I am planning on finishing my basement off and have a few questions. I'm
sure I'll have more as I go.
#1- How far between studs? Is 24" o.k.? I plan on putting insulation between
them, so does it depend more on widths of the bats? They oviously won't be
load bearing walls.
#2- As far as vapor barrier, it goes between the studs & drywall, correct?
#3- I've read the bottom boards/plates(?) should be pressure-treated in case
they come in contact with water...God forbid, Does anyone do this?
#4- Should there be a vapor barrier plastic under the carpet padding when it
First off if you have water in your basement you shouldn't finish it without
fixing the water issue first.
If your going to insulate you should stud every 16". Insulation is more
available in that dimension.
I put a vapor barrier against the cement in my cellar and one over the
insulation before the drywall. Cement foundation walls are inherently damp
and cooler than the insulation, making condensation, which will eventually
ruin the insulation.
Pressure treated lumber is strictly for exterior use, it should never be
inside living space. There are some builders getting away from using it
outdoors now too,
Again if your worried about water you shouldn't be finishing.
If you're interested, I'll tell you how I went about doing my basement. I'm
at the finishing stage now...doors, trim, and ceiling. I'm in limbo now on
how to treat the ceiling, but that's beside the point isn't it.
I live in a part of Canada where the winters commonly dip to -35, and
occasionally we have -40 to -45 Celsius. The soil in my area is extremely
sandy and the water table is high. The block basement walls are in perfect
condition, as is the floor. Not a crack or leak anywhere. Not bad for a 30
year old house. The only time I've had moisture problems was when the rain
gutter was allowed to empty right at the corner of the house. The result
was visibly damp blocks inside the house...just at the corner. But because
the damp sandy soil "wicks" some moisture up through the floor, there is
often patches of white puffy "effloresce" forming.
This being my first house and first renovation project, I was very careful
about doing things right...to the point of going way above and beyond
building codes. Except for the furnace, water heater, and electrical panel
I completely gutted the basement. It stayed this way for a year while I did
research. I talked to local contractors who specialize in foundations, I
talked to renovators and local experienced home builders.
This is how I went about finishing my basement. I painted an oil based
concrete sealer PAINT on the outside walls. At the advice of my local
building code inspector I only painted up to the outside ground level. To
seal the floor, I used a special (expensive) treatment that strengthens and
seals the concrete. In Canada the brand name is "Aqua Guard". In the
States I think "Xypex" is the common name. The factory where I work uses
that product extensively in wet areas. Concrete grain terminals use it to
water proof their huge storage areas. The manufacturer states that the
sealer penetrates inches into the concrete, forming a barrier. Extremely
easy to apply. I'm happy with the results. But I also put a double layer
of heavy poly between the sole plates and the floor.
The walls are 2x4 construction of course, but I left a 2" gap between the
concrete basement wall and the new 2x4 wall. A local house builder uses
that method. This method isolates the 2x4 from the concrete so less heat is
lost through conduction. But more importantly I was able to put 5.5" R20
insulation in the basement walls. (2" gap plus 3.5" equal 5.5"...the
thickness of R20). In case you don't know...this is a good time to warn
you....stuffing and compacting insulation into a cavity is not good. The
fiberglass batts need to expand to it's intended thickness. If you compact
3.5" R12 insulation into a 2" cavity, you won't have R12 protection.
One minor thing I did wrong was to insulate R20 down to 18" above floor
level. The bottom 18" I only insulated R12, because I thought it would be
beneficial to leave a "breathing" gap at the lowest level in case I ever
needed to vent the perimeter with a fan or dehumidifier. Since then I've
learned that leaving that open gap compromises heat loss. Apparently that
2" thick gap all along the bottom perimeter of the wall allows air movement.
Not a big deal seeing that most of the wall is insulated R20, but
still....if you're splitting hairs.....
Don't skimp on the poly that you will be putting between the insulated walls
and the wallboard. Use building code approved poly. The poly will probably
be in excess width of your wall height. Don't cut off the extra. Staple
the poly from the floor up so the excess is at the top of the wall. I used
the excess to wrap over the top plate and onto the sill plate (the wooden
2x8 that sits on top of the concrete wall....the joists sit on top of it).
Remember, you are trying to create a vapor barrier between the moist warm
side of the house and the cold side. In order to fold the poly over the top
plate you'll have to cut and fit the poly where ever a joist runs.
While you're working in that area, remember to insulate between the joists
at the outside perimeter (along the header)...remember you have to have a
vapor barrier there as well. The method I used to insulate between the
joists against the outside header is like this: I cut chunks of R20
fiberglass insulation to fit between the joists. Instead of fumbling with
poly for the vapor barrier I used rigid Styrofoam insulation board...1"
thickness. I cut the foam insulation to fit snugly between the joists, and
pushed it up next to the fiberglass insulation. I then caulked around the
edges of the foam insulation to both secure it and to seal it off. USE A
SPECIAL caulking that doesn't eat Styrofoam.
I spaced the uprights 24 inches apart through out my whole basement. In
hindsight I should have used 16 oc. Also plan your studs very carefully. I
made a few mistakes in that area. With studs spaced 24" o.c. it's more
critical that your drywall is secured firmly...especially with the
insulation pushing on it. If your studs are out 1/4" or if they are not
perfectly plumb, you will find it a challenge where two sheets of drywall
butt up along the stud. If your seam is too much off the center of a 1.5"
stud, you're going to be putting that drywall screw close to the edge, which
compromises the strength of the drywall. This is one of the reasons I would
go with 16 o.c. studs.(more strength over all if you DO run into mis aligned
If you're not experienced with framing and drywalling, I stress
again....PLAN YOUR STUDS carefully. When it came to do the drywalling, I
found myself having to tack on 3/4" boards along the 2x4 studs because I
found myself short of drywall support. ALSO, anywhere you are putting a
light switch or outlet, DO NOT attach the box directly to the stud. Nail an
8" block along the stud and then attach the box to that. The reason for
this is drywall again. If your drywall seam falls on the same stud that
you've put an electrical box, then you only have a 3/4" strip between the
box and the edge of the drywall. This will surely be damaged during
screwing, and it will interfere with the taping and mudding later on.
On taping and mudding: If you're going to be using gloss paint I would
definitely get a professional to do your drywall finishing. Gloss paints
will expose a beginner's job glaringly!! Even if you don't plan on using
glossy paint, I'd practice with the taping and mudding in an inconspicuous
areas. Don't cheap out on the finishing tools, don't get a fast setting
mud. Don't sand drywall without wearing a mask. Either ventilate the air
to the outside or use a shop-vac sanding attachment. If you use a shop-vac,
make sure you use a filter bag specified for drywall dust. If you don't,
you'll ruin your shop-vac and have dust all over your house.
As for the poly under the carpeting...I'm not sure. I've been told that
it's a good idea to put ply under carpeting even if the floor is going to be
a bit damp. I'm not sure what I'm going to do.
In hind sight I would say
1) if you're framing a pocket for a shower, buy the shower package first so
you know the exact dimensions to make the pocket. I didn't do that...I just
estimated. Some how I completely lucked out and made the pocket perfect
size. *whew..."looking towards the sky"*
2) plan your studs...especially your inside and outside corners...get a book
on framing so you know the proper procedures for corners.
I finished my basemennt as a workroom and laundry. I userd stainless steel
studs and they are excellent. They are about the same cost as wood, they
don't warp, they are much lighter to handle, adding cross beams is quick and
easy (they just snap in) and there are holes provided for wires and pipes.
Recommend them highly!
Thanks for all replies.
There's no water at all, just want to try and get a handle on the
cold-air-meets-warm-air-and-make- water thing.
How about attaching bottom board top the concrete floor? Conststruction
adhesive, Tapcon screws, .22cal power loads, combination of adhesive & power
loads? I read somewhere (again) someone didn't think it was a good idea to
put the holes in the floor and just used adhesive.
I just finished my concrete-floor basement where we do have seepage
problems with 2x3s since nothing's structural. You don't have water, but
I think how we did ours might be an idea about how to help your floor
stay a bit warmer. We took scrap sections of 2x3 about 6-8" long and
Tapcon'd them every 16-18" or so into the floor to serve as "feet" of
sorts. Then we laid and air-nailed the main floor 2x3 onto the "feet."
In a perfect world, plowing anything sharp a few inches long into
concrete foundation isn't a good idea given the nature of force and
water hydraulics, but fortunately in this imperfect world, foundations
are thick enough for Tapcon screws long enough to secure a 2x3 to not
create a problem on its own.
The only thing is by doing things this way, you have to have enough
raised flooring solution(s) to bring what will be your final top floor
material up about 2 inches or so.
Power loads on the bottom and shims on the top. I believe I used about
two for every eight foot section. It was fun and fast. On the 24" vs.
16" on-center spacing, you'll save a few studs with the wider dimension,
but you'll have less flexibility when it comes to hanging heavy shelves
and the like.
Here's what I did:
I have basement walls made of solid granite blocks, each about 1-2 feet
high and maybe a foot thick, chinked with cement from a local quarry. This
was the cheap and easy way to do things about 100 years ago when the house
was built. First I spent several years sealing wall leaks with portland
cement. Later I sealed any weepy areas with asphalt roof sealer. Be sure to
check the place where the floor meets the walls. I also grooved the floor
to direct any water that might possible flow in during a flood or really
heavy rain into the floor drains and poured a maybe 4 inch high slab in
front of the door leading to the bulkhead steps to direct water coming down
the bulkhead stairs into a floor drain. This worked OK until the water
table got up to the top of the drains. I built (non-loadbearing) walls, as
close to the granite blocks as I could get. The walls were 2x4 on 2x4
sills. Maybe I could have used 2x3, but I didn't want the walls to flex
once I put on the wallboard. I wrapped builder's poly (4 mil? 6 mil? as
thick as I could get) around the sills so if the floor leaked the wood
wouldn't be sitting in water. I didn't want PT wood where kids or pets
could chew on the arsenate or cuprate or whatever. The studs were spaced 16
inches, but I should have used 24 inches--faster and cheaper to build. I
put builder's poly on the granite basement wallside BETWEEN the false wall
and the basemnent wall so any condensation on the basement wall wouldn't
get the insullation wet. I used R-13 kraft faced insullation; the kraft
went on the inside, toward the warm area, as usual and I faced this with
poly as well, making a hopefully waterproof sandwich with the fiberglass
insullation between two layers of poly. For the ceiling I just put in R-13
held up with chicken wire between the joists. (or use those springy wire
things) I put a couple of vents in the wall--just areas where there were
framed out gaps in the fiberglass so any moisture in the space between the
walls could vent. I got a buy on some interlocking heavy rubber pads for
the floor from the local Surplus Store (don't pay Home Depot prices--I paid
$10 for 16 square feet). Final step was/will be to cover the insullation
with 1/2" wallboard as time and $ permit.
Put down a piece of plastic on the floor and just leave it there for a
while. If water vapor comes through the floor, you'll see it under the
plastic and you'll need to seal the floor. My floor was tight, but I put
down a couple coats of Thompson's Waterseal anyway in case the washer
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Bad advice. Vapor barrier should absolutely go between studs and rock in
a basement if you don't already have it elsewhere on the wall. You don't
want any moisture getting to the back of your rock or it's a mold breeding
ground. You also want to make sure that your rock is as high from the
floor as possible. The bottom few inches are covered by trim anyway. I
usually install a plywood base about 1/2" shorter than the base molding
which makes a better nailer anyway. The better move is to use some kind
of paneling if the look works for you. Wainscoting will keep your rock a
good few feet off of the floor. I did that in my old house.
Um, hate to point out the obvious, but if you're already building your
wall several inches above the floor (and any floor moisture), then your
rock has no way possible to touch the moisture. Last I checked, things
do not mold unless it gets wet in the first place.
Let's say you do vapor barrier. It does nothing about all that roll
insulation most people use between the foundation and the barrier
getting all moist and moldy, does it?
Again, you can vapor barrier all you want, but unless you've got
moisture leaking thru your foundation itself or have some sort of rain
forest-esque humidity between the wall and the rock, it's a complete
waste of money because moisture isn't touching anything that's been set
several inches above floor level in the first place.
I imagine that *could* happen if you keep the thermostat at a constant
95, maybe. You obviously live with old people, or are one yourself.
I've always lived in houses with finished basements over cement
foundation, and every single one of them without vapor barrier in the
walls. Not a speck of moisture or mold in there. Not even at my parents
house, where the original 30+-year-old drywall and roll insulation was
ripped out for remodel.
So ... again ... either you live in a sauna, or someone's been doing
something strange with your own basement(s), kimosabe.
Well regardless of the senseless language, I'm sure God enjoyed it, they do
make roll insulation for 24" centers. 16" or 24 " has to be your personal
choice, 16" probably better and I put vapor barrier between drywall and
sidewall studs as well as ceiling some 36 years ago on main floor and wish I
had in basement side walls where I used rough sawn Wainscot about 40" up .
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