ProcessHouse

Building a Modern Tiny House in Connecticut
Tiny House trailer delivery from Wright Trailers in Seekonk Massachusetts Tiny house trailer with galvalume sheet metal
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"The Trailer" no more - now "The House"

“Did you pump the water off the trailer?”
“Did you put the tarp over the trailer?”
“Did you bring the tools in from the trailer?”


The questions above are the sort that Michael and I used to ask each other a few short weeks ago.

Thinking about what to write for this post, it occurred to me that the phrase “the trailer” doesn’t get used much anymore.  For a little while after the subfloor got completed, I started using the vague phrase “job site” sometimes, but now that real wall framing is almost complete, we refer to the project simply and appropriately as “the house,” because it is really looking like one!

As of the last posting, two sections of wall framing had been assembled and raised into place - the 8-foot long wall at the (bathroom) end of the house - right behind the trailer hitch - and about 8 feet of the adjoining side wall which will contain the main entry door - the same side as the “driver’s side” of a towing vehicle (if we were so fortunate as to have a towing vehicle, which we don’t).

As of this evening, 8/6/16, the entire “driver’s side” sidewall framing is in place, from front to rear of the trailer.  We can see where the “front” door will be and near to it the horizontal, rectangular rough opening that will accommodate a sliding window high in the wall of the main living area.

The most dramatic addition today, however, was the completion of the living area end wall framing with its wall-to-wall opening for the large picture window that will look out onto The Grove.  The window opening is framed on each side and overhead with “Parallam” engineered 4x6 and 4x4 beams - surprisingly not terribly heavy but extremely strong to resist stresses in various directions - stresses that would be resisted in a normal windowless wall mainly by sheathing. The design of this wall was subject to much careful consideration as well as the input of a professional engineer, as wall-to-wall window spans without the aid of heavy steel framing can present an engineering challenge.

This wall was clearly the heaviest one of all to raise upright and then lift and drop into place over the vertical threaded anchoring rods welded to the trailer. Michael and I managed to line up some help from Michael’s brother Ryan, so that we had a three-person team for the big lift.  Tip: before you lift a big wall section into place, don’t forget to pick out and have at the ready some bracing members (Michael used scruffy-looking 2x4s) - also your nailer and/or impact driver and appropriate fasteners, so that your lifting team is not left anxiously holding the wall section upright and hoping a gust of wind doesn’t hit while you are gathering those items. For us, fortunately, the weather was perfect and air was still.

The other wall framing sections completed and raised since the last posting - each at most 8 feet long - were easily raised upright and then lifted over the anchoring rods by just the two of us.

Our approach to building the wall sections was refined a little after the first two sections were completed: Michael decided to request that when I cut studs in advance for the remaining side walls, I make those cuts precise to 1/32 of an inch rather than 1/16”.  (His drafting program, Sketchup, very conveniently can provide lengths of each framing member - to whatever precision desired, reflecting even the differing lengths of the shorter and longer sides of a stud whose end is beveled at a 3.2 degree angle to accommodate the pitch of the roof).

He asked for the increased precision because studs in earlier wall sections did not fit as tightly as desired against the top and bottom plates.  (Really tight framing joints make for noticeably increased rigidity).   The 1/32” requirement led to some challenging development of techniques for cutting with our ancient but reliable 10” Craftsman radial arm saw (which has no laser cutting guide assistance).

At this, point, only 16 feet or so of wall framing remains to be completed, and the momentum of our achievements this weekend is exciting and makes us look forward to wall sheathing and a roof starting to appear soon.  The needed materials are all delivered and eagerly waiting!   :)

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Walls!

The past 2-3 weeks has been focused on wall construction, with three wall segments now standing and one nearing completion.

Before I began on the walls, I still had a few decisions to make. This ended up taking longer and being more stressful than I had anticipated. The main decision I faced was the interplay of the interior headroom, roof pitch, and wall height. My design (which I’ll show more of soon) features a roof that is sloped in the long (24’) dimension, with the lowest point at the trailer hitch, sloping gently upwards towards the far end with a vaulted ceiling and wall-to-wall windows (more on that to come). My design also features a roll-out bed, as it has no loft. To accomplish this (and provide some extra under-floor storage), the kitchen and bathroom at the hitch end of the house are also raised 16”. My trailer deck is roughly 32” off the ground. With a legal road height limit of 13’ 6” and a practical desire to keep the height as reasonably low as possible, every inch counts. It’s also worth considering that the IRC (International Residential Code) specifies that habitable rooms must have a ceiling height of 7 feel (84 inches) in at least 50% of the room. Since tiny houses have a somewhat vague legal status at the moment, this is not necessarily required. In fact, many tiny houses have ceiling heights closer to 78” under their lofts. However, 7’ is generally a good rule of thumb for comfort.

What I eventually settled on was to use the standard of 8’ 2x4s for the rear (bathroom) wall at its lowest point. This put me at around 82” for the ceiling height at its very lowest point, and gets me to a generous 86” at the highest point in the bathroom. At it’s highest point in the living room, the ceiling will rise to a luxurious (but not excessively superfluous) 9 1/2 feet. The slope of the roof comes out to 3.2 degrees, which is a bit more than 1/2” in 12”. This will require a special EPDM or metal roofing which is rated for a low slope.

With that decision out of the way, I was able to start on the bathroom wall. I started by marking and boring 7/8” holes to accommodate the 5/8” threaded rods on the trailer. After ensuring the bottom plate would fit correctly, I clamped the top and bottom plates together and marked the stud locations.

I have decided to go with the traditional 16” on center stud spacing on my house (vs. 24” oc), but am saving weight wherever possible by using “advanced framing” techniques like using single top plates with metal plates at splices, omitting headers on non-load bearing walls, and using header hangers instead of jack studs. It’s important when making the decision to use 16” or 24” stud spacing to also consider the weight of your sheathing, roof decking, interior wall material, and subfloor. Increasing the spacing to 24” often requires substituting a thicker plywood or osb material to compensate, which means you’ve lost any weight savings you may have gained from using fewer studs.

I have also decided to save weight by using spruce (S-P-F) wood. This stuff is amazingly light, easy to work with, and is also inexpensive. However, it is not quite as strong as Douglas Fir or Pine. For this reason, I am also using Douglas Fir strategically on my window wall, to maximize strength where it is needed. If you are using 2x4s for your roof, I would definitely use Douglas Fir and not SPF. However, I am using 2x6’s and will probably stick with SPF for these. If in doubt, check span tables and make sure you know the snow load requirements for your area (assume 30 or 40 to be safe).

I was amazed how light the first wall was. I probably could have raised it myself, but was glad to have my father’s help in saving my back the unneeded additional stress. Once situated, We added some temporary 45 degree bracing to keep the wall from blowing over in the wind. It’s amazing what a 45 degree angle will do for a structure! 

I decided to wait on fastening the bottom plate so that I could adjust the position and square everything up nicely once the other walls were in place.

Speaking of fastening, let’s talk a bit about fasteners. I debated for quite some time whether to use a nailer or screws with an impact driver. I had purchased a 12W DeWalt impact driver a while back, but a few months ago purchased a nail gun and thought for a time that I had settled on using nails, being that they are the tried-and-true (and code-approved) method. However, after talking with Chris, my engineer, he expressed his preference for screws due to their superior resiliency to pull-out. The problem is that there are few screws on the market that are approved/rated and up to the task of framing a house. One of the few that is is the R4 multipurpose/framing screw by GRK. I can’t say enough about these screws. They are extremely tough, well engineered, and go in great every time. Oddly, it is very difficult to find this screw in a 3-1/2” length which would be comparable to a 16d nail. Most stores only carry 3-1/8” and 4” (what gives??!!). 3-1/8” is probably sufficient, but I didn’t want to take any chances. I finally found the 3-1/2” screws on Amazon.com. It’s also good to have some of the #10 3-1/8” screws handy for joining 2x4s, where you don’t want the screws to stick too far out the other side. For attaching subfloor and sheathing, I am using #9 2-1/2”, which is comparable to an 8d nail.

After several instances already where I’ve needed to remove a stud to shave a bit off, or even an entire top plate, I am very glad that I took my engineer’s advice and framed with screws instead of nails.

For the long (24’) walls, I’ve decided to build these in ~8 foot sections, with some variation in length to avoid having to splice a wall in the middle of a window. We have 3 sections in place and have started on the specially engineered window wall at the opposite end, which must be raised before we can continue on any of the other sections. More on that in the next entry!

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Some thoughts on the process so far

First, thanks to my dad (Jon) for stepping in and giving this blog a second life. Before my dad picked it back up, I had resigned myself to the fact that I was going to have to make some sacrifices in order to make ProcessHouse into a reality and not just a blog. Unfortunately, one of those sacrifices was, in fact, blogging.

However, as my father and I began construction back in May, I discovered he was already taking the time to document the process—in quite some detail—in emails to my uncle. Suddenly it became apparent what I should do, so I dusted off the blog and handed it over to my dad.


One thing that I didn’t fully anticipate is how physically and emotionally draining the construction process can be. Although I look forward to long 3 day weekends of all-day building, more often than not I will need one of those days just to recharge from the other two. And forget about weekday work nights—when I do attempt these, usually I end up feeling scattered and making some sloppy mistakes.

The other interesting thing I’ve found is that the construction moves relatively fast and easy when compared with planning and decision making. Once plans are in place, it tends to be pretty smooth sailing. If you’re designing your own tiny house from scratch, you will need to plan ahead with dimensional drawings of the framing. I can’t emphasize this enough. I highly recommend a CAD application like SketchUp for this. It allows you to basically frame your house in virtual reality, so you can run into problems and fix them before any wood, metal, or other real-world (real cost) materials are involved. And once you’re done, you can easily pull your materials list and measurements from the app and start cutting everything to spec.

For this same reason, I highly recommend would-be tiny house DIYers to buy plans from a reputable tiny house builder. Unless you are already schooled in or prepared to learn quite a bit about the field of construction, building codes, and—if your plans are innovative to any degree—some basic structural engineering, you may end up with something that is either unfinished or unsafe.

However, if you are (crazy) like me and want to be the all-in-one architect/designer/builder on your tiny house (and want to do it well), be prepared for a long haul!

In addition to the many tiny house builders/bloggers who have gone before, I’m also grateful to have been able to consult with Nick, a local contractor, and Chris, my cousin, who also happens to be a structural engineer by profession and has been kind enough to give me some advice during my final stages of planning. My attempts to locate structural engineers before had came up short, all of them seeming interested in the idea but ultimately unwilling to take on such an unorthodox project. Thanks Chris!

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Tiny House Subfloor Completed!

On Saturday 7/2/16, Mikey finished cutting the last remaining piece of 5/8” plywood subfloor and fastening it in place.   There was a fairly quiet but enjoyable celebration of the accomplishment (probably some iced tea - no cake).

The plywood is arranged in six large and six smaller pieces, covering the six major rectangular spaces formed by the framing beneath.  Because a single piece of 8’ ply would not span the 99” floor completely (and 10’ long plywood does not seem to be readily available in our area), we decided to cut and stagger the pieces so that the larger pieces spanned across all but one of the joist cavities, with the last piece filling the remaining void. All joints between pieces are centered on 2x4 joists or blocking pieces, with an allowance of about 1/16” between adjacent pieces (lengthwise only) to allow for expansion. Unfortunately the fir plywood we ordered did not come “sized for spacing”, so we weren’t able to add spacing in both directions (I don’t believe this is as much of a concern with subflooring as it is with sheathing).

After each piece was cut and before it was installed, holes had to be bored in numerous locations wherever the threaded anchoring rods welded to the steel perimeter framing of the trailer protruded up through the subfloor framing.  The rods are 5/8” diameter, and after some initial experimentation with fitting the pieces (and a couple mishaps), Mikey settled on 7/8” diameter for these holes. 


Placing the cut pieces over the rods involved both of us, and some warping of the plywood made the placement a little challenging; but once the plywood was fitted over the rods, each piece dropped into place and only a very little trimming of the outside edges was needed on a few pieces to make them flush with the edges of the perimeter wood framing beneath.  After the pieces were in place and before they were glued and screwed down, we used some concrete patio blocks to flatten out the sheets. After about 24 hours the warping was completely resolved.

The plywood is fastened with #9 2 1/2” R4 GRK screws 6” apart on edges and 12” in the field. Before fastening down, we laid a bead of PL Premium adhesive to the top of all the joists, as is typically recommended for flooring.

A single thin coat of Thompson’s Water Seal was applied to the completed subfloor to keep it from absorbing any water while exposed to the elements (though we are doing our best to keep everything under tarps anyway).

Any concerns about plywood not lying flat on the subfloor framing because of rigid foam insulation being too tall turned out to be unfounded - with all screws holding the plywood in place, the resulting subfloor surface was completely flat, and - inexplicably - perfectly level in all directions! Note that if you are filling your floor cavities with rigid foam, anything thicker than 5/8” plywood is really overkill for the subfloor (even at 19 3/16” spacing), as the foam adds an immense amount of rigidity to the floor.

Next up (pun intended): Wall framing!

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Subfloor insulation Complete!

The completed 2x4 framing for the Tiny House floor was divided effectively into 30 rectangular spaces by joists and blocking pieces installed to stabilize them. These rectangles were of roughly similar lengths and widths, and all were 3.5” deep - the width of a 2x4.  Mikey’s plan called for each space to be filled with rigid foam insulation, to be provided in three layers of 2”, 1” and 1/2” thicknesses respectively.   A grand total of 90 rectangles of rigid foam had to be cut from available 4x8 sheets of the three thicknesses.

The bottom layer in each space, 2” thick, was cut allowing for a 1/4” gap on all sides between the rigid foam and the surrounding 2x4 framing.  The 1/4” gap was filled with Great Stuff Pro, dispensed with a handy foam gun attachment from several 20-oz. aerosol cans. A nice foam gun can be had for ~$30-$50 and is highly recommended if you’re going to be doing a significant amount of foaming. It will allow you to reuse the same container of Great Stuff until it’s fully used up. We used the “Doors & Windows” variety of Great Stuff, since it doesn’t expand as much and cures with a bit of flexibility, to hopefully allow for some shrinking/expanding of the framing.

Before installing 2” foam in all spaces, a trial application of the next layer - 1” thick - was made in 3 spaces to validate the technique and check if there would be enough room left above each 1” piece to allow a 1/2” piece to fit flush with the top surfaces of surrounding wood framing.  Two of the first spaces we had done to be re-done entirely (not easy) because the bottom piece of foam was slightly bowed and the top 1/2” piece would consequently protrude above the framing. This was before we developed a good system for installing the 2” pieces, using clamps at each end of the piece to hold it down while the Great Stuff cured.

After the trial, the thirty 2” pieces were installed -foamed in place - throughout.  Next, excess foam had to be cut away so that the next, 1” layer would lie flat on the first layer.  Once the 1” layer was complete, Michael considered a key decision: whether to go ahead with the 1/2” layer as initially planned or leave it out to ensure that the plywood subfloor would lie completely flat on the 2x4 framing.  If the 1/2” layer did not fit perfectly, some of the subfloor weight (and weight of structure above) would be supported by rigid foam rather than the framing itself!  (The rigid foam was effectively incompressible).

Michael decided to proceed with the planned 1/2” layer, and there was an immediate need for me (Jon) -who had been cutting almost all the foam rectangles to that point - to get busy and cut thirty more pieces, this time 1/2” thick.  A race was on, with Michael trimming excess foam, vacuuming up trimmings, and placing 1/2” pieces about as rapidly as Jon could cut them.   The 1/2” pieces were not foamed in place; they were cut to the full dimensions of the cavities and simply pressed into place after trimming excess foam above the 1” layer.

The cutting process itself merits some attention.  Among all the spaces to be filled, there were two different widths (wide and narrow) and two different lengths (long and short).  For each rigid foam layer, there were 16 long & wide pieces, 8 short & wide pieces, 4 long & narrow pieces, and 2 short & narrow pieces.  Width markings for cutting the 4x8 sheets were simplified and expedited somewhat by use a of a homemade marking gauge of length 17 3/16” (for wide dimension) and another gauge a half-inch longer for marking out of full-dimensional 1/2” layer pieces.  Michael’s excellent cordless Ryobi jig saw (fairly light) was used for all cuts.

When the final 1/2” piece was put in place near nightfall on 6/19/16, there was nothing but satisfaction with the decision to install all three layers. With only a few tiny exceptions, the entire expanse to be covered by plywood subfloor was so totally flush that it looked like the cavities were filled with something like reflective liquid mercury (foil backing on rigid foam was shiny).

On to the plywood!

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