A house me & my wife like had some structural movement back in 1985.
After reading the reports underpinning was not done because trees
precluded(i guess stopped and caused) this. So the recommendation was
to "whole of the perimeter wall was and spine wall between the lounge
and dinning room piled, using small diameter piles, either needled
through the wall, or used as tension and compression piles
What does this mean ???
The trees have a perservation order(sorry for the bad spelling)
The same surveyor has again re-assed this prior to going on sale and
the report says "Overrall, there are no indications of any progressive
movements to the property, as externally there were no signs of any
These complications are refelected in the price. They are willing to
knock of 30 - 40k of the price. Price is around 365k
What would people do in my situation...
Any help would be appreciated
Thanks in advance
Your post seems to indicate that the walls were underpinned with pile
foundations and this has prevented further movement. You can do a google
search to find out what pile foundations are if needed.
You also indicate that the trees had caused the previous movement.
Its OK for a surveyor to say that no further movement has occurred, but what
you want to know is the likelihood of it occurring in the future. He should
be able to give an opinion on this which you can use to assess your risk.
Tree preservation orders (and the trees) can be removed if the trees become
dangerous or threaten or cause major structural damage.
This is a lot of money to spend on a house. If you really want it, then you
have to decide what is the worst thing that could occur (possibly further
foundation work) and if the reduction in price would cover this.
If you want peace of mind, then you simply look elsewhere.
Before you do anything check you can get insurance - most run a mile (in our
experience) at the first hint of anything. You do need to tell the insurance
companies. By all means ring a few up but a broker is best - find one who is
good. They may need a copy of the surveyor's statement.
Can you say where this house is - do you know if the soil is London Clay?
There have been 3 exceptionally dry spells since 1985 which have each caused
widespread subsidence damage, particularly 1989 - 1992. If no movement has
occurred during any of these then the piled foundations would sound as though
they're working as intended.
Even though the trees are subject to a TPO, you will still need to manage their
size regularly to minimise the risk of further damage. The more leaves there
are on the tree, the more moisture the tree extracts from the soil and the more
likely the soil is to shrink, so the trees will need to be pruned or lopped
every 5 years or so. You will have to apply to the Planners for permission to
Harry's point about insurance is very important. You need to make certain that
the insurers are told of the previous damage and the work done before they quote
you a premium. Otherwise you probably won;t be covered for any further damage.
Finally remember this. Out of two similar houses built on shrinkable clay, the
one that has been piled or underpinned is FAR less likely to suffer subsidence
damage than the one that hasn't. But it is vital you GET YOUR OWN FULL
STRUCTURAL SURVEY REPORT. Ask the Surveyor to comment particularly on any
structural movement and give him the history. If everything is OK, the price is
right and the insurance can be arranged, then I would say go for it.
You may find only specialist insurers will cover this, and their
policies may exclude subsidence, and may cost significantly more. If
you do have subsidence in future, you may therefore be paying the full
bill. You probably wont know exactly where you stand with insurers
until youve had a full survey, gone over all the paperwork with them,
and their team has assessed your situation - ie you wont know until
the house is yours and youve owned it, possibly uninsured, for a short
Subsidence strikes terror into people out of all proportion to its
problemness, it is an issue but it rarely causes any genuine danger,
and is in most cases fixable at quite a reasonable cost. But of course
there is the occasional horror story that everyone hears about. Should
you ever come to sell the place you might find an unreasonably large
price drop is the only way to shift it, and you may find that most
buyers dont want anything to do with it.
Houses with subsidence history can be a bargain, as long as you
understand what youre buying, and expect and accept the downsides.
I think thats covered the main issues.
An important point is that subsidence due to drying ground is only one half
of the equation. If conditions change so that the water content is restored
to the ground then heave is likely to take place, ie expansion of the
The upshot of this is that applying to remove the TPO in order to remove the
offending trees (if indeed they were deemed to be root cause of the
problem - sorry for pun) would be the wrong thing to do as it could trigger
As Peter points out, you would want to manage the trees to prevent further
damage as they grow.
email me at
richard at olifant d-ot co do-t uk
Thanks to all that replied.
I shall try and answer some the questions and give some more on the
original report- The property was built in the early 1970's. I am
unsure of the soil but one of the estimates assumed "1.0 M below
footing sand clay, below sandy clay firm stiff clay" as ground
conditions on pile design calcs section.
In this report the Probable cause was trees extracting mositure from
the clay content of the sub soil. In addition to normal subsidence, a
torsional effect, which accounts for the unusally large internal
cracking , as house had subsided difeerentially, coupled with a
(couple of may be a silly questions.) Any idea how much for the tree
work that would be required every 5 years(per tree).
If we live in this property for 10 - 25 years and no movemnt takes
place, do you still have to declare it ??? or will this record be
Insurance- The current owner insurance says they will insure it.
The current owner back in 1985 spent in the region of 24k correcting
Once again thanks for all your help ???
Not much if you buy a chainsaw and a nice safe scaffold tower to work
off. You nly need to stabilise the tree growth, not do anythin drastic
with it. Normal practoce is to cu them a given height from the ground
ecvvery few years, and let them spring from there.
Sounds like they built on low foundations too near the trees.
Up to a point all this won't make the house fall down - just crack it a
lot. Infilling the cracks with mortar etc is not unreasonable.
Yu could aslo, under condulatyon from suructural engineers, trench down
the outside with a digger, scrape the las bit out by hand and unfill
with concrete. This isn';t quite underpinning, but it cuts the tree
roots stopping teh shrinkage, and puts a barrier against new. Of course
as the soil wets up again heave is guaranteed - this might restore the
house 'straightness' somewhat tho.
Huh? I am not clear whether it is cleared onr not...if its BEEN
piled/underpined than it should be stabl;e by now.
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