When all the jacks are in position with solid cribbing
beneath, we first extend them until they are fully loaded
— to the point where the cribbing stops pushing down into
the soil. At this point, lifting can begin.
I prefer to work down the long side of the house — the
eaves side of a typical gable house, for example. By sighting
down the long sills and the center girder, I get a good idea of
how the house is behaving as it is lifted.
It’s ideal to have three guys jacking and one guy
going for material as they need it. The three guys position
themselves across the front of the house (if that’s where
we’re starting from), one at each corner and one in the
middle. They’ll each raise their jack just enough to
accommodate a 1/2-inch plywood shim under the adjoining pier.
Then they’ll move down 6 or 8 feet to the next jacking
point and raise that jack 1/2 inch, and so on down the length
of the house. A restrained approach like this eliminates a lot
of consequential damage to interior plaster, doors, and
We repeat the process until the fourth pass, when we pull
out the plywood shims and insert a 2-inch concrete pad. Then
the process begins again, adding plywood shims on top of the
concrete pad until the seventh or eighth pass, when we insert a
4-inch concrete pad. We continue the process again, inserting
an 8-inch pad, and so on, until the house is raised a few
inches above the new specified grade, which might be anywhere
from several inches to 4 feet, depending on the owner’s
Occasionally an owner will ask me to lift the house just
high enough to replace the rotted sills then set it back down
only 3 or 4 inches higher than it was previously. That’s
okay if just one side or section of a house needs work. But if
I’m going to overhaul the entire foundation, I prefer to
lift the house at least 2 or 3 feet so I have room to work.
Usually, once the house is raised up, I leave it up
permanently. It saves me a lot of work, since I don’t
have to take the house back down, and the plumbers and
electricians like it a lot better than swimming in the mud.
It’s also in the owner’s best interest, since there
will be fewer termite and moisture problems, as well as easier
access. If the house gets set back down close to the ground,
it’s only a matter of time before the work has to be done
Once we get the
house jacked to where we want it, we pull string lines to lay
out the new masonry piers. The piers are built plumb and square
from either block or brick and allowed to cure. Then the house
is lowered, in a reverse procedure.
Occasionally, if the client requests, we’ll excavate
down a few feet and put in a half-cellar wall. We build them
out of block; they’re called chain walls in this area. I
leave a ventilation hole by laying every fourth block in the
top course on its side. In our damp climate, though, I prefer
to leave the house up on pilasters and completely open
underneath for good cross-ventilation.
While the house is raised up, I usually spread about a foot
of bank sand underneath to avoid standing water and mosquito
problems. I also slope the grade away around the outside.
Using Pipe Staging for
On a recent job we were able to use our
pipe staging as a jacking platform. It was a carriage house
with an apartment above, built around 1900 (Figure 3).
3. This turn-of-the-century carriage house
was 19 inches out of level and 12 inches out of
plumb before renovation. Termites had made
mincemeat of much of its wall framing.
It had been built on 6x6 sills right on top of unstable
soil. A previous owner had placed reinforced concrete, 24
inches thick in some places, on the floor and under the sills
to try to stabilize the structure, but to no avail. Termites
were eating their way up through the first-story framing to the
second story. When we got there, the building was 19 inches out
of level and 12 inches out of plumb.
We had to support the second-story apartment while we
repaired and replaced the first-story walls. I used my pipe
staging as a convenient jacking platform, setting it up two
bays wide and three rows deep (Figure 4).
4. Staging made a convenient platform for
jacking the carriage house (top), but it had to be
thoroughly braced all the way to the ground. In
addition to continuous cross-bracing in both
directions, the author set 6x6 posts under the
critical jacking points (middle), and made stable
bases for the scaffold legs (bottom) by drilling
holes in 2x6s.
Before using the staging for jacking, I called a local
scaffolding distributor to find out how much weight it could
carry. But rather than rely on the staging to carry the loads,
I used 6x6 posts all the way to the existing slab under each
jack. I put 2x4 cross-bracing along the top of the staging,
connecting all three rows together from the front to the back
of the garage. I also stabilized the bottom by making bases out
of 2x6s, with holes drilled for the feet. I then connected
these bases and the bottoms of the 6x6 posts with double 2x4
braces running across the width of the garage.