I’ve looked around for information on AAC and SIPs and those foam concrete forms, and even asked some people about information on them, and it sure seems like we’re coming back to stick-built for price and ease of construction.

My notes are missing the URLs of a bunch of the wall assembly notes that I’ve found from various sources, so I’m going to have to go back and find those, but if the seismic calculations work out for the roof load I’m looking at, I’m currently tending towards 2×6 studs on 16” centers, R-19 unfaced batting in the middle, gypsum wallboard on the inside, an exterior rated gypsum wallboard on the outside, with an air gap (probably with thin plywood lath), and ferrocement siding.

Using fairly similar materials on the inside and outside of the wall increases the shear strength dramatically (you can see that if you have OSB on the outside and gypsum on the inside, then the gypsum will fail before the OSB and you only get the shear strength of the stronger of the two). The other options for a 1 hour wall stick built seem to be either additional layers of gypsum, or 2×4s on 8” centers with staggered offsets, still resulting in a 6” nominal thick interior space.

Finally, on seismic design, I followed the procedure at this PDF about determining seismic design category and used the app at the USGS hazmaps design page to come up with some numbers (I need to verify my guesses at soil type):

Period (sec)	Sa (g)
0.2	1.500 (Ss, Site Class B)
1.0	0.600 (S1, Site Class B)

I’m not quite sure how to interpret some of these numbers in terms of shear strength, but if all I have to worry about is that .6g number (because flex in the wall will hopefully absorb that 1.5g(!) at the much shorter period), then I can just look at the shear strength tables for my wall assembly and see what’ll give me ten tons (the weight of the living roof) of lateral support.

If we go with a living roof, presumably we’re going to have to up the size of the foundation to deal with the added weight of the structure. I need to dig through and find a bit more about the sort of soil we’re on (clay, which is hard to chisel through in the summer, but relatively easy to dig in in the rainy months) and what sort of foundation requirements that’ll give us.

The online calculators and charts for joist calculations (I’m treating this like a floor because a living roof wants to be a fairly flat roof) I’m finding go to a max of 100PSF live load and 20PSF dead load. I’m finding calculators into which I can type a snow load, but my impression is that snow loads are treated like live loads, and what I really want is to calculate a reasonable span (12-16 feet) for a 140PSF dead load and a 20-30PSF live load (ie: someone walking around on the roof).

Of course the other thing I need to do is double-check those living roof weight numbers, because that’s saying I’m going to be supporting (and carrying up a ladder to install) 22.4 tons of material (A human can generate 1/4HP, right? So if the roof is 12 feet high I should be able to do that in 1 hour, 5 minutes and 10 seconds, right?).

And, yes, I will eventually end up having to hire an architect or engineer to sign off on my calculations, but when it comes to my house I’ve run into too much incompetence from professionals to just lob the whole project over the fence to one.

My shop currently fits in the garage of that house (not counted in that 768 square feet), a space it also shares with laundry. The garage was designed to fit a 1940s car, so we’re not talking sprawling spaces, and sharing it with the washing machine and dryer and a few other things means we’re tight on space and dust control. Out in the back yard we have a covered awning in which we store the bicycles and some yard equipment, it’s got lattice walls so I believe it falls in that nebulous zoning category called “auxiliary structure”, even though at 12×18 it’s got some square footage covered.

It’d be nice if we could replace that with a humidity controlled space and I could move my shop out there and the bicycles to the garage. It’d be even nicer if we could add a couple of square feet.

Unfortunately, it also appears that that structure doesn’t comply with current setback regulations, its built up against the back fence (should be 5’) and about 3’ from the side fence (should be 4’). On the other hand, none of our neighbor’s garages appear to respect the current legal setbacks, and its recognized on the city maps as a building.

I have a number of questions to answer before we can do this. The first is about setbacks: Can we get a variance to put a new structure in that location? What does that take? Can we repair that structure, or convert it into a garage, or does that buy us anything when we’re pursuing whatever variances we need?

The second is about the structure itself: Do we buy a Tuff Shed or similar prefab? How about a steel building, at a quarter the price of a stick-built wood building? If I build it myself, what advantages do I get and what am I getting into?

And, of course, for any variance the city will notify every neighbor within 300’ of the house, and at the very least we need to confer with the closest neighbors most affected to make sure that we’re making all of our worlds better.

Considerations:

It’d be nice to build on the current slab. I need to excavate to find out of the slab is up to code for a garage floor, 3½” of concrete over 4” of gravel, and I’d still need to dig out around it (and probably chip some of it away) to pour a real foundation. A Tuff Shed has its own floor, all we really need to do is shim the galvanized steel sills level, but then we’d be rolling equipment up and down a ramp to get into the shed, and the whole thing would be a foot or so higher.

It’ll probably be easier to get the variance if the wall up against the back fence has a real fire rating. If I built this shed myself I’d probably do Hard-Plank or equivalent with a drainage plane over OSB or plywood sheating, but what about construction techniques I’m not so familiar with, like concrete block, or even AAC (Aerated Autoclaved Concrete)?

How do we run electrical in the steel building? Just put everything in conduit? And what are the noise implications of a steel building versus something that’s likely to be more sound deadening? If I go steel, am I going to be annoying the neighbors every time I fire up the router?

Our neighbor’s bedroom windows look out on the current shed. We’ve got a really small yard. What about a living roof? That’d give us 250 square feet of extra greenery, even if none of it is really harvestable, and make the neighbor’s view better? Of course this means beefing up the structure quite a bit, so we couldn’t do that with any of the prefab options.

And one of the closet with most of the paneling in and the hanger rod back in place, the new hanger rod is maple, the trim is birch:

With the coming of fall weather, the gap underneath the door finally got annoying to the point where I milled a new threshold out of Ipe and installed it. Lessons learned:

1. Despite how hard and dense it is, Ipe actually mills fairly easily.

2. The sawdust stinks, spreads a green (despite the nice color of the wood) dust over everything, and hangs in the air. Definitely open the shop doors and use a respirator.

3. No matter how nicely you prep your work area, if you do finishing outside it’s guaranteed that as soon as you get that first coat of oil on there the wind will come up and blow dust over everything.

Also got the cabinet to the left of the stove in place, the rest of the drawer slide evaluation done, and much of the wood glued up for the pantry shelves. Pictures of that coming as I get more of it installed.

It’s gonna be hotter than the hinges of Hades today, so I went out this morning and finished up the porch rails.

Project page coming, but I want to take a few more pictures with different light.

On the left is how it looks now, on the right is how it used to look. You may think it’s not an improvement, but if you look closely, on the blown-up version of the left, you can see a new lattice there.

When we moved in, the back yard had an awning, with lots of ferns and other low sun plants. Most of what we want to grow wants full sun, so we pulled out the awning, and we really need to replace the fence, but we haven’t gotten there yet. So this is forward enough that hopefully we can keep control of the decorative peas and morning glories that we want to plant there to obscure the fence, until we can get in to clean up the fence, and is set far enough forward that we can build the fence.

The wood is Massaranduba, the top rail is attached with Sipo floating tenons (The Domino, is there anything it can’t do?), and the wires below that are multistrand secured at each end with u-clamps.

The progress on the new front door continues. In my previous front door update, I’d mocked up a couple of images of what the trim might look like, including a few curves. We put a couple of pieces up there, taped out a few curves just to be sure, and rather than having just a touch of whimsy, the curves made the whole thing look affected; it became a parody of Disneyland, rather than just a subtle homage.

So we backed off and went with straight. We were initially going to do a straight joint across the top, but as I sat down to cut the joint I thought “why not?” and slapped a dovetail shape in there. I believe we’ve got enough slop in there to deal with grain expansion, but I do regret not insetting that a little bit more so that it doesn’t get lost in the joint on the side.

The wood is Brazilian Redwood, also known as Massaranduba, that we got from the surplus bin of a local high end deck lumberyard. The side rails for the porch will be made of the same materials.

When I was tearing off the old trim I had some reservations because of how far I thought this process could snowball, but my neighbor not only gave me encouragement, but delivered a ladder that fit the front space better, and a Sawzall, just in case I needed it. I didn’t, but that gave me the encouragement I needed to really get medieval on the trim.

Attachment was done with a Hitachi brad nailer (“Brad Nailer” sounds like an Owen Wilson character, doesn’t it?) that I borrowed from a friend, I have a little technique to learn, because I have to set two of ‘em manually, but wow that’s a different world from swingin’ a hammer by hand.

similar entry at my personal blog.

The ugly “security” door on the front has always bothered me. It’s indicative of a bad neighborhood, where people don’t trust their neighbors, and we were very sure that it was an over-reaction by a person growing old and settling into their fears, otherwise we wouldn’t have bought the place. Thus it’s been important to me that we replace it fairly quickly.

We’d gotten a fir replacement front door door for $10 from one of the local building materials recycling places, sanded most of the stain off of it, were ready to hit it with the chemicals to do the final stripping and refinish it, when this gorgeous mahogany door came up on Craigslist. It was a bit more than we wanted to pay right now, but it was close enough to the door we wanted eventually, and the price was good enough, that we leaped on it. I’ve put a single coat of Penofin for hardwood on it, it’ll get another coat in mid-May, but it’s been sitting in the back waiting for the right time.

On Saturday I dragged the door around front to see how it’d fit, pulled the old door off, and started with the “if I do this, how does it work”, and eventually ended up with the door on hinges, lacking only a little door frame planing to make the whole thing fit. So I took a 1/16th off the top of the frame and installed the locks.

Now we need to tackle the trim. We either need to move in the existing white trim, because of the gaps where the security door frame used to lie, or install new trim. I just got a bunch of “Brazilian Redwood” which would probably be a little redder than the mahogany of the door, but not too much, so I just used a sample of the door mahogany. We’re going to replace those rails on either side of the front stoop, so I whipped up some visualizations of what it might look like:

The door as it is now, with no trim
With a double curve, wide at the top, narrow at the bottom
With a single curve, narrow at top and bottom
Straight

Same content on my personal site.