Phase Three: The Shell

1. Phase Three: The Shell Trailer/Floor: • Order Your Trailer: know what you want and make it clear. Unless you’re getting a trailer from a tiny house company, you’re going have to explain exactly what you want and why it’s important. Do your research beforehand and have a bulleted list of your specs. You’re probably going to want as much width as you can get, evenly spaced cross-members, a low deck, metal flashing underneath, leveling jacks, no railings, no decking, no ramps, and a high weight rating, to name a few things. Place your order 4-8 weeks before you want it to arrive, depending on the company’s wait time. Decide whether you’re going to pick it up or pay to have it delivered.

2. All-Threaded Rods • Hire a Welder: when you have a pick-up or delivery date confirmed, contact a welder about an on-site job and make an appointment. The welder should have standard 5/8” all-threaded rods that they can cut to length for you. Make sure the rods are long enough to go through your floor and the bottom plate of your wall. The welder might have nuts and washers for sale, but it might be cheaper to buy them from the hardware store. When the trailer arrives, you’ll need to mark the locations where you want the rods welded on. Consult your framing plans to make sure the rods don’t interfere with any studs. Also, if you plan on using hurricane ties that secure the rod to a stud, make sure the rods are the right distance away from studs. It’s best to have a rod every 6’ or less. If you’re using 2x4 framing, your rods should be ¾” in from the edge of the trailer (as long as your walls will be flush with edge of the trailer) so that the rod ends up in the middle of your bottom plate. Be aware that your trailer might not be perfectly square. Any welding should be done before insulation or a subfloor so as to not burn either.

3. Insulation • Buy Insulation or Make an Appointment: after researching different insulation options, you should have decided what kind you want. Calculate how much you’ll need for any kind other than spray foam and order it or pick it up from a hardware store. Do this before your trailer arrives in case you do need to order the insulation. If you need fill gaps, like with rigid foam board insulation, buy some foaming sealer as well. If you decided to go with spray foam, after you know the pick-up or delivery date of your trailer, make an appointment (after the welder) for them to come and spray the trailer. You won’t be able to be in the area for 24 hours afterward, and you should have 30’ of clearance on all sides.

4. Estimating • Estimate Materials: do some math and/or use another tiny houser’s numbers to estimate how much you’ll need in the way of adhesive, screws, plywood, and more. Some people use sill sealer between their trailer and subfloor. Depending on your insulation you might need a vapour barrier.

5. Hardware Stores • Buy Materials: you might want to check a few stores to see which has the best pricing. Don’t be afraid to talk to the employees; they’re there to help! For plywood or OSB, consider weight and how far apart your cross-members are. You might want to do some research. Tongue and groove creates a stronger floor, but is more difficult because of the all-threaded rods. Make sure the adhesive you’re buying adheres to wood and metal. Try to find the longest reposition time. Make sure the screws you buy are meant to drill through wood then metal and ask if you need to pre-drill. Buy more than you think you’ll need. Also, make sure you have a vehicle that can fit 4x8 sheets!

6. Getting Started on the Floor • Spray Foam: it’s best to get the insulation sprayed after the welding. It can’t be raining when they do it. After the foam cures, it will reject bulk water, but you’ll still want to get your floor down as soon as possible. You can even cut and dry-fit your wood before the insulation is in if you have time before the appointment.

7. Dry-Fitting • Cut & Drill Plywood: if your cross-members are evenly spaced, it shouldn’t be too difficult to put down large sheets, but if they aren’t you’ll need to do some calculations. Plywood and OSB are meant to be perpendicular to the strength axis – the crossmembers. So even though your trailer is about 8’ wide and so are the sheets, you shouldn’t lay them like that. Tips: You will need another person to help you. Even if you can carry plywood by yourself, you’re going to need someone to help you put the sheets into place and it’s helpful to have someone holding sheets as you cut. You should stagger the seams to avoid creating a flex point. Try to create as little waste as you can by planning your sheets in advance. Measure carefully. Table saws aren’t really practical for cutting plywood. You should only rip on table saws and even with two people, maneuvering would be difficult. A circular saw works well. You can make a fence or follow a line by hand. You should cut with the good side down. Allow for a 1/8” gap between non-T&G edges. For drilling holes for the all-threaded rods, you should drill with the good side up because the bottom is going to splinter more. Use a drill bit that will make a hole big enough for the weld around your rods so that the plywood will lie flat. If you chose tongue and groove sheets, be aware that some of the holes will need to be oval to allow for sliding, and you’ll need to plan the order you’ll put the sheets on and which ones will slide.

8. Securing Your Subfloor • Glue & Screw Plywood: when you take off your dry-fitted sheets in reverse order, mark around them with chalk so you’ll know later where each sheet should go. Number the sheets, so you know what order they go back on. Also mark all your crossmembers on the side of your trailer so you’ll know where they are once the wood is down. If you’re using an insulation other than spray foam, it’s probably best to put in the insulation as you go. That way, if it rains before you get all of your sheets on, you won’t ruin insulations like wool or fiberglass. It’s a good idea to dust off your crossmembers and your wood before you glue; adhesive sticks best on clean surfaces. Also, read the instructions on the adhesive. Your screws should be six inches apart at the edges and 12 inches apart in the middle, the field. Be aware: drilling into metal is not quick! You’ll need an impact driver, and preferably a friend with another impact driver to help.

9. Trailer/Floor Steps • Order Your Trailer • Hire a Welder • Buy Insulation or Make an Appointment • Estimate Materials • Buy Materials • Spray Foam • Cut & Drill Plywood • Glue & Screw Plywood

10. Phase 3:Wall Framing Steps • Finalize Framing Plans: before you can start working on your walls, you need to make sure any changes you want or need to make to your plans have been made. Some small changes might not make a big difference, but any changes can affect what lumber you need. You want to make sure you have the final version of your plans before you start ordering lumber. • Plan Lumber: and before you start ordering, you need to plan out what you’ll need. Go through your plans wall by wall and count up what you’ll need and in what lengths and thicknesses. If you’re lucky and your plans include a materials list, still go through and double-check to make sure the numbers make sense. 2x4x8s tend to be cheaper for the length you’re getting, so for smaller pieces (like around windows), it’s cheaper to get several 2x4x8s to cut up rather than fewer 2x4x12s, for example. Make sure to take note of any pieces that aren’t 2x4s (2x6s, etc.).

11. Spending Money • Order Lumber (plus extra!): Take your totals, add some extra pieces just in case, and then add more again. You’re going to need extras in case there are some warped boards, and you’re going to need extras to use for bracing. This early in the build, you’ll be sure to use up any leftover lumber later. Call around to your local building supply stores, if there’s more than one, to check prices. Be aware that the lowest price might be the worst quality, so try to catch some sales on the higher priced stuff. You can have the lumber delivered – it’s usually not that expensive – or if you have a bigger vehicle or a friend with one you can pick it all up yourself. But that might be difficult if you’ve ordered 2x4x14s! And it could take a couple of trips.

12. Adding Extras • Buy Strapping and Joining Pieces: Find out what your plans or your engineer recommend for any extras to secure your house frame. Strapping and joining pieces can be a gray area. Some people say you don’t need any because the building is so small, while others over-engineer their houses for peace of mind, especially if they plan to take their house on the road a lot. It also depends on what area you live in if things like hurricane ties are required by the building code. Do you need (and/or want) to have metal strapping all the way around your house? Are there any joints that are angled or otherwise difficult that require a metal connector? Do you need/want to use hurricane strapping or ties for your rafters? Some people have even used metal tension rods from trailer to top plate. And others have used a specific Simpson Strong Tie to attach the rods on the trailer to studs – but that has to be planned in advance so your rods and studs are close enough. Check your local building stores to see what they have, and check online for anything you might need to order.

13. Nails Vs. Screws • Buy Nails or Screws: For nails, you’re going to want 3¼” or 3½” for framing, plus some 2 3/8” for when you’re sandwiching two 2x4s together (that way the ends of the nails won’t stick out). You can get smooth or ring shank – I used smooth for my framing so I could more easily pull out my mistakes, and saved the ring shank ones for my sheathing. For screws, you’re going to want similar lengths. 3½” is the standard length for framing. I chose nails over screws for speed and because I’ve found screws can be difficult in two ways. 1, to get the screw to end up exactly where you want it, and 2, to get the screw to pull the second piece of wood in tight. Sometimes with screws, you need a pilot hole, and I wasn’t about to do that for an entire house.

14. Practice • Practice with a Nail Gun: not all tiny housers use nail guns (and some use screws instead of nails) for their build, but if you have one or can buy or rent one, it’ll save you tons of time. A nail gun can be used for several different tasks during your build and for other projects afterwards. So if you’re new to building and have never used a nail gun, you’re going to want to practise with some scrap wood before you go near your soon-to-be walls. Get comfortable with the sound and the weight of the tool, and make sure you’re following all the safety recommendations. Practise making squares out of 2x4s and making sure that your 2x4s stay lined up where you want them as you nail. This is a powerful and dangerous tool, so always be aware of where you’re placing your hands and feet.

15. Angles, Cuts, Lines, and Holes • Figure Out Angles: Refer to your plans and make sure you know any angles you’ll need to cut for your end walls. Do some practice cuts with the saw set to that angle, and make sure it comes out to what you need. Saws can be a little off. • Cut Lumber: Start with the simplest wall and cut all the pieces you’ll need to length. LABEL THEM. • Mark Top & Bottom Plates:Clamp the top and bottom plates of your wall together, lying flat. Then measure where every stud is supposed to go, including the pieces around windows. Use a square to draw a straight line across both boards and put an X to show on which side of the line the stud is supposed to go. It’s a good idea to double-check your measurements, and remember that you don’t need to mark cripple studs and trimmers on your top plate. • Drill Holes: Even if your plans show you exactly where your all-threaded rods are, go measure them anyway. They won’t be as exact as your plans. Measure how far each one is from the back and the side of the trailer, and write down all your measurements on a labelled drawing. Use those measurements to mark your bottom plate. Pick a drill bit that is big enough to give you a little bit of wiggle room around the rod, but still leaves enough wood for the washer to press down on. Drill your holes, then go check that the bottom plate fits over the rods.

16. Put It Together! • Lay It Out: On flat ground, lay out your wall pieces where they’re supposed to go. Nail together any headers using plywood in between two 2xs. • Secure End Pieces: Attach all the outer corners so you have a rectangle. • Check for Square: Measure diagonally from one corner to another, and check that the other corner-to-corner measurement matches. If not, you have a parallelogram, or one of your pieces is the wrong length. • Add In the Rest: Before you randomly start nailing, put together your window frames. Nail together any double studs (using shorter nails) or pieces that need horizontal nails, then add in your normal studs last. You don’t want to nail the normal studs first, then realize you don’t have room to fit a hammer between two studs that are close together. Toenailing isn’t ideal. • Check for Square (Again): Measure diagonally across the wall from corner to corner both ways, making sure that they are the same distance. • Repeat Steps 8-15: Follow all the same steps for each wall until you have them all! For parallel walls, you can lay out the second one on top of the first one to save space.

17. Wall Framing Steps • Finalize Framing Plans • Plan Lumber • Order Lumber (plus extra!) • Buy Strapping and Joining Pieces • Buy Nails or Screws • Practice with a Nail Gun • Figure out Angles • Cut Lumber • Mark Top & Bottom Plates • Drill Holes • Lay It Out • Secure End Pieces • Check for Square • Add In the Rest • Check for Square (Again) • Repeat Steps 8-15

18. Wall Raising! Now that you have all your walls built, invite some family and friends over for the wall raising! Things you’ll want to have ready: • Long 2x4s to brace the walls • Screws and a drill to secure the braces • An extension cord • The nuts and washers for the all-threaded rods • A wrench (or two) to tighten the nuts – make sure it’s the right size • Ladder(s) • A camera • Clamps For my 23’ house, we needed at least 6 people to comfortably carry the long walls. It only took us about an hour to get the walls up and secured! They were wobbly though, so we added braces where we could, and clamped the corners together temporarily. Later I added studs to make California corners and nailed the walls to each other at the corners. The walls went up so fast, I can’t tell you exactly what we did, but it’s pretty straightforward. It’s a good idea to start with a long wall, then while a few people are holding that up, a couple people can get the smaller end walls into place, and then the three walls can hold each other up while everyone gets the last wall up. Have fun!