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My SO and I are looking at purchasing a home with a cinder block basement. The home was built in 1969 and has a sloped lot. The owners (original) have had the basement recently waterproofed. During our first visit, there was water in a small area of the basement. . .and on the second visit--post waterproofing--no water was visible. Both visits occurred 24 hours after heavy rain.
So, my question is: Does anyone have any experience with waterproofing cinder block basements? I am curious about how successful (and costly) the process was. . .because we would want to take this into account before making any offers (we plan to finish the basement).
I've learned that there are people who tend to steer clear of homes built on cinder blocks because of water issues and the costs related to fixing the issue.
Block is difficult for a few reasons. Primarily it is porous, and the joints can crack. If the waterproofing is done on the outside, using both a tar waterproofing and some sort of waterproof sheet, and the excavation has drain tile and the area above the drain tile has the proper stone, and the gods are in a good mood, you can have a relatively dry basement.
That doesn't do anything for the issue of summer moisture condensing on cold concrete walls and making them damp.
I would look at flood zone maps, geodesic surveys, and the permits pulled for the waterproofing. If the soil is clay, I would be concerned. If the land is primarily sand and gravel, I would be less concerned.
The owners (original) have had the basement recently waterproofed. Thanx.
What exactly was done to "waterproof"?
The only "waterproofing" worth it's weight in gold is something similar to what harry mentioned.
It's a spray-on membrane (it not tar; tar becomes hard and brittle. It's a true membrane that can stretch over 100% without rupture.)that is covered with a wicking material in combination with a good drain tile system.
Houses that were built in the 50's thru the 70's weren't "waterproofed", they were damp proofed. Which was nothing more than a tar coating.
If this house has had a perimeter drain system installed- it may relieve the standing water problem- but the damp wall issue will still be there. All that crap that's on the market that you just paint on is just that- crap! When it comes to leaks you have to stop them from the source. Otherwise, the cavity of the block wall will just hold that water.
And if the grade around the house is not at least a 6 in 10 slope, then part of the problem still exists.
I am not sure what type of "water proofing" they had done. . .we are having our agent check on it.
Yesterday, I spoke to an individual who does water proofing for a living (he is a structural (?) engineer/ex-inspector). . .he was out checking our rental because it has some water issues in the basement. He gave me some pointers about what to look for (and ask about) in the basement and lot--of which included looking for evidence of water on the blocks and checking the grade. I am very familiar with effervescence but not sure if I can adequately access the lot/grade.
So K'ledge, when you mention "at least a 6 in 10 slope", what exactly is this? And how do I determine if the grade has it?
Also, can anyone tell me what to expect with cost (and success) when it comes to "correctly" water-proofing the basement? We really do not want to waste the little, old people's time with an offer if the work will be more than what we would like to take on.
So, I just spoke with our agent and he stated that the owners had inside and outside work done . . .and that the company put in "some type of drain system." He gave me the number to contact the company but I am not sure what questions to ask. Any advice? Are there certain "keywords" or phrases that I need to use in order obtain the right information?
It is "efflorescence" not "effervescence," which is what soda pop does. I mention it only because you'll be talking with people that will pick up on that.
You want to know how deep the waterproofing layer extends and how deep the pipe (drain tile) is buried. You may get a straight answer if you play dumb. "Gee, must be the surface water and water from the roof on the uphill side caused the problem. Did you have to go down a foot or more?" If the answer is that the tile is only two or three feet down, then you likely don't have a serious attempt to fix the problem. If the drain is at about the level of the footings and the entire wall is sealed, that would be a happy dance. If you lead with info that makes the company expect you are fully aware of the issues, they may either clam up ("Sorry, don't remember the job") or distract. If they did a proper job, they will be proud enough of it to correct your "assumption."
"So K'ledge, when you mention "at least a 6 in 10 slope", what exactly is this? And how do I determine if the grade has it?"
6in10- 6" of fall in 10 feet of run. In otherwords, from the foundation of the house measure out ten feet. At that point the grade should be at least 6" or more lower than at the house.
The best way to measure is with a transit or laser level. For the average H/O, a string level will work just fine.
So, my question is: Does anyone have any experience with waterproofing cinder block basements? I am curious about how successful (and costly) the process was. . .because we would want to take this into account before making any offers (we plan to finish the basement).
I've learned that there are people who tend to steer clear of homes built on cinder blocks because of water issues and the costs related to fixing the issue.Thanx.
Cinder block walls are not difficult to waterproof and if completed properly should last at least 15 years. The support or stress a cinder block foundation takes can damage the cinderblocks. The reason I never built a home using cinderblocks is stress and leakage of water.
There are exceptions to waterproofing, of course. If the person who waterproofed the exterior of the cinderblock first sprayed on tar then applied a rubber membrain may last a tad longer but the tar can become brittle, separate and leak earlier.... In your case it would be a good idea if the company should provide a written guarantee of the the job.
I prefer building a home using solid concrete walls and reinforce the walls with steel rebar. I also water proof the entire exterior foundation using a pro who provides me with a guarantee.
I would like to have you get a warranty from the RE Agent before you purchase the home....
The biggest problem is having a finished basement is eventually water could wick to your beautiful finished area. Your electronics will get damaged to some extent. Mold and mildue are unhealthy to your health too.
Conclusion:
There is no sure fix or sure sell when avoiding water leakage to the basement of a home. Regardless of being new or aged or cinderblock or solid concrete walls walls do accumulate moisture. However, I know that using blocks meant the home was built and the builder cut corners.
Using my method of building foundations require deeper and extra reabar supports. To date my homes have not experienced leaking because when the walls of the foundation sags due to improper footings cracks will occur......
Thanks everyone for the information. . .it has been VERY helpful.
Harry Chickpea: From the information we received, it appears that the drain tile was placed at the footings. I made an attempt to look for the efflorescence but it was impossible to to detect due to wall paint.
Also, the water proofing company does plan to offer a warranty. . .did not inquire about the duration because we aren't sure about placing an offer on the house. We did revisit the home on Thursday and everything seemed to be dry. So, if we do decide to place an offer, we will be sure to get the warranty transferred and have the basement thoroughly inspected before preceding with a contract.
"From the information we received, it appears that the drain tile was placed at the footings. "
Sounds good. You did your homework. Makes me happy.
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