I assume its too late to put blocking between joists to be able to nail bottom plate to

 

Unfortunately yes. The subfloor was already down when I bought the house. Essentially what I'm doing is framing 4 walls on an existing sub floor in a large space.

 

Not structural u will be fine if u r worried about moving just put little bit of glue under but not necessary

 

Do the walls tie to the rafters?

Gary

 

placing any type of wall between joists and onto sub flooring only is asking for a sagged floor under the wall in the future. how tall the wall is and how thick the sub flooring will determine the rate of sag. subflooring can be cut and removed to allow access for blocking and then the subfloor can be put back down

 

I would go with this advice ... and 16D nails which is probably what you used to build the stud wall.


I myself and quite familiar with the bailing wire method we have here down South, grew up in rural areas myself, but if you ever want to sell that house without having to tear out those rooms, I would make sure you do it to code. I think each space in an unfinished basement needs at least 1 electrical outlet, I would research that and to make sure something similar doesn't apply to unfinished rooms in an attic.

 

since the sub-floor's nailed to the floor joists, i wouldn't worry,,, just did a room over the garage which was about the same,,, 4' kneewall & i screw'd the short vert 2x4 studs into the side of the roof trusses,,, finished off great & have no fat friends under 4'' tall so no problemo :laughing:

use long drywall screws &, if you want overkill, some const adhesive under the plate ( i didn't )

 

I would use construction screws, not drywall screws.

 

uncertain what ' construction screws ' are but i use what on the shelf :yes: then again, never said i was a carpenter :no: another advantage of being raised on a farm - baling wire & chewing gum now updated to version 2.0 - duck tape :laughing:

 

Construction screws look like drywall screws but are much stronger. The head on drywall screws is specially shaped on the underside so it will dimple the drywall, and will often snap off if you screw them into wood too fast. Drywall screws are always black (in my experience anyway), while construction screws are usually gray, brass-looking, and sometimes green. Then there are deck screws, which are coated (or made of stainless steel) to prevent the chemicals in pressure treated lumber from eating them away.

Check the fastener aisle next time you're in a big box store. Each of these three types of screws usually come in different-colored boxes.

 

Sheetrock screws are to brittle for framing, infact no scews should be used in any framing, only nails.

 

just to hold a btm plate ? c'mon, joe - i wanted to finish this part w/o having to run to the nearest apron/vest store,,,,,, scheeeeschhh, there's lateral force on this sole plate,,, IF it makes you feel better, i used lead-shield drop-in's for btm plate on the bsmt exercise room's wall,,, i can see you never had to finish anything w/my bride, nagzilla, hanging over your shoulder :laughing:

i'm not taking any more abuse today ! :no:

 

just to hold a btm plate ? c'mon, joe - i wanted to finish this part w/o having to run to the nearest apron/vest store,,,,,, scheeeeschhh,there's lateral force on this sole plate,,, IF it makes you feel better, i used lead-shield drop-in's for btm plate on the bsmt exercise room's wall,,, i can see you never had to finish anything w/my bride, nagzilla, hanging over your shoulder :laughing:

i'm not taking any more abuse today ! :no:

at the orange big box store spax has some construction screws made that work like cabinet screws with shear strength. an exterior decking screw will also work sometimes for framing applications but will still snap if sheared... can't beat the good old hand driven nail in certain apps, and even nail guns if you got em...

 

Gary,
The walls do not tie into anything up there. They will be 4 independent walls (with a ceiling of course). The rafters are above where the room will be. The subfloor itself is 3/4" T&G that is glued and nailed. I will be screwing it down before the carpet goes down.

Where u see the bottom plate on the right of this picture is where the wall will be going. It is 3 1/2'' off the exterior wall.

 

The only way the subfloor would sag under the weight of that wall would be if the subfloor was 1/8" sheathing. Seeing as how you've said you have 3/4" you'll be fine without blocking, just add construction adhesive if you want to make it a little stronger, also criss cross your nailing pattern to hold the bottom plate in the subfloor.

 

The room is definitely going to be up to code. I pulled permits and it will be inspected. Unfortunately the code doesn't specify this situation. I can put 300+ pounds on the floor and jump and down and the floor is solid.

 

bdunkin please take the time to add your location to your profile.
Main reason is I see you did not add to the rafters so there's no way to fit much insulation and the needed baffles.
http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table
There also need a be a window that meets egress code.

 

Southeast Alabama. 5/0 window is going in existing exterior wall on Tuesday for egress. I will frame a sill around the window on the new wall. There is already a room on the second floor so I have full size steps for second monastery of egress.

 

Why wouldn't u just use the exterior wall itself with insulation.( if u just need thicker insulation add whatever thickness u need an screw into the exterior studs)

 

First off thanks everyone for your replies! The reason I am not using the existing exterior wall is the fact that it is structural and I don't want to cut all the studs to put a header in. And the fact that the wall possibly could not be straight. There is a cross brace (2×4) against all the studs at 7' that would have to move. I would rather not mess with anything structural. That is why I'm having a contractor put in the egress window.

 

The walls won't touch the rafters. That back wall is where the roof slope comes down and there is about 8" of clearance from the top of the wall. The left wall is actually on a floor joist so nailing won't be an issue there. To the left of the left wall will be a storage room with a full size door going into it.

 

That exterior wall on the right is a gable wall only load bearing points are 2 corners and possibly under the ridge, if u r putting a window there u gave to put header anyway. 2nd if the new wall is separated from the exterior u r not going to be up to fire code

 

I'm very curious about not being up to fire code. Can you explain a little further? How would I put a header in the existing wall If that is what i need to do?

 

Fire code if any fire were to happen in a bay u wsnt to prevent from getting to another bay if they r not connected you would have direct flow all a fire needs to grow is air

 

I do it all the time on existing houses. Determine height of window header cut studs to line with saw cut a little bigger than header height ways grind or saw all nails insert header put in jacks. Measure down from bottom of header the tough opening size for window add 3 in cut remainder of 2x4 in the way insert 2 sills and 2 crips on jacks under sill ready for window. Everything done from inside

 

My plans are to insulate that cavity. There's got to be a way around that. Any thoughts on connecting the 2?

 

Connect 2 x to your exterior studs and bottom, top plates with screws

 

I am thinking how would I put a top plate in the existing wall for the ceiling joists to attach to. The ceiling joists will run perpendicular to that wall due to the span of the room.

 

Or use 2x 6 and sister next to studs by nailing together

 

Do you mean take a 2 x 6 and connect both walls together? That seems the easiest way to make it so its one cavity.