Nothing really wrong with that, but you still have to fine where the critters entered and fix that.

 

I believe the vented crawl space is their main entrance. Working on encapsulating crawl space as well. I'm hoping that the foam will at least slow them down a bit.

 

Is this solution plausible?

I don't think so.

If rats can get in, they are not going to be stopped by foam.

 

Worked on a house with lots of blue foam board and the rats loved it. Made for a nice warm winter home. On another house the home owner had flattened a soup can and nailed it over a rat hole. Not a problem, they chewed right through those 2 layers of metal.
As suggested, locate where they are getting in but also be aggressive at trapping.

Bud

 

Worked on a house with lots of blue foam board and the rats loved it. Made for a nice warm winter home. On another house the home owner had flattened a soup can and nailed it over a rat hole. Not a problem, they chewed right through those 2 layers of metal.
As suggested, locate where they are getting in but also be aggressive at trapping.

Bud

When I first got the house, I was killing them in the hundreds. Previous tenants were hoarders. Situation is much more manageable now, but there is an endless hoarde out here. I'm hoping that foam board continues to be effective insulation where fiber glass has fallen down and become useless.

 

Im sure the foam won't stop the rats, but I'm hoping that it will be less attractive as bedding and maintain effectiveness where the fiber glass has just fallen down in 90% of the home. I still plan on solving the rat issue from the crawl space and attic, but 100% rat free is near impossible here.

 

There are wire mesh covers at all vents, but access doors have large gaps for entry. I am sealing vents and making new access doors to seal off crawl space.

 

Foam board is a good insulation remembering its negative side of needing a thermal barrier. But it is also great for air sealing which can be a real problem with the older homes. Be sure all wall cavities interior and exterior walls are fire blocked.

Good luck
Bud

 

Foam board is a good insulation remembering its negative side of needing a thermal barrier. But it is also great for air sealing which can be a real problem with the older homes. Be sure all wall cavities interior and exterior walls are fire blocked.

Good luck
Bud

Thanks for this info. I hadn't really considered any additional requirements for foam board.

I sealed the gaps behind each stud with spray foam (great stuf fire block), does this count as fireblocking?

For the thermal barrier, would 5/8" drywall be considered enough?

 

Codes vary by location and I have been out of construction too long to be a source of related advice. Maybe @Nealtw will comment on fire blocking and drywall.

Bud

 

No offense but how in the hell can you live in a house like that ? Freakin rats in the walls and all over the place, no thanks.

 

I don't live there yet. Evicted hoarders last December and remodeling ever since. It took 3 months just to clean the property. The house is currently down to the frame.

 

1/2 drywall is acceptable in most locales that follow the IRC - you might consider spraying borates (sp?) or something similar to keep them away. Part of the issue for many creatures is they leave a scent trail that says - party / buffet room this way

 

After you close the rat highway, consider spray foam insulation instead of the rigid board.
It will seal tightly, save you money by lowering your energy costs and be more efficient.

 

Certainly take care of rat problem first. Have several rental properties that I bought as tragedies and had rats. Find the opening. If you have a shared wall, you are already screwed. In one property we ran a soaker hose under the bat insulation and pumped and ammonia mixture through it into the cavity soaking everything daily for a month. The floor, walls and insulation keeps the smell for a while and did a good job at preventing the rats. Dropped the treatment to 1 time per month.

Cap opening with steel mesh. They can chew through tin cans...not steel mesh.

 

Certainly take care of rat problem first.

I tried this approach initially, but can't get bait anymore (restrictions). I have largely succeeded in blocking them out. (Or if blocked-in, they couldn't get food or water and perished.)

 

I think you're on the right track. Open cell spray urethane on the walls is nice if you can afford it. Or keep on truckin. Install the ridgid insulation between the studs as good as you can and seal with spray foam.
My concern is moisture. This type of wall will need to dry to the outside. Hopefully no moisture barrier. I'd Install visqueen vapor barrier over the insulation. Although the foam will not transfer moisture easily. Your call again, your looking at it. Another layer of insulation over the top of everything will act as a thermal barrier. Not sure about how thick of insulation you can go under the drywall and not worry about sag. Ask a drywall hanger.
I believe a firewall has seams taped and mudded. 1/2" on walls 16oc, 5/8" if 24"oc. 5/8" on the ceiling.
Man I can only wish you best of luck with your rat issue. Have you considered metal roofing inside ? I would need to put an electric fence where they hang out.

 

About the 2” foam board, that’s what we did. Ours was down to the frame to. Not from hoarders but one nasty traumatized cat and a loser home owner who let it piss and spray anywhere.

 

Parson''s Ammonia mixed with water and then mopped on anything is a very effective deodorizing and disinfectant. Seems like you may need the gallon size.
The spray foam would be very effective insulation as it can fill every crack and space.

 

Perhaps there can be negative ramifications with using spray foam. Imo you should be aware of those before choosing to use it.

 

Rigid foam, spray or sheet, has a balance issue where the ratio of rigid (cold side) vs the fluffy insulation (warm side) needs to maintain the dew point within the foam insulation. If it ends up inside the fluffy insulation it can result in condensation where you don't want it. So, too little foam or too much fluffy can be a problem. The charts that illustrate the advised balance have disappeared, mostly now behind paywalls. If needed I may have a copy saved somewhere.


Bud