Sheathing & Roof

Hello again! I’m terrible at updating the blog, but we’ve made some progress – partial sheathing on the walls and roof!

Sheathing

We’ve got the sheathing up on the two longs walls. It’s been a trial and error process — attaching sheathing to steel studs is a lot harder than to wood. We finally figured out the best way by the very end…

First, use self-drilling screws, like this:

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A self-drilling screw with a low-profile (lathe) head! These can be found at Lowe’s. These are the same thing we put the studs together with.

These are really sheet metal screws — so when you want to pass through wood first, you have a little problem. The screw drills really fast through the wood, and then the wood starts climbing the threads while it slowly drills through the metal. This isn’t so good — it can pull out nearby screws, rendering those holes you drilled useless, and you have to make more. We tried just pressing really hard on the screw gun; this had limited success….

Then we tried pre-drilling small pilot holes to help the screws drill through the metal – basically, the same problem, but we also had to spend forever (and lots of drill bits) drilling through the metal.

Finally, we used our brains — we pre-drilled holes through the wood, large enough for the screw shank to fit through, but not the head. This is the right solution! The screw is just acting as a clamp, holding the sheathing to the studs. Then we learned they make special screws to do this — they have little wings that keep the wood from engaging the threads; those wings (theoretically) break off when they hit metal. They only make these in larger sizes than we needed for the sheathing, but we did buy them for the roof (more below)!

We’ll finish the sheathing on the two ends soon, but wanted to get the roof on. The sheathing that’s out there has been rained on a lot, and it’s quite obviously getting pretty weathered. We’ve had a little bit of warping, but nothing too serious, and no delamination.

Roof Sheathing

Roofing sheathing is like more complicated wall sheathing — thicker, higher up in the air, and at an angle. Our roofing sheathing consists of three layers — 3/4″ rigid polyiso foam sandwiched between two layers of 1/2″ plywood. Since we’re using steel, we need a thermal break outside the rafters. The 3/4″ polyiso gives us R-5, which is enough for Florida. We’ll also be adding more insulation between the studs later. (Check out this cool and helpful post for more info).

With me in the loft and Rob on the ladder, we first lifted one piece of plywood and positioned it. We put in two screws to hold it in place while we positioned the foam (held by a nail) and the second piece of plywood. Then, we screwed the entire sandwich down at once using #12 self-drilling wood-to-metal screws (those fancy ones with wings). The wings are nice, but they don’t always break off… Rob learned how to finesse the speed of the screw gun to get the highest success rate.

Working on the roof isn’t the easiest thing — we only have a couple of 8′ ladders, and it’d be nice to have something taller! So far, we’ve been working over the loft, which has been really convenient. I have a feeling the rest of the roof is going to be a bit more challenging!

It’s really neat to sit up in the loft now that it’s got a ceiling — we’re really feeling what it will be like to sleep there! Especially with the HUGE roof window cut out, it feels quite spacious. And I only ruined one tool making the window (yes, it’s possible for a jigsaw to saw through its own cord 😦 ).

In other roof news, we decided to go with the copper metallic roofing. I went to pick it up in Ocala a little while ago, and it’s really beautiful!!

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Rafters are up!

It was a busy month… I traveled to Missouri for my great grandma’s 99th birthday party, so we missed a work weekend (worth it). We’ve also been taking quite a few beach days, and it’s been so incredibly hot here that we just can’t work some days! My new printing press also arrived, so I’ve been busy printing some jobs for my business, Proton Paperie & Press.

But we’ve completed our rafters, which is a big step! Honestly, we thought they were going to be harder than they were, so maybe we were avoiding them a little bit… Here are some pictures, with more construction details below:

First, we built the ridge beam — for steel framing, this is a piece of “C” inside of track. Since our pieces were 10′ long, and we needed a 20′ beam, we staggered the joins by cutting one of the C pieces into two. It was very sturdy and not too hard to manage with two people. The first two rafters were attached directly to the gable end walls. Then, we lifted up the ridge beam, placed it, and screwed the rafters to it.

The rest of the rafters help support the middle of the ridge beam — they’re connected directly to the beam with a clip angle on one side, and directly to the top track of the wall with a different clip angle. We made all the clip angles ourselves out of left over pieces of track and “C”. This was a bit of work, but a lot cheaper and less wasteful than buying premade ones.

We were a little worried that we weren’t including horizontal ties to prevent the house from “spreading”, like is recommended in steel framing guides (these would make the cathedral ceiling filled with joists)… but most of the span tables for rafters in guides start at 24′ and go up  from there. Since our house is MUCH smaller than that (~8′), we decided to go ahead and try it our way. It seems extremely stable — another win for tiny!

We’re currently working on sheathing the sides, then we’ll get the roof on. We’re trying to decide on a color for our metal roof! What do you think, blue or metallic copper?

Wall framing complete!

Rob and I finished framing out all the walls yesterday! We had quite a few pieces to add since our last post… studs we had left out to make screwing easier, window supports, the other gable end, the loft etc.

We also added a couple of pieces of sheathing last weekend, with the help of our friends Casey & Eric (who is a screwgun master). This weekend, we finally figured out what the jigsaw is perfect for — cutting out the window rough openings in the sheathing.

Our painted subfloor is holding up great! It’s been raining almost everyday, but there hasn’t been any lamination or warping.

Up next, roof rafters (I’m a little scared)!

Finally, it looks like a house!

Look!! We have some walls!!

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Rob and I have been working on framing the walls in the comfort of our garage for the last few weeks. This past weekend, we were finally able to put them up! They are a bit heavy, and it’s difficult impossible to manage measurements and placement with only two people. Luckily, we were able to find some magical internet friends!

Thanks a lot /r/321!! With the help of Cheryl, Price, Amanda, Ellen, Mike, Casey, Eric, Ronnie, Adam, and David (I hope I got those all right… and I can’t forget Brandon, Jade, and Bear), we got all four walls standing and braced. We also celebrated a birthday, and our dog Proton made a friend!

I’m so excited — it really seems like a tiny house now!

Steel Framing

I’ve had a lot of people ask me why we went with steel instead of wood… it definitely has advantages and disadvantages, but overall, I’m very happy with our decision.

The good…

  • Ease of use: The steel is soooo nice to work with — none of the pieces are warped or twisted like with wood, and it really seems like you can get things exactly right if you’re willing to do careful measurements. We were amazed how well everything fit together when we put the walls up.
  • Recyclability: Steel studs are made of largely recycled materials, and the scraps (or the entire structure eventually) can be recycled. [1]
  • Termite resistance: Termites are a big deal down here — we didn’t want our entire house structure to get eaten.
  • Strength & weight: A steel stud is lighter than a similarly sized wood stud. The difference isn’t huge since we’re using 18 gauge steel (some people use the lighter 20 gauge, but this doesn’t meet wind load requirements for our area), but the steel has more strength for its weight.

The bad…

  • Price: I’ve heard that steel and wood are comparably priced — let me tell you, that’s not true around here. I found only one local company selling 18 gauge steel studs, and they were about twice as much as lumber. The fasteners are also more expensive.
  • Possible rust issues: Things rust super fast down here… we don’t think this will be an issue with the galvanized studs, but it could be. Everywhere we make a cut or hole, we use a cold galvanizing spray to protect the bare metal.

Besides that, steel just seemed really cool! I worked on iron and steel for my entire PhD and postdoc, so it’s somehow more personal to me! If you’re considering steel, check out some of the references at the bottom of this post, and definitely consult the Prescriptive Method for Residential Cold-Formed Steel Framing [2] for load tables and lots of helpful diagrams.

Another consideration for steel framing is insulation. Steel acts as a much better thermal bridge than wood, which means that standard “between-the-studs” insulation isn’t very effective. [5] The best method to deal with this is to use continuous insulation on the outside of the steel. This changes the design a little bit from the typical tiny house, but it leaves the space between the studs free for easy plumbing, wiring, and even shelving. More on that in a few weeks…

Leveling & attaching the scissor jacks

We finally got our scissor jacks on the back of the trailer so that it could be leveled before the walls went up. We decided to attach them using bolts instead of welds — that way, we can remove them for transport to get better ground clearance.

In order to have the bolt heads be accessible (so they don’t turn while you’re tightening the nut), we had to go through several layers — the trailer itself (a 6 inch hollow piece of steel), the floor framing, the subfloor, and the bottom layer of track of the wall. This required super long special-order 3/8″ bolts:

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When they arrived, we saw they were only threaded on the bottom bit, and they were a bit too long (you don’t get to be very specific in lengths when you get to foot long bolts), so we added some spacers too. Since the holes we had cut in the steel track were rough & large (so they’d fit over the entire nut), we went back and added steel plates to strengthen things, then we caulked around the edges to prevent water penetration. When the walls go up, we’ll still be able to access the bolt heads from inside the storage area in the couch.

We do plan to add two more scissor jacks in the front — those corners are noticeably bouncier than the back ones now.

We have a little bit more framing to do (some studs we left out for ease of screwing, loft, etc), but luckily we got most of the heavy pieces in place! More importantly, we made some local friends that I hope we’ll see a lot more of 🙂

 

References

[1] SSMA — Green Building

[2] Prescriptive Method for Residential Cold-Formed Steel Framing

[3] Highly recommend this book: Steel Frame House Construction (also includes a copy of the Prescriptive Method)

[4] Buildipedia article

[5] IMPROVING ENERGY PERFORMANCE OF STEEL STUD WALLS, ORNL

Subfloor v2.0

In my last post, I detailed a few problems we were having with our subfloor…

The tarp-tent was a total fail, and we took it down after a few days… the wind kept blowing down our cement bucket poles, and small holes meant that water was still getting in (side note: never buy a 30’x50′ tarp, it’s completely unmanageable)… the wood couldn’t dry when the rain stopped, because the tarp trapped it in. The last straw was the termite family we saw munching the veneer in one of the corners. We decided to try our luck with the open elements, but the waterseal didn’t really stop the delamination which occured from being rained on everyday, and eventually it got so bad that we realized we just couldn’t salvage this floor:

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This time, we’ve used some of the plywood we had designated for our sheathing. It’s rated Exposure 1, which theoretically means it can weather being rained on quite a bit… but we’re now paranoid, and we know that if this second subfloor fails, we might really just give up.

So, we decided to go a bit farther, painting it with Olympia Rescue It! wood & concrete resurfacer. It’s pretty thick stuff with a nice gritty texture. It can even fill holes up to 1/4″, which was nice since some of the plywood had some big knots. Although we’ll eventually be covering it with something else, it requires a tint to mix properly… so we chose an exciting color that should make us feel energized to look at. Can you believe they call it Muted Mesa?

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After getting all the screws out of the old subfloor, we had to pull it up. This was initially a bit of a challenge, since we conveniently glued it to the framing. To cut between the layers, first we tried the jigsaw…

Yeah… no. We keep trying to use the jigsaw, but we haven’t found it’s magic application yet.

Our old friend the circular saw came to the rescue!

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And then it electrocuted me…

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Just a little bit. There was a worn part of the sheathing on the cord, and it zapped me in the lower leg. I felt a bit tingly for a few minutes, but I’m alive…

Luckily, beyond the first board, we didn’t have to do much cutting. Usually if we cut the glue on  one side, we could pry up the rest of the board. The glue was apparently working well on some parts, but (luckily) not so well on others.

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Everything looked pretty decent underneath, although there was some water sitting on the insulation in a few places — all near the breaks in the subfloor, where warping had allowed water to flow in. Bad… but not that bad. We let it dry for a few hours in the sun.

Finally, we got the new boards on! They are only 15/32″, instead of the 3/4″ we had before. There is a noticeable difference in sturdiness & flexibility, but since we’d used 16 OC joists, it’s still workable.

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We also learned that we’re supposed to leave a 1/8″ gap between the sheets to allow for a little bit of expansion & contraction (we didn’t do this on subfloor #1)… but again, we’re paranoid, so we also filled in that gap with Rainseal caulk. And then we filled in every other gap and screw head everywhere with it as well. That will hopefully stop water from getting into the framing & insulation at all.

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We’ve been very hard at work on framing the walls, from the comfort and safety of the garage (yay ceilings). We’ve got those mostly ready to put up, but they are a bit much to manage with only 2 people. So, we’re hosting a house raising BBQ next weekend! We don’t have any nearby friends yet, but we’ve managed to recruit about 15 people from our friendly, local subreddit, r/321! I’m really looking forward to meeting everyone next week and getting our house to the point where it actually looks house-like!

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How not to build a subfloor

Today’s lesson is on how NOT to build your subfloor! As I mentioned earlier, I had this super great idea that we’d just use really nice oak plywood for our subfloor, do a cool faux hardwood look on it (ala this), and then we wouldn’t have to buy a real floor!

Yeah, there are a couple problems with that idea…

First of all, I wanted nails to hold the plywood down, since they are a lot cooler looking than screws. However, it turns out that nails are really inferior to screws for the purpose of holding plywood down flat. Rob already knew this, but I was sure nails would be fine. They weren’t.

Second, I was being a real bitch about keeping the floor in perfect condition which, as you may expect, is really hard to do during construction. I kind of yelled at my friend a little bit when I messed up a bit of the veneer, and then I felt like an asshole. This was just the first of many problems though — sweat made stains, little splots of wood glue, etc, were impossible to avoid.

So, I’m thinking that I’ll just go ahead and finish the thing, stain it, seal it, etc… but since everything takes longer than it should, I had to go out of town for a few days before I got the chance (which is a story of another debacle for another day). We’re like, ‘Ok, let’s just put the tarp on it. That will totally protect it.”

Did I mention it’s the rainy season here in Florida? I come back from my trip, and we lift up the tarp:

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Rusty nails, delaminated veneer… generally, a shit show. It looked a lot worse than in the pictures before it was able to dry a bit. Apparently these tarp things aren’t really waterproof, and water had pooled and seeped through. It was at this point we decided to rethink everything, and realized this was going to be a true subfloor, not a floor.

We thought about removing these pieces entirely… but after pulling all the nails, we realized they were glued down really well, and they were not going anywhere without some serious damage to the floor framing and insulation… so we decided to keep them and carry on. We put a ton of screws all over to get things flat. Luckily, the damage was mainly concentrated in one area, which is going to end up under the kitchen cabinets. We cut off the super bumpy veneer with a utility knife.

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Then we had to figure out how to protect what we had left… we rigged up this super sketchy tarp tent out of some concrete (btw, way harder to mix by hand than they make it sound), buckets, poles, and rope.

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We also put super wood-filler on the part of the plywood where we had removed the veneer (and enjoyed our crazy hot fort for a few hours).

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We also bought water-sealing liquid for the plywood. It says to wait until you have a clear forecast for 24 hours before applying. Since rain was forecasted everyday for the next two weeks, things didn’t look good. But after our trailer sat for a lovely 36 hours under the tent with no rain, we decided to chance the forecast and go ahead and put the sealant on (it did turn the wood a lovely warm color!).

That was last night. As I sit here, there is a huge thunderstorm, rain falling all over our 18-hour-old application of the water-seal. We have such a good sense of timing… I’m taking consolation in the fact that there is so much wind that I’m sure our tent would have blown over anyway, had we been using it. I’m not really sure what the next step it. We literally have no idea what people do to protect their half-finished construction projects from the rain.

So kids, buy exterior grade plywood for your subfloors! And seriously consider some kind of magical inside space to build your house in…

 

Friends!

A couple of weeks ago, our friends Lane and Hannah came to visit. They were awesome enough to help us out with the tiny house between beach visits, and they were extremely helpful, even though we were doing kind of boring stuff.

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We hadn’t finished all the L-bracket attachments, so we were working on getting those finished, as well as cutting the insulation to go between the floor joists.

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The rigid foam insulation cuts really easily with a utility knife, and it’s very nice to have two people to work on each piece, one on each side of the trailer. Also, I recommend cutting a little smaller than you need and filling in the gaps with the canned spray foam (much easier than shaving off a piece that’s too large). But be careful! We were cutting a thin piece, and I was stupid and cut the shit out of my thumb. While sweat was definitely already a structural component, we’ve now got blood and tears as well! I wasn’t allowed to help much for the rest of the day…

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We’re used 2 1/4″ of rigid foam insulation (one 3/4″ piece and one 1 1/2″ piece), even though we had 2 1/2″ of space. I would definitely recommend leaving a little wiggle room– between the canned spray foam to fill in gaps and the waviness of the flashing, this was the perfect amount.

We also managed to get most of the subfloor (that Rob and I had cut earlier) attached.

You might have noticed that our subfloor is pretty nice stuff! We chose oak plywood with the intention of finishing it as faux hardwood plank, and using it as our real floor… for a number of reasons, that didn’t really work, and now we just have a really expensive subfloor. More on that later….

Did I mention we have really cool wildlife in our backyard?

Thanks again to our awesome friends who were so helpful!