On Fri, 25 Mar 2005 05:18:59 GMT, Unquestionably Confused
Brian, the mention of torsion boxes gave me an idea that you might
consider. When I was rebuilding the front of my camper I ended up
creating a torsion box for the floor. (see:
Essentially milled 1"X1" (real dimension, not 3/4") cedar on 1-foot
squares grid with 1/8" plywood glued on each side. It is more than
sufficient to hold up my weight (250lb) on a 4'X7' floor.
I don't know what the shear strength would be of this kind of
construction, but note that the cupboards on my camper (late 70's) are
screwed into a wall made with 3/4" lumber and they haven't moved
despite having been used mostly on very rough Yukon backroads. I'll
let you do the weight calculations to compare it with steel studs. You
might have to make the wall thicker for the lecktrical stuff.
Just an idea, but it brings the whole thing back to wooddorking.
Replace "nonet" with "yukonomics" for real email address
Steel studs are common in commercial construction. I haven't seen a
wood stud in a phone building for at least 15-20 years, regardless if
the wall carries a load. Lots of these walls have counters, cabinets,
etc... mounted to them. A lot of this stuff is installed as an
afterthought, so the wall was not specially designed to carry the
I'm guessing commercial construction uses 20 gauge metal studs for load
bearing walls, not the 25 gauge metal studs they sell at all the home
I was thinking about the 25 gauge studs when I was questioning if any used
them for load bearing walls.
I did some web searching on this a while back, and found a number
of people who claimed to be hanging cabinets from steelstuds with
no problems (I don't know what guage of steel they were using).
I assume the success rate would vary with the amount of weight
and the number of screws (and whether you're using screws
designed for steel studs). It seems to me there should be some
kind of rule of thumb for weight-per-screw. The screws seem to
grip pretty well.
Another possible strategy is to arrange things so that something
else takes the weight, and the studs just hold it upright.
The OP said his walls weren't up yet, so I'd certainly add wood
blocking wherever it might come in handy. For an RV, you also
have to consider dynamic loads. I like the idea of a french
cleat, with a peg that has to be removed before you can lift the
cabinet off the cleat.
Yep, everyone here should recognize that the skin spreads and sustains a
load. Boats, cars, airplanes, all build on that principle.
That's why it's no longer a simple question of withdrawal force on a screw,
because the load has been spread by that infinite fender washer called a
wall skin to other screws, other studs.
Metal studs for a house would be really expensive. A 20 gauge stud is
about $6 each and load bearing walls might need them every 12" instead of
16" with wood.
They make finger jointed wood studs that are extremely consistent in size.
I have no idea if they cost less than 20 gauge steel studs or not.
I would use metal for a house in a heartbeat if it was similiar in price
and I could find a carpenter who has done it before on a house.
I'm not sure I want to go with metal studs yet. I figured I needed to be
sure I could attach my cabinets before choosing metal or wood studs.
Wood studs would be less expensive but heavier.
Brian, Very interesting project. For RV use, I would consider using smaller
studs, say 2" x 2". And where loads exist for cabinets and fixtures, I
would inlay some plywood or 1" x 4"s for securing the cabinets.
All screws eventually work loose in RVs. I would also consider not using
drywall behind the cabinets and use 1/4" plywood instead. This way you will
save a considerable amount of weight and be able to secure the cabinets
using a French cleat system. (French cleat - a board ripped in half at 45
deg. One half of the cleat attached to the wall and the other mating half
attached to the cabinet.)
2x2s would probably work as that is what wood framed RVs are generally
built from. The only reason for thicker studs would be for insulation.
They make special electrical boxes for RVs that fit in a 2x2 wall.
Someone else mentioned drywall. I didn't mention drywall and have plans
to use it. 1/4" plywood covered with something is what I am planning to
use. I'm not sure if 1/4" plywood will really hold up cabinets.
I am a carpenter and was doing the exact same thing at Montreal's City Hall.
We were building a new kitchen for the blue collar works and commercial code
states that metal studs are to be used because of fire code. So here is what
I did. Metal studs are in a shape of a U and always face the same direction.
Where you plan to put your cabinets, you need to add a piece of stud about
12" long in the opposite direction. So that the 12" stud will face the 8'
stud(the U's will face eachother). Since the studs are 16" on center...you
can cut a piece of 3/4" plywood 12"x15-1/2". Use 3/4" drywll screws. Do not
use the self-tapping kind(silver). They will just burn the wood and will
spin. But since you are turning a semi to an RV...if it will be on the road,
I would use 2"x6" pine instead of plywood between the studs. It's cheap and
it will hold your cabinets without a glitch.
consider using plywood instead of drywall for the sheet goods over the
studs. you'll save weight and add both strength and stiffness to the
structure. then you can get an attachment you can count on for the
build the cabinets as light as you can. lauan ply is light for it's
strength, comes with a surface that is smooth enough for laminate but
will likely need some prep before paint.
What we do for commercial jobs is have the GC provide 6"
wide heavy gage (gauge David) coil stock wherever we need in
wall blocking. This is screwed directly to the face of the
stud.. You could also use horizontal steel studs bay making
screw tabs on the ends.
Personally I like 2 X 6's. If your studs are 16" on center
cut the 2X material to 15 7/8"(ish) and notch (dado) the
face of one end to clear the break (wrap) in the steel
studs. Working from the notched end face screw the 2X in
place through the stud and into the face of the 2X. Screw
the other end through the stud and into the end of the 2X.
It's as easy as eating pie.
Yep. Done about a zillion linear feet of blocking that way (at least
it seems that much. Blocking is _boring_ work). Not only can you
drive a screw anywhere you want, but you know the screw won't pull out.
And, the load is distributed along the whole wall. Also, scrap 2x or
3/4 ply is abundant in pieces 15 7/8" long.
Regarding an earlier post, I think maybe the french cleat idea is maybe
not so good, seeing as how the RV will be going over bumps and whatnot.
Hope it helps.
On 24 Mar 2005 18:10:22 -0800, the inscrutable
Simple fix: Use upper and lower sets of cleats and affix with screws
through the backs (into the bottom cleats) to hold them in place.
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