Decking the Floor

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I've gone with 3/4" Adventech tongue and groove sheets for the floor. It's an OSB-type product that's incredibly strong and weather-resistant . . . supposedly it can sit out in the rain for months. The 4'x8' sheets come with a 50 year warranty. They highly recommend it over plywood at the lumber yard - they say it's what all builders use now. Considering the pace at which I build, the fact that it can sit out in the weather for months is its strongest selling point for me. It's not cheap - each sheet is $19 - but I only need 12 sheets:

Laying down any type of OSB or plywood is the final test of how square your framing is, because each sheet is factory-made and perfectly square [a rectangle actually]. My framing turned out to be pretty good . . . not perfect, but off very little, nothing that will make a difference.

The sheets are laid down with their long axis perpindicular to the joists. The long edges are connected with the tongue and groove. Getting the tongue into the groove can be a major pain in the ass, especially if the tongues or grooves are damaged. At the lumberyard they'd strapped the sheets together with heavy nylon straps right across the tongues and grooves. So when the whole load got dumped off the back of the truck, some of them got really torn up.

For these, I used a block or board up against the sheet I was trying to move, beating it repeatedly with a hammer, going from end to end until I got the tongue in. In the future I will always request that the sheets be strapped across the short non-tongue and groove ends. These ends simply lay down on top of a joist with an 1/8" gap between each sheet to allow for swelling.

I used both glue and screws to attach the flooring. For the glue I used subfloor adhesive with a caulk gun - way too much at first. I used a few clamps to hold the sheet down and in place before I fastened, then used a corded drill and 2" drywall screws about every 6" to screw it down. When your joists are straight and spaced correctly it makes installing the flooring easier, because each sheet comes premarked for where you should put the fasteners. Once I finished a sheet I'd crawl underneath the building to make sure I didn't miss a joist anywhere. Usually you can feel it if you do, as the screws will spin out and not bite. But not always.

It's tedious and time-comsuming driving all those screws. And it's hard on the knees. I recommend knee pads. On the non-tongue and groove edges, where the end of the sheet is just catching a joist, I drive screws in at an angle a good 3/16" back from the edge. This way the screw doesn't just plow through the edge of the sheet, or miss the joist altogether. The combination of both screws and glue makes a good permanent bond. And the floor will not squeak.

Here the floor is in:

From the side:

The payoff for me on being meticulous with the girders and the way I framed the floor was when I checked for level. I could lay my 6' level out in any direction, spin it around randomly, whatever, the floor was dead level. Absolutely 100% dead level. I felt like . . . okay, I'm done, I've built a stage, great! If only I didn't have to move on to the formidable erection of the 13' and 15' posts [with only the help of my daughters of course].

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After the decking I went around and put in the sole plates. Since I'm doing a post and beam frame, rather than studs, I don't really need sole plates - I could tie the posts directly into the floor. But the plates will give me an extra 1 1/2" to the height of my posts, serve as a perimeter for the underlayment of our tile/slate, and give a place for interior wall material whether drywall or boards to tie into. I go with 2x6's, the same as what all my posts and studs will be, allowing thicker insulation, and a stronger frame:

The gaps are where the front door and rear french doors will go. I'll come in later and trim the sole plates back for the exact dimensions of the doors:

Patty visits while we're decking the floor, and it's exciting the progress we've made. The cabin so far is a nice stage we can sit up on and have a picnic. Mishka likes to pace around it and keep watch [it took him a while though to get the guts to actually jump up here].

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Though I'm happy and relieved to have gotten to this point, I'm very nervous about the next step. Patty and I have radically altered our plans on the cabin's design. She'd been pushing for a higher loft ceiling for a long time, but I'd thought it would get too difficult and expensive to build. But we've finally worked out a compromise.

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Instead of a shed roof, the main part of the cabin will have a conventional gable roof, though rather shallow (1/4 pitch) to allow for greater headroom upstairs. The posts will be 15' at the center ridgeline, and 13' at the edges, with another 1/2' of height coming from the ridge beams. This will give us a 7 1/2' to 5 1/2' ceiling up in the loft, which makes a better living space. The loft was originally envisioned as a kid place and storage area. Now the loft will wrap around the upstairs area [be twice as large] and serve as our bedroom also.

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The downstairs area will have the kitchen, bathroom, laundry, and wood stove. The rear addition will serve as a covered porch, and maybe ultimately a screened-in porch. The large front addition will be the living room. Ultimately we'll have a 1,000 square feet of usable space. This way even if this is the only building we're able to finish, we can permanently live in it, and it will serve all our needs, as well as be energy-efficient.

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Here's the drawing I've worked out:

. This is the Southeast face of the building - it will have a lot of glazing to be more passive solar.

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The 'greenhouse' / 'sunroom' will be positioned at the south side of the building [on the left], and will step down from the main cabin, as the slope below goes rather steeply downhill. It will only be one step. Though in this drawing the 'greenhouse' is only 8' wide, we've decided to bring it out to 12'. So this addition will actually be 12' x 25' - 300 square feet.

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The more research we do on greenhouses, the better it seems to do a separate freestanding greenhouse, and make this addition more of a living room, insulated and heated. We could use the extra living space.

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The rear porch [on the right] will come out about 9'. It will most likely be screened, and serve as a buffer for cold north winds.
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I'm happy with our new plans. Now I've just got to figure out a way to built it!

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