Preparing to run 3 underground sch 40 pvc from house to detached garage. I have 2 1.25 pvc and 1 2" pvc, my plan was to bore 3 seperate holes (large enough to allow foam to expand around pipes the full thickness of the wall) below grade in the block basement wall of the house and seal around the pipes with waterproof expanding urethane foam and then coat the outside with a liquid roof coating for a little extra protection. Wondering if I can get a watertight seal if I bore one hole large enough for all 3 and leave enough space between them for the foam. Any ideas of the the best way to go?
waterproof underground penetrations
- Thread starter al704
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NWOhioChevyGuy
Well-known member
I would use hydraulic cement, this cement expands as it cures and would give you a good seal to the OD of the pvc.
That is how I have always done it with good luck.
That is how I have always done it with good luck.
Leaflessshadetree
Well-known member
3 separate holes. Hydraulic cement (from both sides). Coat the outside with foundation sealer (a rubber membrane won't hurt for extra protection).
I also like to angle the pipes slightly down (so the outside is a little lower than inside).
Not sure it helps that much but I do it.
I also like to angle the pipes slightly down (so the outside is a little lower than inside).
Not sure it helps that much but I do it.
gregtwojeeps
Well-known member
Yep, this ^^^^^ Same way I have done below ground foundation pipe penetrations for 45 years randomly. A internet search will show all sorts of "through the wall penetration" devices such as compression sleeves etc. Never felt a need to spend that extra money though, when Leaf's method has always worked for me . . JMO
P.S. Try to leave a 1/2 in. hole around the pipe for the HYD. cement to go in to. It works better thicker, (not thin, but mixed to a thick peanut butter consistency) rather than leaving only a 1/8 -1/4 in. of cement thickness. I think its "bond" strength is stronger, when it is made thicker. It will push in to the hole and lock in behind the hole in the block, like a toggle bolt. Don't mix more than enough HC for one pipe hole at a time, as it sets up FAST. Let it dry, then use the foundation sealer all over the HC job. JMO
P.S. Try to leave a 1/2 in. hole around the pipe for the HYD. cement to go in to. It works better thicker, (not thin, but mixed to a thick peanut butter consistency) rather than leaving only a 1/8 -1/4 in. of cement thickness. I think its "bond" strength is stronger, when it is made thicker. It will push in to the hole and lock in behind the hole in the block, like a toggle bolt. Don't mix more than enough HC for one pipe hole at a time, as it sets up FAST. Let it dry, then use the foundation sealer all over the HC job. JMO
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Smoker
Well-known member
Personally I wouldn't put any horizontal conduit penetrations below grade in the house. Every PVC conduit ive come across in the last 20 odd years eventually leaks and fills with water. It'll then drain into your house. Why not stub it up and come through above grade?
pstnbly
Well-known member
^^^^^ This, and then spread "trowel consistency blind nailing cement" which is the trowel version of liquid roof cement.
theoldwizard1
Well-known member
The only way to guarantee no leaks is to bring the conduit up and go through 12-18" above grade.
gregtwojeeps
Well-known member
Yes, above grade pipe entries are best always if possible. But where is the OP's outside grade ? If it is at the basement wall height, then he will have to bore the rim joists band, then LB back down to get in his breaker box. Doable, but a bit more work... but may be worth it to him ? Outdoor pic of PVC's proposed entry point in to basement would be good.
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one pipe is a water service , one is waste water from garage to sewer line in house. Not to sure it's a good idea to run heat tape underground from above grade to frost line
Entry above ground would be 16" below rim joist, penetrations are for water service, sewer and natural gas. Flex tubing will be run inside the PVC for the natural gas, pex inside pvc for water service
roc_on_the_rocks
Well-known member
I might have a need to do something in a near future, so I'm very interested on the topic. How do you plan to seal between the inner and outer pipes?
gregtwojeeps
Well-known member
Well, you have two services that have to enter the basement UG, so in my opinion if you have two penetrations UG to make anyway, use the same good skills while putting those two pipes UG...to make the other PVC pipe enter UG...
Just be sure your lawn slopes away from the house at the UG basement PVC entry points, and that no gutter drops are dumping close to the PVC entry points. Remove all possibilities of standing water at the PVC entry points. Do your penetrations seals the best you can and prime/glue the heck out of every UG PVC coupling joint and watch your trench back fill...no rocks right against the PVC pipes. good luck.
JMO
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larry4406
Well-known member
Well, since you have to dig down to penetrate the buried wall, keep going till you find the house drain tile system (assuming it has it). Then tee into the draintile and bring this riser up to the elevations of the wall penetrations. Make your penetrations as discussed above. Then fill with gravel to the penetration height, cover with geotech (filter) fabric and then topsoil to final grade. This gives a preferential drainage path for groundwater so it won't challenge your wall penetrations.
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Good idea but no drain tile system
If I end up with water leaking thru the outside PVC I'll try the waterproof expanding foam between the inner and outer pipes
stangfan52
New member
- Joined
- May 15, 2016
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I saw a post on a contractors forum that stated that not all hydraulic cement expanded while curing, some shrinks like standard cement so make sure to check for expansion if you decide to go that route
So in following this thread, with the penetrations underground through cinder block, I understand the lines are to be run through a pvc sleeve? So for running direct burial wire and water line, would you use hydraulic cement for the sleeve and then what would you use between/around the sleeve and wire and sleeve and water line?
Jlbc212
Well-known member
I used hydraulic cement around the sewer line which passes through the concrete foundation. It was water-tight for several years before water seeping through became an issue. Water only seeps through when the frost in the ground is just at the right height at the beginning and end of the winter. I tried resealing the outside of the penetration with gobs of roofing tar, but that proved unsuccessful. I may have to dig it all out again, but don't know what to use to seal it as the hydraulic cement failed after several years.
link seal
I've installed hundreds of underground building penetrations and repaired just as many leaking penetrations.
Link seal is the only 100% guarantee that you won't have to worry about for the foreseeable future.
Link seal is a brand name, there is also another company making the same system under another trademark.
Good luck!
I've installed hundreds of underground building penetrations and repaired just as many leaking penetrations.
Link seal is the only 100% guarantee that you won't have to worry about for the foreseeable future.
Link seal is a brand name, there is also another company making the same system under another trademark.
Good luck!
willymakeit
Well-known member
What jfish said. This works.
Core the approiate size hole per link seal.
You need to watch the back fill on the remaining pipe with the correct bedding. Pvc can break and leak at joints and will follow the pipe path.
Core the approiate size hole per link seal.
You need to watch the back fill on the remaining pipe with the correct bedding. Pvc can break and leak at joints and will follow the pipe path.