AC lines through CMU Foundation - how to fix hole?

[sands35]

Couple issues

I have a mouse problem (cats catch about 1 a month or so - they are good mousers). Mice are never upstairs unless a cat brings one up. Only in the basement.

The AC lines (two units, so 4 pipes, 2 conduits and 2 control lines) were installed sometime before I bought the house (10-15 years ago?). They run through a CMU wall out to the location where the condensers are set.

I'm pretty sure that is where the mice are coming in as it's the only place I can find with daylight coming through in the basement.

Complications:
It's a double(?) wall as it is also the foundation for a fireplace. About 2.5' thick or so. AC lines are ~6 feet to the side of the fireplace - I'm not worried about the structural integrity of the foundation. Not sure for certain what is between the rows of CMUs but likely rubble.

It's in a ~3' crawl space - so a pain to get to and work in.

How do I fix this?

I was thinking of splitting a PVC pipe to put around the existing AC service lines and wires, then using mortar to hold that up and fill in the rest of the blown out blocks. Perhaps a couple pipes to make it a cleaner install. The hole in the CMUs isn't that big - ~4-6" diameter or so? Then using tar or something to seal up the PVC. I want to do something reversible so when it comes times to do the AC system, it's not a complete pain to replace the parts. I also don't want to have concrete slowly wear away at the electrical or the copper AC lines from vibration or something.

 

[K'ledgeBldr]

Just fill the voids with Hydraulic cement.

 

[ForceFed70]

Or expanding foam insulation, with a layer of expanded steel mesh near the outside.

 

[gregtwojeeps]

Be sure to not pack mortar or cement around the A/C units bare copper tubing (small line) to where it lays against the copper = corrosion.

 

[Balor]

Or expanding foam insulation, with a layer of expanded steel mesh near the outside.

This ^^^^^^^. rngr1

 

[The FIB]

Cover any bare copper with electrical tape, stuff it with steel wool, and then fill it with great stuff pest block. Taping the bare copper keeps the steel wool from contacting the copper (to prevent corrosion).

 

[sands35]

Ok - thanks for the advice!

 

[rlitman]

Cover any bare copper with electrical tape, stuff it with steel wool, and then fill it with great stuff pest block. Taping the bare copper keeps the steel wool from contacting the copper (to prevent corrosion).

The steel wool keeps rodents from chewing through the foam. The secret is to stuff the steel wool as loosely as possible, and then spray the foam into it so that the expanding foam permeates the wool.

Though I'm not sure how you'd easily tape the copper. Here's a thought, just use bronze wool instead, and the corrosion issue is moot..

 

[Milton Shaw]

If you use foam make sure you get the one with the bitterant added in. Great stuff makes it and bugs/mice will not eat it because it tastes so bad. Home depot has it but it may not be in the same section with insulation products. It was in the concrete block section of the local HD here. They checked on inventory and showed 36 or so cans so I made them look until they found it.

 

[rlitman]

If you use foam make sure you get the one with the bitterant added in. Great stuff makes it and bugs/mice will not eat it because it tastes so bad. Home depot has it but it may not be in the same section with insulation products. It was in the concrete block section of the local HD here. They checked on inventory and showed 36 or so cans so I made them look until they found it.

Interesting. That one is new to me. In the green can, Great Stuff Pestblock. Yeah, that looks like it'd work too, and then you could skip the metal entirely.

 

[BearsFan315]

i know when i had the addition put on and the punched a hole in the wall for the gas line to the Rinnai there was a odd shaped funky hole in the block wall. i put a pvc sleeve around the pipe and then picked up a hydraulic cement type stuff from lowes that was in a tube. it dries like cement and is paintable. put that stuff around the PVC pipe, and sealed up the hole. let it dry and cure, then primed and painted it to match the existing block and you can not really tell the hole was there. turned out really nice !! been there 8+ years no issues. no cracking, flaking, pealing.

my concern was like yours worried about rodents and such getting under the house.

can post picts if interested in what i did and how it looks NOW. the PVC pipe was great to keep the concrete OFF the black pipe lines, and works great as a Sleeve. cut a short piece, then cut a slit into the pvc, slip it over lines, slide into place, then can use a tape to hold it tightly closed till cement dries. clean nice looking install !!

think it was Sika Product i picked up at local Box Store

 

[-Brent-]

I would spray foam enough to fill the inner vacancy and then use Thumb Gum at the exterior portion where the lines enter the hole. Thumb Gum (the actual name of the product) is what HVAC folks use.

 

[Stuart in MN]

and then use Thumb Gum at the exterior portion where the lines enter the hole. Thumb Gum (the actual name of the product) is what HVAC folks use.

The a/c line into my house as well as the natural gas line are sealed up with this stuff. It appears to be the same as Ductseal, used by electricians for sealing up conduits.

 

[BearsFan315]

ductseal would be a good choice as well

i went my route so i could blend and paint it in, clean

i used duct seal on the conduit box for the power under the deck.