base­ment or crawl space and must be repaired to avoid prob­lems with mold, rot, high humid­i­ty and destruc­tion of fur­nish­ings and oth­er property.

These non-struc­tur­al cracks are very com­mon in both types of foun­da­tion and are the lead­ing source of seep­age in poured con­crete con­struc­tion. Pro­fes­sion­al repair is need­ed to ensure an effec­tive and per­ma­nent fix and many home­own­ers’ first ques­tion is ​“How much will it cost?”

The Cost of Poured Con­crete Foun­da­tion Crack Repair

Seep­ing cracks in a poured con­crete foun­da­tion can be repaired from either the inside or out­side of the base­ment. The inside method, pre­ferred when pos­si­ble, involves clean­ing out the crack of loose con­crete and oth­er debris, insert­ing plas­tic injec­tion ports at reg­u­lar inter­vals along its length and seal­ing over the crack with a coat of epoxy. Once the epoxy has cured, the injec­tion ports are used to fill the crack with expand­ing polyurethane that seals the crack all the way to the out­side soil and remains flex­i­ble when cured to pre­vent re-crack­ing caused by minor foun­da­tion movement.

Once the repair has cured the epoxy can be scraped off the wall if desired.

The cost of repair­ing a crack through polyurethane injec­tion is typ­i­cal­ly sev­er­al hun­dred dol­lars and most base­ment water­proof­ing pro­fes­sion­als will offer a reduced rate for mul­ti­ple cracks. Mul­ti­ple cracks, by the way, are pret­ty com­mon because the pres­sure on foun­da­tion walls is such that off­set­ting cracks almost always occur.

When a base­ment is fin­ished or the crack is some­how inac­ces­si­ble from inside, it can be repaired on the exte­ri­or. The repair begins by dig­ging a small-diam­e­ter hole at the site of the crack that extends down to the foun­da­tion footings.

The hole is then filled with a gran­u­lar for­mu­la of sodi­um ben­tonite clay that will quick­ly absorb water from the sur­round­ing soil and form a per­ma­nent water bar­ri­er on the ​“pos­i­tive” side of the foun­da­tion wall. The remain­ing hole is then back­filled and the repair is invisible.

Because of the labor involved and the cost of mate­ri­als, seal­ing a crack from the out­side costs more than inject­ing it from with­in but is still a very rea­son­able means of pre­vent­ing dam­ag­ing base­ment seep­age. Again, a reduced rate for mul­ti­ple cracks is customary.

Regard­less of whether the crack is best repaired from the inte­ri­or or exte­ri­or, a home­own­er with seep­ing cracks in a poured con­crete foun­da­tion needs the assis­tance of an expe­ri­enced base­ment water­proof­ing con­trac­tor. At U.S. Water­proof­ing, we got our start back in 1957 by spe­cial­iz­ing in exte­ri­or crack repair and have become one of the country’s largest full-ser­vice base­ment water­proof­ing com­pa­nies with more than 300,000 sat­is­fied cus­tomers on our books. Why not ask for our free advice when you spot a crack in your basement?

If you’d like to know more about the cost of repair­ing cracks in a poured con­crete foun­da­tion, please post your ques­tions in the Com­ments box below.

Tags: cost of foundation crack repair, foundation crack repair cost

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