Basement Foundation Cracks and Crack Injection

Frost Adhesion Damage

When you have leaks in your foundation in your Ontario home, and perhaps your budget does not allow for a complete foundation repair, a possible alternative may be repair through crack injection.

Homeowners are often concerned about concrete cracking that may have been caused by thermal contraction, shrinkage, applied pressures, or settlement.

Any type of crack can be particularly unsightly, but if it is the source of leaking water it will have to be dealt with as soon as possible. If cracks have occurred before the concrete has completely hardened the cracks may be caused by shrinkage. The shrinkage is caused by a loss of water in the concrete.


Where Cracks Appear


Cracks are likely to appear in:


  • Concrete swimming pools
  • Foundations
  • Around pipes located in concrete walls
  • I-beam pockets located in basements
  • Subway tunnels
  • Layered concrete structures
  • and many other areas


Settlement Cracks


Settlement cracks tend to develop around openings or embeds. Cracks around a window, door, or a beam pocket are not uncommon. Cracks such as these are usually caused by a lack of concrete coverage that’s spread over reinforcing steel, dry mixes, or insufficient consolidation.


Structural Cracks


Structural cracks that are found in the foundation of home are usually caused by horizontal pressures, settlement pressures or loading. Cracks such as these are much more likely to occur in the walls of a block basement. In cases such as these, hydrostatic pressure has usually caused the cracks. When water begins to build and build the soil beneath the block basement will begin to move both outwards and downwards. This movement forces a lot of pressure on the walls and will cause the cracks.


Epoxies are the preferred material when sealing a structural crack, this is because they won’t expand. However, epoxies have the ability to form really solidly which makes them ideal for repairs such as this. If you wish to use epoxies, two-component epoxies are the best bet. This is because they are durable, very strong, and have a watertight bond.


Diagonal Wall Cracks


Diagonal wall cracks that are almost as tall as the wall indicted there is a settlement issue. If this type of crack is suspected it’s vital that you deal with it as soon as possible.


Dormant Cracks


Cracks in your basement that are no increasing in size are known as “Dormant cracks”. This type of crack have traditionally had mortar or cement grout added to them. However, these materials only solve the problem until there’s unexpected movement or a build-up of water.


Active Cracks


Active cracks are those which are thought to be moving and, therefore, require any sealant that’s used on them to be flexible. It is essential that any active cracks are dealt with properly and with care.


Crack Injection


Small/fine cracks can be sealed with epoxy resin or polyurethane grout. Epoxy resins tend to be the more favored option on dormant cracks. Many epoxy resins are available that can fill in cracks that are 0.1mm narrow, or less.


– Epoxy Grouts


Epoxy grouts can be used as they stick to hardened and fresh concrete, some specific formulas are available that are capable of sticking to surfaces even when they are wet. Epoxy grouts have low shrinkage and are very strong, what’s more, is they are very chemical resistant, even as far as alkalies are concerned.


Epoxy grouts are typically used under pressure. Injection points or nipples are put along the crack and the surface of the crack is sealed. The epoxy is injected and once it has hardened it the repaired area is typically a lot harder than it was before.


– Epoxy Resin


Epoxy resin is used to seal wide cracks that are more than 1 mm in width. Cracks that are typically on vertical surfaces are typically filled with epoxy resin. Cracks that are on horizontal surfaces may be filled with poly grout that is poured into the crack.


– Polyurethane Resins


Polyurethane resins may be used to seal some very fine cracks in the wall as they tend to have a lower viscosity. This means they are capable of penetrating the crack a little easier than grouts or resins do but they are unable to bond as well as resins or grouts.


Some people do suggest that poured wall crack injection is the best way to repair foundation cracks. The repairs can be made from the inside of the foundation meaning that absolutely no excavation work is required. This process involves attaching ports along every 6 – 10 inches of the crack.


The ports serve as entryways for getting the resin into the cracks. They remove the need to drill directly into the concrete, this reduces both time and mess.


The crack will then be sealed with a two-part paste material. Once the crack is sealed, a urethane foam product or an epoxy product will be injected into the crack. Once the crack is full the ports are taken out and a finish coat is added to ensure there’s a watertight repair.


The ports should be left in place for 24 – 48 hours at room temperature. This will allow the polyurethane or the epoxy to make its way into the cracks. The injection ports will need to be removed and this can be done by hitting them with a hammer or a trowel.


Live Cracks


If you have a live crack the ideal way to deal with it is to inject it with polyurethane. Polyurethane is flexible and is, therefore, capable of dealing with any movement. Epoxy resins that are flexible can deal with small movements but a polyurethane tends to be the more preferred choice.


Preparing the Surface


Before a crack is filled the surface should be prepared. The surface will need to be cleaned so that any loose materials and contaminants are removed. The click will be blown with dry, clean air so that the resin can flow into the crack freely. The resin is then injected into the crack under pressure.


Benefits of Sealing Foundation Cracks


The benefits of sealing foundation cracks are:


  • No external excavation is required
  • It takes just hours to complete
  • The cracks are permanently repaired
  • When applied correctly, the repair is a reliable waterproofing method
  • The foundation’s integrity is restored
  • Sealing foundation cracks this way is one of the cheapest options


Cracks should only be treated when they are a threat to the structure or they are causing large leaks. If there are cracks that have been caused by corrosion you should not use the injection method to treat them.


Risks of Sealing Foundation Crack with Crack Injections


Cracks in walls that have been filled in with poured foundation can leak water in addition to dangerous soil gasses. Before any solutions are considered you should check:


  • The depth and width of the crack
  • If the crack is dormant
  • If the crack is active
  • If appearance needs to be considered
  • If you need to seal against any pressure


Contact us


To determine if crack injection is a suitable option for your basement leak issue, contact us for a free, no obligation consultation. We will evaluate the extent of damage and what practical options you may have including the possibility of crack injection.


    This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.