She's a Brick....House
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Can You Cure A Wet Basement?

from the desk of
Richard A Hetzel
Architect (NY) Home Designer (PA)

Water in your basement or crawl space?  Dampness?  Musty odor?  Mold?  Structural decay?

Our area of the Pocono Mountains is blessed with all manner of natural and man-made water features...lakes, ponds, streams, rivers and bogs, all with their own surrounding wetlands and resplendent flora and fauna. But all these natural resources also mean that we face some special challenges in balancing our love of our specialness with what is best for our health, well-being and property.

How do we live with the sometimes inevitable eventuality of some water and/or dampness in our crawlspaces?  Well, it's only inevitable if things weren't done right when the house was built, or if needed repairs aren't made.  The overwhelming majority of damp or wet foundations can be cured, and most times for only moderate expense.

If it's only dampness, and not water, the first thing is to be certain there is a vapor retarder on or beneath the floor.  Often crawl spaces have earth floors, and often, someone has rolled out some polyethylene film on the floor and thought that they had installed a vapor retarder.  Well, they missed a couple of items.  First, all seams between sheets of film should be lapped at least six inches and taped.  Second, the film should be turned up against all walls and other penetrations (such as pipes, columns, posts, etc.) and taped to the wall or penetration.  Only then is the vapor retarder complete and fully effective.

Then, look to see that there are sufficient vents in the crawl space, and be sure the vents are open.  The total free area of all the vents should be one square foot of vent free area for each 150 square feet of crawl space floor area.  It is difficult to determine the net free area of existing vents, but generally, if you assume that the free area is about 50% of the area of the vent, you'll be close.  If you can find a manufacturer's name and model number, you may be able to find the net free area on the manufacturer's website.

Now, what if you have water?  If you have water, it is entering from outside the foundation.  If someone gives you baloney about hydrostatic pressure under your floor, show them the door.  If someone tells you your foundation was waterproofed when it was built and it didn't work then and it won't work now, show them the door.  There is a difference between "damp-proofing" and "waterproofing", and almost no homes are "waterproofed"...some, in fact, are not even "damp-proofed", especially homes that are maybe 20 years old or older in the Poconos.  Dampproofing is meant to keep minor moisture from wicking out of the soil and into the foundation wall, and that's all.  Waterproofing is meant to stop the infiltration of water completely.

Water enters a foundation in the following ways:    

     1.  Cracks in the foundation
     2.  A failure in the parging (plastering) of the foundation
     3.  A failure of the damp-proofing of the foundation
     4.  Open tie rod holes in concrete foundations

What causes cracks in the foundation?

     1.  Insufficient wall thickness and/or reinforcing for the height of soil supported.
     2.  Improper backfill (rocks, construction debris)
             {what?? rocks in the Poconos?? do you believe that??}
     3.  Tree or shrub roots
     4.  Heavy equipment or vehicles running near the wall, either during construction, or after
     5.  Hydrostatic (water) pressure in the soil outside the wall

This is important: Do not select a solution to the problem BEFORE the cause is determined!!  Also important is the fact that where water is seen entering your basement may not indicate where it is entering on the outside,  It is possible, and frequent, that there is a crack outside which won't show up inside.

One can determine the cause by first performing a hose test. With a garden hose, start at one point outside your foundation, and lay the hose on the ground so that it runs full blast at the foundation.  Let it run for about 45 minutes, and see if water appears inside the basement or crawl space.  Then move the hose about six feet and repeat the process, and continue doing so until you've gone all around your foundation.  Keep careful notes about where the water enters.  Now you know where the problem is, but you don't know why yet.

Now comes the hard part.  Dig, or better yet, have someone dig at the locations where your hose test showed that water enetered.  If your foundation is more than about three feet below grade, it's best to leave the digging to professionals who can recognize soil types and predict their behavior, because the risk of a cave-in becomes greater as the excavation gets deeper.  Let the pros take that risk.  If you dig yourself, do not pile the excavated soil at the edge of the excavation!  That could cause a cave-in.  Take it away by wheelbarrow.  The dig should extend out from the foundation wall about 18 inches.  By the way, the digging should be by hand, and not by machine, so that the walls aren't stressed or damaged by machinery operating close to the walls.

Having duFoundationcrackg, you should be able to see the problem...a crack (see photo - putty knife inserted in crack for illustration), a hole, chipped parging, insufficient or absent damp-proofing...could be any of those.  If it's a crack or hole, clean it as best you can and patch it with hydraulic cement.  Then, apply a THICK coating, preferably two coats, of bituminous dampproofing compound (black sticky tar), and in the final coat, embed a sheet of 6-mil polyethylene sheet in the dampproofing, extending from finished grade down to and over theWaterproofedfoundation footing. (The second picture shows the same foundation waterproofed) Finally, backfill with pea gravel up to within a few inches of finished grade.  If you only had one place of water entry, that's all you have to fix.

A word about "inside" drainage systems:  rarely are they the right answer to a wet basement.  They are a one-size-fits-all solution to a problem that has not been defined.  Yes, they may keep water off your floor, but they won't keep it out of your basement, and they won't stop the entry of vermin, insects or radon gas, all of which can enter through the crack or whatever is letting water into your basement.  They will not reduce dampness, which is why those who sell them often recommend dehumidifiers.  Finally, they can cost many times the cost of fixing water problems where they should be fixed, and that is outside the foundation.  You may find that companies who sell such systems apply high sales pressure, and you may find that those companies also have many unsatisfied complaints with the Better Business Bureau.  Yes, they offer a "lifetime guarantee", which, if read carefully, doesn't guarantee very much.  You will also find that these companies frequently go "out of business' and then re-open under another name, and there goes the "lifetime guarantee".  Beware of such companies and their high-pressure sales tactics.

If you follow the steps outlined here, you will be able to diagnose and, yes, solve almost all wet basement/crawl space problems, with only moderate expense, and minimum disruption to your home and yard.  Usually, they can work behind landscaping and leave it in place undisturbed by the repair work.


Mrs Anderson

Thanks for the solid basement waterproofing information.


One of the most common solution for this problem is basement waterproofing. It is quite a messy and long process but the result is very satisfying.

foam coating

your post is so informative! i have actually learned a lot from it and will surely follow some of your tips. thanks for sharing Lisa.:)

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