Basement Insulation Mice -- Help

[Woodchuck34]

We moved into a 14 year old house 1 year ago and I have been crossing items off the honey-do list at a good pace. Last week, SWMBO asked me to look at the basement insulation, which we knew had some mice issues. The house had sat dorment for about 6 months before we bought it (no one crazy enough to do all this work), so the mice had free reign. As I started pulling down the fiberglass bats, the fecal matter kept raining down. Ultimately, I ripped all of the insulation down and still feel that it was the right decision due to the amount of droppings.

I have been researching the insulation options and need help. Our intention is to finish the basement into a playroom for the kids in the near future. I do not want to have to repeat the expense/time of ripping down insulation and cleaning the mess again. Right now I'm leaning towards gluing rigid foam board insulation inbetween the ceiling rafters and either screwing/gluing (or both) a layer of drywall directly to the insulation for fire safety issues. The drawbacks of the rigid foam as I understand it are that is not as safe in a fire as fiberglass and its more expensive, but I don't want to create another mouse highway in my basement with fiberglass bats.

My questions are these:

1. Is the rigid foam and the method I'm considering even going to keep the mice out (at least in between the subfloor and the insulation)? If not it not worth the expense.

1. If #1 is yes, is attaching a layer of drywall an adequate fire retardent (SWMBO is big on fire safety)

2. If I use this method and eventually finish the basement; I will be installing a drywall ceiling. Is it acceptable to then install a drywall ceiling to the rafters (since I will essentially be installing a second layer of drywall).

Here are the other considerations:

-Poured concrete foundation approx 8.5'

-the plan is to finish the basement, but not necessarily constantly heat it, rather just heat it when its being used (I mention this because I've read that it isn't even as important to insulate under the 1st floor, but might be better to spend the money insulating the basement walls instead)

-we've had an extreminator on contract since the dog "gave" SWMBO a mouse in the old house. They have put out poison and are coming tomorrow (first time they'll get a great look since the insulation is gone). Point is we have a professional involved. They did mention that mice aren't likely to chew through drywall. They just don't like it.

-Basement is mostly dry but now is ready for me to seal every nook and cranny. Also will be looking for mice entry points.

-have not found evidence of mice protrusion into the rest of the house except for the attic

Any help/opinions would be very much appreciated.

Thanks,

WoodChuck34

[Steve Barker LT]

Give serious consideration to blown in place cellulose. It's better insulation, it's fire retardant, and also mold and bug resistant. You can start your research at:

steve

[Woodchuck34]

Steve,

Thanks for the reply. I'm not considering cellulose insulation after reading the following article:

Check the author's notes at the bottom.

Also, Cellulose Insulation would not solve my mouse highway issue. I couldn't use blown in insulation anyway, because I'm talking about insulating the ceiling of my basement.

Chuck

[HeyBub]

I don't think so. Mice can squeeze though an unbelievably small space. Insulation, I don't think, can be made mouse-proof. Even if the insulation was air-tight, the mousies would gnaw through it, so you might as well go with insulating qualities when deciding.

I never heard of a basement burning, so the emphasis on fire retardation is, perhaps, excessive.

Sure.

1. Dried mouse droppings in the wall do not need to be removed.

1. Think cat.

[Woodchuck34]

HeyBub,

Thanks for the reply. Unfortunately a cat, while probably the best solution, won't work due to SWMBO's severe asthma. We felt it was necessary to clean out the droppings in the basement for the same reasons.

Maybe I'll just skip the insulation on the ceiling all together and spend the money insultating the foundation wall instead.

Chuck

[RickH]

The only thing I insulated in my basement were the ducts themselves, and this was mostly to make the home quieter overall and not so much for thermal reasons, leaving most of the joist pockets open. My basement has a combination of drywall and drop ceiling (maybe 70 percent drywall, with drop ceiling for pipe access areas). Even Insulating basement walls IMO is overrated as below 42 inches or so the ground temp is constant year round. The main thng about the walls is to prevent seepage and condensation that will mold up under insulation.

[franz frippl]

A small building I acquired last year had mice. Thought I had eradicated every last one until the day I baked bread only to discover another nest in the oven's insulation.

I cleaned up all debris and removed all nesting materials. Set out traps and Just One Bite bait. Also cut back grass and vegetation around building's perimeter to make the place less appealing to the critters. Through some extra Just One Bite beneath the porch.

It doesn't take much of a hole for a mouse to squeeze through, but if you can stay a few steps ahead of them, you might have a chance.

You might consider foam insulation around building perimeter where siding meets foundation and wherever you can imagine a mouse getting in. Open garage doors are an invitation but the critters can crawl in where gasket meets door corners.

Keeping yard mowed and trimmed will help discourage mice. Cleaning up yard waste, too.

[Steve Barker Garage]

I read the article and the note and it's absolutely untrue. the stuff i referred you to will not burn. Even with a direct flame. Also, putting it under a floor without a ceiling is not a problem either. They staple up a special fabric and blow it on top of it. To each his own i suppose. Fight the fiberglass if you please.

[HeyBub]

Bah! She can get shots for that.