Joined at the Hip

It turns out that a hip roof (think of a four-sided pyramid) is harder to frame than one might think. Much of this post is cribbed from an email exchange with Andy, one of the projects expert advisors.

I planned to have the four main rafters (one from each corner of the tower) ascend to meet each other at a "capstone" piece. This was a non-starter, though it did waste a few hours, as the capstone eventually splintered to pieces as I tried to drill through it.

In the end I laid two hip rafters from opposite corners, meeting at the peak. These were straightforward to cut and measure; I did it the same way I framed the gable rafters on the main room. (Of course, the birds-mouth notches are not angled on their interior to match the external corner. See photo. But I figure they'll be mostly invisible, shielded by fascia on the outside and by the interior framing on the inside, so good enough.) I've now cut 15 rafters like this, including the four I had to discard, so I'm getting a little better at it.

What I wanted to match up well was the peak, where the hip and common rafters come together, and (eventually) the joints with the jack rafters that will fall from them to the wall. Because these joints are all visible from inside the tower.

I calculated the angles you would see if you looked directly down on the roof from above (a 5'x3' rectangle, with two diagonals -- plain old trigonometry). The height of the roof I determined by fiddling around until it looked right; it was quite pleasing to discover that the vertical angles (ie, looking straight in from the side) are EXACTLY the same 28 degrees as the horizontal.

So why did it take another hour, and five false tries, to cut the last rafter I got done this morning? Well, there's this little angle adjust on the skilsaw that runs from 0 to 45 degrees. I set it at 28 degrees, and the cut was way off. OK, I decided I calculated wrong, and just kept trying different measurements until I finally hit on the right one, which turned out to be 17 degrees . . . see where this is going?

17 = 45 - 28

If you've actually followed this, you can see why it took me a while to stop swearing when I realized.

The only other difficulty is making straight cuts with the skilsaw. It tends to move around on me, especially when the blade is angled. Clamping rails down, as I did for all the plywood cuts, doesn't work when the blade is angled (the motor body interferes).

Is there a power miter saw that rotates along TWO axes? That would sure make this whole thing easier.

Power Tools

Rain today, so not much got done. Instead, here's a photo of the compound miter saw Pat lent me -- one of the three power tools that are making this project possible.

The little piece of wood on the platform will be the "capstone" for the tower rafters, where four of them come together at oblique angles. It is precisely cut, 28 degrees x 62 degrees, accurate far beyond what I could have done by hand even if I'd spent all day trying.

My father -- who built two real houses in his forties, not the children's version -- had more of the old-fashioned tools. A brace-and-bit, not a cordless drill; a maple miter box and one of those rectangular saws. Did the chop saw even exist back then? And my grandfather did EVERYTHING by hand.

I'm no craftsman, but these power tools cut years off the necessary apprenticeship.

Oh, the third one is the circular saw. I never could have cut the plywood cladding without it.

Progress

As you can see, the plywood cladding is all on, and I've started the rafters. Finishing the walls took about ten hours, mostly on Saturday. Perhaps it wasn't necessary to cut the door and window openings so precisely, but it was one of the aspects I could get right -- unlike, say, perfect squareness -- so I did.

My assistants really wanted to be in today's blog photograph, but the pictures with them were all blurry and over-contrasted. Also Elliot had just gotten a splinter, or thought he had, and had entered a stage five trauma, which wasn't very photogenic. As we've had occasion to observe before, it's a good thing he's never going to give birth.

Framing, Continued

After more hours Sunday and today, the walls are up. Disappointingly, I was unable to get the verticals exactly true -- the level bubble is within the marks, but not centered. How do real carpenters do that?

My assistants were able to help today, holding the sheathing plywood in place while I marked it, delivering nails and so forth, which made them more happy to spend time out there.

The town is going to dispatch a building inspector to check progress later this week. Just like a real house!

Squareness

After Andy reminded me that the easiest way to square a frame is by equalizing the diagonals, and to use temporary cross-braces, matters fell back into line and progress continued. Now that two walls are up, the house seems really big -- the peak of the tower roof will be about 14' off the ground.

I've already finished most of a 5-lb box of framing nails. Too many, perhaps, but since I'm using about twice as much wood as necessary, I might as well use twice as many fasteners too.

Fundamental Law

Yesterday I started framing the walls. As usual, nothing is as easy as it sounds -- not if the goal is "square and level." The first one went up OK. But the second wall (which you can see still lying on the floor, not fully assembled, in the photo) . . . well. Here's the problem: the outer 2x4's are precisely cut, each within 1/16" of what they should be. Three of the four corners are square. But the fourth corner is NOT.

How can that be? The rectangle's opposite sides are equal. Three interior angles are 90 degrees each. The fourth is wrong. It's a violation of the laws of geometry!

I'll probably end up using it anyway, and the children can ponder the implications of general relativity.

A Professional Job

One of the pleasures of this project is that all functions typically done by separate contractors -- architect, GC, carpenter, laborer, painter, excavator, landscape artist, and more -- reside conveniently in one person, me. Instead of disputes and finger-pointing and buck-passing, I just stare off into space for long periods. Anyway, it is gratifying to report that the job so far is going well; perhaps 20% done and we are already weeks behind schedule and substantially over budget. Just like the pros!

The photo shows the lumber stock, delivered last week but diminished by the floor and decking.

Decking

Putting down the four-inch deckboards required five hundred screws. All had to be pre-drilled.

You can see one of my assistants in the photo, providing quality control.

The next step was to stain the wood, before I start framing the walls, but we've had a lot of rain lately, so I had to wait. Unfortunately the blue tarp I'd just purchased was cheap and flimsy (like everything nowadays, but that's a rant for another post) and it leaked and left damp patches which had to dry out. I finally got the stain on after dinner. Hopefully the forecast thunderstorms will pass us by tonight.

Framing the Floor

Next step was to frame the floor. Pat, who lent the power tools that are making this project possible, helped with the first part: cutting the posts and rim joists. Then it was hours of leveling, measuring, squaring, swearing, re-leveling, re-measuring, swearing, checking squareness again, etc.

The internal joists went in smoothly enough, though as with every step, the last was much easier and faster than the first!  I'm learning everything as I go.

Readers with a keen eye will note the 12" centers -- overkill for a playhouse, but they'll keep the floor decking more stable.  In general, the whole building is over-engineered to a fare-thee-well, partly from personal inclination, and partly in the hope that doing so will compensate for the many inevitable errors during construction.

Grunt Work

Each pier required digging a 2- or 3-foot deep hole.  Two days of hacking out rocks and roots, that is, since this is New England, not the beautiful stone-free lawn shown in the how-to book.  Then 8" cardboard tubes were set on gravel, leveled, and surrounded with backfill.  There are 400 (dry!) pounds of concrete in those four piers, believe it or not.

Site Prep

The first step of actual construction was to lay out the site using "batter boards."  They are all leveled; the strings define an outline of the actual building dimensions.  This photo doesn't make it clear, but there's a 30-inch change in grade from the upper to lower corners.  The playhouse will therefore rest on concrete piers and posts.

Getting Started

Oh, I had grand ideas to start:  an octagonal rotunda, perhaps, or a Queen Anne two-story.  Reality prevailed, however, and it became a simple shed-style space with a porch and a half-tower.  I had to mock up a little paper model so I could figure out the design.

The plan is to be done by August. Hah! With luck, no later than the first hard frost.