I have some freinds with a wet basement under an addition. (Think 1″ or so of water
when it pours out.) The basement under the main house is dry, but the sump pump
runs quite a bit. We’ve added sealant to the block walls of the addtion
basement, and put plastic up under the floor joists to confirm that ground water is
coming up thru the slab rather than humid air condensing.
The gutters run into PVC & run toward daylight away from the house.
Seems like sealing the floor is not likely to work, but adding a 2nd sump pump is
potentially expensive and may not work. I’ve looked through the archives for
threads on adding a sump to an existing slab, with not much luck. Thoughts?
thanks and happy holidays.
-d
Replies
Dare I ask what idiot, when adding on to an existing house with a known wet basement problem, failed to add footer drains to the new foundation?
You could ask, but it wasn't me and I don't know. I've heard conflicting stories
from my freinds who own the place. Unfortunately, they have a problem
and I'd like to help them fix it. So I came here.
-d
Well, the proper fix is to excavate and install footer drains.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
gotta agree with dan h . do what should have been done in the first place. always more expensive after the fact.
There you have it.... BT in action. Certainly not the news I wanted to hear,
but I had my suspicions that simply digging a sump wasn't going to cut it.
-d
whoa..... each situation is different
sounds like a high.... but not too high , water table
a sump in the new addition MAY be all that's needed
that's where i would start
what is the existing soil ?.... gravel.....clay..... mixed ?Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
The area is known to have a high water table. The soil is clay.
As previously mentioned, the foundation for both the house and addition is
concrete block. The main basement is dry, but a sump pump killer.
-d
full foundation, or crawl ?
full, right ?
can you dig a gravity drain to daylight ?
if so.....then that would be my first choice.... but most people can't
so, i'd dig the sump and try it
if that does'nt work.... then i'd extend the slab trench , pipe it , and stone it
and it would feed the sump
but one inch of water sounds like the slab is barely above the watertable, so it may not take much to lower that
footer drains won't do anything if they can't drain, a watertable is a watertable...
your description has already made it plain that at some times the watertable is higher than the addition slab
sure there were things that could have been done during construction to mitigate it....but the watertable would still be where it is
you can't raise the slab, so you have to lower the watertable.... either by a drain-to-daylight...... or by a sumpMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
"full foundation, or crawl ?"
Yes, it's a full foundation under the house. The addition has a ~5 foot deep
basement. It's more than a crawl, but about 3-4 courses of block above the
basement in the house.
"can you dig a gravity drain to daylight ?"
It would probably require some serious exavating
"your description has already made it plain that at some times the watertable is higher than the addition slab"
Yes, I did some work earlier in the spring, and I thought
I had it solved. But when the heavy snow was by rain, it became clear I didn't.
You can't raise the slab, so you have to lower the watertable.... either by a drain-to-daylight...... or by a sump
I'll take a look again this week. The yard is pretty flat IIRC, so I think the footing
drains would need to be pretty elaborate after thinking about it. Would it make
to go a little deep with the sump?
-d
edit : so the crawl space addition slab is higher than the full basement ?
why do you suppose the basement is dry , but the addition is wet ?
must just be the clay retains the water after wet periods .... so.....
i would dig a big sump, fill most of it back up with crushed stone, then go to HD , buy one of those black plastic sumps
cut the inlet holes at say, 6" above the bottom , install the sump...., then the pump
then figure out where i was going to discharge the water
Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Edited 12/28/2008 9:14 pm ET by MikeSmith
Originally, I was thinking of discharging it into the sump of the main house.
Obviously if the pump at the main house failed, there'd be a problem. Although...
there'd be a problem either way. Bad idea?? It's the cleanest install I can think of.
The house is on a septic system, so I'd rather not put it in the main waste line.
-d
well , where does the existing sump discharge ?
you don't want to pump into the septic system, or the leach field, or any where near it Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
The septic is in the rear of the house. The sump discharges to a county "ditch" for
lack of a better word. It's not a sewer or storm drain, it's just a 12" corregated steel
pipe that runs parallel to the road and carries water off to designated runoff areas.
It's been like that since the 60's and seems to work fine.
-d
then i'd make sure it winds up in the same placeMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Let's see if e have all of the mental picture of this.
Existing house has a dry basement (floor), but kills sump pumps.
What kills the s/p? Sump is full, sump is dry?
New addition is 2-3" higher than the existing basement, and "pours 1" of water"--correct?
Is that the slab drips over/through the existing-new transition?
Or is that the new adds an inch to the existiing sump?
Or, does the existing basement floor have standing water 1" deep until the existing sump catches up?
Or, doesw the new space's ratslab build up 1" of water before it drains?
I'm wondering if the joint between the new work and old work is the source of leaks; or the cold joint between the new slab and the cut-into existing basement wall. But, that is just a general feeling from the description.Occupational hazard of my occupation not being around (sorry Bubba)
Let's see if e have all of the mental picture of this.
Existing house has a dry basement (floor), but kills sump pumps.
What kills the s/p? Sump is full, sump is dry?
The sump pump in the main house runs a lot during the winter & spring. A few years ago, I put a Liberty Pump in it (commercial) with a check valve and it's been holding up much better.
New addition is 2-3" higher than the existing basement, and "pours 1" of water"--correct?
Is that the slab drips over/through the existing-new transition?
Or is that the new adds an inch to the existiing sump?
Or, does the existing basement floor have standing water 1" deep until the existing sump catches up? Or, doesw the new space's ratslab build up 1" of water before it drains?
Make that 2-3 ft (courses of block higher) than the existing basement.
The 1" of water is standing in the basement and the floor is not pitched towards the
main house, so it just sits and gets stinky. There is some holes punched in the
"transition" opening between the basement and house where I can broom or
squeegee the water back to the perimeter trenches in the main house. I did this and
ran a salamander heater in there over the weekend, I managed to try it out for
about a 1/2 hour before it started right back to where it was. Got rid of the smell for
a dinner party though so I guess it wasn't a lost cause.
I'm wondering if the joint between the new work and old work is the source of leaks; or the cold joint between the new slab and the cut-into existing basement wall. But, that is just a general feeling from the description.
Very well could be. Little difference in color down low in the corners.
To Mike's point, is it the water table forcing through? I don' t
know.
thanks for the interest
-d
All:
Thanks for the responses. I appreciated coming in here to bounce ideas around.
From a rookie who hasn't seen much.
thanks,
-d
> I'm wondering if the joint between the new work and old work is the source of leaks; or the cold joint between the new slab and the cut-into existing basement wall.It's a fool's errand to try to find and fix the "source of the leaks". Yeah, you might be able to temporarily reduce the rate of water flow into the area, but you'll never stop it completely, and any fix will only be temporary.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
a fool's errand to try to find and fix the "source of the leaks".
Well, my goal was to define where the new infiltration was, rather than letting the discussion wander about (as it seemed to at first).
Probably the addition could have been built better. From the sound of it, the original, reasonably water-tight existing basement was compromised when the addition was stabbed on it.
It could be that the simplest thing could be to create a new sump where the addition is adding water to the existing basement. That would keep water from pooling on the floor (from OP's own words).
My only intention was to focus on the where the new problem was occurring rather than the, for want of a better phrase, "the weaknesses of all basements."
That, and the only-five-foot addition meaning that there was some sort of sill/step to the existing basement.Occupational hazard of my occupation not being around (sorry Bubba)
If the existing basement has a sump, I would guess it also has footer drains or some such.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
nah........ i wouldn't bet on it.....
sumps are usually an after thought.... or an "after the the first wet spring" thought
i cut my teeth on high water tables, full basements and soils with bad perc rates
so we always over dig our basements, add 12" of crushed stone, interior drains leading to either daylight or a sump....
but i see most homes get built without any of the aboveMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
If the sump pump's running full time, as described, then water would be running across the floor in the original part, if there are no footer drains. The fact that the new part is wet would be even less of a surprise.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
don't know.... not there.... hard tellin , not knowin
but... a lot of times if you install a sump.... the water will form it's own drain channels to get to the sump
so the sump will perform better the more it is used...
my experience is that most people who install footer drains , install them on the outside of the foundation and then have no idea of what to do with them...
they are just there... they don't drain to anyplace... they don't do anythingMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
The original house has 2 pipes coming into the sump crock. So I'd guess that it
has a drain system of some sort. (Whatever was around in 1962 when it was built)
Have no clue about the addition. My guess is nothing. Hence the problem.
-d
Could be a grade issue (have you noticed that is my generic response for all wet basement/crawlspace/ slab issues? There is a reason for that)
No doubt, grade has a lot to do with it. I've had a lot of luck starting with grading,
but on this place, it looks pretty good. I can do a little bit, but not much... say less
than a yard of topsoil. I went out yesterday when it was pouring, and the perimeter
looked pretty good. I'm thinking the grading will be a bonus, not the cure.
-d
Are the PVC pipes that run away from the house draining as they are supposed to? These are often clogged and could be the source of the water. Also, are the drains perforated? they are sometimes. Simply cleaning and replacing perforated pipe with solid pipe may reduce the flow into the basement.
What is the soil around the foundation walls? Footing drains and waterproofing should be in place for soils that are mostly sand and/or gravel. Footing drains and waterproofing probably won't work in soils that are mostly clay.
If the bottom of the footing is deep, then a sump pump may be much cheaper than drains and waterproofing.
I think you can get creative with miradrain and install a drain system from the interior of the basement. But, you'll have to pump the water out anyway. With the miradrain, at least it would be "managed."
gassed,
The soil is definitely clay. I did check the PVC that the gutter drain into, and
it was clear. The little that I dug up was solid, no perforations. At some point,
someone dug down and put tar on the outside of the foundation, and as I
mentioned, we put sealant on the inside. Got a link for the miradrain?
-d