Posts from the “Trailer” Category

Air sealing the house

Posted on April 18, 2016

High-res version

When it comes down to it, we’ve probably spent the most tiny house research time on building envelope systems.  The building envelope is what protects the inhabitants of the house from wind and weather, and it’s made up of siding, air barrier, sheathing, and insulation.  And if you ever talk to any architect about this, they’ll tell you that building envelope science is a murky world of half-truths and maybes.  Folks, this ain’t easy.

Using information from articles like the ones here, here, here, here, and here, we determined that we want a vapor-permeable air barrier to wrap around our house.  This will keep drafts and water out, but will allow water vapor to diffuse in and out of the house.  We decided against a vapor barrier on the inside of our walls thanks in part to the sheep’s wool insulation we plan to use.  We came up with these decisions because we’re concerned about water condensation and mold buildup in our tiny house, which are issues for tiny houses in general, but also for Christine in particular.  We’re happy to talk about this in more depth!  But frankly, building envelope science doesn’t interest most people, so if you want to know more please ask in the comments.

We decided to use the product Henry Blueskin VP100, which is a residential grade vapor-permeable air barrier that is locally available.  It’s self-adhesive, like a giant sheet of sticker, and it seals itself at the seams.

For our first step, we routed out each window opening, and then spent the better portion of two weekends sticking the Blueskin to the outside wall sheathing.

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The difference it made to the inside of the house was noticeable immediately. Stepping into the house at mid-morning this past weekend, we realized the house felt stuffy.  And this with a gaping hole where the door goes!  No more airflow through the cracks between our sheathing.  I’d call that a success.

One area of the house where we paid particular attention was at the wheel wells.  We left a 1/4″ to 1/2″ gap between the plywood and wheel wells of our house.  This is so water can’t condense on the metal wheel wells and then be absorbed into the plywood, making for a weak point in the walls where mold can occur.  However, we also wanted to make sure water couldn’t migrate into the house through this gap and soak our insulation.

This is another problem particular to tiny houses.  Tumbleweed doesn’t address this with their trailers (although they might in their house plans, I’ve never checked), but there is a trailer company that has an optional welded flange all around their wheel well.  You’re supposed to build your walls so that the plywood sits just on the outside of the flange, which prevents water from creeping in to your house. It’s a pretty cool solution, but it’s one that we didn’t have, and I’d still be concerned about water condensation where the metal touches the plywood.

We opted to use EPDM rubber roofing flashing tape at our wheel wells.  It feels like a long rubber sticker, and we stuck it to the wheel well and then up onto the walls.  Our housewrap came down over the EPDM.  We’re not sure how it will hold up long term, but it seemed like a good option, and it provides a thermal break between the metal wheel well and the wood walls.  We’ll see how it goes.

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You can see that it pulled away a little bit from the corners after a week or so on the trailer, so we did have to cut and patch it once already.  But overall, we’re pleased with how it came out.  We’ve got high hopes!

Next up is roofing, and after that will be windows, the door, and siding. And then we can start work on the inside.  Is that supposed to be the easy part?

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Insulation and Lumber

Posted on August 16, 2015

With the trailer finally ready to go, we placed an order for wood and insulation. “Wait!” I can hear Seth saying, “it wasn’t that easy.”  Of course it wasn’t!  Because when you’re Christine, you have to research everything about everything, all of the time.  What can I say?  It’s what I do. For insulation, we needed 2.5″ of rigid foam to fill the space within the trailer. Rigid foam is lightweight, it cuts easily, and the kind we picked doesn’t absorb water.  This is important because we want to discourage mold growth as much as possible, thanks to my health sensitivities. We chose to go with 1″ of xps insulation, and 1.5″ of polyiso insulation.  In the best of all possible worlds, this will…

Leveling the trailer

Posted on August 16, 2015

Every tiny house trailer is unique. Even Tumbleweed trailers, though they’re “standardized,” have their own quirks trailer by trailer.  It’s just the way it goes when you custom fabricate large obects.  Each weld is different, each component of each axle, the way the lights are attached, they shape of the tongue.  If you’re thinking about purchasing a tiny house trailer, accept this now: Your trailer will not be perfect. New or old, you will have to account for something wonky. This is something we didn’t recognize, so when we began leveling the trailer, we were frustrated, despite the fact that the steps to leveling a trailer are actually pretty simple. Purchase trailer leveling jacks.  We bought 6 of these jacks, and used them all.…

Flashing Repairs

Posted on August 16, 2015

We took a weekend away from working on the house in July to meet up with some friends for vacation, and over the weekend it rained. This is not a vacation recap! It was nice seeing our people, but the point of this post is the tiny house. When we came back to the trailer, we realized part of the flashing had torn away. You see, the rain over the weekend collected in the tarp over the trailer. The water in the tarp weighed down on the flashing, putting too much pressure on the screw points. And since the flashing is only thin pieces of aluminum, it couldn’t withstand the weight and pulled loose along one section. The aluminum was beyond repair and had…

Flashing: Finis

Posted on July 15, 2015

Because we bought a trailer that is just a frame with wheels, we had to perform some alterations to ready the foundation of our house before we can build on it.  Namely, we had to install flashing on the underside of the trailer.  The flashing protects the insulation, which we will be laying directly into the trailer frame, as well as the sub-floor, which will go over it.  Flashing makes the house road-worthy.  No sense in making a beautiful house if the floor is going to rot out from under your feet. In addition to installing flashing, we added a 2×4 “nailer” to each side of the trailer.  See, our trailer’s width extensions are not made of thick enough metal to support a piece…

Choosing a trailer

Posted on June 7, 2015

Seth and I sent in a deposit for our trailer just after receiving the go from Grace Church, thereby guaranteeing that we will have a trailer by late June. We waited until we had a build site locked down before ordering because we wanted to be sure we bad a place to put it. No sense in getting a trailer and then watching it rust and taking up our neighbors’ parking spaces, you know? A lot of tiny home builders salvage a trailer from an existing RV and beef it up to account for the added weight of a wood framed house.  Seth and I decided not to go this route, despite our green thumbs, for a couple of reasons: For starters, salvaging a…