
Even though I move buildings for a living, not every old house
is worth saving. Once you factor in the expense of preparing a
building for lifting or moving, and the cost of the actual lift
itself, it may well make more sense to demolish and start new.
But, fortunately for my business, there are also enough good
reasons to salvage an older house. For example, in order to add
a second story to an existing building, the builder must prove
that the foundation can handle the added structural load. If
the foundation fails on analysis, replacement is a common
option, facilitated by raising the house. Then, there are older
houses of good quality that are sold cheaply to be relocated to
a new site. With some cosmetic repair and re-connection to
utilities, these houses get a new lease on life. And,
occasionally, a house is defined as a valuable antique and
worthy of preservation, even if it means a delicate and
expensive relocation. That was the case with a recent job we
undertook moving the ancestral home of the Nickerson family, a
classic Cape Cod house, across town and onto a new foundation.
The house was not large, measuring 25 by 31 feet, with a small
kitchen ell that could be cut away and moved separately. The
main structure, however, had to remain intact. But it's one
thing to move a house built in 1972, where standardized
construction makes the process predictable. This exemplary
post-and-beam house was built in 1772, and there was nothing at
all predictable about moving it. Nonetheless, it provides a
good extreme case study.
Evaluating the Structure
One of the first steps in evaluating a building for lifting is
to check the condition of the building's underpinnings —
the perimeter sill and floor joists. In this case, that meant
hand-digging a few exploratory holes to inspect the framing
over the marginal crawlspace foundation. The foundation was a
double-wide course of locally made brick, laid about six high
directly on grade. The stable, free-draining sandy soil on the
site has to be credited with the exceptional condition of the
oak sill and floor joists, which had only inches of clearance
above the roughly leveled grade (see Figure 1).
| Figure
1.The house originally
stood only inches above grade on a low brick perimeter,
with intermediate wood posts at key framing junctions
in the floor system. With the exception of a circular
root cellar under the ell (above), there was virtually
no clearance below the joists. In spite of this, the
wood was in remarkably good condition
(left). |
This was an unexpected piece of luck, as the rotfree framing
would allow us to proceed conventionally by lifting from
underneath the sills and floor system. Otherwise, contrary to
preservation efforts, we'd have to destructively alter areas of
the antique structure in order to lift the building by its
walls (see "Extreme Lifting," below ).
Extreme
Lifting
In 2003, we raised a large new house still under
construction. The builder was blind-sided by a
misinterpreted order of conditions for installing a
foundation on a coastal dune. Coastal dunes are
generally dynamic formations shaped by wind and
waves and provide a natural line of defense against
catastrophic beach erosion. Therefore, any proposed
building on a coastal dune must conform to strict
job-specific conservation regulations.
Unfortunately, this project was well under way and
tight to the weather when the stop-work order was
issued. After long delays and legal wrangling, a
solution was reached stipulating that the
foundation must be modified to allow dune sand to
drift naturally under and around a portion of the
building. Instead of a continuous, solid wall, the
foundation was to be replaced in part by regularly
spaced wood pilings tied to existing helical
footings. In addition, the building's elevation was
to be raised by about 2 1/2 feet. Of course, this
revision turned out to be much easier said than
done. 
We were forbidden to dig access holes around the
foundation to insert the large steel I-beams needed
for lifting under the sills. That meant that we had
to work from inside the foundation instead, break
through the floor at strategic locations, and lift
the house by its walls using temporary, nailed-on
ledger boards. It also meant that the I-beams would
have to be fed in through existing door and window
openings. The house measured 135 feet along its
delta-shaped length, was 60 feet at its widest
point, and incorporated a masonry fireplace and
chimney that the builder and homeowner wanted to
preserve intact. Not only that, but there were many
expensive teak windows already installed that we'd
have to take pains to protect from breakage.    Ledgers nailed across studs
(top) provided lifting points for steel beams,
which were fed in through window openings (bottom
left). Because coastal regs prohibited digging
around the perimeter of the house, cribbing had to
be stacked through the floor joists with the
subflooring removed (bottom right).
To make a long story short, we prepped the house
for lifting from seventeen separate jacking
locations (in contrast to the average of four to
six), then I called on a colleague, Norman Messier
of East Montpelier, Vt., to supplement my 6-jack
machine with his 12-jack machine. After cautiously
nudging up each jack in turn to test the system and
listen for telltale structural creaks and groans,
we raised them all in unison, ultimately lifting
the structure almost 5 feet. The hydraulic gauges
registered an aggregate load of 175 tons. Three
weeks later, we lowered the building 2 1/2 feet
onto the modified foundation without a single
broken window or a crack in the chimney. I slept
pretty well that night.
— R.H. |
Although I determined that the building could be safely
lifted, the owners, who planned to open it to the public as a
fully functioning period-style home, didn't want to proceed
unless the original central brick chimney could also be lifted
intact. This was a far dicier proposition. The chimney was
actually made up of three back-to-back fireplaces with
individual flues and an unusual beehive oven, all in fragile
condition. I pulled out nearly 40 loose bricks, fallen from who
knows where, simply by reaching up into the throats above the
fireboxes.
There's virtually no flexibility or forgiveness in a masonry
structure, especially not one that's stood for a couple hundred
years. The owners sought an evaluation from masonry restoration
specialist Richard Irons of Limerick, Maine. Irons declared the
beehive oven exceptional and especially fit for restoration and
further pointed out that, if demolished, it could not be
recreated because its construction did not meet current code
clearances and guidelines. With this encouragement, I had to
decide on the best way to shore it up and lift it intact.
The building would be taken over the roads and had to clear
tree limbs and power lines. Even without the masonry above the
roofline, I'd be working with a 26-foot clearance height,
including the 25-ton-capacity dolly wheels, something that must
be considered when moving a building over the roads and under
electrical utility lines. This part of the chimney was far too
deteriorated and fragile to consider saving anyway, so we took
it down to a point just below the ridge where it was bracketed
by the roof framing. We saved all of the bricks for Irons's
later use in reconstruction. Underpinning the chimneys for
lifting was the really tricky part. First, I had to determine
what I had to work with.
Reinforcing the Chimney Mass
There's nothing structural about the brick hearth or floor of
the firebox, so we removed these bricks to expose the chimney
underpinnings. As expected, there was no actual base pad;
instead, the three flues rested on a platform of dry-laid field
stones, set in sand. Behind the walls above the fireboxes we
found more trouble in the old, crumbly mortar. Gravity alone
was holding everything together.
To prevent the bricks from shaking apart during the move, we
applied a sticky "skin" of rich masonry cement, reinforced with
embedded chicken wire, to the fireboxes and brick above the
lintels (Figure 2).
Figure 2.A parge-coat of masonry cement held the
bricks steady for lifting and transportation (left).
Restoration efforts included making a temporary access hole
(shown patched in the photo at right) to send a small mason
inside the chimney to repair and reline the three throats and
flues.
Simultaneously, we selectively removed field stones and earth
from the sub-hearth area. With the foundations of all three
fireplaces now somewhat exposed, we beamed a laser level from
one firebox to the next and established a common, uniform level
to work to. After spreading poly sheeting on the ground to
prevent earth bonding, we reinforced the hearth area with
2-inch steel box tubing and rebar set on chairs, then filled
the excavated area with a 4-inch-thick pour of 5,000-psi,
site-batched concrete. We used a sand mix without stone
aggregate to ensure good flow and penetration of the
interstices between stones and bricks. I was hopeful that this
temporary base would integrate the three chimneys and beehive
oven sufficiently for the subsequent jacking operation. Before
proceeding, we allowed the concrete to harden for about a
week.