Basement Framing Question

smuth10

I have to frame up some walls in a basement with 8.5' ceilings. The drop down ceiling will need to come down to about 7.5' in order to drop down past the duct work and what not.

Is it ok to only build 8' walls on the exterior walls to save $ on materials. I could use small pieces of 2x to tie the walls up into the joists. I realize the top 5 or 6" will not be insulated, but the ceiling will come down past this point. I just don't want to have to buy 10' lumber and drywall and have a ton of waste.

Thanks, Scott

paul100

There is no reason to buy 10' studs. Just double up the top and bottom plates and use 8' studs. That will get you to 8'6". If you are going over a concrete floor you should use a pressure treated bottom plate or put something on the floor so that the wood wont touch the concrete.

smuth10

I would still need to buy 10' drywall though, right? I like the idea, but I was trying to save a little $ and still do it the right way. Do you think leaving the top 6" exposed is a problem if the ceiling comes down past it?

II Weeks

personally, I would use metal studs that come at 10' anyway. Use your standard 4X8' sheetrock hung horizontally and use the mildew resistant blue board on the bottom. Frame up. Wire and cable up and then call in a spray foam company to insulate the outside walls down to one foot below the frost line then install the rock.
I would also recommend sound board on the ceiling before you do any framing.

A lot of details to go over but think this option over.

paul100

Build the walls like I suggested then just run the 8' sheet rock. It doesnt matter if the top 6" is open since you are putting in a dropped ceiling.

AtlRemodeling

A couple of points:

1) You can also use 104 5/8" studs that are set up for 9' ceilings and you will only have a very small amount of waste.
2) Irregardless what size studs you use make sure you fireblock the area above above the dropped ceiling. There is a very informative thread on this site:

How to fireblock framing

with lots of good pics and methods to proper install the fireblocking.

smuth10

Thanks everyone. This is exactly the info I was looking for. I will definitely look into all of these things.

Much appreciated!

ClemS

you don't need to frame the walls all the way up. and you don't need to rock all the way up.

code says you have to use PT plates on concrete. concrete has no adverse effect on wood. if your basement is dry, don't bother it's a total waste.

ccarlisle

Is that really what you think...or are you guessing.

Scuba_Dave

Without framing the walls all the way up they will not be bearing against the top joists
That top part provides a lot of support when someone leans against the wall
PT is required by code based on years of experience with building
Water vapor comes thru concrete...even in a dry basement
Not doing it to code & spending the few extra $'s is just stupid

I'd use the PT bottom plate, & a double top plate with 1/2" plywood sandwiched in between
That gets you to 8' 5" which you say you need
Double top & bottom = 8' 6" which is 1/2" too much

Walls should be out 1-2" from the concrete wall, studs should not be against the wall
Best way seems to be rigid insulation against the wall, then stud wall w/insulation

My additon walls are 8' 4.5" tall, the bottom 4.5" will be partly covered by the flooring & rest covered by baseboard

ClemS

i have not seen masonry/concrete having an adverse effect on untreated wood.

most homes around here that are 25+ years old, have an untreated fir sill, with no damage caused by concrete they're laying on. any damage that does exist is water and/or termite related. otherwise the sill is completely intact.

some of the older homes have redwood sill plates, that behave very similarly. if there is a water problem, the sill is gone

same goes for new houses with PT plates. mind you, the PT stuff that is readily available is not ground contact or full submersion in water. It's your regular household above ground PT. If there's a water problem and the stuff is getting drenched, it will rot fairly quick.

CODE is however to use PT wherever wood is in contact with masonry/concrete. so whenever you do anything that will be inspected, use PT, if for no other reason than to appease your local official. but if you're fixing up your basement and really don't care for using/cutting/breathing chemically treated lumber, don't worry about it that's all I'm saying.

ccarlisle

OK I get it, you guessed according to what you see...but I see lots of concrete and wood put together in all sorts of situations and have yet to see one that didn't fail...OK perhaps longer term that 6 months - but no exceptions. It's a pH question. We always see foam sill protector rolls up here. Oh and no metal studs in a basement either...

ClemS

foam sill seal is not used to keep wood and concrete separated. it is used as a gasket to eliminate air flow under the sill due to concrete imperfections (and there is no reason to use it, other than it's code). same goes for termite shield, another myth, but code nevertheless.

what exactly do you mean by failing?

paul100

I thought the same thing at first to use the plywood to make 8'5", but then I reread the original thread and they say 8.5'. So I am now assuming they mean 8'6". That is why I suggested double top and bottom plate.

Scuba_Dave

Ah...good catch......8.5' equals 8' 6"