I pulled up the floor to the crawl space just in the back part of the
house to put black plastic down and insulate it and I found a one foot
square hole to the outside and the air coming in is FREEZING. There is
a half basement with a small window and another small vent about 7
inches in diameter under another room next to the big freezing one.
The house was build in 1900.
Can I seal up that airspace or put insulation over it? It also has a
grating outside on the ground and I bet when it is raining that water
gets in too.
What are my options?
the vent is to allow moisture to leave, and dirt tends to become moist
on the other hand, there are people who argue that crawlspace vents should
be sealed and moisture problem handled with sump pump. in fact there are
companies whose business is to seal up your crawlspace
What I've always done is; cover them after the first frost & open them
up after the final thaw. I may misjudge the final thaw, but this isn't
rocket science, I may even wait till it hits 80 degrees out. I bought
some automatic vents that have a bi-metal spring to open & close them
at a set temperature. I haven't installed them yet, but they will free
up 5 minutes a year.
As ventilation is generally a good thing, perhaps put fiberglass bats
on the underside of the floor over the crawl space. Then the cold
(fresh) air in the crawl space won't chill the floor so badly.
If you have any dirt still showing in your
crawlspace/basement. Cover it with 4-6 mil
plastic. Make sure that you have 2-3 foot
overlaps so that any water that gets in can drain
to the ground through the overlaps.
Yes, seal the whole thing up in the winter. Plug
every hole and opening with fiberglass insulation
and cover the outside of holes with wood to keep
the fiberglass dry. I would add something over
the window too unless you use if for illumination,
in which case, I would cover with 4 mil plastic in
the winter. You can remove the insulation from
the big areas and replace with screens in the summer.
Don't understand about the grill on the ground and
water coming in. Water should drain away from the
A 1900 era house is so leaky that you shouldn't
need to worry about air for combustion of a
furnace. If a furnace guy says you need more air,
then run a cold air pipe from outside to the
furnace and put a damper on the pipe (opens when
the furnace draws combustion air).
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