Drainage project: three questions
Hi everybody. I’m working on installing drainage tile around my foundation that will flow to an existing sump pump. The pipe exiting the sump pump is going to be re-routed to carry the water down to the street (the pipe now drains into the back yard). I am almost done with the digging and have three questions I’m hoping you can help me with, as I am stuck. First, what size gravel would be best to use in the backfill around the pipe, and should it be round or does that matter? And how do you estimate how much to buy? My other question concerns cutting holes in concrete–I need to cut one through the curb for my pipe going to the street, and I need to bore one in my basement wall to get my drainage into the sump pump. I would run the exterior pipe directly to the street, but my grading in no way makes that possible. So how do you make these holes? Are they made in the same way, with the same tool, or are they done differently? OK, so this is four… er, five questions. I haven’t been able to find information about these things, although I’m sure it’s got to be out there somewhere. I would really appreciate your assistance. Thanks in advance.
AL
Replies
1. Gravel size: 3/4 " will work well and pea gravel will work well.
2. Use round perforated pipe and some type of cloth that will allow water to pass through but no soil.
3. Gravel is usually sold in cubic yards. length x depth x width divided by 27 will give you cubic yds.
4. Cutting through the curb I would use a concrete saw or a circular saw with a carborundum blade and cut a square notch in the curb and fill in around the pipe with grout. For the basement wall use a hammer drill and drill a series of holes to form a circle slightly larger than your pipe. Drill them as close together as you can and also drill several in the center of the circle then use a cold chisel and hammer to knock the core out. You could rent a core drill but I would not recommend it unless you had experience with one.
Good Luck,
Rick
Strangbean is correct, good call on his part. LOL.
Thanks to everyone for responding. Believe it or not, I actually did a fair amount of research on this project beforehand! :) I really did. It just often happens that as I get started actually doing whatever project it is, that extra little bit of specificity required to actually pull it all off seems to have a whole world of mischief hiding inside it. I really appreciate you taking the time to answer my questions.
AL
I'm not sure oif the stone size or type, but you need to cover the pipe with a filter fabric to keep silt and fines out of the pipe.
You estimate the amount of stone by volume. Some places sell it by the ton, but if you have cubic yards they can convert. Length x width x depth. You only need to cover the pipe by about 6-8 inches.
Cutting the curb can be done with an angle grinder and either a diamond wheel or a cut off blade. Have you checked with the city to see if they will let you cut their curb? The hole in the wall can be chipped out with a chipping hammer, or a star drill and 2 lb sledge if you want to work on your muscles. Be sure you seal the hole well after the pipe is installed.
I'm sorry, I thought you wanted it done the right way.
3/4" river washed gravel is good. You don't want sharp edges that can puncture your drain tile. Some places may sell it by the 'scoop' or 'bucket', which is one of whatever loader they use. They should be able to tell you the cubic size of it. Also, the quanity of rock is somewhat fungible. You can generally use up whatever you order. The amount you put on the top is fairly flexible.
There are 'socks' for the drain pipe to keep out dirt, but you also want to keep silt out of the gravel. I lay Geotec fabric along the two sides with some overlap for the top, put some gravel in, put the pipe in, add more gravel to within about 5 to 6" of grade, and wrap the Geotec over the top of the gravel. I think you could line with just one piece of fabric, allowing it to cover the bottom, but some people feel like the bottom should be open to allow water to rise into the drainage area.
If you punch through a wall below grade, be sure to water proof the opening well. I can't tell if this is your situation or not.
The apartments behind me just put drain in the curb. They cut through the sidewalk rather than tunneling underneath. Then patched the sidewalk and curb. As someone else pointed out, this usually requires permission and performance bonds from local authorities, unless the sidewalk is literally yours.
Thanks a lot for the information. I definitely feel I can order the gravel now. But the holes, I still have a couple of questions--First off, i probably should contact my city about cutting the curb. I seem to recall from a long time ago that they do not let you cut the curb and patch it; my neighborhood is full of drainage holes along the curb, but they look like they've been bored. As far as cutting through the sidewalk goes, I won't have to, because a couple of years ago they replaced some of the sidewalk segments on our street, and I got them to put a three inch pvc pipe under the slab before they poured it.
The hole through my basement wall will be below grade, down low by the footer. I realized I didn't tell you before that my basement walls are concrete block--I don't know if that affects how you should make a hole in it. I plan to seal around the pipe coming through the hole with an expanding foam, and then from the outside the whole thing will be patched with hydraulic cement where needed, and then tarred over with sealant. I've heard some people mention a kind of flexible barrier that goes on kind of like the ice guard that you put along the edge of a roof when you roof. But I haven't seen anything like that at any of the stores I've been to.
I also haven't seen the kind of membrane I'll need to use to keep fines out of the gravel. Where do you get it? All I've seen is landscaping fabric that is way too narrow to be used--it isn't wide enough to enclose everything inside just one piece of it.
Man, I've got more questions than I realized. Here's my last one. And I thank you for your time and patience. How do you tie together the black perforated drainage tiles? I'm planning to use that type of tile down around my footer leading to the sump pump, but I don't know how to join the pieces.
Or do you think PVC would be better for the drainage going to the sump pump, as it could tie directly to the pipe going through the wall?
Thanks again. You are a great help.
Concrete block is easy to punch through. Lay out the hole and drill a bunch of small holes with a masonry bit. A hammer drill will make it easier, but it can be done with a regular drill. Drill a series of holes all around the marked circle and then chip it out with a hammer and chisel.
Use the 4" perforated pvc pipe from HD. Landscape fabric from HD would work. Usually it come in long rolls about 3 ft wide ... why won't that work? If you use 4" pipe, you can cut the fabric in half and use 18" strips. Be sure to use the fabric that says it allows moisturte to pass through.
I'm sorry, I thought you wanted it done the right way.
Ed,
I was planning to backfill with gravel to within a half foot or so of grade, and wrap the whole thing, drain and all, in filter fabric. I saw it done that way in a Taunton book on foundation work I looked at to see the basics of what to do. If I were just wrapping up the pipe with a smaller amount of gravel, the landscaping fabric would definitely work, but with this, I don't know where they get the larger pieces of filter fabric.
Thanks for your advice.
AL
I don't know where they get the larger pieces of filter fabric
On a narrow roll--lay the roll out along the edge of the slab, and cut it with a bit of overlap. Lay the pipe over the fabric, and wrap the fabric up and over the pipe, now backfill with the water-washed rock. Think of a "6" sort of shape.
I prefer the filter fabric, as it keeps the "fines" out of the drain tile, which keeps them out of the sump pump. And not wondering if the sump pump is sanding itself into uselessness makes for less insomnia.Occupational hazard of my occupation not being around (sorry Bubba)
CapnMac, thanks for responding. The thing was, I wanted to wrap up the gravel too, to help prevent it from getting clogged by fines from the soil. That's why I wanted a larger piece of fabric. In the end I decided to just use the narrower fabric I'd found and to make a series of layered "burritos" out of it, the deepest one of course containing the pipe and some gravel, and then all others with just gravel. During my excavation work I came across a rinky dink drainage effort someone had formerly made, and it consisted of a drainage tile about a foot below grade, running in a big circle around the house, but draining nowhere! It's the kind of thing that would be rather humorous if it weren't your house. It's like a bunch of guys standing in a circle shooting at something in the center, just kind of retarded. But the thing about it that pertains here is that the pipe was packed in gravel that was badly clogged with soil--which made me see what my gravel would wind up looking like if I didn't wrap it in some kind of fabric.
Al,
I hand dug and waterproofed our basement two houses ago.Sucks don't it?
Two things.You haven't mentioned waterproofing your exterior block walls.You ARE going to do that while it's open,right? I scraped mine down with a shovel,hosed it off and let it dry,parged the whole surface with mortar,painted it with driveway sealer,embedded visqueen in it,...then backfilled.Your exterior mortar joints are shot and allowing a LOT of water into the cells,which then moves through the block and onto the interior surfaces.All of those companies that try and waterproof from the inside(channels,etc.) are a joke.
I had enough fall to take my footer drains to daylight so I was blessed not to have to deal with the sump pump issue.A lot of people here have trouble with them being overwhelmed in heavy rains or just being useless when the power is out.I think you should re-consider taking your downspouts into this system and thus into your house.Don't underestimate the amount of water that comes off of your roof.Can you take the downspout drain toward the street separately and then combine it with the line coming from the footer drains away from the house?
Barry
Hi Barry, thanks for responding. How you describe handling the downspouts is in fact what I am doing--there are essentially two pipes I'm laying, one down by the footer to channel water into the sump pump, and then one up top, carrying everything away to the street--sump pump and downspouts.
I cleaned up the wall like you did, scrubbed it with a wire brush and washed it down; then I patched cracks with hydraulic cement and slathered the whole thing in tar sealant. Working in a confined space with that stuff was a real treat.
Yesterday I got the bottom pipe put in around the footer and the pipe going from it to the sump pump; and I got maybe a third of the top pipe done. Putting the hole through the wall for the pipe going to the sump pump was harder than I thought it would be; really cramped space and long drill bit. Awkward place to swing a hammer at a chisel too. Also, the voids inside this old block are different from what I was expecting; much narrower; by sheer luck the place I wanted to put the hole happened to be in a spot where there was a void ... just the same width as the pipe I wanted to put through. Put in the pipe, then sealed around it with expanding foam and packed it in with hydraulic cement.
It's one of those projects that won't die easily; it feels like I keep getting closer to being done, and yet there is always a lot left to do. I cringe to look out my front windows right now, because there are two huge piles of gravel out there waiting on me.
AL
Al,
It will be worth it when you're done.My old basement would have water coming through mortar joints on the bottom three courses when it rained hard.After I was done it was dry as a bone.Don't forget to coat that hydraulic cement with some sealer as a second barrier.
One thing I should have said in my first post,please be careful working in the excavation.Even if it's dry watch out for cracking in the sides.A couple of years ago I was doing electrical work in an emergency room when they brought in a basement waterproofer whose excavation had caved in on him.He was so freaked out that even with broken bones he kept fighting everyone.The ER doc eventually shot him up with Demerol and had to call for security to help hold him down.I guess almost being buried alive is pretty scary.
Barry
Look in the Yeller Pages under "concrete sawing, cutting, and boring"
They'll come out quick and bore the cleanest, prettiest round hole in the curb to specifically fit yer drain pipe. Be there with an example of your pipe so's the guy can select the proper size coring bit.
Write him a check (close to $80 per hole, depending...) and he'll be done in no time. Have him core out that foundation hole at the same time.
One possible catch to boring through block is if has been filled with mortar (grout). Unlikly, but not impossible. I don't know specifics of waterproofing after cutting a hole below grade, except that you want to use a cement like hydroplug that will deal with being in a wet environment while curing.Geotec is a specific filter fabric,made by DuPont I think. It will last longer that cheap filter fabric. Good building supply houses will have it. I think even Lowes does now.There is a rigid drain pipe now with bell shaped ends that does not require glue. Just insert and forget. Or use flexible and get it long enough. I like rigid without the ridge. I figure water gets out better and doesn't collect and freeze. But that is just gut feeling by me.
around here if you touch a sidewalk or curb the city will drop the jail on you. so on mine , I stop about a feet from the curb and my pipe ends in a hole about a foot deep and foot in diameter. I filled completely with pea gravel to grade elevation.. The water will overflow out the pipe, out the hole and go over the top of the curb. after awfile grass will grow over the pea gravel but it will still work.
Hi AL3*.You mentioned you planned on using black flexible drain pipe ( the corrugated type) for your drainage tiles (lines).
A bettter pipe to use would be ( as mentioned earlier) a ridgid type of pipe with a bell on one end. The bell allows the pipe to move a bit due to ground pressure, but the pipe will still stay together. You don't neccessarily have to glue the pipe because the bells hold just fine. Do not use foam core pipe...this is too soft for underground use and can easily burst.
I would suggest you use a ridgid PVC pipe known as SDR35 which stands for a sewer/drain pipe capable of withstanding 35,000 lbs PSI....hence this pipe won't crush very easily. For groundwater foundation drainage, you need the perforated pipe, which has pre-punched holes in the pipe to allow the ground water to seep in and then be carried out. This type of pipe is installed with the holes pointing downward ( basically in the 4 oclock and 7 oclock positions). The printing info on this pipe is always situate right on top; which is how to lay this pipe correctly...the printing on top assures you that the hole positions are correct.
Unless you would have to place pipe directly under a ddriveway, the SDR35 is the right pipe to use. Use schedule 40 or thicker only if crossing under a driveway or road...sidewalks do not count.
The ridgid pipe (SDR35) have larger holes to allow water infiltration and are smooth inside ( unlike plastic corrugated pipe) which allows the water to flow more easily.
For directing water out of a sump pump ( the discharge pipe), you need to use solid pipe; not perforated. Again, SDR35 also comes in solid form. There are plastic fittings (elbows, Tees, 45s, etc) that resemble schedule 40 PVC that are made to be glued to the SDR35 where ever needed. Any reputable hardware/pipe supplier that carries the SDR will also carry the fittings. The pipe uses regular PVC glue.
I use river gravel for bedding down my drainage pipes...the more the better, but just remember to keep your perforated foundation lines (we call em "French Drains" in my region) next to your concrete footer. It does no good to run this pipe too high up off your footer...for in doing so, groundwater has to travel higher up to reach the pipe and flow away....the higher the water table at your foundation, the more likely that such water may find a path into your home rather than be diverted through your drain lines.
The socks that are frequently mentioned to use for covering over your perforated drain, are simply not available where I live. I guard against silting up mainly by washing down the gravel before backfilling, and by using lots of it...approx 6-8 inches underneath the pipe, and 40 inches or higher above the pipe.
For cutting a hole through a concrete block wall....the advise about simply using a hammer drill and drilling a series of holes was the best info you could have. Hammer drills will make quick work...and a sledge hammer helps immensly. To round out your hole, use the peen side of a ball peen hammer to ease any irregularities.
After sliding your pipe through this hole, if the block were hollow, use spray foam inside the cavitiy areas to fill in the voids, then patch perimeter with hydraulic cement. After patching with the hydraulic, pack a few bags of Quickcrete ( or Sakrete or equiv.) around the exterior side of the hole before backfilling. The ground moisture will harden these bags and be added protection against water infiltration at this entrance site.
When running your pipe out to the curb, remember to cap the end with a vermin proof cap that will keep chipmunks and such out of your pipe.
One last comment.....if your discharge run from your sump to the curb is a very long run, you may want to think about installing a clean-out somewhere on your property in case this line should one day get clogged up. Just a thought.
Good luck on your project....happy digging!
Davo
"I would suggest you use a ridgid PVC pipe known as SDR35 which stands for a sewer/drain pipe capable of withstanding 35,000 lbs PSI..."Where did you get the SDR35 can withstand 35,000 psi. I certainly don't want to be near any that is attemped to pressurized anywhere near that amount.SDR stands for a ratio. Don't remember exactly, but it relates to the thickness of the sidewall to the diameter. This idea is that different size pipes will have the same 'strenght'. Whereas schedule pipe has the same wall thickness, for a given schedule, requardless of the diamater."Any reputable hardware/pipe supplier that carries the SDR will also carry the fittings."There is another piping system, Sewer and Drain. It has a specific ASTM number that I have forgotten. S&D will phyysically interchange with SDR35 (in the 4" size, but is a different spec.I found that the local hardware store as with the home horror stores would have the one type of pipe, but the different type of fittins. I ended up mixing and matching without any problems."For directing water out of a sump pump ( the discharge pipe), you need to use solid pipe; not perforated."Yes, but that will be a much smaller pipe. 3/4 - 1 1/2". I use use sch 40 or PE pipe.
Once again, thanks for the information. I feel like it's all coming together here. The digging is done, basically, except for the trench to the curb--I'll finish that today, hacking, er, digging to the curb. We've got a lot of tree roots. It's still gravy, though, compared to digging down around the basement to the footer. As I was doing that, I couldn't help but think that I was fulfilling every little boy's dream, to actually dig a hole to China. If only digging a hole now were as entertaining as it was then.
I went out and bought the white drainage tile you suggested with the bell-shaped ends, and it seems much nicer than the black perforated stuff. I haven't been able to find Geotec fabric anywhere, though. Lowes didn't have it. They just had landscaping fabric that didn't look especially good for this kind of thing. HD didn't have it either, but they did have a better looking landscaping fabric, so I got some and figure if worse comes to worse, I can pour my gravel inside a series of smaller "burritos" of landscaping fabric, instead of just one big one. The soil around my house is clay big time, and I'm just sure it will clog up my gravel in short order if I don't wrap it in some kind of filter.
The suggestion by Davo to pour some dry concrete around the below-grade hole makes a lot of sense to me, and is something I had not thought to do. Thank you.
The one remaining problem I'm having is with the small pipe that will go through the below-grade hole--that pipe is going to penetrate the filter fabric and the drainage tile, presumably, so as to carry the drainage water into the sump pump. My problem is that I'm not sure how to connect that small pipe to the drainage tile. What I've thought I would do is just cut a hole for it in the side of the drainage tile, stick it through, and then caulk around it from the outside where the two pipes join. Or is caulk not necessary? And is there a different way to do it that would be better? I didn't see any fittings for this kind of thing at the store--not for the 4 inch drainage tile anyway, going from 4" to 1 1/2" or to 2".
As far as the hole in the curb goes, I guess I'm related in an extended sort of way to some guys who do excavating and who have some equipment that can make the hole pretty easily. So they are going to drop by and plunk a hole in there for me.
Thank you to everyone for responding. Your information has really saved my ... buttocks. You've really filled that gap for me where after reading about how to do something, you invariably wish there were someone you could call with your questions. Thanks again.
AL
Al, you should not nhave a problem with the clay clogging your pipes. When it's wet, the clay sticks together real well, and when it's dry it doesn't move much either. The silt would come from a soil with more sand or regular dirt.
I'm sorry, I thought you wanted it done the right way.
Depends on the clay.Now I have not had mine analysised but I don't think that there is much sand in it. Lots of very fine clay particals. Yards and Yards of lake dredge.And it MOVES when wet. Hard as a rock when dry.
May I jump into this conversation....
I am just finishing a year of building my home, down to the last details, like gutters, drainage, landscaping, etc.I've built slab on grade, I have guttered the roof and moved the water away from the house. Do I need still need to put drain tiles around the foundation? The soil is clay, but the climate is relatively dry with exception of winter snow.Thanks.
First I am not a pro.And secondly, even if I am have no idea of your conditions of your soil and terrain.However, if the slab is at/above the level the surronding terrain on all sides that certainly reduces the chance of a problem.If you are not too long in the landscaping I would still go ahead and add the drain tile.Even not practical then "wait and see".
Why not go with the full 4" into the sump. AFAIK that is what is normally done.If you want to 2" or 1 1/2" then you can get adapters that go from SDR35 (or S&D) to sch 40. Then in the sch 40 you can get reducers.The home horror stores should have them.
Thanks for the suggestion Bill. I had actually considered doing it that way, but it seemed like an awfully big hole to put in my wall, when a smaller hole seems it would be sufficient. Although a larger one would be more averse to clogging I suppose. In any case, I'm not sure the adapter to Sch 40 then the reducer to smaller pipe will all fit between the pipe and the wall anyway. I'm about to go and look at the fittings at the store and make the final choice. All of the pipe is going in today, and the gravel is coming this afternoon. The project should be finished in a couple more days. I can't tell you guys how much I've appreciated your input.
some of your questions confuse me.
you should take a look at the diagram i have included. i am not sure why you are going to take the sump pump outlet pipe through your foundation wall just above the footer. where is the footer height in relation to the street elevation ? do you have slope in your property from the pipe exit location to the street ? if so, the water can flow by gravity once it exits the building. otherwise, your pump will be working hard to pump the water all the way to the street.
are you sure the bottom of the previously installed 3" pvc pipe under the sidewalk is above the level of the paving in the street ? typically, 4" of concrete are there for the sidewalk + 3" of pipe puts the bottom 7" below top of curb. curbs are often 6" or less above paving. paving overlays complicate this.
usually the sump pump outlet pipe is 1 1/2". if you have pitch outside to the street, you can transition to 3" with fittings. will the pipe be deep enough to prevent freezing in the winter ? this depends on where you live.
carpenter in transition
Hi Tim,
Thanks for responding. I looked at the diagram you attached. Thanks. My situation here is this. The tile around my footer lies far below the level of the street, so there is no way that drain can flow by gravity to the street. There is an existing sump pump that was placed by a previous owner within the basement. The tiles for that sump pump were installed beneath the perimeter of the basement floor. They stupidly ran the drainage pipe from the sump pump into the back yard, where the grading seems to essentially carry the water back to the house, so the water travels in a big circle. Every time it rains heavily, the sump pump runs constantly. We have not had flooding, but the basement is damp and moldy, and the sump pump goes off days after it has rained.
My goal with this project was to carry drainage water away from the house and improve drainage around the basement. So I dug down and am putting a drainage tile around the footer that will drain into the existing sump pump, and the drainage from the sump pump, along with all downspouts on that side of the house, are being tied together and carried to the street. There is a slight slope from the pipe under the sidewalk to the curb--not much, but enough. The pipe to the street will not below the freeze line, but virtually no pipes to the street in this area are, and there are LOTS of them. People don't seem to be having problems with freezing, and our old sump pump drainage line never froze either.
So basically I'm putting a hole in the wall just because a sump pump is already there, and I have no other way to get rid of that water around the foundation. You might expect that the tiles and sump pump that are already there should be enough, but our grading sucks, and the soil is dense clay against the basement walls. So I figured rather than just take the existing downspouts and sump pump pipe to the street, I'd install an extra tile and backfill with gravel. The dirt that came out will be used to alter the grading some. This whole thing just really needs to get fixed.
AL
I'm just going to throw my two cents in here - this may not apply to your area. I plan to do something similar to what you're doing but I would be very concerned about running the water into a sump inside my basement.
I realize it's done all the time but the thought of a power outage or sump pump failure during a big strorm with a lot of rain would concern me. I suppose it concerns me because I am away from home a lot but it's something to think about.
You can get marine batteries and backup sump pumps that run on the battery. Or a backup generator with auto kick in, if you are REALLY worried.
Actually, I'm having the switch/panel wired for the generator when I have the house rewired. I'll get the generator when finances allow (probably never - but I'm always hopeful). I'm still not going to run the drains into the basement - it just seems counterintuitive to me.
Thanks for your input, OHF. I wasn't crazy about that idea to begin with either, but then again, the water is already essentially getting into my basement, so all I'm really doing is getting it to go where I want it to go, and then kicking it out. I plan to have a battery backup for the sump pump for the times when the power goes out. The whole thing is a little less than ideal, but it should work; it's an old house with a lot of "less than ideal" aspects to it. This is our first house, and it has been quite a learning experience.
AL
Bill, I think the 35,000 psi he is referring to is the crush strength of the pipe, not the air pressure. I'm not saying he's right, but I think you misinterpreted his intent.
I'm sorry, I thought you wanted it done the right way.
Still don't believe it 35,000 psi is not for anything to hold.Now when I was looking at specs a few years ago I saw one of them, don't remember if it was the S&D or the SDR35, but indicated that it has a crush strenth of 3000 lbs (IIRC the number correctly).But I could never find out out that was was actually figured. Was that per foot? It could not be by stick because they came in different lenghts (8, 12 and 20 ft if I recall correctly as manufactured, not just cutoffs). And was that measured on a plain piece of pipe with a flat plate on it or was the pressure evenly distributed by x" of gravel over it?