Chapter One of The Complete Modern Guide to Basement Waterproofing

In order to gain a greater overview of a complex problem, let^'s look at how the average American basement gets built. First of all, the contractor digs a hole in which to place the basement. Often times this excavation takes place in dense, heavy clay typical of many areas in the Midwest, throughout the Northeast. Mid-Atlantic and Southeastern states. If it rains copiously during the excavation period and before the basement is built, one can see large amounts of water standing in the excavation hole because the rainwater cannot percolate downwards through the dense clay. If the excavation takes place in an area where springs are active, water can be observed gently running into the excavation site from the sides of the hole continuously, even in the absence of rainfall. Basements or crawlspaces are placed anywhere from 3 feet to 14 feet deep in the earth and the depths of excavations vary according to the architect's design. One thing is for sure, if the soil type traps and holds water for longer than 48 hours, then the basement built there is in jeopardy of leaking unless properly waterproofed and drained. But, we'll get to that later.

After the space for the basement is fully excavated and is large enough to accommodate the basement as well as an additional six to seven feet working space beyond where the walls will stand, the footing is poured. The footing is the continuous ribbon of concrete on which the foundation walls will be placed. The structural integrity of this footing is extremely important since tons of foundation walls, plus the superstructure of the house will be permanently resting on it. If shortcuts are taken or if the footing is somehow 'sub-code, then the chances that the basement will leak rise dramatically.

Once the footing is in and cures, the walls are begun. In modern times, the typical construction materials used for basement walls are cinder blocks, cement blocks or poured concrete. Sometimes they are combined on a single foundation. Figures 1 and 2 show both a hollow wall and a solid wall and a solid wall. Cinder or cement blocks are laid one upon the other in a staggered and interlocking fashion, thereby creating a hollow, two-sided wall. The poured concrete wall is solid. The techniques used to solve water seepage problems affecting these two types of walls are quite different. Can you see some obvious differences with how the water enters the two wall types? Hold those thoughts. They will be pertinent later.

After the walls are laid up, as in the case of cinder blocks, or poured into forms as with poured concrete, and they cure (or strengthen as the concrete becomes harder day by day), they are ready for the conventional waterproofing techniques of today.

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How and Why Does My Basement Leak?