So, it looks like we found where some of the occasional mice are coming in from!
This is a sump pump outlet. On the inside, the pipe is well-sealed. But somehow, the occasional mouse goes in and comes out in the same spot at an adjacent wall, right into a trap.
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On the inside, the area around the pipe is well sealed with what looks to be some type of [hydraulic?] cement.
For the outside, I’ve seen conflicting internet advice. 2 magazine-type sources say that it should (could?) be filled with expanding foam, and then covered with roof flashing that is tarred to the foundation surface.
When I found a similar forum thread somewhere, some folks advised against hydraulic cement, since the rigidity could damage the pipe over time.
What would you guys advise?
(Normally, there’s a tall clear-out pipe blocking the view. The soil around this pipe must have been eroded recently, or dug out, as it was well covered over the winter.)
Thanks!
Addison
Hydralic cement.
Tyler
I came to say the same thing. This will last and won’t be susceptible to rodents and pests.
Rob
Cement right against the pipe isn’t the best way, due to contraction on the pipe. I used to run geothermal and water lines into houses for a past job, and i found the best way was to put either a pvc or metal sleeve, usually an inch or two larger, which is cemented into the wall. Then put a size reducing rubber boot (usually Fernco brand) between the sleeve and the outlet pipe. So for a 2″ outlet, 3 or 4 inch sleeve. The fernco is clamped with hose clamps to the sleeve and outlet pipe. This also allows whatever vibration from the sump pump to not be transmitted into the cement.
fred
As Rob says sleeves and boots or collars are superior to any “cemented in solution” as they allow for expansion, contraction and movement – plus will make your life easier should you need to replace the pump and discharge line in the future.
If the hole in the wall that surrounds the discharge pipe is nicely round – perhaps you can find a firestop collar (Hilti or others) that will fit.
firefly
I really like this method for new installation. Though it will take quite a bit to retrofit this into an existing installation.
Rob
This is true. You would probably have to cut the pipe off and core a clean hole with either a diamond drill or an SDS hammer drill with a big hole bit, or hammer drill out a bigger hole if you wanted to leave the existing pipe in place, although you would have to cut it to slide the sleeve over it anyway.
Raoul
I second the hydraulic cement. I had a similar problem in the late ’90’s I fixed with it and it’s been good since. If another problem arises bust it out and do it another way. My problem was water though and you could probably get away with something less permanent/rigid if there is no water penetration problem.
Bruce
Insulating foam and good tight flashing will probably solve your mouse problem. I’ve used hydraulic cement but only on steel pipe penetrations. I’ve been happy with it’s performance, but there is no doubt that it puts a load on the surrounding surface. That looks alike an electrical line running over the top of the pipe. Be careful with the flashing, nothing brightens up your morning like getting the angry pixies riled up.
Stuart
I’m fairly certain that the wire is low voltage, but yea – I’m not inclined to be careless around it.
I haven’t found suitable-looking flashing, though. Nor have I found much advice about whether expanding foam is suited for below grade use like this.
Bruce
Great Stuff shows underground pipe penetration sealing as one of their applications on their knowledgebase site.
Nate
Mice will chew thru foam, fyi.
Paul
I have found if you go to Dollar Tree and buy their stainless scrubbing pads and stuff them into the hole. Then take a second pad and pull it apart and also pack it in but not quite a tight. Then use the expandble foam, it goes in almost a a liquid and soaks into the pad. When it dries if the mice or rats try to chew trough it they cut their mouths on the pad in the foam. I live in a wood frame house in Fla. and have used this for a few years now and have never had a repeat of a mouse or rat trying to come back in where it has been repaired.
Nathan
how deep does it need to be filled? IE how far in do you have to press material to fulling fill the void.
If under 10 inches I would probably try to use some sort of urethane caulk. Yes I know it would take alot but it would live there for quite some time and allow for any movements.
I would not use the cement – of I would pull the pipe and then cement it in – then put in a new pipe if it’s needed.
Otherwise I would probably use the foam idea mostly to fill the voided area – then on the outside instead of the flashing I would use this mortar repair material. I forget what it’s called but it feels like urethane caulk that has some agregate dust in it and is colored to match common mortar colors – like grey cement.
It’s often next to the mortar in the hardware stores. I think quik-crete made it. I used some 10 years ago to fix up a spot on my old house where they mucked up installing the hose spigot. Left a crescent gap around 1/2 inch thick around the pipe that they tried to fill with mortar but never set. so less than a year later it fell out.
This repair material filled in – cured- flexed a bit – and blended in with the grey mortar of my house – and was still there 15 years later when I sold the place.
I’m curious what other suggest.
Stuart
I’m not sure. Assuming nearby blocks are hollow, I figured the outer 2″ should suffice.
Hmm, so you’re saying expanding foam, and then a skim coat of mortar repair material? That sounds better to me than flashing as well.
The goal is for expanding foam to fill the void, and then something else that won’t be eaten through or eroded by water, snow, and other environmental factors.
krashtd
Expanding foam for large/deep voids, caulking for less than 1/4″ gaps, finish with concrete/mortar repair patch and paint as needed.
Eric
I had a similar problem. Tried expanding foam but mice ate through it. Then I used plumbers putty, haven’t had a problem since (6 years).
Keith
When filling voids to stop mice I have used expanding foam but before you put the foam in pack in some hardware cloth 1/8″ grid and foam through and around the hardware cloth so if the varmints go to chewing on the foam they will encounter the embedded wire mesh
Stuart
Good idea. I’ve got some copper mesh in the hole since discovering it. I can keep it in and foam around it.
The area will also be mostly buried by topsoil.
ktash
I’ve used both hardware cloth and steel wool combined with foam to keep the mice out. Also, there’s some Great Stuff Foam that’s supposed to deter mice and bugs and I used that in combo with the mesh or steel wool, depending on size and what I had on hand.
MacLean
Loosly pack in steel wool and caulk over the surface. Mice will chew through caulk and spray foam unless reinforced with steel wool. If that’s a metal pipe wrap it with pipe tape to minimize corrosion.
Cristobal
The Copper equivalent of steel wool also works embedded into the foam and will not rust. It is a little more expensive but worth it in situations such as this.
PB
I concur with some of the other comments.
If I was doing it, I would:
-Clean all surfaces of loose material
-Fill the gap with stainless steel wool
https://www.mcmaster.com/#stainless-steel-wool/=1duq636
– Use a concrete compatible RTV
Dow Corning 790 looks to be a best fit because it sounds stiffer that other RTV and for filling concrete joints.
but I also see 995 and 832 recommended.
Unfortunately, 790 & 995 say not for below grade, so I guess it depends if you fill it over with dirt later.
832 does not have the below grade warning.
– If you were worried about dirt contact with the RTV filler, you could use a different compound to seal on top of the RTV maybe a masonry tar seal. But it would probably have to be able to stick to the RTV.
Other things:
I think I would also move the wire to be below the pipe, if you can get the pipe out.
I would either clear out the dirt further away from the drain pipe, and/or raise the drain pipe and pump pipe a foot or so higher. But to do that you would probably have to shift the drain pipe further away to get clearance for the pump pipe bend fittings.
Curt Shields
Dow Corning 790, 832, and 995 are one-component, neutral-cure, silicone-based sealants. 790 and 995 are definitely not wanting to use these below grade, or in constant immersion in moisture (sealant is OK, bond to concrete is not predictable). Dow Corning 832 is more appropriate (approved for marine uses, excellent unprimed adhesion to CLEAN AND DRY concrete/mortar surfaces, etc.), but still unpredictable.
IMHO, for this application building sealants aren’t a great fit – rodents won’t eat them for food, but they can still chew through them. Repeating what others have said, going with one component moisture-curing spray polyurethane foam (i.e. Great Stuff, etc.) and copper/stainless steel mesh is more effective. Recommend going with black polyurethane spray foam formulated for UV exposure and high adhesion to moist surfaces (“Great Stuff Pond and Stone” or “Touch n’ Foam Landscape”). Lightly mist water on the mesh, pack it in, apply foam, cut excess after full cure.
PB
As Farid said below, I just looked up the spec sheet for MasterSeal NP 1 and it seems better than these silicone RTVs in strength and stiffness.
But polyurethanes will break down due to UV light over time, so the filler would still have to be protected from sunlight through a covering/coating.
Jimmy
Great stuff makes several expanding foam products they say are rated for exterior use, but they don’t say anything either way about use below grade.
One is specifically marketed to sealing exterior plumbing penetrations and the like to keep out critters. It’s called “Pestblock.”
The consumer straw-application version says it is for up to 1″ gaps, the profession gun-application version says it is for up to 3″ gaps.
Adam
There is expanding foam specifically for pests. I can’t recall if that included up to mice, but I know it was for sure for creepy crawler types. Same company that makes most of the other foams, this one is in a green bottle I believe.
Tom
Perhaps a combination of foam and a sealing tape, like Wigluv? Not sure what would work best for below grade.
KokoTheTalkingApe
I was told that mice will chew through insulating foam and even fine steel wool. I imagine they might chew through copper wool as well.
So for my mouse entry holes, I am going to try coarse stainless steel wool, and then spray foam. That would likely not be enough for below grade, though.
There is foam that is supposedly mouse repelling (maybe it tastes bad) but I wouldn’t put much faith in it.
Farid
I have used BASF MasterSeal NP 1 Polyurethane before and it lasted 20 years without separating (it might still be there but I moved from that house). It is rated for above and below grade. Sikaflex also makes pretty good equivalent.
However, the gap seems too big. Even with backer rod, you would only apply to 1/2″ depth. So, you would have to pack fiberglass behind it for insulation.
As others have said, expanding foam and wire mesh is probably the better option It is water tight as well (it is used to seal basement wall cracks). Just don’t use the water cleanup kind.
Either way, I would use a good concrete cleaner first to make sure you have a perfect seal.
FYI: at the the risk of sounding like a commercial, Masterseal NP1 is great for sealing around flashing, siding, vertical cracks,.. etc, as it stays flexible for a long time and it comes in different colors. The Sikaflex SL is great for driveway or walkway expansion joints.
Curt Shields
NP1 is like duct tape – it sticks to everything. Great general purpose sealant.
Mrtoolfool
My vote is for NP1 urethane. I have this stuff in cracks around my foundation and it has been in place for 10 plus years. I am also a huge fan of SL1 self leveling urethane for any cracks in cement on level ground.
Mrtoolfool
Someone mentioned that urethane breaks down with UV light…….
Urethane is used in commercial building applications all the time that are in direct sunlight. It is the main type caulk used in concrete joints.
Jess
I would stuff if with Xcluder fill fabric and leave it. Caulk over it with a concrete gap caulk if you think that will help keep it in place but I don’t see why it would be a problem
Stuart
Mouse still got in when hole was jammed full of copper mesh. It’s too big for Xcluder or copper.
They did the same on the other side, too, with a much smaller hole.
Andy
I worked in pest control for close to 10 years. However, that doesn’t mean I know everything about building materials. Anyway, hear is what I’d recommend: stuff the copper mesh in as far and tight as you can. Basically make it as close to a solid fill as you can. Then silicone sealant on top. I’d go with clear so it’s as unobtrusive as possible. While nothing can stop a motivated mouse, this will deter all but the fanatics. I usually would suggest filling the inside gap with spray foam. The foam is no impediment to a rodent but it will serve as a very obvious signal that one has returned if you ever see a pile of chewed up foam. While you’re at it check the rest of the mechanical entrances to the house (HVAC/plumbing/etc) and seal up anything you find. A good rule of thumb is anything larger than a pencil diameter can let a mouse in, so copper wool on any big openings and silicone on the small ones.
Ron
Spray foam backing, leave space for an application of hydraulic cement.
Matt Jones
Depending on the size of pipe and opening, you may be able to use a split flange. I’d still back it up with spray foam and/or wire mesh, but you could then fasten or adhere the flange to the face of the wall and have a solid face around the opening that should deter anything from getting in. Split flanges can be found in stainless or PVC, but not usually at big box stores. You’d probably have to go to Grainger or a plumbing supply house.
Josh
Pick up one of these: https://www.homedepot.com/p/Wal-Board-Tools-Texture-Pro-200-Hopper-Gun-with-3-Spray-Tips-52-020/100660219 and a back of quickcrete. Go crazy.
Jim P.
Hydraulic cement is the way to go
Mike
I’ll also vote for Hydraulic cement, with a spray foam core. You don’t need more then a 2-3″ cement. Then some good caulk to seal around the pipe. Maybe some kind of brush on sealer over the whole thing once done too.
As I look at it more maybe just a mesh blocker and some good caulk. Hard to judge the size.
Sounds cheesy but might be worth a try how about spray foam trimmed flush and Flex-Seal. I’ve been pretty amazed how well that stuff has worked, compared to the high dollar industrial stuff we order.
Brian
I’m masonry contractor and I think I’d recommend getting some of the metal lath that is used for stone veneer and use tapcons to attach the lath to the wall over the hole and then get regular mortar mix and smear it over the lath. I don’t think the mice will chew through the metal and the mortar will help seal it.
John Blair
If I were you, in this case, I’d move. Perhaps to Belize. Little house on the beach. Probably not helpful advice, but given the heat, I may be dreaming of tropical breezes and a beach somewhere.
Andrew McConnell
Couldn’t agree more. Obviously the house is a total loss. Sell it for what you can get. The mountainous regions in Belize are perfect.
Framer joe
Expanding foam is not waterproof….first.clesn the area, next wrap the pipe with flex tape…it hardens after it’s applied, then use minimum expanding foam leaving at least an inch around the opening, finally hydraulic cement…..the hardended flex tape will protect the pipe and the cement is waterproof and mice proof…..proplem solved and done right…….there’s doing things and doing things right….
Bill
Greatstuff Pestblock expanding foam. Insulates, fills, and can be painted or caulked over. I have have had good results so far.
Chris
Expanding foam then a layer of cement. Hydraulic cement is more for cracks. I wouldn’t fill a huge hole with it.
Justin
Hydraulic cement puts pressure on everything around it to seal out water. Fast set cement just fills holes. If its not leaking water, I’d just toss some fast set in there. If the surrounding blocks are hollow and the cement will just keep falling through I would fill the voids with foam (where its protected in the wall) then pack the hole with fast set.
Redcastle
Fischer Express Cement in a choice of grey or beige is a tube based “mortar” which is very effective in sealing gaps. Alternatively we have used panels made out of Hardibacker round the pipe and with a thin bead of flexible sealant for exactly this purpose. The use of expanding foam even reinforced with steel wool did not provide more than a short term solution. To cheer you up one exterminator I dealt with said its good news there are mice, when I said why is that good news he said it means there are no rats. Apparently the two species do not cohabit. On a serious note regardless of the voltage that cable needs to be moved and run in a safe fashion i.e. well away from the pipe that setup would cost an electrician his licence over here. Have you considered getting a cat?
Jon
Vinyl patching cement. Easy, durable as heck, and available at Home Depot. I run an excavating and sewer and water company and that’s what I would use. We use it to grout around the sewer main boot in manholes and has never failed. If it works for that it will work for that little pipe. Keep it simple.
Michaelhammer
Listen to me now and hear me later. Use great stuff as a backer. You want it to be about one inch from the face. Pack it with hydraulic cement. You want it to be hydraulic because it is waterproof. It will in no way harm your pvc pipe. When that cures, seal around the pipe with Lexel. When that cures, bury the thing with soil. FYI , you can use foam below ground. It is not waterproof and everybody, everybody loves to chew on it and make little cozy houses in it, Pest block is effective, but not a permanent solution.
Stuart
I think I’m headed in this direction.
Foam as backer, and then something, over it, whether hydraulic cement or concrete & mortar repair compound, or something else recommended.
I figure I’ll work the foam tomorrow, and then figure out the next part shortly after. I don’t want to wait too long, lest another critter finds its way in.
The yeti
Yes great stuff spray foam
The yeti
Spray foam
The yeti
If worried about pests. Get a piece of pressure treated wood. Fix to outside. Cut hole for pipe. Spray foam for inulation. Fix a piece of normal painted plywood on inside. Simple fix. Less than an hour.
Blythe
I would be inclined to get get a piece of concrete expansion foam( sold in 50-100ft rolls normally, but maybe you can find a local concrete contractor to buy a few feet for 5 bucks) and put one wrap around the pipe. Spray adhesive works nice to keep it on, just read the instructions-spray the pipe and the foam separate, let them tack, and then apply. Make sure to face the tear strip out obviously, and put the edge in plane with the outside of the wall
https://www.homedepot.com/p/203151902
Now pack the hole with a repair mortar, I like Rapid Patch Multi purpose repair, but that seems to be a Menards exclusive. This quikrete product from Home Depot seems similar. Make sure to use cold water, start with a small amount, and don’t overmix-it hardens really fast if you work it up to much.
https://www.homedepot.com/p/207102852
The nice thing about concrete expansion foam is the tear away strip, it’s perforated so after your patch cures you tear the strip away and fill the 1/4”x 1/4” void with a good elastomeric caulk, and you should be good to go.
Blythe
Although looking at your picture again, that may be a bit overkill for something that small, plus the access doesn’t seem very good. I would probably try the repair cement by itself if it was me, but you could always put the expansion foam on the parts you can get to.
To the earlier discussion about spray foam, they do make a pest block version, but I’m not a fan of using spray foam in any exterior application
Breegan
Polywater, the 2 part variety.
Steven
As a journeyman plumber(In canada) we never pipe subsoil water out the foundation wall at the same level of grade. It is counterproductive as your structure is open to water infiltration and in your case mice.
Remove the pipe, seal and repair old hole, relocate sump discharge pipe above grade minimum 1ft. If it can be drilled through a rim board or wood great, make a snug hole to match pipe od.
This doesnt help your existing issue, however it is a solid reason to break out and test the plethora of free shit you get to test.
ktash
Come to think of it, my sump pump is through a hole in wall but well above grade, at least one foot, but I think more. That seems much cleaner. Solves the problem in a different way.
Jeff from Tool Box Buzz
I’m with Steven on this. If you can move your pipe up, great. The other benefit is that you can have an air gap above grade so when the corrugated freezes up in the winter, the sump discharge can just overflow onto the ground. Now if it freezes, it fills up that hole and then can freeze the pipe in too.
If you can’t move the pipe, I’d throw a sanitary T on where that elbow is, pipe it up above grade and put a couple elbows on top as the overflow. Then snap the PVC to the corrugated so there’s no gap and you can fill in the hole.
Stuart
That’s something I’ll consider too. Right now, my immediate concern is mice coming in. There’s not a lot of room for me to raise the discharge pipe before it reaches the ceiling. A few inches? Maybe. I think it was done this way because there’s a bunch of other stuff in the area – landscape lighting controls, irrigation connections, a faucet.
I need to have a talk with a drainage pro – last year our back was swampy, this year with irrigation scaled back the grass is brown – and so I might bring this up at the time too.
The drainage pipe might have frozen over last winter; I have a broken connection 1 foot away from the street that I need to fix.
MT_Noob
Time for a collaboration with they guy from the “mouse trap monday” youtube channel…
: )
firefly
We have a big hole in one of the exterior garage brick wall. Not certain why the hole was there but it’s look like one of the brick is intentionally missing. It is the bottom brick near where the meter is. We have seen mice running into that gap before so we finally got around to closing that gap. We got two kind of expanding foam, large gap filler and the Pest block kind that have been mentioned here. So far we have only used the large gap filler.
Will see how long it last. My guess is that it will last at least 5 years or so. I know that mice can chew through it if they want to and I could just put up a piece of wood or metal screen against the exterior though I haven’t just to see if a mice is determined enough to get back in there. There is enough foam in place that it will take enough time for whatever in there to get out. With the recent heat wave in Texas I am guessing whatever it is will be cooked long before they can fight their way out.
I wonder the mice get into the gap because the gap was there or will they be determined enough to fight their way back in. Will a new mice that have never been into that gap care enough to destroy the foam? This will let me know whether they are opportunist or the curious type (ie hey… this is foam vs brick let see if we can get in.)
ktash
My old garage had an intentional small opening at ground level, in case of flooding, the water can get out there. You can see from the way things slope that this is the case. In a couple of very heavy rain years, the water did just that. Hardware cloth will keep critters out, but won’t keep the water in. Only you can tell if that’s the reason for the brick being left out.
firefly
Does the hole that you have open all the way through the wall into the inside? Mine doesn’t, it open up to the in between of the interior wall.
From the look of it I am guessing it was used to assist with running various cables (ethernet, coax, sprinklers) into the house/garage. I should have taken a picture to share prior to sealing it up though.
The water heater is on the opposite size of the garage. Mine garage door is not an airtight seal though it’s properly sloped so in the event of a food water should have no problem seeping through various small gaps between the garage door and the frame/concrete.
ktash
Yes, all the way through. Yours for cables make sense, too. The old garage is pretty old, pre-1900. I suspect it was a small barn at one time that got converted. The original building probably used cats to deter mice. Mesh is a poor substitute for barn cats, but then I’ve never heard of garage cats :D, they probably wouldn’t be happy there.
firefly
Thanks for the reassurance. I think the brick missing in my case was just a contractor being lazy.
Some cats work wonder for mice. Some like to show off their catch and drag it everywhere, it’s not a pretty scene 😀
Ken
You could always just fill it with pea pebbles. Just keep adding them in and packing with a wooden dowel until it’s full.
Mice can’t chew through granite…
Jon Boggio
If your do the expanding insulation foam press some fine steel wool into the out most face of the foam. Just in case a mouse gets under the flashing it won’t eat through steel wool as it hurts their teeth.
bobad
I would use mortar caulk. (I know for sure Dap makes it and maybe GE) It looks like brick mortar, but is close enough to concrete color. It takes several days to harden to a firm but rubbery consistency. It’s gritty, and unpalatable to mice. It’s also flexible enough that it won’t scuff your pipes.
Hang Fire
A thin layer (1/4″ or so) of Electrician’s Putty all over, then fill the gap with Hydraulic Cement.