Replacing shallow concrete foundations - worth it?
 

Hi,

Our N.Z. timber house is on a slope. The side of the house facing the valley
has concrete foundations that are very, very shallow (probably no more than
8-10 inches deep). My guess is that when it is raining very very hard, and
for a long time, the foundations can move a little bit. Another issue is
when kids are playing with the garden hose... (ouch!)

We've had to replace one foundation that was kind of going down the valley
actually.
Four other concrete foundations could be replaced.

The inside of the house is quite new, I'm scared that the repiling process
may damage the nice work that been done inside.
Is the repiling process safe? Is the house likely to move when repiling?

The house is on clay.

Any opinions?

Thanks for any advice.

Replacing shallow concrete foundations - worth it?
 

Hi John,
Usually on a slope grade a foundation is roughly the depth of.....
level out 5 feet from the grade and measure the distance to the ground at 5
feet.
The footing should be this depth plus 18 inches.....
So if I leveled out from grade 5 feet and measured down to grade and had 2
feet I would build a footing that was 3 feet 6 inches deep.
This is rule of thumb and not necessarily engineered for your soil type.
A person could build a retaining wall out at a distance and backfill this to
support the existing faulty condition also.....
Good wishes.
jloomis
"John" wrote in message
. ..
Hi,

Our N.Z. timber house is on a slope. The side of the house facing the
valley has concrete foundations that are very, very shallow (probably no
more than 8-10 inches deep). My guess is that when it is raining very very
hard, and for a long time, the foundations can move a little bit. Another
issue is when kids are playing with the garden hose... (ouch!)

We've had to replace one foundation that was kind of going down the valley
actually.
Four other concrete foundations could be replaced.

The inside of the house is quite new, I'm scared that the repiling process
may damage the nice work that been done inside.
Is the repiling process safe? Is the house likely to move when repiling?

The house is on clay.

Any opinions?

Thanks for any advice.

Replacing shallow concrete foundations - worth it?
 

Hi,
Thanks for the info but that wasn't my question.
Do you think the repiling process (replacing the existing concrete
foundation with a new one) is safe enough for the house?
I fear the structure may move a bit and damage the indoor work done so far.

In other words how safe is the foundation replacement process for the house?

"jloomis" wrote in message
...
Hi John,
Usually on a slope grade a foundation is roughly the depth of.....
level out 5 feet from the grade and measure the distance to the ground at
5 feet.
The footing should be this depth plus 18 inches.....
So if I leveled out from grade 5 feet and measured down to grade and had 2
feet I would build a footing that was 3 feet 6 inches deep.
This is rule of thumb and not necessarily engineered for your soil type.
A person could build a retaining wall out at a distance and backfill this
to support the existing faulty condition also.....
Good wishes.
jloomis
"John" wrote in message
. ..
Hi,

Our N.Z. timber house is on a slope. The side of the house facing the
valley has concrete foundations that are very, very shallow (probably no
more than 8-10 inches deep). My guess is that when it is raining very
very hard, and for a long time, the foundations can move a little bit.
Another issue is when kids are playing with the garden hose... (ouch!)

We've had to replace one foundation that was kind of going down the
valley actually.
Four other concrete foundations could be replaced.

The inside of the house is quite new, I'm scared that the repiling
process may damage the nice work that been done inside.
Is the repiling process safe? Is the house likely to move when repiling?

The house is on clay.

Any opinions?

Thanks for any advice.

Replacing shallow concrete foundations - worth it?
 

John,

The process is called underpinning and is performed regularly without damage
to the structure above. It's not a complicated job for a building the size
of a home, but there are several methods and you really need site specific
direction from a local engineer.

Tom

Hi,

Our N.Z. timber house is on a slope. The side of the house facing the
valley has concrete foundations that are very, very shallow (probably no
more than 8-10 inches deep). My guess is that when it is raining very
very hard, and for a long time, the foundations can move a little bit.
Another issue is when kids are playing with the garden hose... (ouch!)

We've had to replace one foundation that was kind of going down the
valley actually.
Four other concrete foundations could be replaced.

The inside of the house is quite new, I'm scared that the repiling
process may damage the nice work that been done inside.
Is the repiling process safe? Is the house likely to move when repiling?

The house is on clay.

Any opinions?

Thanks for any advice.

Replacing shallow concrete foundations - worth it?
 

"John" wrote in message
. ..
Hi,
Thanks for the info but that wasn't my question.
Do you think the repiling process (replacing the existing concrete
foundation with a new one) is safe enough for the house?
I fear the structure may move a bit and damage the indoor work done so
far.

In other words how safe is the foundation replacement process for the
house?

If you really do need piles.... There are two ways to do it - drill them or
hammer them. Drilling them causes a lot less noise and vibration than
hammering.

Replacing shallow concrete foundations - worth it?
 

"jloomis" wrote in message
...
Hi John,
Usually on a slope grade a foundation is roughly the depth of.....
level out 5 feet from the grade and measure the distance to the ground at
5
feet.
The footing should be this depth plus 18 inches.....
So if I leveled out from grade 5 feet and measured down to grade and had 2
feet I would build a footing that was 3 feet 6 inches deep.
This is rule of thumb and not necessarily engineered for your soil type.
A person could build a retaining wall out at a distance and backfill this
to
support the existing faulty condition also.....
Good wishes.
jloomis

Interesting. I think that's quite a bit shallower then we would dig here in
the UK on clay. Any trees around and you can be talking three times that
depth - in which case piled foundations usually work out cheaper.