On Monday, December 28, 2015 at 5:40:01 PM UTC-5, Boris wrote:
Access to exterior walls, usually that isn't the problem. The problem
is the insulation would need to go in the walls and that doesn't have
good access. Considering it was built in 78, the wall cavity should
already have insulation, no?
I can walk under the entire area.
Assuming the studs you're talking about are the exterior wall studs,
how are you going to get easy access to put that insulation in?
Usually putting insulation between the joists in a crawlspace is
trivial compared to getting insulation into wall cavities. No
insulation in those exterior walls already?
Yes, the exterior of all living space is insulated. I'm talking about
exterior walls of the crawlspace. It is defined as a crawlspace, but
it's really tall. As a matter of fact, there's a standard size door that
connects it to the garage, both of which are below the first floor. From
the garage, I walk into the 'crawlspace'. It's a hoarder's paradise
under there. (Me no hoarder.) Anyway, the foundation sill has the
standard 2 x 4 on top of it, and on top of that are the 2 x 4 exterior
wall studs, unfinished (no sheetrock). The exterior is stucco. In some
places, these walls are 4' tall, and in others they are 8' tall. The
house is built on a slope. From the sidewalk view, the left side is
higher, and the land slopes down to the right. The right hand walls are
the taller ones.
No, these are the unfinished (no sheetrock) exterior walls in the
Are there any water pipes in the crawl space ? If t'were me I'd insulate
the walls with batts between studs then add a 1" layer of foam on top of
that . I'd also lay down some poly sheet on the ground to help with moisture
control . They make automatic crawl space vents that open when it gets hot ,
you might want to put some in while you're down there .
Based on what you wrote above, my vote would be to insulate the unfinished
"crawlspace" walls first -- basically to help keep the "cold" from getting
into the crawlspace from the outside. (I know, technically it is to keep
the heat in the crawlspace from getting to the outside through the
now-uninsulated crawlspace walls -- since heat energy flows from the warm
side to the cold side, not cold flowing to the warm side).
After that, if you decide to insulate the crawlspace ceiling, you could do
that too. But, I would do the walls first.
Be clear about what you're trying to accomplish.
You made no mention of heating cost.
If your problem is that the floor is too cold and/or you'd like
reduced heating cost, insulate under it.
If you plan to inhabit the space, put something over it to contain
the insulation dust.
Look up the historical dewpoint.
You wanna make sure that you don't condense moisture on the underside
of the floor in summer. Vapor barrier may be required.
Now, you've just made the crawlspace colder. If there's anything in
there that's sensitive to cold, like plumbing, you may need to address
that with insulation or pipe tape or ????
Insulating the walls will help. I've lost track of the crawlspace
floor, but you also may need insulation and vapor barrier there too.
Depends on the ground temperature.
I'm in Oregon. If I close the air vents, the temperature under
my house is 55F or thereabouts year round.
My attic and crawlspace were insulated at the same time, so I don't
have any individual measurements of the effect on heating costs.
When I changed from carpet to fake wood floors, they felt colder,
but I'm not sure it made any actual difference in the heat lost/gained.
I fixed that problem with area rugs everywhere.
On Tuesday, December 29, 2015 at 8:09:18 AM UTC-5, CRNG wrote:
But there are diminishing returns and he's in SF, which has a
moderate climate. Between unfinished basements and the living
space typically isn't insulated. My basement is probably ~55F
all year long, in SF I wouldn't be surprised if a crawlspace,
with some limited vents, is not too much different.
Someone else pointed out that some more info on what the real
objective is would be helpful. He said that after replacing
carpet with wood flooring, it takes a lot longer to heat the
house. I don't think that makes much sense. I can see carpet
feeling warmer, but from a heat transfer perspective, I doubt
carpet vs wood is going to make much difference. Also, he says
he has a 20 year old furnace. If heating bills are an issue,
replacing that might make more difference in how much energy
it takes to heat the house than insulating the crawlspace.
I lived in a place one time which had a cement
floor in the bedroom. (No kidding, hold my
beer, woman.) One night as I was laying on the
bed, watching TV, noticed my one foot was less
cold than the other. Some investigation finds
two layers of carpet under one foot, one lay
under other foot. I moved the carpet scrap to
be under both feet, and that was much more
Since that time, I've moved. However, I've made
sure to always have a carpet sample next to the
bed where my feet land.
Some carpet stores sell samples of old design
carpet. Those can make great foot pads.
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