Wondering how to prevent your home’s foundation from cracking? If so, you understand the importance of a strong foundation. A foundation that isn’t strong and stable will eventually cause structural damage to the building sitting on top of it. Therefore, all homeowners should aim to spot foundation issues early before they become big problems that will cost a lot of money to repair.
Most foundation cracking is caused by a phenomenon called differential settlement. Differential settlement happens when a foundation settles into the soil unevenly. This contrasts with the very slight uniform settlement most structures experience after they’re built. While uniform settlement is usually not a problem, differential settlement puts stress on the building and can cause structural problems in your home’s foundation, including cracking.
But, what causes differential settlement? We’re going to find out in the next section.
Causes of differential
Various things cause differential settlement. However, the most common is soil movement under the foundation, and that’s usually caused by water. In other words, water – either too much or too little – causes most foundation problems, including cracking. Here’s what happens…
When a house is built on expansive soil – Certain types of soil are expansive. When they absorb water, they expand, and when they release water, they contract. (Soil with a lot of clay acts this way.) This swelling and shrinking – which is usually seasonal – creates movement in the soil under the foundation, and when the soil moves, so does the foundation. Whenever a foundation moves, structural damage, including cracking, is possible.
When a house is built on erosion-prone soil – Soil that’s prone to erosion can also cause movement under the foundation as the soil washes away and voids form. The foundation then sinks into the voids, causing structural damage and cracking to the building.
Other causes of differential settlement include:
- Soil that wasn’t adequately compacted before construction – Houses are heavy, and if you build a house on top of soil that wasn’t compacted before construction began, you’re asking for trouble. After construction, the heavy structure will press down on the soil, and since it almost certainly won’t be uniform settlement, you’ll end up with foundation trouble.
- Weather changes – An example of this would be a home built on expansive soil during the dry season. When it starts raining during the wet season, the soil will swell as it absorbs water creating movement under the foundation.
- Heavy excavation next to the foundation – If you’re wondering how this might cause foundation trouble, picture a chair on your lawn. If you start digging too close to the chair, it could eventually fall into the hole because even though you’re not digging under the chair you’re causing the soil it’s sitting on to become unstable. While your house probably isn’t going to fall into a hole, digging too close to your foundation could cause trouble, including cracking.
- Earthquakes and other natural disasters – We probably don’t need to explain how these can cause cracking and other serious foundation issues.
How to prevent your
home’s foundation from cracking
Since water causes most foundation problems, including cracking, you can prevent trouble by doing what you can to control the groundwater around your home’s foundation:
- Re-grade your yard – The yard around your home should slope away from the foundation. If it slopes toward the foundation, water will drain toward your home, pool around the foundation, and cause trouble.
- Clean your gutters regularly – If your gutters are clogged, water could flow over the side of the house and into the ground next to the foundation.
- Install downspout extensions – Your downspouts should release water 5-10 feet away from the foundation. If they don’t, install extensions.
- Install an underground downspout and bubbler pot – Water flows into the underground downspout and gets channeled toward a bubbler pot situated several feet away from your foundation. The bubbler pot works something like a sump pump. When the bubbler pot fills with water, it pops up and releases the water away from the foundation.
- Don’t plan water-hungry vegetation next to the foundation – When you water the shrubs and flowers, you’ll just be adding more water to the soil around the foundation.
- Install a drain tile system – A drain tile system prevents water from building up in the soil around the foundation. There are two types of drain tile systems: exterior and interior. While installing a drain tile system is not a DIY project and will cost considerably more than the above options, it’s an excellent way to protect your foundation.
While you want to make sure the soil around your home’s foundation doesn’t get saturated with water, you also don’t want to let the soil around the foundation dry out. See California Drought And Your Home’s Foundation for more information.
How to repair
Repair options for foundation damage caused by differential settlement include underpinning with push piers, helical piers, drilled concrete piers, and slab piers. For more information on repair solutions, see Foundation Settlement.
Common signs of foundation problems include:
- Doors and windows that no longer open and close properly
- Uneven floors
- Ceilings and floors that are separating from the wall
- Cracked floors – Look for cracks that go all the way across the floor, wall to wall. A crack limited to one or two tiles probably happened when something fell on the floor.
- Basement walls that bow inward
- Cracked walls
- Torn or wrinkled wallpaper – The wall behind the wallpaper might be cracked.
- Nails popping out of the drywall – This indicates there’s movement in the foundation, which is causing stress.
- Cabinets that are separating from walls
- Diagonal cracks above windows and doors
- Moldings that have separated from the wall or ceiling
- Stair step cracks in brick or masonry
- Chimneys or porches that are leaning away from the house
If you see any of the above or something suspicious not mentioned here, contact a foundation repair contractor for an inspection.
If your home’s foundation is cracking and you’re in our service area in Northern California, contact us for a free inspection and repair estimate.