Leaky basement blues

My basement has been diagnosed with groundwater problems. The basement consists of poured concrete walls sitting on the foundation and a separatley poured slab with some expansion material around the slab where it meets the wall. I have been having constant seepage at the wall/floor cove for 3 weeks with no end in site. I am onle collecting between 1/8" and 1/2" of water on the floor due to good run off towards the sump. The house is almost 2 years old and this is the first problem we have had. The groundwater table is up extremely high(older locals never remember it being so high) this year due to lots of snow and heavy rains throughout the spring and early summer. There is an existing external drain system that seems to be doing it's job very well. It is filling the existing sump every minute or so.
Two waterproofing contractors have suggested the same remedy of installing an interior perimeter drain system consistng of digging out the 12-18" concrete slab perimeter and trenching to the footer. Installing stone aggregrate and drain pipe and then covering with stone, vapor barrier and "mira-drain" material at the wall/floor joint up to about 1" above the replacement slab level. They will then reinstall an improperly installed sump pit/pump and add an additional sump pit/pump on the other side of the basement. There will be a battery back up system installed as well. They think the house is sitting on a spring. Lucky us!
Both contractors will issue a "dry walls and floor basement guarantee" for as long as I own the home and it is able to be passed on to 1 future owner. I can also receive a certificate of dry basement for future mortgage requests.
There is 146 ft. of linear pipe to be installed along with 2 sump pits. The prices were both within $600 of each other @ about $11,000 for the job.
1. Will the fix work? 2. Does the price sound reasonable?
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If ground water is the only culprit, it may work. However it sounds like your first attepmt should be having a new sump pit installed with a higher capacity pump. (or perhaps two) Also make sure that the discharge from the pump takes water far away and down slope from the house. Additional drain tile may not be necessary.
If it comes down to installing interior drain tile, $11,000 is way too much. You should look to pay $25-30 per linear foot of interior drain and $200-$500 per new pump set up depending on the GPM rating and quality of the pump.
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If you have a tensioned slab cutting it could prove to be very dangerous. The tendons are under great stress. Careful, Seamus J. Wilson

drain
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Ignore Lyle Harwood, he has a leaky head. To really take care of the problem, you will need to excavate around the outside and treat the problem, even improve drainage around the footing?

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€ Two waterproofing contractors have suggested the same remedy of € installing an interior perimeter drain system consistng of digging € out the 12-18" concrete slab perimeter and trenching to the footer. € Installing stone aggregrate and drain pipe and then covering with € stone, vapor barrier and "mira-drain" material at the wall/floor € joint up to about 1" above the replacement slab level. They will then € reinstall an improperly installed sump pit/pump and add an additional € sump pit/pump on the other side of the basement. There will be a € battery back up system installed as well. They think the house is € sitting on a spring. Lucky us! € € Both contractors will issue a "dry walls and floor basement € guarantee" for as long as I own the home and it is able to be passed € on to 1 future owner. I can also receive a certificate of dry € basement for future mortgage requests. € € There is 146 ft. of linear pipe to be installed along with 2 sump € pits. The prices were both within $600 of each other @ about $11,000 € for the job. € € 1. Will the fix work?
In my opinion, once water has penetrated the concrete, damage has already been done, and therefore, no interior "fix" will "work". Water must be kept out of the concrete. Any solution must be executed outside the building envelope. Water in concrete does damage, to the concrete itself during freeze-thaw cycles, and to the rebar. Furthermore, water inside a basement, whether standing or running, is a bad idea, health wise.
In "problem" areas, (such as areas with high ground water) specific solutions may need to be developed for specific sites. Each site is different, and each solution is different. These solutions must be professionally designed, and such design is not what contractors do- it's what engineers or architects do. Contractors execute designs once they've been designed.
You don't need a design based on the idea that someone "thinks the house is sitting on a spring". You need to know if the house is sitting on a spring, and design accordingly.
For what it's worth, I have yet to see a house that really is sitting on a spring. Houses aren't easy to build, and most of the builders I know are too lazy to build a house while wading around in a spring. What I have seen is many houses that different people said were sitting on springs, when what they meant to say was "there's lots and lots of water in the basement".
Some contractors "specialize" in waterproofing. When such a contractor recommends an interior solution, it's because they don't understand the problem, and aren't capable of correctly analyzing the situation and designing a solution for it, or it's because they have some pet "solution" that they sell, and they are convinced that their one wrench fits every nut. These "solutions" frequently take the form of magic gunk, magic glue, inject-a-goo, interior trenches, sump pumps, and my favorite, heavy nylon and plastic stapled to the inside of the basement wall.
In my city, (a wet one, Seattle) dozens of these waterproofing "contractors" open their doors for business every year, and every year, dozens of them fail. The reason I know is because I've picked up behind them for many years, after they've failed, and the customer's basement is still wet. The only part of this that disappoints me is that the customer ends up paying twice for the same work, and I am, therefore, working uphill, against suspicion, to satisfy him. One of the main reasons I'm still in business is because I know how to recognize what I don't know, and I know how to call for the professional services I need to get a project executed correctly. Wet basements are really bad places to cut corners or save money.
Enough of that.
The first thing I do is call out an engineer to look the project over, and tell us The Truth. We're not talking about a lot of money, we're talking about a couple hundred dollars. With your check already in his pocket, the engineer becomes our hired gun, and he has no reason not to tell us the truth, and every reason (professional liability and reputation) to give us the whole, ugly list of things that are causing water to enter the basement.
What you get, then, is a fast, accurate answer, that either Standard Solution A (new exterior footing drain, new emulsified asphalt, gravel and landscape fabric), Standard Solution B (a rock pit) will work, or, C, a custom design is needed. Note that none of these options include water penetrating the building envelope. The goal is to Keep Water Out.
If A, great. We locate a Place For The Water To Go, and start digging. Water likes a place to go. In fact, it likes a place to go so much that it will always, always find one. Water is also very lazy. It will always choose the easiest place to go. Water is relentless, particularly in its choice of route. But most of all, water hates to be anthropomorphized.
If B, great again. Now we need a place for the pit. Placing it so it floods your neighbor's basement usually isn't good for the local political climate. Only do this if the political relationship with your neighbor can't deteriorate any further, and you are already at war. In that case, it makes a great weapon, but be warned that it will almost certainly trigger the nuclear threshold, and loose the lawyers.
If it's a custom design that's needed, we proceed as necessary. We pay for the design, and then we execute it precisely. If your site is real trouble, (for instance, if it really is sitting on a spring) the solution can be expensive. But if that's the case, it is what it is- better to know, and build accordingly. The worse the site is, the worse the choice of proceeding without a professional design becomes. No one wants to put yet another 2 gallons of water into a radiator that has a hole in it. Sooner or later, you loose the engine.
Designs and professional advice are worth every penny. What you get in return is a dry basement.
€ 2. Does the price sound reasonable?
No. I wouldn't pay a penny for an interior solution. Water inside your basement can make you sick, literally. I refuse to have mosquito nurseries in my basement. If I really couldn't find a way to keep the water out, I would sell the house, and move. Really.
Best of luck, and let us know how it comes out!
--
Lyle B. Harwood, President
Phoenix Homes, Inc.
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wrote:

Let me guess one of these companies was Mid-Atlantic waterproofing..right? Look around you can get it done for half the price they quoted you if you decide to go this route.
I got the same speal. No thanks. Don't want a bunch of red necks jack hammering around my house's footing. I wouldn't go this route unless 2 or 3 structual/foundation engineers said it had to be done to prevent the house from falling down.
Lyle makes some very good points. But first I'd grade the hell out of the property and bury all the downspots so they empt well away from the fooundation. That is what I am in the process of doing. I've built up the grade on the outside of one of my walls so it slopes almost a 12 inches 5 feet away from the wall. It looks strange, but the dirt next to the wall is bone dry. after a heavy rain.
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wrote:

Then this may be one of those 100-year occurrences. Any chance that you can just wait it out?...that yer just jumpin' the gun and it may actually take care of itself?

Try to get the original plans from the builder. Find out what interior and exterior perimeter drainage you have in place NOW. And consider putting in exterior cleanouts if necessary.

Improperly installed sump pit? It sounds like ground water is draining into it...and is being expelled properly. What's 'improper' about the installation?

Why? This should not be necessary.

And, what?...you've had the spring turned off for 2 years?! lol
HOGWASH!!

It'll only be good for as long as you own the house...or 'till they go out of business...whichever comes first! And, if it DOES leak again...would you want them doing the work AGAIN?!! And what would they even DO?
Take the time to find a good contractor instead...and I'm not sure you've found a good one with the one's you've gotten for the estimates.
Have they suggested cleaning out the existing tile?

Have them print it on soft paper for you...so you can use it for what it'll REALLY be worth. lol

We have no idea, of course...nor do you. See if you can get some references from them...for jobs that have been in place for 5 years or more. Check their reputations...especially with the local licensing bureau.

Seems high for the interior. A good rule of thumb for the outside (MY rule of thumb...lol) is about $3,000-$5000 per wall...but that includes digging to the footer.
I think you have a SPECIFIC, PECULIAR problem. Again, this may just be a '100-year-flood' problem...that you may never see again in your lifetime.
Find out what you have NOW in drainage. Find the original building plans. Your city might have a copy of them.
Since yer not having wall problems, you might consider putting in interior channel...and take it to the sump pit. You can easily do this yourself...and the cost would be MUCH lower than what you've been quoted.
But this is NOT waterproofing, per se...only directing the water.
Good luck.
Have a nice 4th weekend...
Trent
Help keep down the world population...have your partner spayed or neutered.
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Been there, done that with a townhouse in Northern Va.
I tried all the grading, downspouts, etc.. didn't do jack. Clearly the problem is improper waterproofing methods employed when the house was constructed. Can't fix that now, short of digging up your entire basement down to the footer, then doing it properly. That would be costly, and it would work. The interior jackhammering with the draintile worked for us, only drawback was the small odor (damp mold smell) that always existed afterword because you're not fixing the problem, only redirecting the water thats coming in.
Choose your approach, then get many estimates. Our townhouse cost us $2000, but that was 10 years ago, and only 40 feet of jackhammering.
-Kevin
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