Concrete Block Foundation

Concrete Block Foundations

A block foundation is constructed by stacking and interlocking blocks of concrete. Mortar is used between the blocks to facilitate bonding, add strength and keep the weather out.

Concrete Block Problems

1. Horizontal and Vertical Cracks

A crack in your concrete block foundation can be a serious problem. A horizontal crack means the wall has a lower tensile strength than is required to support the wall structure. Our bowed wall section can provide more information on how to solve the problem. A vertical crack can be a structural problem if it has significantly changed in size. If these cracks appear in more than one area, it can be an indication that your house is settling unevenly. A non-structural crack will still have slight movement due to changing soil conditions and thermal changes in the wall itself. Stair-step cracks form when your home is settling unevenly.

If the mortar that connects the blocks degrades in any one area, it allows water to fill up the empty cavity of the block. It then travels into surrounding block cavities until it finds a way into your basement. You may see efflorescence, a white crystalline structure that results from the water leaching minerals from the concrete followed by a subsequent evaporation of the water. However, in most cases, the water damage will reveal itself as significant dampness on the wall, or more commonly, as an active flow onto the basement floor. There are two permanent solutions that qualify for's industry leading Lifetime Transferable Warranty: Internal Breakout and Exterior Excavation. Your Estimator will explain which methods will guarantee that you will no longer have a wet basement.

2. Bowed or Buckling

If you see that one or more blocks have actually moved, it is the result of soil pressure exerting itself against the wall. It may have originated from heavy traffic or frost pressures. This leaves the wall with inadequate tensile strength. It has lost its integrity to withstand continued lateral pressures. The problem will only continue to worsen, so we strongly recommend that you act immediately. If ignored, it can result in complete wall collapse. Please continue to our Foundation Stabilization section.

Concrete Block History

With the invention of a new style of cement in 1824 called Portland, it would not be long before innovative people began making decorative blocks that were designed to look like stone. These first precast, concrete blocks were cast in wood frames, dried like brick and then laid like bricks with mortar. The first house constructed entirely with this new concept was in 1837 on Staten Island, New York. Production was improving, prices were dropping and at the turn of the 20th century the first mechanized production of blocks began. Recipes varied and the quality of the resulting blocks varied as well.

3. Weeping Tile

Depending on the age of your house and the type of soil that surrounds it, you will likely find weeping or drain tile around you property. Over time, weeping tile will become plugged with soil or roots. As a temporary fix, it may be possible to flush out the tile, allowing it to pass water until sediment inevitably blocks it up again. Root obstructions may be able to be removed using a sewer machine but this also is a temporary fix. Trees need water and the weeping tile around your house is an excellent source. There are really two options, replace the weeping tile or abandoning it. 

Replacing your existing tile is accomplished with an Exterior Excavation, which as its name implies, is done from the outside. Abandoning the tile does not mean ignoring it and letting it leak, or filling in the basement with concrete. It means installing a new weeping tile system inside your home, hence the name Internal Breakout.

4. Window Wells

Any time a window is located below grade, a well of some sort is required. A window well is a shaped piece of corrugated galvanized steel that protect your basement from leaks. 

A basic galvanized well may seem like a simple item with simple installation. If that were true, fixing window wells would not feature so prominently in our business. Improper sizing, placement, installation, and drain structure are just some of the problems we remedy on a regular basis. Visit our Window Well section for more information.

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