In the photo below you can see the brown drain mat, behind which is the dampproofing, and white drain tile with some gravel (after this picture was taken much more gravel was added) For 90 degree corners, two 45 degree elbows are used to avoid clogging. The pipes are turned vertically to the surface for a 'clean out' if an obstruction does occur.
Friday, November 19, 2010
The two main systems used to keep the basement dry, dampproofing and drain tile, have just been installed on Pratt House. Dampproofing consists of a sprayed-on waterproofing agent, applied directly to the concrete below the finished grade, and a drainage mat (similar to a rainscreen system) to allow water to freely flow down the foundation to the draintile. The drain tile consists of a 4" perforated pipe surrounded by 8" of crushed gravel. Instead of flowing under the foundation and into the basement, water will enter the drain tile and flow to the city sewer.