Wish I had a nickel for each time I've been on this topic! I look at several things to try and get the best answer. I'll briefly cover Seller habits, Land Topography, Basement Type, and Direct Evidence in this post.
What do I Look for in the Basement to see if It gets Wet?
Generally, the easiest place to start in your water penetration detective work is the basement. You can look for direct evidence of water penetration by looking at the following.
A) Water. (oddly enough, water in the basement isn't always from flooding, but that's another post.)
B) Look for mineral deposits, or dirt around cracks on the concrete or foundation. Mineral deposits are often white, and scale easily if there's enough of them
C) Look for staining of water by any wood that is in permanent contact with the floor. I usually check the stairwell to see if the wood shows evidence of water or water staining. Many times, there's is evidence, but I really look for repeated water stains, replaced wood, rotted wood, etc.
D) Look for sump pumps. Folks, Sump pumps are almost always a good thing. They are a great way to get a basement that occasionally, or even frequently gets water to one that stays dry. But most people don't put them in preventively - it's almost always a response to an issue that happened at one point.
What might the sellers habits tell me about their basement?
I also like to look around at what the seller is doing about "water worry". People that have basements that get wet frequently are usually pretty careful about putting cardboard, books, paper, clothing, and other items that respond poorly to water on the floor. If they are expecting water, you'll see everything up on blocks, on metal shelves, etc. You won't see anything on the floor. Sometimes you can tell how long stuff has been in place, and in some basements, it looks like items have been on the floor for years. Clearly, the sellers aren't worried about flooding if that's the case.
What about the Lot? Can that tell me about Water Issues in the House
Water goes downhill, I think most of us know that. So if you home is at the top of a hill, you're usually in pretty good shape. There are exceptions to every rule of course! It's more of a concern when the home, or part of the home, is at the bottom of a hill. If it rains hard enough and long enough, that water is going to start
coming at your foundation awfully fast. When this is the case, I usually look outside, and look for evidence of perimeter drains (many of which are not visible) or other evidence that the water is pooling or not being directed away from the home.
What do different Foundation Types tell me about Water Penetration into the Basement
You can read more about different foundation types here, but in general, fieldstone is almost always going to have some water penetration issues, at least in wet parts of the world like Massachusetts. Even poured concrete however, is no guarantee (far from it!) as it is porous as well, and at best slows down the rate that water will come in.
What else Should I know about Water Penetration into the Basement
Well you should be aware that ANY basement can get flooded. Just because the previous owners had no problems doesn't mean you won't. Let's say that the previous owners had gutters and always cleaned them - but you forgot that first year. That might be the difference maker. Also, trees/shrubs planted close to the foundation grow over time and change absorption rates, or course New England is famous for huge swings in precipitation from day to day and year to year. Maybe you put in a pool, reducing the amount of absorption possible by your lot! Maybe your perimeter drain stops working. There are literally dozens of things that change from year to year, and if the conditions are right, you'll get wet.
Having said that, don't panic! Almost all basement can stay dry, or at least not flood, with good rainwater diversion techniques and routine maintenance, and occasionally specialized systems to deal with more severe problems. The goal when looking at homes is to try to make sure you're not walking into a issue without being aware of what the situation might be. In general, systemic water penetration is very difficult to conceal, and with these tips, you'll be in line to spot it.
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