Sinking yard -- what could cause it?

[me]

I live in a four-family building of townhomes, less than five years old.
The yard in front of the building has been sinking for some time, two or
three years. The sinking runs a line from one sewer clean-out valve at the
side of the building, down that side, turning a corner under the driveway
(which has cracked) into the yard to the next sewer cleanout valve, and out
from there. About three feet out from there is a small plum tree that his
now sitting in a sinkhole, it's probably 8 to 10" lower than the ground
around it. Besides this sinking, there is an area between that and the
homes, right in front of a decorative rockbed, which seems to be sinking in
the middle, forming almost a saucer-look to it. That part is almost exactly
behind the tree and about four or five feet back.

This has been noticed with concern by the lawn people, and most recently two
sewer companies who came to fix a backup, because they said it can be
indicative of a break in the sewer line. However, they dropped a camera
down the lines and found no breaks.

Both my neighbor and myself are getting concerned because it continues to
get worse. There are no basements, and when my carpet was pulled up
recently, I found a crack in the concrete extending from one end of the unit
to the other -- the builder tells me this is not a big deal, all concrete
buckles, and as long as the crack is going in one direction and not
spidering off, and as long as the crack is less than 1/4" wide and both
sides are level, it's nothing to be concerned about. The sidewalk has also
formed a horizontal crack, and the slabs are becoming quite uneven.

I realize that normal settling occurs after building, but this seems
extreme. Other than a sewer line break which has been ruled out, what could
cause ground sinking like this?

[DanG]

Mother Nature likes soil to have about an 88 Protctor density.

The soil under commercial construction is usually required to be a
"select" material. This material will have specific properties
that allow it to be compacted. Select material will be low in
clay content and no loam or biodegradables. Typical compaction
required on commercial work will tend toward 95 Proctor density.

These requirements seldom are considered or required for
residential work. Consider digging a trench across old, well
settled soil. You cannot put all the dirt back in the ditch
without using tamping equipment. After a year of rain,
freeze/thaw, you can usually see ditch lines where Mother Nature
has finally regained her normal compaction. This is also true of
dirt outside basement excavations and the loose fill shoved up
behind a curb on which the sidewalk is poured. If these areas
have not had mechanical compaction as they are placed they will
settle.

Perhaps your area was "filled in" land that is just now settling.
Another possibility would be a break in a storm or sanitary sewer
that would allow the slow erosion of the subsoil. You have
eliminated the sanitary, but you may look into municipal or other
storm drainage. Other possibilities are buried trash. We had one
reoccurring sink hole in which we dumped multiple loads of dirt.
When I finally dug it up, we found the last remnants of a Model A
at about 15 feet. I suspect an old well as there were many glass
bottles also.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing. . . .
DanG

Post by me
I live in a four-family building of townhomes, less than five

years old.

Post by me
The yard in front of the building has been sinking for some

time, two or

Post by me
three years. The sinking runs a line from one sewer clean-out

valve at the

Post by me
side of the building, down that side, turning a corner under the driveway
(which has cracked) into the yard to the next sewer cleanout val

ve, and out

Post by me
from there. About three feet out from there is a small plum

tree that his

Post by me
now sitting in a sinkhole, it's probably 8 to 10" lower than the ground
around it. Besides this sinking, there is an area between that and the
homes, right in front of a decorative rockbed, which seems to be sinking in
the middle, forming almost a saucer-look to it. That part is

almost exactly

Post by me
behind the tree and about four or five feet back.
This has been noticed with concern by the lawn people, and most recently two
sewer companies who came to fix a backup, because they said it

can be

Post by me
indicative of a break in the sewer line. However, they dropped a camera
down the lines and found no breaks.
Both my neighbor and myself are getting concerned because it

continues to

Post by me
get worse. There are no basements, and when my carpet was

pulled up

Post by me
recently, I found a crack in the concrete extending from one end of the unit
to the other -- the builder tells me this is not a big deal, all concrete
buckles, and as long as the crack is going in one direction and not
spidering off, and as long as the crack is less than 1/4" wide

and both

Post by me
sides are level, it's nothing to be concerned about. The

sidewalk has also

Post by me
formed a horizontal crack, and the slabs are becoming quite

uneven.

Post by me
I realize that normal settling occurs after building, but this

seems

Post by me
extreme. Other than a sewer line break which has been ruled

out, what could

Post by me
cause ground sinking like this?

[b***@cruller.invalid]

Post by me
I live in a four-family building of townhomes, less than five years old.
The yard in front of the building has been sinking for some time, two or
three years. The sinking runs a line from one sewer clean-out valve at the
side of the building, down that side, turning a corner under the driveway
(which has cracked) into the yard to the next sewer cleanout valve, and out
from there. About three feet out from there is a small plum tree that his
now sitting in a sinkhole, it's probably 8 to 10" lower than the ground
around it. Besides this sinking, there is an area between that and the
homes, right in front of a decorative rockbed, which seems to be sinking in
the middle, forming almost a saucer-look to it. That part is almost exactly
behind the tree and about four or five feet back.
This has been noticed with concern by the lawn people, and most recently two
sewer companies who came to fix a backup, because they said it can be
indicative of a break in the sewer line. However, they dropped a camera
down the lines and found no breaks.
Both my neighbor and myself are getting concerned because it continues to
get worse. There are no basements, and when my carpet was pulled up
recently, I found a crack in the concrete extending from one end of the unit
to the other -- the builder tells me this is not a big deal, all concrete
buckles, and as long as the crack is going in one direction and not
spidering off, and as long as the crack is less than 1/4" wide and both
sides are level, it's nothing to be concerned about. The sidewalk has also
formed a horizontal crack, and the slabs are becoming quite uneven.
I realize that normal settling occurs after building, but this seems
extreme. Other than a sewer line break which has been ruled out, what could
cause ground sinking like this?

Do you live in west central Florida?

<http://www.swfwmd.state.fl.us/emer/sinkhole/sinkpage.htm>

[Joseph Meehan]

Dan did a good job of explaining it, but I will try as well.

The people who built the building and did the excavation work did not do
it right. They did not back fill properly. There are two fixes. Wait
until it quits moving and then repair any damage. Fix it now by
re-excavating much of it and this time back filling properly.

I chose the second method and took my builder to court. On the other
hand the first method is likely to be cheaper, as look as you are sure it
has finished compacting. Depending on local conditions this could take
years longer or it could be done. In my experience a couple of really wet
years usually settles things nicely.

There is also an odd chance that there is a sewer problem. Not likely
in my opinion.
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math

Post by me
I live in a four-family building of townhomes, less than five years old.
The yard in front of the building has been sinking for some time, two or
three years. The sinking runs a line from one sewer clean-out valve at the
side of the building, down that side, turning a corner under the driveway
(which has cracked) into the yard to the next sewer cleanout valve, and out
from there. About three feet out from there is a small plum tree that his
now sitting in a sinkhole, it's probably 8 to 10" lower than the ground
around it. Besides this sinking, there is an area between that and the
homes, right in front of a decorative rockbed, which seems to be sinking in
the middle, forming almost a saucer-look to it. That part is almost exactly
behind the tree and about four or five feet back.
This has been noticed with concern by the lawn people, and most recently two
sewer companies who came to fix a backup, because they said it can be
indicative of a break in the sewer line. However, they dropped a camera
down the lines and found no breaks.
Both my neighbor and myself are getting concerned because it continues to
get worse. There are no basements, and when my carpet was pulled up
recently, I found a crack in the concrete extending from one end of the unit
to the other -- the builder tells me this is not a big deal, all concrete
buckles, and as long as the crack is going in one direction and not
spidering off, and as long as the crack is less than 1/4" wide and both
sides are level, it's nothing to be concerned about. The sidewalk has also
formed a horizontal crack, and the slabs are becoming quite uneven.
I realize that normal settling occurs after building, but this seems
extreme. Other than a sewer line break which has been ruled out, what could
cause ground sinking like this?

[Jeff Cochran]

Post by me
I realize that normal settling occurs after building, but this seems
extreme. Other than a sewer line break which has been ruled out, what could
cause ground sinking like this?

Uncompacted fill, decomposing materials in the fill, underground
caverns and sink holes, giant mole people from Neptune, take your
pick. You'd need a backhoe to examine it, or pour more fill on top
until it stops settling.

Jeff

[Sporkman]

Post by Jeff Cochran
Uncompacted fill, decomposing materials in the fill, underground
caverns and sink holes, giant mole people from Neptune, take your
pick. You'd need a backhoe to examine it, or pour more fill on top
until it stops settling.
Jeff

Your last idea is REALLY stupid advice if the problem is a true
sinkhole. The next to last idea could be just as bad.

[Joseph Meehan]

Post by Sporkman

Post by Jeff Cochran
Uncompacted fill, decomposing materials in the fill, underground
caverns and sink holes, giant mole people from Neptune, take your
pick. You'd need a backhoe to examine it, or pour more fill on top
until it stops settling.
Jeff

Your last idea is REALLY stupid advice if the problem is a true
sinkhole. The next to last idea could be just as bad.

While it may be a sinkhole, in most parts of the world Jeff's idea is
much more likely.

[JohnB]

Post by Joseph Meehan

Post by Sporkman

Post by Jeff Cochran
Uncompacted fill, decomposing materials in the fill, underground
caverns and sink holes, giant mole people from Neptune, take your
pick. You'd need a backhoe to examine it, or pour more fill on top
until it stops settling.
Jeff

Your last idea is REALLY stupid advice if the problem is a true
sinkhole. The next to last idea could be just as bad.

While it may be a sinkhole, in most parts of the world Jeff's idea is
much more likely.

I grew up in a community which made its living from coal mines.
Occasionally somebody would find their basement floor a lot lower
than on the previous visit because the timbers holding up the
mine roof under the house rotted and collapsed.

I now live near a community named "Mine Hill" because they used
to dig for iron ore. Somebody recently had a shaft collapse
which damaged their yard or their house and then complained that
they had no idea there were mines in the area.

[d***@sprynet.com]

Post by me
I live in a four-family building of townhomes, less than five years old.
The yard in front of the building has been sinking for some time, two or
three years. The sinking runs a line from one sewer clean-out valve at the
side of the building, down that side, turning a corner under the driveway
(which has cracked) into the yard to the next sewer cleanout valve, and out
from there. About three feet out from there is a small plum tree that his
now sitting in a sinkhole, it's probably 8 to 10" lower than the ground
around it. Besides this sinking, there is an area between that and the
homes, right in front of a decorative rockbed, which seems to be sinking in
the middle, forming almost a saucer-look to it. That part is almost exactly
behind the tree and about four or five feet back.
This has been noticed with concern by the lawn people, and most recently two
sewer companies who came to fix a backup, because they said it can be
indicative of a break in the sewer line. However, they dropped a camera
down the lines and found no breaks.
Both my neighbor and myself are getting concerned because it continues to
get worse. There are no basements, and when my carpet was pulled up
recently, I found a crack in the concrete extending from one end of the unit
to the other -- the builder tells me this is not a big deal, all concrete
buckles, and as long as the crack is going in one direction and not
spidering off, and as long as the crack is less than 1/4" wide and both
sides are level, it's nothing to be concerned about. The sidewalk has also
formed a horizontal crack, and the slabs are becoming quite uneven.
I realize that normal settling occurs after building, but this seems
extreme. Other than a sewer line break which has been ruled out, what could
cause ground sinking like this?

if you dont own the property dont worry about it.. the owners never
worried about it when they had it built.. the ground was probably filled
with earth that kept rotting and never settled and its still trying to
settle... in my area you can only use fill that will not rot when
filling lots..... that is what they should have done in your area and
probably never did.. its too late now....

[me.]

Post by d***@sprynet.com

Post by me
I live in a four-family building of townhomes, less than five years old.
The yard in front of the building has been sinking for some time, two or
three years. The sinking runs a line from one sewer clean-out valve at the
side of the building, down that side, turning a corner under the driveway
(which has cracked) into the yard to the next sewer cleanout valve, and out
from there. About three feet out from there is a small plum tree that his
now sitting in a sinkhole, it's probably 8 to 10" lower than the ground
around it. Besides this sinking, there is an area between that and the
homes, right in front of a decorative rockbed, which seems to be sinking in
the middle, forming almost a saucer-look to it. That part is almost exactly
behind the tree and about four or five feet back.
This has been noticed with concern by the lawn people, and most recently two
sewer companies who came to fix a backup, because they said it can be
indicative of a break in the sewer line. However, they dropped a camera
down the lines and found no breaks.
Both my neighbor and myself are getting concerned because it continues to
get worse. There are no basements, and when my carpet was pulled up
recently, I found a crack in the concrete extending from one end of the unit
to the other -- the builder tells me this is not a big deal, all concrete
buckles, and as long as the crack is going in one direction and not
spidering off, and as long as the crack is less than 1/4" wide and both
sides are level, it's nothing to be concerned about. The sidewalk has also
formed a horizontal crack, and the slabs are becoming quite uneven.
I realize that normal settling occurs after building, but this seems
extreme. Other than a sewer line break which has been ruled out, what could
cause ground sinking like this?

if you dont own the property dont worry about it.. the owners never
worried about it when they had it built.. the ground was probably filled
with earth that kept rotting and never settled and its still trying to
settle... in my area you can only use fill that will not rot when
filling lots..... that is what they should have done in your area and
probably never did.. its too late now....

Unfortunately, I do own the townhome, and being in an association, do own
the yard (common area) along with the rest of the homeowners. I suspect
that unless there is reasonable cause to think there could be future
structural damage (and who makes that decision) or other issues, digging up
the yard and refilling isn't something the association is going to want to
spend $$ on (and would probably have to special assess if they did0. If it
is settling, I wish I knew when it was going to stop.

Thanks for all the responses.

[Nick Hull]

Post by me.
Unfortunately, I do own the townhome, and being in an association, do own
the yard (common area) along with the rest of the homeowners. I suspect
that unless there is reasonable cause to think there could be future
structural damage (and who makes that decision) or other issues, digging up
the yard and refilling isn't something the association is going to want to
spend $$ on (and would probably have to special assess if they did0. If it
is settling, I wish I knew when it was going to stop.

The general rule is that fill dirt sinks for 7 years

[JerryMouse]

Post by me
I realize that normal settling occurs after building, but this seems
extreme. Other than a sewer line break which has been ruled out,
what could cause ground sinking like this?

1. The builder dug a sewer line, as much as five or more feet deep.
2. He put in the sewer pipe.
3. He filled the trench with leaves and dead frogs.
4. He put sod on top.

[Sporkman]

WHERE ARE YOU?
If you're in an area of Karst (soluble limestone) you could be seeing a
literal cave-in . . . the gradual type. Sinkholes abound in certain
areas of the country and are quite possible in several widespread
regions of the country.

I live in a four-family building of townhomes, less than five years old. ...(clip)...

[bloggs]

if a tree has been removed or tree roots removed...as the roots/stump rot
and decompose they shrink ...this can cause the sinking of the ground?

Post by me
I live in a four-family building of townhomes, less than five years old.
The yard in front of the building has been sinking for some time, two or
three years. The sinking runs a line from one sewer clean-out valve at the
side of the building, down that side, turning a corner under the driveway
(which has cracked) into the yard to the next sewer cleanout valve, and out
from there. About three feet out from there is a small plum tree that his
now sitting in a sinkhole, it's probably 8 to 10" lower than the ground
around it. Besides this sinking, there is an area between that and the
homes, right in front of a decorative rockbed, which seems to be sinking in
the middle, forming almost a saucer-look to it. That part is almost exactly
behind the tree and about four or five feet back.
This has been noticed with concern by the lawn people, and most recently two
sewer companies who came to fix a backup, because they said it can be
indicative of a break in the sewer line. However, they dropped a camera
down the lines and found no breaks.
Both my neighbor and myself are getting concerned because it continues to
get worse. There are no basements, and when my carpet was pulled up
recently, I found a crack in the concrete extending from one end of the unit
to the other -- the builder tells me this is not a big deal, all concrete
buckles, and as long as the crack is going in one direction and not
spidering off, and as long as the crack is less than 1/4" wide and both
sides are level, it's nothing to be concerned about. The sidewalk has also
formed a horizontal crack, and the slabs are becoming quite uneven.
I realize that normal settling occurs after building, but this seems
extreme. Other than a sewer line break which has been ruled out, what could
cause ground sinking like this?

[v]

... The sinking runs a line from one sewer clean-out valve at the
side of the building, down that side, turning a corner under the driveway
(which has cracked) into the yard to the next sewer cleanout valve....

Well since the sinking is in a line following the pipe, the 99.9%
answer is that the fill on top of the pipe was not compacted vey well
and is settling. Not a big deal, just level it.

-v.

[JackS]

replying to v, JackS wrote:
Hi, I google this topic and find this old discussion since I ran into the same
problem. I don't know whether the original poster had resolved this problem if
he/she can post the experiences, it will be greatly appreciated.

I owned a townhome built in 2005 by Ryan Homes and now is my rental property
since 2012. I noticed there was a sinkhole in my front yard around 2008. My
mother-in-law used a one and half feet long stick to try to measure it but it
could not reach to the solid bottom. So I filled with some soils and bricks
and did not really pay attention to it.

I did some yard work there recently and noticed the whole front yard were
sinking. There is a basement in the house. In 2013, I noticed there was a
leaking in the sewer line about 5 feet below the ground. I turn off the water
in the house. It is still leaking. So the leaking water is not from the house.
I asked couple of plumbers. None of them could figure it out and it became a
mystery to me. Now, my question is can I hold Ryan Homes accountable for
this? I checked my purchase contract and it cover the structure for 10 years
which is apparently over. But I remembered the sales person did mention that
the foundation would be covered lifetime. Is this consider a foundation
problem? What options do I have to reduce my financial loss? Thanks.

--
for full context, visit https://www.homeownershub.com/maintenance/sinking-yard-what-could-cause-it-538212-.htm