My wife and I have been in our new home (new construction) for 16
months. It's a 2200sq. ft colonial. Approximately after 2 months
after moving-in the foundation started cracking. As of today there are
19 or 20 cracks in the concrete walls and floor. Eight of the 20
cracks are in the concrete basement walls. I'm not concerned about
the floor cracks as they are hairline and have not changed since I
first noticed them. And most of the cracks in the walls are hairline
as well and don't concern me because they have not changed either.
With the exception of one wall crack all the wall cracks have occurred
at beam pockets and basement windows and from what I understand this
is to be expected. All the wall cracks are essentially vertical
cracks.

There are two vertical cracks however that have me concerned and
concerned for sometime now. Crack #1 is the most concerning and starts
at a beam pocket and goes all the way to the floor. There is also a
hairline crack in the floor where this vertical crack meets and
extends about 7 or 8 feet from the bottom of the wall. The vertical
crack vertical crack of concern is a tapering crack. It's wider at
the top by approx an 1/8 of an inch and pretty much disappears before
meeting the floor. This particular crack started as a hairline but
has steadily progressed to widen at the top of the foundationwall over
the last year.

Crack #2 is vertical crack which starts at a window and goes to the
floor. This appears uniform from top to bottom. It has shown signs of
movement but very little movement. In fact, the movement is more like
an oscillation. It widens and closes and repeats the cycle. This
crack is hairline for the most part but I think it might have a
relationship with the bigger crack since they are on adjacent corners
and only 6 or 7 feet apart.

Being concerned about crack #1 and #2 last year I did a couple of
things to monitor all the cracks in the basement and the suspected
movement of the cracks in question. I used foil tape and made
butterflies to tape across all the cracks. This proved useful on all
the cracks as this showed me others were not moving but showed I had
two that were moving. On crack #1 I fabricated a movement gauge
simply by gluing to nails to the concrete 2 inches apart on both sides
of the crack. Using a thin metal rod (about 3 feet long) I curled on
end of the rod and slip the curled end of the rod over one nail and
rested the rod on the other nail. This cantilevered rod amplifies the
microscopic movements of the wall.

Crack #1 moves the most. It actually oscillates a few times then
expands. Where as crack #2 only seems to oscillates.
What crack #1 seems to do is oscillate up and down then expands a
several hundreths of an inch then stops then the cycle repeats itself.
It has been doing this now for over a year to the point the top of
the crack is about 1/8 of an inch.

I had sidewalks put in recently and I had the contractor who did them
look at my foundation and this particular crack. He has 30 years
experience with foundation work and comes with excellent references.
The first question he asked me was if the sill plates were tightened
down. I said no because I discovered there were no nuts or washers on
the bolts when I was sealing air leaks from all the penetrations
coming into the house. I had found a bunch of nuts and washers in the
corner of the basement and figured they were extra and chucked them in
the trash. He said secure all the sill plates as tight as you can make
them. He also offered the idea that the back fill on this wall was
pushing the concrete in. He had noticed the crack seemed to be wider
on the inside than on the outside. I'm not easily convince that this
alone is causing my problem especially with the crack in the floor
that meets crack #1.

I had a structural engineer look at it last year and told me really
not to worry about it and just monitor it. If it goes beyone a 1/4"
then be concerned. I'm concerned at an 1/8 of an inch and it's still
oscillating and moving as I write this.

With those ideas I'm wondering if two things maybe happening. So my
questions are; What is actually happening here? Is the ground
pushing up or is the corner sinking? How long can I expect this to
continue this trend? Will it stop? I don't know what side of the
foundation is moving but it seems to me that it just that corner of
the basement that seems to move. I haven't seen cracks in the
sheetrock. I can't tell if the corner is trying to move away. I also
noticed when stomping on the floor in the area of crack #1 it sounds
hollow underneath the concrete.

Any ideas or advice? You may direct question here or to my email
address. Thanks.

Bob