Got a water problem in the dental clinic we are finishing. Half the floor area has a finished basement, the rest is 4′ crawl space. Water is seeping into the basement area. I have a small sump with a temporary pump running 24/7 into city storm sewer that is barely keeping up.
At first we thought there was a problem with plumbing since it was very cold last week when the problem started to appear. Building isolation valve was shut and system pressurized; it held. Then the city shut off its valve at the property line and we pressurized between that and our valve inside: same result. OK, so the city’s water main out under the street must be leaking. The city had the leaking water tested and it showed no trace of chlorine at all. Hard to believe, but it must be groundwater.
We did the foundations back in September and everything was dry as a bone. The soil is a mixture of sand and 6″-12″ pebbles (Penticton potatoes) so it transports water very easily. Now the temp has gone way up and the deeper than normal snowpack is melting rapidly as we enjoy unseasonable spring weather. Bad for skiers and bad for us too. There is a creek about 1/2 mile away that would appear to be the culprit. According to city guys there are very few houses around this neigbourhood with basements because of this. We are lower than most things for several blocks, so it would appear that the water table is higher than the footings and basement slab. Water is getting through the gaps between slab and foundation wall and hey presto, we’re vacuuming and pumping water.
We cut the floor slab under the stairs, jackhammered it out and started to dig for a sump. But the plastic sump insert is 3′ deep and digging is next to impossible with water constantly flooding the hole and undermining the slab. I was hoping for another freeze so things would dry up a bit but that doesn’t look like happening for a while, as the Pacific keeps throwing tropical air at us. In the meantime the painters have just about finished upstairs and we’d like to get the job wrapped up and on to the next thing.
The best thing we can think of is the sump and pump. There is no footing drain (french drain) but it wouldn’t help, the water is below that anyway. If anyone has any bright ideas I’m always willing to listen. And send me the not-so-bright ones too, I know you will anyway and it gives me something to do…
Wally
Replies
ok lady ...
we're done installing yer inside swimming pool ....
sorry ... that's all I got.
a heater ... a blower ... ya got a hot tub. Up sell it!
Jeff
Buck Construction
Artistry in Carpentry
Pgh, PA
Running water into a dental clinic?
OK. Spit. Rinse. See the receptionist for your next appointment.
Cut the bottom out of a plastic drum, larger than the sump insert you plan to use. Set it over the hole and as you dig inside the drum keep pushing it down into the hole. Slip form in reverse. Even a large sonotube would work - for a while. Then get a bigger pump.
Negotiate with the insurance company for a lower rate. You have water on site for the fire department.
I had a house years ago in Halifax NS that ran a stream of water from one end of the basement to a storm drain in the other every spring. Water would bubble up occasionally through cracks in the floor now and again without reason at any time of the year and then disappear just as suddenly. I found 200 years ago the street I lived on was a river.
You can't stop Mother Nature.
This has been an insane winter for BC. in the last few weeks. If you can't pump out the water, smash the slab and fill the basement with gravel.
Or you could wait till the foundation cracks.
Dentists eh? Looks like we're talking an addition out back or on top to replace the finished basement.
They can't be fixing teeth in a mouldy basement
Running the footing drains to daylight is your best bet. Much better than a sump pump. But it doesn't sound much like that's an option.
If you have to go with pumping the water, I'd suggest 2 pumps instead of one. They certainly won't last forever, and you definitely want a backup.
This website has pumps with capacities up to 5,000 GPH:
http://www.littlegiant.com/
.
This one has battery backup pumps and water alarms:
http://www.basementwatchdog.com/
A: Walking into a wall with an erection and breaking your nose.
"Running the footing drains to daylight is your best bet." Explain.
Wally
Lignum est bonum.
By "running the footing drains to daylight", I mean that they drain to a ditch or other low place. Like down a hill or to a ditch near the building. That's much better than using a sump pump, since the water just drains away by gravity. You don't have to depend on a mechanical pump or electricity.
If you lend someone $20, and never see that person again, it was probably worth it.
There is no footing drain (french drain) but it wouldn't help, the water is below that anyway
Excavate the upstream side of the building deep enough to get below the basement floor level. Waterproof the outside of wall very well. Might have to build a false foundation wall so you have something to stick the waterproofing to. Add a deep french drain system with a sump pump in a shaft so it can be pulled for servicing. Backfill with porous material so all above and in-ground water drains into the sump.
I'm sorry, I thought you wanted it done the right way.
I think you are wrong about the french drains not working. We run into sites that have water flowing underground constantly. Springs or whatever source. The drains collect it. We generally cannot use the town storm drains or the sewers. I had two houses in a row where we could have put a bottling company in the basement. Fresh, clean, cold water 24/7. On one there was no place lower for it to go so the town let us use the storm drain. On the other we had to run it across adjoining property to a drainage ditch. We call 'going to daylight' a "positive drain". It means you have to find a place to run to that is lower than the french drains. The water will flow down hill. If you rely on a pump, you need to provide a battery back up for power outages. You also have to pay the electric bill. Putting a foundation in without french drains both inside and out won't pass inspection around here, just because of the circumstance you speak of. We also don't want water building up around the foundation that might freeze and lift or break the concrete. You have to collect it and move it on it's way the best you can. With a pump hole you will fill the basement as soon as the pump stops working. I hope your furnace is up on blocks if you have one down there.
Beat it to fit / Paint it to match
You recieved several good suggestions. Maybe a combination of them will work.
(1) Buy or rent a bigger pump than you need.
(2) Cut a second hole in the slab near your sump hole, but up stream.
(3) Auger the hole in the ground and slip a sono tube in the hole, as a cassing.
(4) Run the new pump, while you finish the excavation and installation of the permanent sump pump.
(5) After the sump is up and running, use it to keep the water table down while you fill and patch the second hole.
(6) Find some one in you area that does the high pressure epoxy injecting, to seal the joint at the floor to foundatoin wall intersection.
Dave
Some good suggestions here; thanks to everyone.
Unfortunately running a drain to daylight would be very difficult here as the land around is quite flat and the basement slab is 10' below finished grade. We are also 2' below city storm sewer. Took a few trial shots and we would have to cross at least three property lines to get a drain to surface and maintain 1% fall. City doesn't like suface water and the legal issues involved would be intimidating to say the least.
Our local code doesn't require footing drains - this place is semi desert with only 12" of rain annually. People out in the 5 acre lots outside town are drilling down 200-300 feet to find water. It's funny how no one will tell you this stuff before building starts, but we've been told the creek originally went through the area we are on - it was diverted about 100 years ago to irrigate orchards and actually run into another creek's drainage. Now we are downhill from the creek, but then so is everything else on this fairly busy street.
The exterior foundation walls are dampproofed with sprayed tar which appears to doing quite well since the water is not seeping in through the walls but up from below the slab.
I won't bother putting the furnace up on blocks as we are using roof top units.
We are hunting for something to use as a casing then will insert that and continue to dig and finish off the sump pump installation. I daresay this pump will only run during tricky situations like the one we have now: a foot of snow followed by a week of melting temps. When we did the fdn back in Sept everything was bone dry down there. Large amounts of precip are pretty rare in these parts.
We will try to avoid footing drains if possible, as the sidewalks around the building and parking lot curbs are already in place. Costs would be extortionate so we will pursue other routes first.Lignum est bonum.
We are hunting for something to use as a casing then will insert that and continue
Take the sump liner to the store and see if it will fit inside of a stock metal, straight-sided, trash can. If you find one, then you just have to cut the bottom out (or off, sometimes the 90º cut from the side is easier), and drive that in.
Have to hope that the bottom of the water table is lower than your "low" pit elevation, though . . . Occupational hazard of my occupation not being around (sorry Bubba)