Transcript No Slide Title

A Way Forward
(or a better Protocol)
P.G. Biddle
Determining which remedy:
• Persistent deficit (significant heave)
– Underpin with full anti-heave precautions
• Seasonal drying (predominantly)
– Vegetation control
•
•
•
Fell
Prune
Root control
–
Underpin
(if
tree
of
sufficient
value)
P.G. Biddle
Information required:
• Seasonal or Persistent deficit
• Which vegetation is involved.
• If vegetation control, proof of whether it has
been effective.
• Extent and duration of heave.
• Extent of movement for partial underpinning.
• Appropriate level of proof for situation.
• Speedy resolution for house owner.
P.G. Biddle
Efficacy of investigations.
Prelim
Assess
Seasonal or
persistent def.
Which vegetation

Involved.
Whether remedy
effective
Extent and
duration of heave
Extent of partial
underpinning.
Appropriate

level of proof
Speedy resolution
P.G.
Biddleowner 
for house
Trial
Soil
holes Invest.
Root
Ident.
Crack
monit.

Level
Monit.
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Preliminary assessment
Pattern of damage
Time of development of damage
Probable geology (BGS survey).
Proximity and type of vegetation
If conclusion probably vegetation ……
P.G. Biddle
Other factors to consider:
Ownership of the tree:
Own tree
Third party
TPO or Conservation Area
Value of the tree.
P.G. Biddle
Value of the tree.
LTOA use CAVAT
Relevant to remedial options, not to
extent of investigations
If the owner values the tree, it is
worthy of proper investigation
P.G. Biddle
Other factors to consider:
Ownership of the tree:
Own tree
Third party
TPO or Conservation Area
Value of the tree.
Number of trees / shrubs
P.G. Biddle
Essential
Desirable
Useful but not necessary
Waste of resources
Scope of
investigations
Value
Owner
of
ship tree(s)
Own
Tree /
shrub
Third
Party
tree
Number
of trees
Low
Single
Many
High
Single
Many
Low
Single
Many
High
Single
Many
TPO or
Cons. area
P.G. Biddle
Single
Many
Level Crack
Monit. Monit.
Trial
hole
Root
Ident.
Plast. Desic. Desic.
index autumn other
Preliminary assessment sufficient
Application of level monitoring
9
Initial
diagnosis
Confirm
diagnosis
Confirm
efficacy
Action
8
Movement (mm)
7
6
5
4
3
Only if needed
2
Soil
invest.
1
0
O
P.G. Biddle
N
D
J
F
M
Trees
felled
A
M
J
J
A
Earlier!!!!
S
O
Application of level monitoring
• Install level monitoring at first visit
• Level distortion survey if possible
• 2nd set of readings (after 6 weeks) :
• Initial diagnosis of pattern.
• Initial diagnosis of which tree(s) involved.
• Put TP on notice. TPO application or CA notification.
• 3rd / 4th sets of readings (after 12 / 18 weeks)
• Confirm diagnosis. Update TP and Local Authority.
• Consider need and location for soil investigations.
• Decide on and implement action.
• Continue monitoring to confirm efficacy.
P.G. Biddle
Level monitoring with late notification
9
Confirm
diagnosis
8
Movement (mm)
7
Action
6
5
Claim
notification
4
3
2
Set
up
1
0
O
P.G. Biddle
N
D
J
F
M
A
Initial
diagnosis
M
J
J
A
Confirm
efficacy
s
O
Risk assessment
P.G. Biddle
Castellain Mansions
Castellain Mansions
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
0
Datum April 1995
Movement Sept 1995
-10
-20
P.G. Biddle
Risk assessment
•
With suitable data, one can
identify overall degree of risk
•
But not which individual tree
poses that risk.
•
So should be trying??
P.G. Biddle