Groundwater 2

[Marilyn803]

I'm looking for some guidance. I live in a condo community with 56 units (small). Water leaking into basements has been an issue since it was built 17 years ago. The grading is horrible. Our Association spends thousands each year repairing leaks in basements, changing the grading outside, etc., but nothing seems to help. There are several areas between the units that appear to be small "bogs". I use that term loosely because I'm not really sure what a bog really is. We would like to hire an expert to come out and tell us what really needs to be done. Waterproofing people and landscapers really don't know. I'm guessing we need a Civil Engineer. Where does one go to find one? I live in Michigan (a suburb of Detroit). Any help/direction you can provide would be appreciated. I also might add that we live not far from a flood plane.

 

[cvg]

you might be able to find some information on these sites

http://region3.asce.org/

http://www.ilspe.com/

 

[oldestguy]

There are several possible factors involved.

Source of the water could be ground water or surface water or both. I will try to summarize treatments. Assumed here is that downspouts are routed well away from the structure and the ground surface is sloped away.

I suspect that there may be failed perimeter drains at the building. If so, it is likely some well meaning builder (and unfortunately too many engineers and architects)call for surrounding the drain pipe with gravel. Gravel is not a filter of soil and the voids easily plug and the system fails, sometimes the first year of use.

If there is a perimeter drain system, dig down to typical places and check for the condition.

You msy or may not have to replace it. If the source of water is actually ground water, yes replace it. however, this time use a good filter around the pipe (slotted plastic). You may find some folks in this group that say surround the pipe with a filter fabric, or they ay say surround the gravel with a filter fabric. that may work, but I have seen the sock covered over with mud and seals it shut. Surrounding the whole system with fabric is very labor intensive.

A good way to do this is place the pipe and then simply dump in a good filter to cover the pipe and go maybe a foot or two above it. A good filter is ASTM C-33 FINE AGGREGATE (CONCRETE SAND). Very easy and concrete sand does a great k=job of filtering all types of soil.

On my jobs, the specs say "No gravel allowed on site" or some well meaning workman will use gravel instead of the sand.

It may be possible to correct the problem by waterproofing the ground surface.

Do this in this manner, after you remove all landscaping plastic, decorative stones,bark chips and the like.

Fill in depressions, as between sidewalk and building.

The strip sod in all areas where there is backfill to the building. It may go 15 feet out from structure.

Apply 2 pounds of powdered bentonite to this earth surface and mix in thoroughly in the top 2 to 3 inches.

Do not use granulated bentonite, since it does not work as well. Do this on a calm day, Use a garden roto-tlller for this mix and be thorough.

Work around bushes as close to them as possible. Do not try to seal stone landscaping areas in depressions and hope to seal a bathtub. This "roof" all should be sloped.

The sod can be replaced and grass will grow great. Bentonite ( a natural volcanic clay) fill soils voids when damp and is a great seal.

If you can't do the whole job, do the most likely places first.

Don't use excessive bentonite or you will have soggy lawns for all summer.

 

[oldestguy]

Hey!! I made a goof and here is what you do for the bentonite.

Apply 2 pounds per square foot. That is, in every 5 x 5 foot square use one 50 pound bag.

You get this at plumber supply houses and do not use granulated. You must use powdered bentonite. Common term is Volclay or driller's mud.

This forum system accepted my text before I wanted to (above), but maybe this will help.

 

[oldestguy]

As to finding a civil engineer on this topic, you probably will not find any that have done what I am suggesting.\

I would contact a large sized landscaping firm and tell them you have a method that they must follow. If you check in the local yellow pages under civil engineers, look for one that does site development, but you still need a good landscaper and they must do it my way.

I have trained many a landscaper, since none that I ever found knew about this method.

Also, I never knew a civil engineer that has done this either.
However, it works great when done as I describe.

 

[cvg]

oldestguy has some good ideas for mitigating groundwater and surface runoff which is affecting your foundation - however, you need to do some detective work before you go through all of this effort with the clay and perimeter drains. What if you have a leaking waterline? You could also be getting excessive storm runoff from offsite that is ponding on your site. You might even have a plugged, undersized or surcharged sewer line in the area. All of these could be causing the excess water. It would not hurt to get a professional out to look at the site first and determine the cause before you jump in trying to repair it.

 

[Marilyn803]

CVG...I agree, but we do not know where to turn to find a professional to figure out exactly what the problem is. What kind of professional am I looking for? Landscaping companies do not seem to know what they're doing, as we have the same or worse problems when they get done with what they believe is the "fix". What kind of professional am I looking for?

 

[cvg]

well, it kind of depends on the problem, but a general civil engineer would be a good start. I can't recommend anyone in Detroit and besides I don't know if references are allowed on this site. But check the links I provided to ASCE and NSPE which should both have local chapters in Detroit. Also, you can contact your city engineer (or county engineer if you are outside of the city limits) and they might be able to recommend somebody.

 

[RWF7437]

Google: Civil Engineers in Detroit, MI

http://maps.google.com/maps?client=...Oe9GIq6jgO98qj7Bw&sig2=bqTVxl1YvGiGTI2eUrgydw

 

[RWF7437]

http://www.engin.umich.edu/directory/DisplayPlace.do?name=CEE

 

[oldestguy]

I'm back.

In looking to hire an engineer, first ask for their references for jobs like this solved.

Then check with those references, and see if the problem really got solved.

If you don't get a positive comment, move on to others.

The engineer category most likely to solve it is Geotechnical Engineer, a branch of Civil engineering.

 

[Marilyn803]

Thanks. I'm doing my research as we speak and have a couple of leads.

 

[Marilyn803]

I want to thank everyone for their help. I have been in contact with a Civil Engineer who specializes in this type of problem and have received a lot of good information. Our Board of Directors is working with him now. Thanks for all your help.