Solving a persistent water problem
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For a block foundation, drill weep holes in the blocks so that water trapped in the voids of the block can drain out.
First, make sure that rainwater runs away
from the house foundation. To pinpoint
problem areas, go outside while it's raining
and observe how the water flows off the roof
and onto the ground around the house. Pay
particular attention to areas below roof valleys
where lots of water runs off.
Add soil to slope the ground away from
the foundation. The grade should slope a
minimum of 1 in. per foot for the first 4 to
6 ft. If necessary, direct roof water away with
gutters and downspouts.
If these measures fail, you may have to
install an interior drain tile and sump basin. The corrugated floor edging
catches water running down the inside of
the foundation wall and seeping under it
and then directs it to the drain tile. The
drain tile carries the water to the sump
basin, where an electric pump automatically
The materials are relatively inexpensive,
but the labor is huge. You'll need to jackhammer
out a strip of concrete around the
perimeter, haul out concrete rubble and
dirt, carry in gravel, and then patch the concrete
floor. This is dusty, sweaty labor. Pros
charge several thousand dollars for this job.
To install this system, follow these steps:
- Break out and remove an 18-in. strip of
concrete around the walls to expose the
footing and underlying dirt. Rent an electric
jackhammer for this task.
- Dig a 12-in. wide by 8-in. deep trench
alongside the footing.
- Find a location for the sump basin (an
unfinished room is best). You'll need an
electrical outlet for the sump pump and a
way to run the discharge pipe outside. Break
out additional floor, dig a hole and set the
basin in place so the top is flush with the
- Lay about 2 in. of gravel in the bottom of the trench (use crushed stone or river rock).
Run the perforated drain tile in the trench
and push its end through the knockout of
the sump basin. Try to make a complete
loop of the basement with the drain tile and
run both ends into the basin. Fill the trench
and around the basin with more gravel,
leaving room for 3 to 4 in. of concrete.
- Hang 6-mil polyethylene sheeting from
the top of the foundation wall. Leave the
bottom edge hanging just above the footing.
- Lay the floor edging on the footing. Make
sure the polyethylene runs behind it.
- Lay a strip of polyethylene on top of the
gravel and pour concrete to patch in the
- Install the sump pump in the basin and
run the discharge pipe outside. Make sure
the pipe runs at least 6 ft. away from the
foundation so you aren't just dumping the
water back against the foundation wall.
If you have a concrete block foundation,
you'll have to drain the block cores by
drilling 1-in. holes through the face of the
block. Rent a rotary hammer
with a 1-in. masonry
bit; it's worth the
Drain Tile Details
Water is channeled down the wall to the drain tile, which feeds it into the sump basket and is then pumped outdoors.