On a recent project, my crew and I incorporated a number of
traditional Japanese building features, including a series of
turned, structural cedar posts bearing on natural fieldstone
footings. The posts support a wide roof overhang, which sheds
its runoff directly onto a "moat" of 3/4-inch crushed stone
that wraps the building's perimeter between the foundation and
the drip line (see photo below).
The footing stones appear to "float" in the gravel bed but are
actually embedded in concrete on top of conventional,
10-inch-diameter sonotube piers that terminated just below
finished grade. We stood the sonotubes on Bigfoot bases
(F&S Manufacturing, 800/934-0393,
www.bigfootsystems.com) to ensure good
distribution of the admittedly minor point loads they'd be
supporting. But the $14 Bigfoot form makes it simple to
excavate for, support, and center each tube precisely on
layout, an otherwise fussy, time-consuming task.
Irregular Logic
To secure the stones to the concrete piers, we drilled a
1/2-inch-diameter hole in each stone, tapped in a steel pin,
and inverted the stone, embedding the pin in the wet concrete
(see Figure 1).
Figure 1.The decorative footing stone elevates the
turned wooden post above grade. The author drilled the stone
for a steel pin to create a secure connection in the wet
concrete.
The challenge we faced on this detail was how to accurately
scribe the ends of the 4- to 5-inch-diameter posts to fit the
irregular stone footings. What I needed was one of those
banded, multifingered molding copiers, but one flexible enough
to wrap around a post. I've never seen one of those, but,
working in pseudo-Japanese mode as I was, I figured a handful
of bamboo teriyaki skewers might do the trick.
The diameter of each post varied, as did the shape of each
stone. And, because we had to fit the posts between two fixed
and unmovable points (roof and rock), I decided that the surest
method would be to cut a short length from the post at each
location and make a custom pattern for each of the stones. I
plumbed the cutoff atop the stone, using a bit of modeling clay
to steady the piece. I located the line points for the scribe
by sticking the skewers, one at a time, onto parallel rows of
double-stick tape wrapped around the post. To secure this
mini-palisade, I then wrapped packing tape around the outside
and slit it vertically to unpeel the skewer pattern from the
post (Figure 2).
Figure 2.The tip of each skewer, affixed on bands
of double-stick tape, defines the contour line of the stone at
the perimeter of the post pattern. The author then used chalk
to transfer high points from the stone and hollowed the
pattern's end accordingly.
After hollowing the end of the sample post with a wide spade
drill bit, I used a jigsaw to cut to the scribe line. Then I
began fine-tuning, rubbing chalk onto the stone to reveal and
transfer the high points to the post end. I hogged out some of
the waste using a cutter on a 4-inch grinder and fine-tuned
with a rotary rasp in my drill. Once the pattern piece matched
up nicely on the stone, I tacked it to the end of the
full-length post to transfer its scribe line, using an ordinary
pair of dividers. To fill and seal the crude recesses inside
the final scribe, I packed a glob of thickened epoxy onto the
end grain and planted the post on the stone.
The roof rafters rested on a dropped purlin, which allowed us
to stand the post on the stone, a couple of degrees out of
plumb, and mark its top end for a fit. After cutting the post
to its final length, we used a bottle jack to lift the purlin
about 1/4 inch, just enough to let the post slip into place.
Releasing the jack allowed the weight of the roof to press the
post firmly into its epoxy bed on the stone.
Malcolm Meldahlis a builder and designer in Truro,
Mass.