Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years ago.

The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a drain and
where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted the area
and levelled it, no sign of any roots pushing up. But now the area is back
up again.
The area is about 2 meters x 2 meters and has rising about 50mm to 75mm in
the middle, since last year.

Is it Heave and how long can I expect this continue?

--
Best Regards
Baz

Baz wrote:
Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years ago.

The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a drain
and where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted the
area and levelled it, no sign of any roots pushing up. But now the
area is back up again.
The area is about 2 meters x 2 meters and has rising about 50mm to
75mm in the middle, since last year.

Is it Heave and how long can I expect this continue?

Local industrial estate is block paved and there are bumps all over the
place, mainly near the drains.

It was built on marshy ground and apparently the whole lot has sunk slightly
except where the drains were - which had extra piles to support them.

Could it be something like that?



--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

"The Medway Handyman" wrote in message
news:KOTao.74656$ux5.67013@hurricane...
Baz wrote:
Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years ago.

The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a drain
and where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted the
area and levelled it, no sign of any roots pushing up. But now the
area is back up again.
The area is about 2 meters x 2 meters and has rising about 50mm to
75mm in the middle, since last year.

Is it Heave and how long can I expect this continue?

Local industrial estate is block paved and there are bumps all over the
place, mainly near the drains.

It was built on marshy ground and apparently the whole lot has sunk
slightly except where the drains were - which had extra piles to support
them.

Could it be something like that?



--
Dave - The Medway Handyman
www.medwayhandyman.co.uk


Thanks for your prompt reply Dave.
But no. This definitely coming UP. The bit over the drain is still nice and
flat.
Baz

On 18 Aug, 16:42, "Baz" wrote:
Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years ago.

The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a drain and
where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted the area
and levelled it, no sign of any roots pushing up. But now the area is back
up again.
The area is about 2 meters x 2 meters and has rising about 50mm to 75mm in
the middle, since last year.

Is it Heave and how long can I expect this continue?

--
Best Regards
Baz

No big trees nearby?

Baz wrote:
Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years ago.

The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a drain and
where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted the area
and levelled it, no sign of any roots pushing up. But now the area is back
up again.
The area is about 2 meters x 2 meters and has rising about 50mm to 75mm in
the middle, since last year.

Is it Heave

yes.


and how long can I expect this continue?

Until the soil that used to be sucked dry by the forsythia, gets as
soggy as everywhere else.


Classic case of 'kill tree, ground swells'

[Default] On Wed, 18 Aug 2010 19:21:33 +0100, a certain chimpanzee,
The Natural Philosopher , randomly hit the
keyboard and wrote:

Baz wrote:

and how long can I expect this continue?

Until the soil that used to be sucked dry by the forsythia, gets as
soggy as everywhere else.

Conventional wisdom (i.e., the NHBC) has it at 2-3 years. If the
forsythia was removed 5 years ago, it should have settled down by now.

Classic case of 'kill tree, ground swells'

But not widely known about by small builders, it seems. Typical
conversation:
BCO: "You'll need to dig your footings another x00mm because of that
tree there".
SB: "We'll cut it down, then".
BCO: "Whatever. You'll still need to dig your footings another x00mm,
or leave it to settle for three years".
(SB: Grumble, grumble, "...I've been doing this for nn
years...next-door Council never ask for this...etc.")
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?

Hugo Nebula wrote:
[Default] On Wed, 18 Aug 2010 19:21:33 +0100, a certain chimpanzee,
The Natural Philosopher , randomly hit the
keyboard and wrote:

Baz wrote:

and how long can I expect this continue?
Until the soil that used to be sucked dry by the forsythia, gets as
soggy as everywhere else.

Conventional wisdom (i.e., the NHBC) has it at 2-3 years. If the
forsythia was removed 5 years ago, it should have settled down by now.
Classic case of 'kill tree, ground swells'

But not widely known about by small builders, it seems. Typical
conversation:
BCO: "You'll need to dig your footings another x00mm because of that
tree there".
SB: "We'll cut it down, then".
BCO: "Whatever. You'll still need to dig your footings another x00mm,
or leave it to settle for three years".
(SB: Grumble, grumble, "...I've been doing this for nn
years...next-door Council never ask for this...etc.")

Pretty much what mine said. I listened to the BCO. he was very rational.

On 18/08/2010 23:34, The Natural Philosopher wrote:
Hugo Nebula wrote:
[Default] On Wed, 18 Aug 2010 19:21:33 +0100, a certain chimpanzee,
The Natural Philosopher , randomly hit the
keyboard and wrote:

Baz wrote:

and how long can I expect this continue?
Until the soil that used to be sucked dry by the forsythia, gets as
soggy as everywhere else.

Conventional wisdom (i.e., the NHBC) has it at 2-3 years. If the
forsythia was removed 5 years ago, it should have settled down by now.
Classic case of 'kill tree, ground swells'

But not widely known about by small builders, it seems. Typical
conversation:
BCO: "You'll need to dig your footings another x00mm because of that
tree there".
SB: "We'll cut it down, then".
BCO: "Whatever. You'll still need to dig your footings another x00mm,
or leave it to settle for three years".
(SB: Grumble, grumble, "...I've been doing this for nn
years...next-door Council never ask for this...etc.")

Pretty much what mine said. I listened to the BCO. he was very rational.

I dealt with lots of claims for subsidence and a few for heave.

Clay shrinks when it dries out and swells when it gets wet. Regs have
increased depths for house foundations over the years to reduce the
problem for buildings.

A plant or tree getting larger may well cause a reduction in moisture
content of the soil resulting in subsidence.

Cutting down may result in heave.

Situation may result from a drain leak or from forsythia being cut down.
There may have been an old leak the forsythia was drinking.

Unfortunately if there is no reason for the soil to dry out again there
is no reason to believe it will shrink again.

If you cannot live with it it could be expensive.
If the forsythia was taken out 5 years ago I would have thought the land
should have stabilised by now.
Is the drain to a sewer or to a soakaway?

"Invisible Man" wrote in message
...
On 18/08/2010 23:34, The Natural Philosopher wrote:
Hugo Nebula wrote:
[Default] On Wed, 18 Aug 2010 19:21:33 +0100, a certain chimpanzee,
The Natural Philosopher , randomly hit the
keyboard and wrote:

Baz wrote:

and how long can I expect this continue?
Until the soil that used to be sucked dry by the forsythia, gets as
soggy as everywhere else.

Conventional wisdom (i.e., the NHBC) has it at 2-3 years. If the
forsythia was removed 5 years ago, it should have settled down by now.
Classic case of 'kill tree, ground swells'

But not widely known about by small builders, it seems. Typical
conversation:
BCO: "You'll need to dig your footings another x00mm because of that
tree there".
SB: "We'll cut it down, then".
BCO: "Whatever. You'll still need to dig your footings another x00mm,
or leave it to settle for three years".
(SB: Grumble, grumble, "...I've been doing this for nn
years...next-door Council never ask for this...etc.")

Pretty much what mine said. I listened to the BCO. he was very rational.

I dealt with lots of claims for subsidence and a few for heave.

Clay shrinks when it dries out and swells when it gets wet. Regs have
increased depths for house foundations over the years to reduce the
problem for buildings.

A plant or tree getting larger may well cause a reduction in moisture
content of the soil resulting in subsidence.

Cutting down may result in heave.

Situation may result from a drain leak or from forsythia being cut down.
There may have been an old leak the forsythia was drinking.

Unfortunately if there is no reason for the soil to dry out again there is
no reason to believe it will shrink again.

If you cannot live with it it could be expensive.
If the forsythia was taken out 5 years ago I would have thought the land
should have stabilised by now.
Is the drain to a sewer or to a soakaway?

It is a Sewer Drain. 3 or 4 meters deep.

Baz

Baz wrote:
Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years ago.

The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a drain
and where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted the
area and levelled it, no sign of any roots pushing up. But now the
area is back up again.
The area is about 2 meters x 2 meters and has rising about 50mm to
75mm in the middle, since last year.

Is it Heave and how long can I expect this continue?

It is heave and as TNP says it won't stop until the ground has sorted itself
out WRT moisture levels etc.

You can stop it now, but that means removing the ground...IE dig out a
fecking big hole 2m by 2m and at least a metre deep and infill with MOT,
which will have to be whacked in layers of 150mm.

A 4 yard skip, at least 5 tonne of MOT, lots of hard work and a weeks
whacker hire is what's required to do the job properly, anything else is
just cosmetic

--
Phil L
RSRL Tipster Of The Year 2008

Phil L wrote:
Baz wrote:
Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years ago.

The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a drain
and where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted the
area and levelled it, no sign of any roots pushing up. But now the
area is back up again.
The area is about 2 meters x 2 meters and has rising about 50mm to
75mm in the middle, since last year.

Is it Heave and how long can I expect this continue?

It is heave and as TNP says it won't stop until the ground has sorted itself
out WRT moisture levels etc.

You can stop it now, but that means removing the ground...IE dig out a
fecking big hole 2m by 2m and at least a metre deep and infill with MOT,
which will have to be whacked in layers of 150mm.

A 4 yard skip, at least 5 tonne of MOT, lots of hard work and a weeks
whacker hire is what's required to do the job properly, anything else is
just cosmetic

Or just wait till it settles, and then re-lay.

The Natural Philosopher wrote:
Phil L wrote:
Baz wrote:
Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years
ago. The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a
drain and where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted
the area and levelled it, no sign of any roots pushing up. But now
the area is back up again.
The area is about 2 meters x 2 meters and has rising about 50mm to
75mm in the middle, since last year.

Is it Heave and how long can I expect this continue?

It is heave and as TNP says it won't stop until the ground has
sorted itself out WRT moisture levels etc.

You can stop it now, but that means removing the ground...IE dig out
a fecking big hole 2m by 2m and at least a metre deep and infill
with MOT, which will have to be whacked in layers of 150mm.

A 4 yard skip, at least 5 tonne of MOT, lots of hard work and a weeks
whacker hire is what's required to do the job properly, anything
else is just cosmetic

Or just wait till it settles, and then re-lay.

IME that can take years, and in the meantime he's got to put up with a drive
that looks like a ploughed field!

--
Phil L
RSRL Tipster Of The Year 2008

On 18/08/2010 16:42, Baz wrote:
Hi Guys.

I had my front "Lawn" (scabby bit of grass) Blocked Paved 5 years ago.

The ground is Heavy Clay.

I have a bit that appears to be Heaving. This area is next to a drain and
where a Forsythia grow for 20 or 30 years.

The contractor who laid the paving came back last year and lifted the area
and levelled it, no sign of any roots pushing up. But now the area is back
up again.
The area is about 2 meters x 2 meters and has rising about 50mm to 75mm in
the middle, since last year.

Is it Heave and how long can I expect this continue?


Maybe the drains are leaking, clay expands when wet, shrinks when
dry.Movement of the clay may have damaged the drain pipes. In dry
weather the ground will sink except for the wet bits which may be around
the leaking drains? Just a thought.
Don

On Aug 18, 4:42*pm, "Baz" wrote:
The contractor who laid the paving

Whacker plates can damage drains if old & weak (their impact does not
go far into the ground).

By "old" I mean white porcelin or brick, rather sad nearby in that
every time a house got sold they brought in the block paving crowd and
whacker plates, then a few weeks later a minor drain repair, then pump-
out truck, then another pump-out truck, then the whole lot up again to
replace the drains. Soil is clay, houses pre 1930. House By House,
magpies & pidgeons come from miles around to watch placing bets on how
long.