Is there any rule of thumb on size of crawl spaces? I am building a
three season 10'x24' porch on piers off the family room. The
family room has a cement foundation with a concrete floor. How much
room do I need between the floor joists on the porch and the dirt below
them? Do I need a vapor barrier? Does the crawl space need and what
size vents?

for buffalo ny:
under my porch is concrete. for a porch or deck think about rainwater,
snow, and a permit. those piers holding up my second floor porch of
your size 10 x 25' are 8"x8" pressure treated sunk 4 feet into the
ground. go look at the neighbors incorrect deck made of 2x4" and make
all yours 2x8" at 16" on center with 2 x 6" deck. make it twice as
sturdy as any carpenter says, and it will be just as sturdy at 20 years
of age as the day it was built.
locally you would in buffalo ny 2 years ago see your local city hall
permit office, phone ahead to see what paperwork you need to take there
such as 5 copies of your survey and permit fee money as required. some
city websites have online permits.

wrote:
Is there any rule of thumb on size of crawl spaces? I am building a
three season 10'x24' porch on piers off the family room. The
family room has a cement foundation with a concrete floor. How much
room do I need between the floor joists on the porch and the dirt below
them? Do I need a vapor barrier? Does the crawl space need and what
size vents?

Is there any rule of thumb on size of crawl spaces? I am building a
three season 10'x24' porch on piers off the family room. The
family room has a cement foundation with a concrete floor. How much
room do I need between the floor joists on the porch and the dirt below
them? Do I need a vapor barrier? Does the crawl space need and what
size vents?

Around here (Pacific Northwest), code requires 18" between the ground and
the floor joists, though that can be reduced to 12" under beams. However,
if you ever have to crawl under the porch, you'll wish you had more space.

We designed 24" stemwalls on 6" thick footings for a total 30" high
crawlspace. Our footings actually ended up being thicker in places, so we
have a little more than 30" in many areas. I find 30" to be quite
comfortable to move around on my hands and knees, as well as dragging
pipes, insulation, or whatever through the crawlspace.

As for venting, we have to have 1 square foot of vent for every 150 square
feet of floor area. There are supposed to be vents close to the corners,
and allowance made for cross ventilation.

Of course, if your porch is built on open piers, venting won't be much of
an issue.

Anthony

why on piers?.........to answer your question your building code is
going to dictate all of these concerns. Id just exstend the familyroom
slab and build on this. If you cost it out a concrete slab is MUCH less
exspensive and eaiser.


wrote:
Is there any rule of thumb on size of crawl spaces? I am building a
three season 10'x24' porch on piers off the family room. The
family room has a cement foundation with a concrete floor. How much
room do I need between the floor joists on the porch and the dirt below
them? Do I need a vapor barrier? Does the crawl space need and what
size vents?