Building an interior wall questions

So I am about to put in an interior wall in my garage. If I attach the top plate to this truss, what do I attach the side of the wall to since there isn't a stud there? Does it need to attach to anything other then the top and bottom plate?

If the wall is anchored to the slab, and well secured at the ceiling if might not need other attachment, but for what little it would cost, I'd probably add a couple of studs butted up against each other to tie the wall into 3 different planes instead of just two parallel ones.

In reply to STM317 :

Ok sounds good. I'll throw in a couple extra studs then.

In theory since the wall isn't really holding any weight, I wouldn't worry about it.  Once you skin the wall with drywall or whatever you're putting on it, the 2x4 at the end won't have the opportunity to bow in/out.  If you wanted to go the extra mile you could throw a stud in that exterior wall where directly under the rafter so you have something to tie to.  You could also cut some 14" (or whatever) scraps and put them across between the studs so you have something to tie to.

Add blocking between the studs. Attach to the blocking.  2 blocks will do it. 
 

If you do nothing, your drywall will probably crack at the corner. 

In reply to SV reX :

Ok there is one about 3 feet up. How many should I add? One more?

Edit: apparently missed the two total when I first read your post

In reply to 93EXCivic :

Split the difference from the top plate and the existing block. One or two extra won't hurt a thing if you feel like adding more.

Not knowing the building code in your area Civic, but two people mentioned "blocking", those cross brace things between studs.  Here that is required not only for lateral support but as a fire break.  In the event of a fire, the space between studs will act as a chimney!  The cross brace will slow it down and also keep the wall from becoming a parallelogram.

Pics please when it's over please.

In reply to 914Driver :

Unless those walls are ridiculously tall, fire blocking is not required. The top plate (and bottom plate) suffice. 
 

The only time fire blocking is required is when 2 spaces are connected (like the downstairs to the attic, but the top plate suffices), or when the spacing between blocking exceeds 10'. 
 

You need additional studs in the existing wall to support the ends of the drywall at the corner. Install them so they are outside the end footprint of the new wall. That will give you something for the drywall screws to bite into. 

Same thing at the top. You need to install blocking or something for the ends of ceiling drywall to attach to. 

In reply to Cadman5 :

Maybe. There are other ways to do it. 
 

It could also be done with drywall clips, or blocking, or leaving the end stud loose so the drywall on the outside wall can pass through. 
 

With the cost of lumber now, it's worth considering the other options. 

This is blocking I have now.

Top plates (mostly need to add one more segment) and blocking in.

I whipped up this little detail today of typical wall corners, wall intersections and ceiling drywall nailers in continuously sheathed braced walls buildings.  They are guaranteed not to crack the drywall. My original drawing has been corrupted from the old computer's crash so this one doesn't have the detail it should. :) The blocking that is in your exterior walls is to support the vertical OSB 4x8 panels along the panel edges at any splice joint. 

Edit: You don't need double top plates on non bearing interior walls unless you need them for height requirements.

I'd block it anyway personally.

You could also California Corner it ( what Cadman5 is talking about) but blocking is fine

In reply to VolvoHeretic :

What is the height requirement for double top plates?

Thanks for the diagram. I was going to ask how to do the corners.

There isn't any height requirements that I know of. Double top plates are used to tie long runs of wall together and for load bearing from floors and roofs. The drywall nailers basically are a top plate. How many plates you use depends on what the floor to bottom chord height is and if your studs are long enough without needing to buy almost 2' longer studs and cut most of them off. What is the floor to roof height? Does your slab slope to the O.H. door? Make sure to use a treated bottom plate against the concrete and you might want a double bottom plate so that you can screw-off the drywall while leaving at least a 3/4" gap between the floor and the sheetrock to prevent water wicking up into it. The wall doesn't need to be a super tight fit to the roof framing, you can shim the top plate a little. Running along the sloped floor, we would lay out the studs on the plates, attach the top plate to the ceiling, and measure each stud to cut and fit and then toe nail them in place with 3 nails at each end of the stud.

There is nothing wrong with using double top plates and it might be easier to follow the sloping floor with a double top and bottom plate attaching the top and bottom plates in place and nailing the middle plates to the studs and standing them up and nailing them off. (As long as you didn't cut your studs to long.) 

There are multiple ways to build a corner. 
 

Most people building with wood use 4 studs to build a corner or Tee intersection. 
 

Commercial buildings often do the same job with only 2 studs. 
 

4 studs per corner is honestly a little overbuilt, and causes energy efficiency issues in the building envelope (there are cavities created which are almost impossible to insulate when the time comes for insulation).

Double top plates are not a necessity.  They are only required in load bearing walls IF the floor joists or ceiling joists above do not align with the studs below them. Since trusses are usually laid 24" o.c. And walls are typically built 16" o.c., it's just easier to double up the top plate. 
 

Non load bearing walls do not require a double top plate, but pre-cut studs are 92 5/8". (Or 108 5/8" for 9' walls). If you use precuts for the load bearing walls and don't use a double top plate on the interior walls, every stud will have to be 1 1/2" longer than standard pre-cuts. That's a lot of labor to individually cut every stud, so the default is generally to use pre-cuts and double top plates for everything. That makes it easier. But there are ways to build quality construction that use a lot less wood.  The problem is, every trade will have to think more, and that usually doesn't happen. 

In reply to VolvoHeretic :

I need to measure again but it is a bit over 10 feet because the 10 ft 2x4s I bought are a few inches too short... I was thinking of doing a double bottom plate to make up the difference but I hadn't thought about using treated bottom plate.

In reply to 93EXCivic :

We've talked a lot of theory. 
 

In your case, you don't need any blocking. Your building is fine. 

In reply to 93EXCivic :

Double bottom plate is fine. The bottom piece touching the concrete should be pressure treated. 

In reply to SV reX :

Well said. I would just say that a box corner can be pre-built and it is very easy to attach the walls to each other in the corners or intersections. Also, wood is R-1 pre inch but you definitely don't want to forget the fiberglass insulation before installing the sheathing. Same thing for box headers. You also have to save your straightest lumber for the corners and door openings.  We would only use a single top plate when finishing off basements, garages, or a vaulted ceiling.

These are typical corners:

Note that the 4 stud corner is not as thermally efficient as the 3 or 2.  Wood has a high water content, and is not a good insulator. By leaving the void like the 2 or 3 stud corners, it can be filled with better insulating material. 
 

A standard commercial corner looks like this:

Corners can be built in wood the same way. The challenge is that the inside stud needs to be left loose, and secured after the drywall is installed on the first wall. This is easy in commercial, because the same crew that installs the metal studs installs the drywall (with the same tools). It's not as easy in residential wood construction, because the framing crew is a different crew than the drywall crew, and they use different tools. 

In reply to VolvoHeretic :

Right, but insulation installed in a framed wall before sheathing in wood construction has a high likelihood of getting wet before construction is complete, which can lead to dry rot of the structural components. 
 

It's much better to do ALL of the insulation at one time after the building is completely dried in. 
 

Framers suck at insulating, and building inspectors can't inspect the building envelope insulation.