We are just finishing up the insulation in our crawlspace. We installed
kraft face R-30 batts in the joist bays, with the kraft paper facing up
towards the living space. The batts themselves are held in place using
metal wire insulation supports every 12"-16".
However, we would like to cover the insulation with something that will
help keep insects (ants and crickets mostly) out of the insulation.
My first thought was to use window screening, but a quick price check ruled
out that option as far too expensive.
Plastic sheeting would probably cause moisture problems, and I think tyvek
house wrap would probably be similar. Another option was landscape fabric,
but I wonder if the bugs would just eat right through it?
Is there a material commonly used for this sort of thing?
I know it's not "necessary" to cover the insulation, but it's an addition
we would feel more comfortable with.
I didn't mention it in my message, but we'll be covering the ground with 6-
mil plastic sheeting. This should keep the majority of the ground moisture
out of the house.
I'm primarily looking for something to keep the ants and crickets out of
the insulation, but do not want to put a vapor barrier on the underside of
the joists and trap moisture from the house inside the joist space. I'd
rather have bugs than mold and rot.
See my previous response. Since you are already putting
down a plastic sheet, it looks like all you need to do is
plug any cracks or openings, and make sure the ventilation
holes have good screens on them. No bugs. If there are
bugs now, put a bug bomb down there when you finish to you
work. You might still find a spider or two, but most will
be too big to get in, and it will be such an inhospitable
place for bugs that there will be very few. Besides, most
bug don't really like insulation.
BTW, Tyvek is not a vapor barrier, it is a moisture barrier,
meaning that it stop liquid water but not water vapor.
As I mentioned in my message, I would be concerned that it would cause
moisture problems. Aren't housewraps (like Tyvek) designed to keep moisture
out? I don't want to trap moisture inside the joist bays.
I'm not any kind of expert, but I wouldn't think it would be a problem to
leave it exposed. There's not going to be anything in the insulation to
attract them, and I would imaging the sharp edged glass fibers would be a
deterrent to wandering insects.
- Mike O.
Anything that is acceptable will be expensive. You could
use canvas, burlap, screening, etc. The cheapest might be
Tyvek, it breaths and is used to wrap house. You didn't
need those metal supports if you used Tyvek.
However, the question begs the real answer regardless of
your "feeling comfortable." You are suppose to keep
insects, bugs, mice,etc. out of the crawl space in a regular
house built on a concrete foundation. All cracks and
possible entryways are suppose to be sealed (calk,
insulation, boards, or something), the ground is supposed to
be covered with 4-6 mil plastic (overlapped sheets), and the
air openings are supposed to be covered with screening. So
forget covering the insulation and do it the correct way
which will probably be cheaper anyway.
That's sounding like my best option right now. I apparently confused it as
moisture barrier instead of an air barrier. I'll have to check the price of
this on my next trip to the store and decide if the cost is worth it.
Our crawlspace is sealed off nicely, except the foundation vents are
covered with 1/4" wire mesh. It will certainly keep out mice, squirrels,
etc. but insects can easily walk right through it. I suppose I could
install window screening on the backside of the wire mesh to keep out bugs
too, but wouldn't that reduce airflow through the vents?
I'm probably overanalyzing this problem like I've done every other step of
our house construction. Ha. Ha.
What I think I would do if I were you-
Do like everyone said. Make sure you have all the cracks and openings sealed.
Then just wait 6 months to a year then go and chack it out. If you have a
problem, then put up some sheeting like you wanted.
I only say this because you might just be wasting your money here and it would
be better off used else where.
Hope this helps...
Remove NoSpam to reply, Thanks
Yep, that's what we decided to do... I priced the housewrap at the home
center, about $110 for a 150 foot roll. We would need two of those to
completely cover the underside of our floor joists. Right now that $220 is
better spent on other items. It won't be any more difficult to install the
wrap in a year than it would be now, so we figure we'll wait. With any
luck, we won't need it at all...
Thanks for the feedback!
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