UKTC Archive

RE: Heave Risk Assessment

Subject: RE: Heave Risk Assessment
From: Jon Heuch
Date: Jan 20 2021 15:27:13
“it might be very difficult to predict…..”


No need to shoot you down in flames, Alastair. The basic issue is that it is
very difficult to predict what might happen but when heave does happen you
don’t really want to be held or even thought responsible. The arboricultural
rule of thumb based on age is simplistic. Yes, what you outline is the basic
type of situation but buildings are complex things, possibly of different
ages, of different foundation type and depth. Some of these cases go on for
years. I have one on my desk with site investigations dating back to 2011
and vague rumours of previous claims in 1990 or 1997 (who would keep
paperwork that old!)…..and they are still trying to work out how deep the
foundations are at different parts of the building and what the soil
conditions are under the property.


Giles’ book does describe persistent moisture deficits occurring after
buildings are built; it’s all very well saying the building will move back
to where it started from but that assumes soil swelling is uniform both over
time and over the whole structure. This really isn’t very likely. Much more
likely is that some parts of the soil swell more quickly than others.
Differential movement may occur and that is what causes cracking.


So ensure or at least recommend that the houseowner has appropriate house
insurance with standard “heave, landslip and subsidence cover”. Excess
likely to be £1,000 and if more it suggests a previous claim or restrictions
on the policy. The unpredictability of the situation is therefore covered
and whilst heave is best avoided, the houseowner at least has the support to
take them through a  process that may be long & stressful. Life gets
interesting when the houseowner doesn’t have insurance…..




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