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  #1   Report Post  
The Natural Philosopher
 
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Default Underpinning costs...?

Been looking at a poetntial buy for a friend, and it looks like part of
it - a rather shoddy 70's extension - has a bit of a subsidence problem.
Possibly due to a couple of trees nearby - one a willow.

IF - and pending investigation - it needs underpinning, has anyone any
ball park estimates for costs?

Walking away from the buy is not in the frame really - its more about
price adjustment to reflect the condition.


Relevant information is :-

- access for machinery is no problem
- it's on clay soil, and wettish clay (quite low lying)
- about 20 meters of wall might need treatment.
- my guess is there are minimal foundations - one or two feet at the
very most.

My wet finger guesstimate was a grand a meter absolute tops, thinking
that it could hardly take more than a week for a bloke with a shovel and
a cement mixer to dig out a bit and fill it with concrete. At 10 quid a
day max.

It could be possible to take up the internal floors as well if this is
desirable, but that would be far more of a job.

I am after any information anyone has on techniques that are employed to
do this job, and any real world data that is better than my wet finger
guesstimates.

In fact any information on mild subsidence and its remedy would be welcome.
  #2   Report Post  
Mike
 
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Default


"The Natural Philosopher" wrote in message
...
Been looking at a poetntial buy for a friend, and it looks like part of
it - a rather shoddy 70's extension - has a bit of a subsidence problem.
Possibly due to a couple of trees nearby - one a willow.

IF - and pending investigation - it needs underpinning, has anyone any
ball park estimates for costs?

Walking away from the buy is not in the frame really - its more about
price adjustment to reflect the condition.


Relevant information is :-

- access for machinery is no problem
- it's on clay soil, and wettish clay (quite low lying)
- about 20 meters of wall might need treatment.
- my guess is there are minimal foundations - one or two feet at the
very most.

My wet finger guesstimate was a grand a meter absolute tops, thinking
that it could hardly take more than a week for a bloke with a shovel and
a cement mixer to dig out a bit and fill it with concrete. At 10 quid a
day max.

It could be possible to take up the internal floors as well if this is
desirable, but that would be far more of a job.

I am after any information anyone has on techniques that are employed to
do this job, and any real world data that is better than my wet finger
guesstimates.


Four years ago it cost a neighbour £4k to drill and fill sixteen piles of 25
feet deep. As I assume this situation isn't so bad (this was on an
ex-marsh) you should be able to interpolate down.


  #3   Report Post  
Peter Crosland
 
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Walking away is the only rational option. It will be impossible to insure
the property and the costs of a properly designed scheme would certainly
escalate way beyond your estimate.

Peter Crosland


  #4   Report Post  
Andrew Mawson
 
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Default


"The Natural Philosopher" wrote in message
...
Been looking at a poetntial buy for a friend, and it looks like part

of
it - a rather shoddy 70's extension - has a bit of a subsidence

problem.
Possibly due to a couple of trees nearby - one a willow.

IF - and pending investigation - it needs underpinning, has anyone

any
ball park estimates for costs?

Walking away from the buy is not in the frame really - its more

about
price adjustment to reflect the condition.


Relevant information is :-

- access for machinery is no problem
- it's on clay soil, and wettish clay (quite low lying)
- about 20 meters of wall might need treatment.
- my guess is there are minimal foundations - one or two feet at the
very most.

My wet finger guesstimate was a grand a meter absolute tops,

thinking
that it could hardly take more than a week for a bloke with a shovel

and
a cement mixer to dig out a bit and fill it with concrete. At 10

quid a
day max.

It could be possible to take up the internal floors as well if this

is
desirable, but that would be far more of a job.

I am after any information anyone has on techniques that are

employed to
do this job, and any real world data that is better than my wet

finger
guesstimates.

In fact any information on mild subsidence and its remedy would be

welcome.

I seem to recall a test case (?? in Wimbeldon??) where if the work was
done on the extension when it was built under normal planning and
building regs control the local authority picked up liability as they
had charged for inspections. It was following that case that local
authoities increased the required depths of foundations markedly.

AWEM


  #5   Report Post  
The Natural Philosopher
 
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Mike wrote:

"The Natural Philosopher" wrote in message
...

Been looking at a poetntial buy for a friend, and it looks like part of
it - a rather shoddy 70's extension - has a bit of a subsidence problem.
Possibly due to a couple of trees nearby - one a willow.

IF - and pending investigation - it needs underpinning, has anyone any
ball park estimates for costs?

Walking away from the buy is not in the frame really - its more about
price adjustment to reflect the condition.


Relevant information is :-

- access for machinery is no problem
- it's on clay soil, and wettish clay (quite low lying)
- about 20 meters of wall might need treatment.
- my guess is there are minimal foundations - one or two feet at the
very most.

My wet finger guesstimate was a grand a meter absolute tops, thinking
that it could hardly take more than a week for a bloke with a shovel and
a cement mixer to dig out a bit and fill it with concrete. At 10 quid a
day max.

It could be possible to take up the internal floors as well if this is
desirable, but that would be far more of a job.

I am after any information anyone has on techniques that are employed to
do this job, and any real world data that is better than my wet finger
guesstimates.



Four years ago it cost a neighbour £4k to drill and fill sixteen piles of 25
feet deep. As I assume this situation isn't so bad (this was on an
ex-marsh) you should be able to interpolate down.


Thank you muchly sir!


  #6   Report Post  
The Natural Philosopher
 
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Peter Crosland wrote:

Walking away is the only rational option. It will be impossible to insure
the property and the costs of a properly designed scheme would certainly
escalate way beyond your estimate.


Can you actually prvide evidence for that? I have seen underpinnig done
roun here and it was certaily not a total ecsalation such as you
describe. Lbour intensive, messy, and a right royal pain, but it took
only about 6 weeks of three blokes to do a similar section.

At a garnd a weekm thats 18 grand...

...walking away is not an option here, unless it truly is 'cheaper to
demolish and start over'...which would be about 100k estimated.



Peter Crosland


  #7   Report Post  
The Natural Philosopher
 
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Andrew Mawson wrote:

"The Natural Philosopher" wrote in message
...

Been looking at a poetntial buy for a friend, and it looks like part


of

it - a rather shoddy 70's extension - has a bit of a subsidence


problem.

Possibly due to a couple of trees nearby - one a willow.

IF - and pending investigation - it needs underpinning, has anyone


any

ball park estimates for costs?

Walking away from the buy is not in the frame really - its more


about

price adjustment to reflect the condition.


Relevant information is :-

- access for machinery is no problem
- it's on clay soil, and wettish clay (quite low lying)
- about 20 meters of wall might need treatment.
- my guess is there are minimal foundations - one or two feet at the
very most.

My wet finger guesstimate was a grand a meter absolute tops,


thinking

that it could hardly take more than a week for a bloke with a shovel


and

a cement mixer to dig out a bit and fill it with concrete. At 10


quid a

day max.

It could be possible to take up the internal floors as well if this


is

desirable, but that would be far more of a job.

I am after any information anyone has on techniques that are


employed to

do this job, and any real world data that is better than my wet


finger

guesstimates.

In fact any information on mild subsidence and its remedy would be


welcome.

I seem to recall a test case (?? in Wimbeldon??) where if the work was
done on the extension when it was built under normal planning and
building regs control the local authority picked up liability as they
had charged for inspections. It was following that case that local
authoities increased the required depths of foundations markedly.


I would not be surprised.

When I pulled down my old house, which had foundations of a massive 6
inches, and was showing mild signs of subsidence due to trees and clay,
in one corner they made me go down 2.2 meters...for the new ones..

But these days, with a digger and simply pouring concrete,the
opportunity cost on a new property is not that great, to add massive
foundations.

I often wondered what 'Time Team 3000' woild have to say about it in due
course..
..

AWEM


  #8   Report Post  
tim
 
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Default


"The Natural Philosopher" wrote in message
t...
Peter Crosland wrote:

Walking away is the only rational option. It will be impossible to insure
the property and the costs of a properly designed scheme would certainly
escalate way beyond your estimate.


Can you actually prvide evidence for that? I have seen underpinnig done
roun here and it was certaily not a total ecsalation such as you describe.
Lbour intensive, messy, and a right royal pain, but it took only about 6
weeks of three blokes to do a similar section.

At a garnd a weekm thats 18 grand...

..walking away is not an option here,


"Been looking at a poetntial buy for a friend"

What's there not to walk away from?
Is it the only house for sale in the world?

tim


  #9   Report Post  
The Natural Philosopher
 
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Default

Huge wrote:

The Natural Philosopher writes:

Peter Crosland wrote:


Walking away is the only rational option. It will be impossible to insure
the property and the costs of a properly designed scheme would certainly
escalate way beyond your estimate.


Can you actually prvide evidence for that? I have seen underpinnig done
roun here and it was certaily not a total ecsalation such as you
describe. Lbour intensive, messy, and a right royal pain, but it took
only about 6 weeks of three blokes to do a similar section.

At a garnd a weekm thats 18 grand...

...walking away is not an option here, unless it truly is 'cheaper to
demolish and start over'...which would be about 100k estimated.



You really, really, *really* should make sure you can get buildings insurance
on this property. If you can't, even should you be foolish enough to buy it,
you won't be able to sell it, so it will be valueless.


Its insured right now, and there may be a claim on it by the current owners.

Its not for residential purposes BTW. That's why its had to walk away.
Its required for business purposes and has the requisite planning for
that type of activity, and is in a perfect location for it - with no
suitable alternatives anywhere remotely near.


I totally agree that an uninsurable property is worth only plot value
less clearance costs.

Its not as bad as you think - there are signs of cracks and maybe up to
an inch of sink in the worst place. Since estimated 1970. I don't think
its dangerous, or will fall down, but fit for purpose means stopping the
process and making good the existing damage.

Costs of fixing it to a level that satisfies BCO and insurance companies
is the issue.

One assumes contacting the correct type of structural engineers, and
getting a report and recommendation and implementing it is what will
have that effect.



BTW, and this is from personal, current, experience, underpinning is no
longer flavour of the month. We have a problem due to adjacent trees (mainly
a mature oak about 20 feet from the house) and the insurers want all of them
cut down. When I mentioned underpinning, both my structural engineer and
the insurer's structural engineer said "it doesn't work".


Well it does, and it doesn't.

As I said before my house had tree problems. I being reluctant to remove
them, the engineers simply said 'well we well go down soil sample wise
to a level at which the tree roots are not present in any form, and then
some, and build a concrete wall that will stop fresh roots dead in their
tracks' essentially. They also insisted on a raised concrete floor to
allow the already shrunk earth to expand without upsetting the floor
levels, which is a serious problem if you simply cut the tree down -
soil moisture returns, expansion happens and the building gets pushed up
again.

The essence of underpoinning or piling - as I understand it - is to get
the solid base of the fondations down to a level with stable
charcteristics, and let the soil above move as it will, without that
affecting the structural integrity of the house.

I am intersted in the piling type methods - that was given to me as a
potentially cheaper way in my case, but that would have consisted of
building a sort of viaduct of vertical concrete posts, with beams laid
across othe top, to form the foundations.

I cannot see how it cold be done as a remedial method.

If anyone knows, please share.


We await the men with chainsaws. (


Indeed.That is an option as well in the current case, for a couple of
nasty conifers.

But the main protagonist is a rather nice weeping willow some 10 meters
from the worst corner. I am fond of willows, though they have a
reputation for this kind of thuggery.

What might be very simple and totally possible is to trench down a
couple of meters about a foot from the footings, and fill that with
concrete. That would cut the roots there, and stop any further
penetration to the footings area. I believe willow roots are pretty
shallow.

Of course doing that UNDER the footings and backfilling with concrete
and mortar would be ideal..



  #10   Report Post  
Peter Crosland
 
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RIBA recommend a minimum of forty metres for willows!

Peter Crosland




  #11   Report Post  
Lobster
 
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Default

The Natural Philosopher wrote:
Huge wrote:

The Natural Philosopher writes:

You really, really, *really* should make sure you can get buildings
insurance
on this property. If you can't, even should you be foolish enough to
buy it,
you won't be able to sell it, so it will be valueless.


Its insured right now, and there may be a claim on it by the current
owners.


I would add that you should contact the current insurers and check
whether they are willing to insure any future buyer of the property to
ensure continuity of cover by the same insurer. I always thought there
was an 'unwritten rule' amongst insurance companies that they would
always do this; however when I recently looked into buying a property
which had been underpinned (properly, with all necesary guarantees etc)
the current insurers said 'no'. Which rang alarm bells. A few
enquiries via brokers produced either responses of
'not-with-a-bargepole' or 4-figure annual premiums (where about 150GBP
would be the norm).

We walked away!

David

  #12   Report Post  
Roger
 
Posts: n/a
Default

The message
from The Natural Philosopher contains these words:

snip

You really, really, *really* should make sure you can get buildings
insurance
on this property. If you can't, even should you be foolish enough to
buy it,
you won't be able to sell it, so it will be valueless.


Its insured right now, and there may be a claim on it by the current owners.


Would the current insurer have an obligation to continue to offer
insurance on the property?

Its not for residential purposes BTW. That's why its had to walk away.
Its required for business purposes and has the requisite planning for
that type of activity, and is in a perfect location for it - with no
suitable alternatives anywhere remotely near.


I totally agree that an uninsurable property is worth only plot value
less clearance costs.


That seems a bit extreme. If the property doesn't get any worse then not
insuring might be financially beneficial. Total loss claims are very
rare and those from subsidence even rarer. I once tried to shift my
house insurance but putative new insurer wouldn't cover it for
subsidence on the grounds that it was too old and decrepit with shallow
to nonexistent foundations and, to add insult to injury, refused to
reduce the premium to take account of the lack of cover for subsidence.

snip

I am intersted in the piling type methods - that was given to me as a
potentially cheaper way in my case, but that would have consisted of
building a sort of viaduct of vertical concrete posts, with beams laid
across othe top, to form the foundations.


I cannot see how it cold be done as a remedial method.


If anyone knows, please share.


ISTR reading somewhere that piles are inserted both sides of the walls
and linked at the base of the existing foundation. However that was a
long time ago and memory fades ....

--
Roger
  #13   Report Post  
The Natural Philosopher
 
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tim wrote:

"The Natural Philosopher" wrote in message
t...

Peter Crosland wrote:


Walking away is the only rational option. It will be impossible to insure
the property and the costs of a properly designed scheme would certainly
escalate way beyond your estimate.


Can you actually prvide evidence for that? I have seen underpinnig done
roun here and it was certaily not a total ecsalation such as you describe.
Lbour intensive, messy, and a right royal pain, but it took only about 6
weeks of three blokes to do a similar section.

At a garnd a weekm thats 18 grand...

..walking away is not an option here,



"Been looking at a poetntial buy for a friend"

What's there not to walk away from?
Is it the only house for sale in the world?


Its the ideal place to run a specialised business from, has planning
permission for it, and is in every other way totally ideal for the job.
There is nothing or 15 miles - the catchment area of that business -
remotely as good.


tim


  #14   Report Post  
The Natural Philosopher
 
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Huge wrote:

The Natural Philosopher writes:

[90 lines snipped]


But the main protagonist is a rather nice weeping willow some 10 meters


from the worst corner. I am fond of willows, though they have a


reputation for this kind of thuggery.



The arborist who came to look at our situation said that the rule of thumb
is 1.5 times the diameter of the drip line for oaks and twice for willows,
although the rule I've heard for willows is that if you can see them from an
upstairs windows, they're too close. Pity, 'cos I like willows.


Ten that is probably the actual real live issue, and cutting its roots
will stabilize that corner.

I am leaning (haha) towards it being less of a problem than I thought.

I think the next thing is to await the sellers structural report.

My gut instinct is to go deep alongside, and pour some concrete to
prevent the roots getting back in.

  #15   Report Post  
The Natural Philosopher
 
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Default

Peter Crosland wrote:

RIBA recommend a minimum of forty metres for willows!

Peter Crosland


And RIBA gave an award to the ghastly monstrosity up the road here, that
frankly was a candidate for demolition before it was even up.


  #16   Report Post  
Ed Sirett
 
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Default

On Fri, 14 Jan 2005 23:01:04 +0000, The Natural Philosopher wrote:

snip
Isn't this what building insurance is for?

guesstimates.

In fact any information on mild subsidence and its remedy would be welcome.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html


  #17   Report Post  
Andrew Chesters
 
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Default

Ed Sirett wrote:
On Fri, 14 Jan 2005 23:01:04 +0000, The Natural Philosopher wrote:

snip
Isn't this what building insurance is for?


[cynic]

No. Building (in fact, all) insurance is there to make money for the
share holders. They REALLY don't like paying out. Give them 1/2 an
excuse and you're on your own!!

[/cynic]
  #18   Report Post  
The Natural Philosopher
 
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Default

Lobster wrote:

The Natural Philosopher wrote:

Huge wrote:

The Natural Philosopher writes:

You really, really, *really* should make sure you can get buildings
insurance
on this property. If you can't, even should you be foolish enough to
buy it,
you won't be able to sell it, so it will be valueless.



Its insured right now, and there may be a claim on it by the current
owners.



I would add that you should contact the current insurers and check
whether they are willing to insure any future buyer of the property to
ensure continuity of cover by the same insurer. I always thought there
was an 'unwritten rule' amongst insurance companies that they would
always do this; however when I recently looked into buying a property
which had been underpinned (properly, with all necesary guarantees etc)
the current insurers said 'no'. Which rang alarm bells. A few
enquiries via brokers produced either responses of
'not-with-a-bargepole' or 4-figure annual premiums (where about 150GBP
would be the norm).

We walked away!


Good advice. I will relay that to the prospective purchaser.

However in terms of 4 figure insurance, well 1000 quid a year more is -
at say 5%, £20,000 equivalent on purchase price. So since this is a
commercial buy, simply another factor in the cost benefit equation.
Knock 20 grand off the asking, and it comes to the same in the end.

I reckon the site alone is worth about 150k, and the current 'guide
price' is 300, but we suspect that it might be worth offering 265...

My 'demolish and rebuild' costs show that it could be reproduced in good
order as a 4-5 bedroom house for around 450k including purchase, so in
the final analysis, if the property is cheap enough its not a losing
proposition.





David

  #19   Report Post  
The Natural Philosopher
 
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Roger wrote:

The message
from The Natural Philosopher contains these words:

snip


You really, really, *really* should make sure you can get buildings
insurance
on this property. If you can't, even should you be foolish enough to
buy it,
you won't be able to sell it, so it will be valueless.



Its insured right now, and there may be a claim on it by the current owners.



Would the current insurer have an obligation to continue to offer
insurance on the property?


Its not for residential purposes BTW. That's why its had to walk away.
Its required for business purposes and has the requisite planning for
that type of activity, and is in a perfect location for it - with no
suitable alternatives anywhere remotely near.



I totally agree that an uninsurable property is worth only plot value
less clearance costs.



That seems a bit extreme. If the property doesn't get any worse then not
insuring might be financially beneficial. Total loss claims are very
rare and those from subsidence even rarer. I once tried to shift my
house insurance but putative new insurer wouldn't cover it for
subsidence on the grounds that it was too old and decrepit with shallow
to nonexistent foundations and, to add insult to injury, refused to
reduce the premium to take account of the lack of cover for subsidence.


Thank you. hat ou aresaying is that it would be pssible to insure for -
say - loss by fire, and accidental damage, but not loss or damage due to
subsidence?

That is a possible and very attractive option, since we know that
extension has been up for years, and isn't falling down...its just
caused some noticeable cracking - up to 6mm in places.



snip


I am intersted in the piling type methods - that was given to me as a
potentially cheaper way in my case, but that would have consisted of
building a sort of viaduct of vertical concrete posts, with beams laid
across othe top, to form the foundations.



I cannot see how it cold be done as a remedial method.



If anyone knows, please share.



ISTR reading somewhere that piles are inserted both sides of the walls
and linked at the base of the existing foundation. However that was a
long time ago and memory fades ....


So you DO need to pull up internal floors yes? That adds to the cost
quite a bit...
  #20   Report Post  
Roger
 
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Default

The message
from The Natural Philosopher contains these words:

Thank you. hat ou aresaying is that it would be pssible to insure for -
say - loss by fire, and accidental damage, but not loss or damage due to
subsidence?


That is a possible and very attractive option, since we know that
extension has been up for years, and isn't falling down...its just
caused some noticeable cracking - up to 6mm in places.


That is the way I remember it but I have been unable to unearth the
correspondence. This was quite some time ago, maybe as long as 15 years.
Perhaps I should try firing up my Sinclair Sprectrum and see if any of
the microdrives still work. :-)

snip


I am intersted in the piling type methods - that was given to me as a
potentially cheaper way in my case, but that would have consisted of
building a sort of viaduct of vertical concrete posts, with beams laid
across othe top, to form the foundations.



I cannot see how it cold be done as a remedial method.



If anyone knows, please share.



ISTR reading somewhere that piles are inserted both sides of the walls
and linked at the base of the existing foundation. However that was a
long time ago and memory fades ....


So you DO need to pull up internal floors yes? That adds to the cost
quite a bit...


That is how I understand it but I have been unable to find the leaflet I
had on the subject. I believe I got that from some government dept after
the leaflet had been mentioned on this ng but that too was a
considerable time ago, but by no means as long as 15 years.

I had a quick google and found 2 threads on underpinning (1998 and 1999)
and the 2nd mentioned that piling both sides was optional but that it
produced a more stable structure. No reference to any lealet though.

--
Roger


  #21   Report Post  
 
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The natural philospoher:

What might be very simple and totally possible is to trench down a
couple of meters about a foot from the footings, and fill that with
concrete. That would cut the roots there, and stop any further
penetration to the footings area. I believe willow roots are pretty
shallow.


I dont see how that would make any difference. In fact it might
possibly cause extra problems.


Of course doing that UNDER the footings and backfilling with concrete
and mortar would be ideal..


yes


Any property in sound structural condition can be insured if you take
insurance that specifically excludes subsidence. There are specialist
insurers that take on these kind of risks.

Any property suffering from undiagnosed untreated subsidence will not
get insurance, at least not without deception, which would render the
policy invalid anyway. So its pointless phoning around. The only
company to ask if the existing insurer, who might be prepared to
continue insuring - although at several times the price, and, be aware
of this, any fault that existed when you bought woulod be automatically
exlcuded from insurance. Of course they might not mention that to you.

Do realise that house insurance is optional. Of course its desirable,
but I would not assume that it was automatically essential.

If you get the present owner to make an insurance claim, they would
hopefully fix it all up for you, minus the excess. Unfortunately this
will seriously blight the property value, insurability and sale value.


I totally agree that an uninsurable property is worth only plot value


less clearance costs.


This isnt at all realistic imho. There are loads of uninsurable
properties that function as houses just fine. Mortgage cos will
absolutely not lend on such houses, dramatically cutting the field of
potential buyers. Sale value may be a few tens of k less.


My gut instinct is to go deep alongside, and pour some concrete to
prevent the roots getting back in.


I really doubt it would make any difference. Understand the problem:
trees cause changes in water levels, which cause shrink or expansion in
clay soils. It is this that cracks houses.



That is a possible and very attractive option, since we know that
extension has been up for years, and isn't falling down...its just
caused some noticeable cracking - up to 6mm in places.


6mm is not large. If its not currently moving you could probably just
glue it together at the cracks and leave it at that, although of course
it is your surveyors advice you should follow, I'm certainly not trying
to supplant that. If it is moving, things would be different, and
probably a lot more expensive.


NT

  #22   Report Post  
Rick
 
Posts: n/a
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On Fri, 14 Jan 2005 23:01:04 +0000, The Natural Philosopher
wrote:

Been looking at a poetntial buy for a friend, and it looks like part of
it - a rather shoddy 70's extension - has a bit of a subsidence problem.
Possibly due to a couple of trees nearby - one a willow.

IF - and pending investigation - it needs underpinning, has anyone any
ball park estimates for costs?

Walking away from the buy is not in the frame really - its more about
price adjustment to reflect the condition.


Relevant information is :-

- access for machinery is no problem
- it's on clay soil, and wettish clay (quite low lying)
- about 20 meters of wall might need treatment.
- my guess is there are minimal foundations - one or two feet at the
very most.

My wet finger guesstimate was a grand a meter absolute tops, thinking
that it could hardly take more than a week for a bloke with a shovel and
a cement mixer to dig out a bit and fill it with concrete. At 10 quid a
day max.

It could be possible to take up the internal floors as well if this is
desirable, but that would be far more of a job.

I am after any information anyone has on techniques that are employed to
do this job, and any real world data that is better than my wet finger
guesstimates.

In fact any information on mild subsidence and its remedy would be welcome.


In my experience underpinning is about having enough balls to dig the
dirt out in the first place, it is a DIY job - but it gave me some
sleeples nights.

I would get a strutrial engineer in, to design the underpinning, and
even dig an exploritry hole at the house before you purchase. This way
you know the costs. If you tell the engineer you want to DIY the job,
he should be able to design a DIYable answer.

Rick

  #24   Report Post  
Anna Kettle
 
Posts: n/a
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On Sat, 15 Jan 2005 14:13:22 +0000, The Natural Philosopher
wrote:

What might be very simple and totally possible is to trench down a
couple of meters about a foot from the footings, and fill that with
concrete. That would cut the roots there, and stop any further
penetration to the footings area. I believe willow roots are pretty
shallow.


Roots are pretty persistant and can get through concrete so I wouldn't
leap into doing this without more research. Maybe a plastic board
would stop the roots better

Anna



~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repairs
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642
  #25   Report Post  
 
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Yes, if the OP is getting a mortgage, he's probably stuffed.

A business partner might be the other option if finance is lacking.
NT



  #26   Report Post  
The Natural Philosopher
 
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wrote:

The natural philospoher:


What might be very simple and totally possible is to trench down a
couple of meters about a foot from the footings, and fill that with
concrete. That would cut the roots there, and stop any further
penetration to the footings area. I believe willow roots are pretty
shallow.



I dont see how that would make any difference. In fact it might
possibly cause extra problems.



Well, accordng to teh guys who did soil tests and advised on foundatns
or here, what happens is that teh tree roots permeate teh soil, and
lower the local water content, causing long term shrinkage.

If youi remove the tree, or cut the roots, the water content returns to
normal.

In order to satbilise my house, they isnisted teh foiundations go below
teh level at which they ad found root hairs, and also insisetd that teh
foundations be lined with polystyrene to abosrb any heave, and that
tehfloors be suspended conctere for the same reason,. the raionale being
that as the cut roots died, the soil would expand again slowly.

It would seem to me that a concrete underground wall going down below
tree root level, would essentially place the tree in a 'pot' that would
stop its roots drying out that part of the soil under the house, and
immediately adjacent to it.

Of course teh attendant heave would result thereafter...



Of course doing that UNDER the footings and backfilling with concrete
and mortar would be ideal..



yes


Any property in sound structural condition can be insured if you take
insurance that specifically excludes subsidence. There are specialist
insurers that take on these kind of risks.


Good. In the end, we may simply do nothing, other than cosmetic
patching, and pay extra insurance...and use that to get a price reduction..

Any property suffering from undiagnosed untreated subsidence will not
get insurance, at least not without deception, which would render the
policy invalid anyway. So its pointless phoning around. The only
company to ask if the existing insurer, who might be prepared to
continue insuring - although at several times the price, and, be aware
of this, any fault that existed when you bought woulod be automatically
exlcuded from insurance. Of course they might not mention that to you.


Thanks. I take that point well.

Do realise that house insurance is optional. Of course its desirable,
but I would not assume that it was automatically essential.


It is when you borow money against...the property. Its a condition of
lending.

If you get the present owner to make an insurance claim, they would
hopefully fix it all up for you, minus the excess. Unfortunately this
will seriously blight the property value, insurability and sale value.



We shall see.


I totally agree that an uninsurable property is worth only plot value



less clearance costs.



This isnt at all realistic imho. There are loads of uninsurable
properties that function as houses just fine. Mortgage cos will
absolutely not lend on such houses, dramatically cutting the field of
potential buyers. Sale value may be a few tens of k less.


This is not a cash buty - its part of a business plan doen on all
borrowed money. The option to have a total loss of the structure is not
something the bank would contenmplate.



My gut instinct is to go deep alongside, and pour some concrete to
prevent the roots getting back in.



I really doubt it would make any difference. Understand the problem:
trees cause changes in water levels, which cause shrink or expansion in
clay soils. It is this that cracks houses.


Yes, but they don't e.g lower the water table in outer mongolia when
growing in milton keynes.

The important thing is to prevent localised lowering in the vicinity of
the structure. Keeping the roots from appraching closer than about 6
feet is probably good enough.

Its obviously useless on new builds - why no make the foundations that
deep anyway? - but may have merit as a remedial action. I'll see what
structural engineers have to say.




That is a possible and very attractive option, since we know that
extension has been up for years, and isn't falling down...its just
caused some noticeable cracking - up to 6mm in places.



6mm is not large. If its not currently moving you could probably just
glue it together at the cracks and leave it at that, although of course
it is your surveyors advice you should follow, I'm certainly not trying
to supplant that. If it is moving, things would be different, and
probably a lot more expensive.


Yes. The question is how far and how fast.

The more I think about it the more I keep comong back to those trees.

Maybe they will have to go and thats that.



NT

  #27   Report Post  
The Natural Philosopher
 
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Anna Kettle wrote:

On Sat, 15 Jan 2005 14:13:22 +0000, The Natural Philosopher
wrote:


What might be very simple and totally possible is to trench down a
couple of meters about a foot from the footings, and fill that with
concrete. That would cut the roots there, and stop any further
penetration to the footings area. I believe willow roots are pretty
shallow.



Roots are pretty persistant and can get through concrete so I wouldn't
leap into doing this without more research. Maybe a plastic board
would stop the roots better


Roots cannot get through uncracked concrete. But I take your point.

Anna



~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repairs
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642

  #28   Report Post  
 
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Roots cannot get through uncracked concrete. But I take your point.

I think they can. A growing tree applies absolutely enormous forces to
anything that gets in its way. How on earth trees muster such forces I
dont know, but they can push retaining walls over, break them in two,
crack them etc. Having seen huge underground roots, I would assume they
can do exactly the same below ground.

NT

  #29   Report Post  
 
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Well, accordng to teh guys who did soil tests and advised on foundatns

or here, what happens is that teh tree roots permeate teh soil, and
lower the local water content, causing long term shrinkage.


Right. So building a shallow wall round the house isnt going to change
how much water comes into and out of the soil - I wouldnt think anyway.


It would seem to me that a concrete underground wall going down below
tree root level, would essentially place the tree in a 'pot' that

would
stop its roots drying out that part of the soil under the house, and
immediately adjacent to it.


I guess we made different assumptions, maybe if it went well below root
level it might work. But a surveyor will advise.


Good. In the end, we may simply do nothing, other than cosmetic
patching, and pay extra insurance...and use that to get a price

reduction..

I dont see how that will run. Banks dont finance buildings without
knowing the slightest thing about them. And whatever you do, those
cracks are uninsured when you buy.


Do realise that house insurance is optional. Of course its

desirable,
but I would not assume that it was automatically essential.


It is when you borow money against...the property. Its a condition of
lending.


Yup, which is why I mentioned a sleeping business partner. But that
might not suit you.


This is not a cash buty - its part of a business plan doen on all
borrowed money. The option to have a total loss of the structure is

not
something the bank would contenmplate.


Then I see the present owner making a claim before exchange as being
your only option, unless youre going to go the wealthy partner route,
or take the dodgy risk of pretending the cracks dont exist.


The important thing is to prevent localised lowering in the vicinity

of
the structure. Keeping the roots from appraching closer than about 6
feet is probably good enough.

I doubt that, but I lack the expertise to actually know.


NT

  #30   Report Post  
Ed Sirett
 
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On Sun, 16 Jan 2005 10:37:20 +0000, Andrew Chesters wrote:

Ed Sirett wrote:
On Fri, 14 Jan 2005 23:01:04 +0000, The Natural Philosopher wrote:

snip
Isn't this what building insurance is for?


[cynic]

No. Building (in fact, all) insurance is there to make money for the
share holders. They REALLY don't like paying out. Give them 1/2 an
excuse and you're on your own!!


Entirely agree - settlement of the building so that under pinning is
required is relatively uncommon.

I am assuming that the current owner has kept the property insured if it
needs under pinning due to ground movement they'll have to pay.
Buildings insurance is one of the few insurances I believe in.
However I was delighted to find that I could halve the premium if I took a
£2.5 excess. Since I don't want to pay for other peoples minor trouble
and will likely find it quicker and easier to fix minor stuff myself I was
happy. £250 quid /year saved every year. Probability of a major claim I
reckon is less than 1%.

If the current owner did not insure his house against the really big
trouble then he will have lost tens of thousands off the value for
under-pinning.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html




  #32   Report Post  
The Natural Philosopher
 
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wrote:

Well, accordng to teh guys who did soil tests and advised on foundatns



or here, what happens is that teh tree roots permeate teh soil, and
lower the local water content, causing long term shrinkage.



Right. So building a shallow wall round the house isnt going to change
how much water comes into and out of the soil - I wouldnt think anyway.



It would seem to me that a concrete underground wall going down below
tree root level, would essentially place the tree in a 'pot' that


would

stop its roots drying out that part of the soil under the house, and
immediately adjacent to it.



I guess we made different assumptions, maybe if it went well below root
level it might work. But a surveyor will advise.


Oh yes. That is mandatory. Otherwise its totally useless - roots will
just go under. This was the philosphy teh soil people passed to me - get
your foundations below root hair level or else.

Willows travel far, but not deep IIRC. Beech likewise.

Ash and maple go deeper. Particualrly I think Ash.



Good. In the end, we may simply do nothing, other than cosmetic
patching, and pay extra insurance...and use that to get a price


reduction..

I dont see how that will run. Banks dont finance buildings without
knowing the slightest thing about them. And whatever you do, those
cracks are uninsured when you buy.


The bank doesn't care any more than the property is worth X in good
condition, and there is insurance to cover any potential reduction of
its value below X.



Do realise that house insurance is optional. Of course its


desirable,

but I would not assume that it was automatically essential.



It is when you borow money against...the property. Its a condition of
lending.



Yup, which is why I mentioned a sleeping business partner. But that
might not suit you.


Not sure what that has to do with anything?


This is not a cash buty - its part of a business plan doen on all
borrowed money. The option to have a total loss of the structure is


not

something the bank would contenmplate.



Then I see the present owner making a claim before exchange as being
your only option, unless youre going to go the wealthy partner route,
or take the dodgy risk of pretending the cracks dont exist.

Its importamnt to evaluate the risk and get insurance. That is true I
think. It may be better cost/benefit to get the place cheaper and pay
higher insurance though.



The important thing is to prevent localised lowering in the vicinity


of

the structure. Keeping the roots from appraching closer than about 6
feet is probably good enough.


I doubt that, but I lack the expertise to actually know.


I think there is alot of paranoia and myth about subsidence. Apart from
the few houses that fall into mineshafts or off the edge of cliffs, most
houses just warp, twist, settle and lean. Like the tower of Pisa. Took
several hundred years to et to a dangerous state...:-)



NT

  #33   Report Post  
The Natural Philosopher
 
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Ed Sirett wrote:

On Sun, 16 Jan 2005 10:37:20 +0000, Andrew Chesters wrote:


Ed Sirett wrote:

On Fri, 14 Jan 2005 23:01:04 +0000, The Natural Philosopher wrote:

snip
Isn't this what building insurance is for?



[cynic]

No. Building (in fact, all) insurance is there to make money for the
share holders. They REALLY don't like paying out. Give them 1/2 an
excuse and you're on your own!!



Entirely agree - settlement of the building so that under pinning is
required is relatively uncommon.

I am assuming that the current owner has kept the property insured if it
needs under pinning due to ground movement they'll have to pay.
Buildings insurance is one of the few insurances I believe in.
However I was delighted to find that I could halve the premium if I took a
£2.5 excess. Since I don't want to pay for other peoples minor trouble
and will likely find it quicker and easier to fix minor stuff myself I was
happy. £250 quid /year saved every year. Probability of a major claim I
reckon is less than 1%.

If the current owner did not insure his house against the really big
trouble then he will have lost tens of thousands off the value for
under-pinning.


Current owner is a property management company who has let it in the
past. I suspect its condition is one reason its about to be up for
sale..its insured, and we beliecve a claim may be made, pending results
of vendors structural survey.

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