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View Full Version : How to divert water seeping under the house?


KKreno14
Nov 29, 2013, 05:16 PM
My house is in Queensland where we get heavy seasonal rain. The house is built into a slope with retaining walls in the back garden. A 2 car garage is underneath one half of the house, the other half has foundation stumps on a rocky dirt crawl space with a one metre high brick foundation around the 3 edges of the house.

During heavy rainfall, water seeps out of the rocky dirt and flows into the garage creating a large pool of water. During very heavy rain the water flows out of the rocky dirt like a spring fountain flooding the garage.

smearcase
Nov 29, 2013, 06:08 PM
Can you install a stone filled trench (actually a perforated pipe surrounded by stone if it is a high volume flow) between the area where the drainage originates and the garage? The pipe would have to continue to a point where it could be outletted and drain away from your garage and house. The pipe (called underdrain in highway construction) is placed on a few inches of stone near the bottom of the trench with pipe perforations down, then stone on the sides and top of the pipe. As the water builds up in the stone trench it enters the pipe and can flow (at about 1/4 inch per foot fall) through the pipe to a point where it is of no concern. Filter cloth is placed to deter dirt infiltration into the stone and we used crushed stone or natural gravel about the size of a golfball, referred to as #57 stone. Solid pipe is normally used once you are out of the wet area.
It is a method of intercepting surface or ground water. The water is moved from an area where it can cause damage to a point where it can be safely discharged.

speedball1
Nov 30, 2013, 11:20 AM
Smearcase is suggesting installing a French drain,(see image)
You may also install a sump pump and pipe it outsides. Let us know what you decide. Good luck, Tom.