Exterior Wall Sheathing

Exterior Shell, The Walls

Prior to starting our wall framing, we checked in with Tim’s dad Kerry for a few tips and pointers on how to go about it all, and he mentioned that he likes to sheathe his walls while they’re still on the floor. It’s a lot easier to line everything up that way, with gravity working on your side. We liked that idea, but were nervous that the walls would be too heavy for us to lift with all that plywood nailed on, so we decided to wait until after the walls were raised to do the sheathing. I am happy we did this because the walls were heavy enough with just the studs; however, if we had easy access to a few more bodies to help on short notice, I would DEFINITELY sheathe the walls while they’re on the floor. It would have been a lot easier.

The first sheet!

The first sheet!

1/2″ standard plywood was our pick for the sheathing rather than OSB because it is lighter, will not soak up as much water, and is generally more durable and strong. Plywood is more expensive, but again, with the tiny house you can choose quality over quantity. Also, if you remember me discussing during the subfloor stage the requirement to orient plywood so that its long edge is perpendicular to the strength axis of what it’s being affixed to – the same applies here. Plywood comes in 4′ x 8′ sheets, and since our vertical wall studs are our strength axes, we made the 8′ side of our plywood sheets run horizontally. Also, like the subfloor, it’s important to stagger your pieces from row to row, like how bricks are laid, so that you don’t get seems lining up and forming major linear weaknesses in your wall.

IMG_20151001_180518Starting at the bottom, we did an entire row all the way around and then did another run above that, working our way up to the top plates. Fortunately, we have scaffolding to work with. I can’t stress enough how much of a blessing it was to not have to work from a ladder and be constantly moving it.

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We actually cut our pieces of plywood such that the door and the big 6′ window were left open, but all the other windows we sheathed over because it is a lot simpler to just cut them out afterwards. Unfortunately, since the overall length of our long walls is 28’4 1/4″, we couldn’t have nice round 8′ and 4′ pieces the entire way… we had to divide it up a little oddly (three 8′ pieces, and a 4’4 1/4″ at the end; or, two 8′ pieces, a 6′ piece, and a 6’4 1/4″ piece). CONFUSING! Additionally, we also wanted to make sure to maintain the ~1/8″ gap between all the sheets to allow for swelling in the case of moisture absorption. Throw in the desire to minimize waste by using up our scrap pieces, and a seemingly simple job turns into a weird wooden version of Tetris.

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The process generally involved the following steps:

  1.  Measure the space on the wall – the required length of the sheet going in.
  2.  Transfer that measurement in pencil to both the ends of the plywood sheet (which has been patiently waiting on the saw horses while you took your sweet time double checking the measurement :P)
  3. Snap a chalk line to follow when cutting to size.
  4. Fire up the circular saw and zip off your waste.
  5. Hoist the sheet up to the platform on the scaffolding.
  6. Hold the sheet into position, one person at each end, using your hands, knees, feet, head, whatever works in order to make it straight and square. Simultaneously, wedge a 2 1/2″ nail under each corner between the bottom of your sheet and the top of the one below, to act as a 1/8″ spacer.
  7. Nail the top left corner, the top centre, and the top right corner, quickly but carefully. Leave the nails sticking out a little so you can remove them and re-position if necessary.
  8. Check all four sides for level and square, and that enough space is left on the end stud for the next sheet to join in. If any issues, re-position and try again, with copious curse words.
  9. Permanently nail the sheet in – we used a 6″ nailing pattern on the edges and in the field.

In total, it took us four full, long, draining days to get the sheathing up, but by the end of it we had a structure that somewhat resembled a house. The walls were opaque, relatively sturdy, and you could no longer walk or see through them! At this point, we decided to bring all of our scrap material and tools into our house, organize it all so we knew where to find things, and be as out of the way as possible.

IMG_20151007_131607On October 8th, we cut out our 11 remaining windows, using a reciprocating saw. This was harder than it looked, and you have to have some serious upper body strength to wield that tool overhead for extended periods of time. We wanted to cut the windows out from the inside so that we could see exactly where the perimeter studs were located, so we used a ladder inside the structure to get at the windows.

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It’s funny how exciting and joyful new chapters on this build are, and to notice how they become more routine and easy as they approach their close. In addition, each new task brings renewed enthusiasm, but a sort that only lasts a short time. The focus and commitment required to finish each task after the sparkly beginning wears off can often be draining. And the draining feeling seems to be cumulative. During the first month of the build it was easy to bounce back from challenges and get immersed in each new task as it presented itself. As time marches on for this project, it seems harder to keep on initiating the new tasks because we have obtained a very clear understanding that (A) things always take a lot longer than you expect and (B) things will likely not go smoothly and perfect like they do in the YouTube / instructional video. With that said, it is crucial to not let yourself get bogged down in the frustrating side of reality, and focus on the sparkly part 🙂 It has been really important for us to take little breaks now and again to recharge / switch off from the Tiny House and go be around people who can distract us entirely from the project.

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Framing is Complete – The Bones of the Tiny House

Exterior Shell, The Walls

At the time of the last post I wrote, we had the front and back walls built and raised, and needed to complete the smaller left and right walls. Well we finished everything on Friday evening, September 25th – a month and five days after our first day at the build. The framing took 8 days in total, and we certainly became more proficient at it as time went on. Here’s a video we made showing all four walls going up!

The first nail (we used 3 1/2″ galvanized nails) I drove took somewhere around 25 smacks… pretty bad accuracy haha. My best now is 5!! On the topic of nails, we weren’t sure how many to get and started out with a mere 10 lbs. These lasted about a day and a half, and we went back to the store and bought an entire box – 50lbs. It is cheaper by almost $30 to buy the whole box compared to the same amount using the per pound rate. Lesson learned! By the end, I estimate we used about 35 pounds for all our framing needs. We also bought 3 lbs of 2 1/2″ galvanized nails for toe-nailing, which was definitely sufficient. Toe-nailing is when you attach a vertical stud to a horizontal plate using a nail on an angle.

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Using Pythagorean theorum to solve for the hypotenuse – our top plate 🙂

Gradually, we relied on the computer model less and less as well, because it was just
easier to decide exactly where the windows were going ourselves based on the centre line of a wall. Once you’ve logically thought all this through, it’s easy to then mark out the studs accordingly. The narrow end walls were interesting to design since they connect two parallel walls of differing heights. The front, high wall, is 10’11” and the lower back wall is 9’8″. This meant that the top plate had to be positioned on a 10° angle, and each stud running from bottom to top had to be a different height. It also meant that each stud connecting with the top plate needed to be angled (mitred), to fit snugly into place. The best way to lay this out is on the floor, using chalk lines, outlining the angles and various heights of studs. I even did a little bit of math in order to get the exact length of the top plate – imagine that! Although these walls were smaller, they took a day each to complete because of the added complexity with the angles. We were so glad to be completely done!

To give you some perspective on the process of actually framing a wall, we made a video of the fourth wall coming together. It’s the rake wall on the right hand side of the house, where our guest loft and bathroom will be located.

A few words on window placement: the windows that are located in the loft areas were easy to position, because we needed them as high as they could go in order to have as much wall/floor space as possible up there. The windows on the main floor area were a little trickier. Given that we are having two lofts at either end of the tiny house, we had to find a happy balance between headroom under the loft, headroom in the loft, and the height of counters, and couches. The size of our windows had been decided on, based on our Google Sketch-Up model we had designed. So those were fixed variables that could not be changed at this point; but of course, you can’t have a window intersecting the platform that forms your loft floor. IMG_20150922_145226To make it easier to visualize, we actually got a piece of 2′ x 4′ and suspended it from the tops of our front and back walls using rope, at various heights, until we were happy that we had enough space downstairs and upstairs for everything we needed. At first, we assumed that we were going to install standard height counters (36″ from the ground), but during our window positioning process, we realized that since we are building this ourselves, we can actually venture away from the standards and choose something that fits us better, personally. I did some reading and found out that the standard counter height of 36″ has been around since the early 1900s, at a time when people were on average, much shorter. Ergonomically, the best height for a counter is that which results in your forearms being positioned at a 45° angle when your palms are placed flat on the counter top. Keep in mind – to achieve this, it isn’t how tall you are overall that is important, just the height of your elbow since it is the lower arm that does (or should be doing) all the prep work when at a counter. When a counter is not at the correct height for your body, you will compensate for this unconsciously by changing your position in order to get your arm into the right position for working on the surface. If the angle is greater than 45° (counter is too high), approaching 90°, you will have a tendency to step or lean back a little; and if the angle is smaller than this (counter is too low), you will have a tendency to lean forward. Both of these scenarios end up in pain – upper back and shoulder pain with counters that are too high, and lower back pain with counters that are too low. Here’s a good source that I found very useful on this topic.

We decided that we are going to go with 38″ counter tops, as we are both a little taller, and I do spend a lot of time experimenting and creating in the kitchen. Might as well make it more enjoyable since we have the option! Our kitchen window sill will then be positioned 2″ above the counter height, which means our loft platform allows us a total vertical space of 6’5 1/2″ in the kitchen and bathroom. All our ‘downstairs’ windows are 3′ high, so we positioned them all at the same height from the floor based on this carefully calculated kitchen window position. It works out great for the height of our sectional couch and living room window as well, and the window in the bathroom. Remember to factor in the thickness of your finish flooring when making this decision for yourself!

Once we had all four walls framed, we had to permanently attach them to one another at the corners before we could remove the bracing. This part actually wasn’t incorporated into the plans we bought, but we emailed the designers and they were able to explain what to do via email! Such a relief.

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You basically have to shove the walls into place so that any given corner will be level and square. This was made easier by ratchet-strapping the left wall to one of the axles. Ratchet straps are awesome! Tim and I have been maintaining some really good teamwork throughout the framing process, but of course, we have our ups and downs. We are getting better at being able to read when we’re too tired or too hungry, or experiencing the dreaded h-anger (when you’re so hungry that you start to express anger in a seemingly unwarranted manner)…. ok I’ll admit that I am the bigger victim of feeling hangry (lol). I feel like I’m in a snickers commercial sometimes. I’m just not myself when I’ve worked for 9 hours and I’m hungry! We’ve both become more forgiving with respect to differences of opinion if it means that one of us will be a lot happier if we do something a certain way. Sometimes it is likely unnecessary or redundant, but our comfort level and the gift of being on the same page is totally worth it!!

Sub-floor Prep

Exterior Shell, Sub-floor

Now that the trailer has been completed, we have started what we’ve been fondly referring to as “The Real Build”. The anticipation to start working with wood has been high, and we got our first taste of it on Friday, August 28th. It took us nearly 9 hours to install the wooden rails around the outside perimeter of the main frame of the trailer. These rails will provide a nailing surface for our plywood sub-floor and the bottom plates of our studs. IMG_20150828_153023I have to say, it was really enjoyable! Wood is a DREAM to work with compared to metal. Even though we were still attaching wood to metal, it was the wood that we were manipulating and levelling, and what a difference!!!

The first thing we did was spend about 10 minutes levelling the trailer from all four corners using our 2-ton scissor jacks, and then we were ready to get at it. We used 2″ self-tapping screws to go through the 1.5″ of wood and 1/4″ of steel, and staggered each screw 1′ apart along the length of each piece of wood. Alternating our screws from a higher position to a lower position, with respect to the centre line of the wood, prevented the creation of a single axis of screws along which the wood could curl and potentially crack, over time. IMG_20150828_183357Our purchased plans said to place screws every 2′, but this didn’t seem sturdy enough to us, so we went with the 1′ intervals. The imperial system is still driving me nuts, but on top of that, I find it so irritating how the measurements of wood are not even true to their imperial names. 2″ x 4″ wood in reality is actually only 1.5″ x 3.5″. AND, any given piece of so-called 2″ x 4″ has a better chance of spouting maple syrup than it does being actually straight! Rant over….

It wasn’t in the plans we bought, but it was mentioned to us that it might be wise to use a cushioning / water barrier material between the wood side rails and the metal of the trailer frame, as well as when we’re laying down the plywood sub-floor. I brought this query to the awesome facebook group “Tiny House People”, where I got a resounding “Yes!” to this question. So glad that we decided to do this. I’ve already complained about how wood isn’t straight, but we didn’t really take into account the fact that even though our metal should theoretically be flat, after painting, the surface was a little uneven due to drops of paint having dripped down and hardening into little convex ridges here and there. We picked up a roll (in the range of 80′) of 6″ sill gasket, and wrapped it around the entire exterior perimeter of the trailer frame in one continuous piece, sandwiching it with our 2″ x 4″ wood rails as we went. It filled any gaps between the two materials, creating a nice tight seal. This stuff is basically composed of a squishy, white, open cell foam sheet.
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Before we could start attaching anything, Tim notched out cylinder shaped channels in the wood where it would line up with our welded-on threaded rod. We didn’t really have the right tool for the job… I think a router would have worked well. But we had a grinder, so Tim marked lines showing the needed width of the grooves and just ground out the wood with a wheel on his grinder. Not perfect, but it worked.

C-clamps are now my very best friends. They are amazing. If there’s a bow in your wood, or it’s twisted in any way, they are there to reduce the amount of profanities used and make your life generally easier. Self-tapping screws however… we’re not as good friends. I’ve heard you can buy ones that actually work, but ours were a big sham. Somehow, the very first one went in ok, but after that they kept breaking so we had to drill pilot holes.

We bought a box of 100 screws, and ended up having 5 left over. Sunk a few additional screws around the pieces of welded-on threaded rod, to bring the wood as tight as we could around those, as well as any other places that needed a little extra coaxing to be tight and straight.

In addition, we made the realization that our trailer is actually about 3/4″ longer than expected! We measured everything and it turns out that the 24′ pieces of HSS from the mill were slightly longer than spec. Never even considered that could be possible! Haha. The wooden 2″ x 4″s come in 10′ and 8′ lengths, so we needed two 10s and an 8 to flank each side of the trailer entirely. With the newly discovered discrepancy, this meant we had a little 3/4 inch gap between the tail piece and each side rail. To accommodate, we cut two small blocks and hammered them down into each gap and screwed them in from the end. No biggie.

I feel terrible writing about all of this next bit, it will be such dull reading. But, I’m afraid if I don’t write it down, I will forget the small details if we do this all again someday. If you’re curious about the specifics, read on! If not, stop here 🙂

 


 

The process of sinking each screw went a little like this:

  1. Place the sill gasket against the metal trailer frame with left hand, then hold the 2″ x 4″ wood against the sill gasket with right hand. Tighten clamp around the whole thing. Your partner does the same thing at the other end.
  2. Take a measuring tape and stretch it the length of your 2″ x 4″. Mark a vertical line with a pencil at each 12″ interval, making sure to have the two end screws 2″ in from the edge of the wood, regardless of where the nearest 12″ interval lies. Mark a horizontal line at each interval, 1″ down from the top or 1″ up from the bottom, alternating, creating a zig-zag pattern. The intersection of the lines at each position will be the home for each screw.
  3. Make sure the top of 2″ x 4″ is flush with the top of the metal using a combination square and a level, so that the plywood sub-floor will lay flat across them both.
  4. If the situation isn’t level, use a rubber mallet to hammer up or down on the wood, whichever is necessary, on the outside of the clamp. Doing this allows small increments of change in the position of the wood, all the while keeping it snugly in place thanks to the clamp.
  5. Drill a little piece out using a 1/2″ drill bit, to a depth of about 1/8″ to 1/4″, giving a space to counter sink the screw head. This way, the heads of the screws won’t be poking out making it impossible to get our sheathing and siding flat against this wood down the road. Pro tip: wrap some painter’s tape around the tip of the bit, making an edge so you know exactly how deep to go when drilling. Don’t want to make these too deep.
  6. Drill a pilot hole through both the wood and the metal so that your “self-tapping screws” (i’m convinced this concept is a sham) will go through without getting worn down or snapping off. We used #10 screws, which have a shank diameter of somewhere around 13/64″ (imperial, whyyy???) so we needed the pilot hole to be smaller than this. I think it was something like 9/64″.
  7. Sink your screw, at last. Move clamp further down the line.
  8. Repeat