There are many reasons why your basement would have cracks developing. It’s most common to find hairline cracks about one month after construction finishes and then into the first year, foundation cracks will likely begin to appear.
These are typical and mean very little – if anything – to the structural integrity of the building. There can however be some problems with water leakage. Sealing basement cracks is about preventing water damage that can compromise the construction so it’s always wise to address them before they allow this damage to occur.
If the cracks in your basement are vertical or they run at a bit of an angle, these are just foundation cracks caused by the settlement of the building into the earth. These are non-structural and can be fairly easily remedied by using an injection of polyurethane foam. Sealing basement cracks using this method is permanent and you won’t have to repeat it in the future. Because the repair is carried out inside the wall, it is not subject to the elements such as rain, wind and UV exposure.
When you go to buy the injection material, buy enough to fill the entire depth of the crack and not just to apply a minor repair. This will help to prevent any further weakening of the concrete because it will stop moisture from eroding the crack.
Another great advantage of injected polymer is that it coats the steel inside the concrete and negates the potential for corrosion. Thus, sealing basement cracks is not just about repairs, but prevention as well … a 2-in-1 solution for a minor problem.
Particularly where clay soil is present, the constant expansion and shrinkage due to alternate dampness and dryness causes lateral pressure on the walls of the foundations. This results in horizontal cracks roughly midway up the wall and your wall could actually become structurally compromised.
This is where sealing basement cracks may become a job for the professionals. If they are larger than 1/8” wide, have misaligned edges or become noticeably larger or longer over a relatively short space of time, it’s best to seek an assessment by a professional.
Time to Call in the Pro’s
Less of a DIY job than a contractor’s speciality, sealing horizontal basement cracks involves a process called slabjacking. This is where cement grout is pumped through holes created in the slab. Or, your contractor could use piering which is where mechanical jacks are placed in prescribed locations to lift the settled beam to a point where no more shifting should occur.
Examine, Don’t Panic
Cracks can be very worrying indeed, especially if you notice them suddenly in a place where they didn’t exist the last time you looked. It’s wise to remember though that every home will inevitably shift into its foundations, trying to settle on a firm footing where it will remain for decades to come. Before sealing basement cracks, determine if they are really serious or if it’s just a matter of waiting until the settling has finished.
As with anything, if you’re concerned, contact a professional and seek advice. Chances are, the problem is minor and even if you do seal the basement cracks now, more settling may occur and the cracks will need to be re-sealed at another time in the future.