Expert: Bruce E. Johnson - 2/9/2010

Question
My home was built in the 70's. The living room is approximately 8 inches lower than the rest of the house. Whenever we have a large rainfall or like now a heavy snow it leaks and I spend hours drying concrete, padding and carpet. There are visible cracks in the foundation. When the carpet is pulled back I can see it seeping. Are there any economical ways to fix the problem? If we filled the living room with concrete to be level with the rest of the house would it possibly stop the flooding. We also have a wood burning fireplace in the living room. Thank you.

Answer
Hi Kristie, I don't know how inexpensive it would be in your area or if you can do the work yourself but obviously the problem is outside your house. Poor or inadequate drainage accounts for 100 per cent of ground water intrusion problems.  First of all you need to check the elevation of the ground where your floor steps down.  Is it possible that the ground outside is higher than your slab?  If so, water will naturally seep through the foundation wall onto your slab.  Also, having positive drainage away from this area will help.  If possible you can regrade around your house so that water will flow away from it instead of against it.

 Finally a good foundation footing drain will help especially if you live in a very wet climate.  A foundation drain consists of digging a trench around the house and putting gravel into it and a perforated pipe.  The idea is that ground water will build up inside the pipe which can then carry it away from the foundation before it is allowed to penetrate.  

I suggest you start with something simple.  In the area of the lower slab:  dig around the room from the outside until you are 8" below the top of the slab and the foundation wall is exposed down to that point.  Let the dirt on the foundation dry and then brush it off with a stiff broom.  Go to your local hardware or big box home improvement store and get a good foundation mastic/waterproofing compound.  Get one that is rollable so you can use a paint roller to apply it.  Put as many coats you can letting each coat dry before the next.  Once you get some good coats of mastic on the wall then you can backfill the dirt and if possible make sure it is higher at the house and slopes away from the building preferably into a swale that keeps it moving off your property.

As far as just pouring a new slab on top goes? It will definitely keep the water from the flooring but you should put down a visqueen vapor barrier on the existing slab and lap it up the walls so that the water intrusion won't get to the new concrete which will in time soak it up and become moist.  I hope this information helps please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonsonconsulting.com