[anuvanoob]

We had/have a rat in our mostly unfinished basement where my office and workshop is. The pest control professional said it might have come through the joist between the crawl space and basement where the HVAC ducts pass through. He recommended we have these openings patched, so we called our favorite jack of all tradesman, but you know, quarantine.

Attached are photos of the joist pass through openings (insulation is currently stuffed in these places, but the professional said rats will simply push through that). How can we seal these pass through openings ourselves to prevent rats from coming through considering ducting, wiring and piping passes through??

 

[3onthetree]

If you insert blocking for the larger portions, you could spray foam the gaps. Blocking could be wood or rigid insulation. I haven't seen little guys go through foam in my experience, maybe others have better advice on using these materials though. But never dealt with rats (except for politicians).

Question, if you block the rats from entering the main basement, won't they just have a free-for-all in the crawlspace then?

 

[Nealtw]

Is the crawlspace vented with an insulated floor above?

 

[anuvanoob]

If you insert blocking for the larger portions, you could spray foam the gaps. Blocking could be wood or rigid insulation. I haven't seen little guys go through foam in my experience, maybe others have better advice on using these materials though. But never dealt with rats (except for politicians).

Question, if you block the rats from entering the main basement, won't they just have a free-for-all in the crawlspace then?

Rigid insulation, that's a great idea! Can't believe I never thought about that. Easy to contour around the ducts too.

Yes, rats have been in and out of the crawl space for as long as we've owned the house (8+ years) and likely for as long as the house has been built (100+ years), but only between outside and the crawl space. Recently is the first time since we've owned this place has one entered the basement side (evident by a few sightings and droppings).

Sent from my ONEPLUS A6013 using Tapatalk

 

[anuvanoob]

Is the crawlspace vented with an insulated floor above?

I'm not sure what you mean, but the crawl space does have 12 x 9-ish vents on the north and south exterior walls. The joists in the crawl space are not insulated though (the living room floor is cold to the touch in winter time because of this).

Sent from my ONEPLUS A6013 using Tapatalk

 

[Nealtw]

I'm not sure what you mean, but the crawl space does have 12 x 9-ish vents on the north and south exterior walls. The joists in the crawl space are not insulated though (the living room floor is cold to the touch in winter time because of this).

Sent from my ONEPLUS A6013 using Tapatalk

I would insulate the floor with rock wool and then apply a wire mesh to hold it in and keep critters out. You can also add a bug screen for the insects.

 

[3onthetree]

Yes, rats have been in and out of the crawl space for as long as we've owned the house (8+ years)

Recently is the first time since we've owned this place has one entered the basement side.

Well, at least that you've seen evidence. I'd guarantee they've been over there if it's that easy to access. IMHO it's time to stop the rodent problem at the house perimeter, rather than working to allow them to be confined to just one section below your house.