Tiny House Wall Framing, Corner Sheathing, and “Plumbing” of Walls

The end of May we finally got around to wall framing once our subfloor was completed. If you have your lumber delivered on-site, the lumber is usually strapped together.  Do NOT unstrap whiteboard until you are ready to use it, as it will bow and twist really easily with temperature/moisture changes. At this point, make sure your trailer is leveled and subfloor finished.

our wall lumber has been delivered

You will also need to have headers ready if you plan on having windows (or a door), which I assume you’ll likely have at least one! I will explain how to create window headers in a separate blog post.

two constructed headers example

Every lit bit of your house is going to contribute to weight. With that in mind, we did 24” studs on-center instead of the typical 16” on-center.  We recommend laying at your wall studs on the trailer itself, which will make it easier to hang in place.  There’s a science to determining which walls to hang and move in what direction first as you’ll have support braces in the way too, so don’t hang your walls randomly- plan.

Speaking of weight, write down or take a pic of your starting wheel well distance between the frame and tire; it wouldn’t hurt to know as you build how well your trailer is stabilized and holding weight as it should.

starting wheel well distance

Our walls were done in three sections, starting with the rear of the trailer that had the more complicated pieces (dealing with wheel well).  Since we have a shed-roof design, we start with high-side wall first.  Using a speed square, you can carry over your stud measurements marking 2’ centers.  We used pressure-treated lumber for our bottom kick plate that touches the trailer; the rest was regular whiteboard.

laying out 2 foot centers for top and bottom plate
We decided to use pressure-treated lumber for our bottom kick plate touching the trailer.

Unless you do this for a living, planning goes a long way! People may disagree, but planning a tiny house layout is 10x harder than building a 2000 sq ft home, so allot enough time to ensuring blueprints are ready on build day; a pencil width makes all the difference! Our wall layout changed dozens of times and took 5 months.  Your blueprints will change once you have trailer in hand too.  Have these blueprints accessible on build day.

137 - Copy
Renee and Larry going over the fine points of our stud layout.

We used mostly nails for wall framing/toe-nailing.  Some tiny house goers prefer the use of screws; there are advantages and disadvantages to either one, so ‘pick your poison’ after some homework and go with it.  We did use self-tapping metal screws for the bottom kick plate, and Headlok bolts in strategic areas to secure walls corners together.  Maybe it goes without saying, but I wouldn’t try to do this (all wall framing) yourself; invite a friend up or family to help on this important day.  Not all is going to sit nicely on your trailer for nailing, nor always get the nailing right (as Renee points out below!).  In our defense, we have gotten A LOT better with a nail gun since then!

Add headers above window openings and door frame:

placing window header in frame 2

When framing windows, use rough opening dimensions (as opposed to actual opening dimensions). If you never done this before, sketching out a typical window rough in helps:

When our frame was together, we measured diagonals (one corner to the other) to ensure equal measurements.  You do not want to put up a racked wall.  You may need to screw the wall to the trailer frame temporally with decking screws to move the top or bottom frame to where it needs to be without the whole wall moving on you.

Once we knew all wall dimension were correct, we put a diagonal brace on to keep it in place without moving on us. Just use decking screws (you’ll want to be able to remove it!).

diagonal cross support for wall frame

We leveled our wall before securing into place with cross supports.  The larger the level (such as a 4’ level) the better for this task. You may find you’ll need to re-adjust these before final “plumbing” of the walls.

use level with wall raising

Our first raised wall!

We didn’t intend to do this below (and maybe will work out better!), but the high-side of our trailer ended up with a double kick plate at the wheel well (just in case you notice in photo above). The low-side only had one on the wheel well.  Nonetheless, communication when making cuts is key!

Don’t think you’re getting carried away with supports- you’ll need them! This is why choosing what walls to do when is important.

lots of cross supports back wall

Let’s talk corner walls. You’ll see many tiny houses carry their “long” walls out to the end.  We believe for better support, let your corners carry more of the support by having a full corner kick plate from end to end.

illustrating that will make back and front plates carry across for better support.JPG
Why carry these walls out when you can make your tongue & rear walls more load bearing?

There are also different arrangements your corner studs can come together (two examples below). We sandwiched our corner studs so that you can place insulation between them and so wiring can be run easier.

After finishing the high and low side of our “back walls” (note we saved corner walls for very last- I only mentioned it sooner to see what we did with this section), the next section was the high-side wall in the front. The middles (which had the wheel well) was the smallest section and done second to last.

Given our space, we needed to build two of our walls on top of each other:

building walls on top of each other

Having temporary “side support” brackets will help ensure your wall doesn’t fall off the frame when inching it near the edge:

Some tiny housers will bolt the walls to the trailer.  As mentioned before, we used several 3” self- tapping wood to metal screws.  We also used wood to metal adhesive underneath. If you take this approach, you’ll need to pilot drill a hole big enough that the screws will want to anchor, and remove any shavings while you pilot. These shavings we found will just cause the screws to spin and not anchor otherwise.

And here are the screw bolts (Headlok) we used for securing corners and wall sections together:

You’ll eventually need a door, and should indicate where that kick plate will eventually be cut out. Almost all contractors just cut this once the walls are already up, and someone could cut or damage the floor.  One cool trick of the trade is to precut the bottom of this plate, so later when you go to remove it by sawing, the saw never comes close to the floor. Just make sure to change the depth of your circular saw when you “kerf” the pressure-treated bottom kick plate.

The tongue and rear walls were “fun” as they have an angled piece that must incorporate our 2/12 pitch of the roof. Keep in mind 2/12 is really the minimum you should do.  If you go with a standing seam metal roof like we did, some companies require at least 3/12 pitch or can compensate with customized peak trim.  We laid these out on the ground since there was no room on the trailer (or for error!). Constantly measure diagonals to keep measurement lined up, but remember your high and low walls studs are different measurements (if shed-style roof), so temporarily brace a board across at your lowest point to get a perfect square; once the “U” is where it needs to be, then you can prep for the top piece.

laying out front and back

You will need to notch out where the angled piece goes on your corner studs. A giant T square can help you when placing your pitch. Roof rafters will eventually be “bird-mouthed” onto the top of the angled whiteboards.  When moving your finished wall, don’t make the same mistake we did where a diagonal brace is in a place that either needs removed or will get in the way (pictured brace was okay).

brace on front wall

angled tongue wall in place

Some other tidbits before showing finished photos! Where your wall sections come together, particularly the middle of your layout, try to have extra support for keeping these walls together as one unit.

We used structural insulated sheathing (SIS) which is normally near the weight of regular sheathing, and also has some R value; we also used SIS when insulating our wheel well undercarriage.  At least the corners of sheathing need support, so we added some 1x wood which were added using a Kreg system.  We’ll be using it a lot more in the future for cabinetry and picture framing other tiny house structures. We attached some of our corners before the walls went up.  Follow whatever staple layout is recommended for the sheathing you are using.

staple layout
Example of the two staple layouts we must follow when using structural insulated sheathing (SIS).

We went ahead and remove part of the vapor barrier we no longer needed on the  walking subfloor face:

removing vapor barrer plastic from middle of subfloor
In addition to the subfloor, our walls will eventually have a vapor barrier as well.

Below are pictures of our wall framing! Your last step is “plumbing” the walls using Mason string by attaching blocks and running a 2×4 in and out of the string starting in the back and moving your way forward.  You will need help with this step for someone to pull in/out on the walls and re-brace if one of your wall sections is more bowed in/out, etc.  Any specific questions about the process? Comment below!

plumbing a wall with string block on outside
In this picture, we’re were trying to make sure our tongue and rear wall sloped pieces were angled correctly.  If the string is looser or tighter in some spots with your whiteboard, then you may need to re-cut.
plumbing back wall see mason string
Showing mason string going across where one of our shed-style slope cuts was going to be placed.  Once all walls our up, you place the mason string outside of the walls & run a 2×4 block in-between systematically from back to front to move walls into plumbed positions with your braces.
mack and renee wall framing
Any pictures I seem to take of Renee and me end up blurry or out of focus do to the habit of placing my phone by the chop saw.  Perhaps it’s about time I clean out the camera lens (and stop doing that!).
renee in wall framing
Renee enjoying the house being framed and coming together.

 

rear wall
Rear wall.
tongue wall front
Tongue wall (never really know what to call front or back or “sides” on a tiny house!).
low side wall framing
Low-side wall, in the direction our shed-style roof slopes.
all walls up but three side view
High-side wall with all sections up except for a section over the wheel wells.
tiny house all wall framing done side view
Completed wall framing! In this pic, there is mason string blocked on the rear wall. Once that was plumbed, we moved to the rest of the tiny house.

 

 

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