Traditional foundation materials are stone, brick, concrete block, cinder block, poured concrete, and in many locations clay tile. In older homes, keeping the basement dry was never intended. Basements were simply an extension of the footer that was needed in areas were the ground freezes. By digging below the frost line, around 3 feet, the structure could be made stable and not subject to frost heave that comes with the freeze/thaw cycles. Dig another few feet and you could stand up and store some items in basements
Over time, building techniques improved, as did our need for space. Enter the finished basement. Suddenly we expected that hole in the ground to be dry and comfortable. In modern construction, this is more easily done through the use of drainage systems and sealed exterior walls.
If you're among those who don't live in a newer home, you might have a clay tile foundation. This was a structural block made of clay, much like a flower pot. It can also be compared to a chimney flue. Typically they have one or two hollow chambers, open on the ends. Unlike today's more common concrete block, which also has hollow chambers, these would be laid in place with their hollow core horizontally. They are often fluted, with "grooves" parallel to the hollow chamber. I've seen flat ones, glazed ones, square ones, they come in many varieties.
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| Here is an example of a clay tile. It's been painted white on the outside. Normally, you won't see the open ends like this. |
The pros to the builders were their weight and cost. The cons to the the homeowner is that they could be considered inherently wet by design. By having all those horizontally aligned cores, water leaking into your basement at the corner of your foundation can travel the length of the all and appear anywhere, making locating the leaking area difficult.
In addition, these blocks tend to soak up moisture when it's wet and release it when it's dry. The trouble is, many people paint over these blocks in an attempt to "water proof" their basement walls. The paint will fail, and once painted, the cycle of scraping and painting will never cease.
So, now that I've talked about all the trouble with these clay tile blocks, what can you do if you have them in your basement? If a dry basement is desired, it may never be completely possible, but there are always solutions.
Before you do anything, make sure your walls are sound. There should be no large cracks or bowing, which could indicate structural problems. As home inspectors, when we see things we're not sure of in foundations, we recommend structural engineers to further evaluate the walls. They will typically charge a fee for their service, and will provide you with written documentation stating the foundation is stable or in need of repair.
Keep in mind that free estimates are usually given when the company evaluating the work also wants the job of repairing it. If you're not comfortable with the information received, contact another company and compare the information.
I'll continue this discussion in my next blog, talking a bit about the exterior drainage systems used in older homes and going over possible causes of wet basements. I'll also make suggestions for determining the specific cause of your water trouble and then discussing different types of repairs.
