Examination of Witnesses (Questions 4140
- 4159)
4140. What we have here is that part of the
Phase 3, Stage 1 Settlement Assessment Report in respect of 17
to 25 Wilkes Street.[27]
We have put this up because my understanding is that Mr Wheeler
owns a property within this group and this page is summarising
findings in relation to structural sensitivity, sensitivity of
particular features and finishes, and other matters in relation
to that building. Can you just tell the Committee what you get
from this information please?
(Professor Mair) Yes, what I described before
lunch was essentially the engineering analysis part which is shown
here and I explained that that led to the conclusion for this
particular set of buildings that the maximum tensile strain was
estimated to be 0.024 per cent which itself is a very conservative
estimate, and that would put it in the `negligible damage' category,
zero. That is the engineering part of the assessment as far as
settlement and potential tensile strain is concerned, but there
is also, and this is of particular relevance for listed buildings,
the question of the sensitivity of the building in terms of two
aspects, and I will enlarge upon these. One aspect is divided
really into two parts, the sensitivity of the structure, and,
by that, I mean the sensitivity of the building to tolerate movement
without significant distress, and there is an additional consideration
given to that which itself has a score. There is a second part
which is the sensitivity of particular features and finishes within
the building and the question as to how vulnerable or sensitive
those features are, and that also has a score. The table shown
near the bottom of this page summarises the position and, first
of all, you will see the sensitivity, the `predicted damage' category,
which is the third line down, and there you will see the score
zero, which corresponds to the `negligible' category in terms
of the engineering analysis leading to the tensile strain. You
will see that there are two other scores, one, the sensitivity
of the building structure, which in this case has given the score
one, and I will elaborate a bit more about what the significance
of the scores are, and there is also the question of the sensitivity
of any special or vulnerable features and finishes, which in this
particular case has given the score zero. The total of the three
scores are then added up to give the final total score which in
this case is one, and again the significance of that I will go
on to describe, but this is really by way of introducing the point
that, in the case of listed buildings, there are these two extra
criteria which are taken into account, the sensitivity of the
structure as a whole and the sensitivity of any particular features
and finishes within it.
4141. Now, in order to explain those two matters,
that is to say, the structure and particular features, we need
to go to a table which is to be found at page 11 of information
paper D12. We have got that up on the screen.[28]
My Lords, it is in your red pack of information papers, as you
saw yesterday, in the D divider, so you have hard copies of it
as well. I am so sorry, this is not the right one, is it?
(Professor Mair) I think you need table 2 which
is the next page.[29]
This table explains in some more detail what I have just been
describing. This is, if you like, the special scoring system for
the sensitivity of listed buildings and there are two separate
groups. The left-hand column is the sensitivity of the structure
as a whole to ground movements and sensitivity to interaction
with its neighbouring buildings, and the scoring system for that
is zero, one or two in terms of really increasing sensitivity
or severity, so, if it gets a zero score, that would be saying
that it is a masonry building with lime mortar, not surrounded
by other buildings, with uniform façades with no particular
large openings. If that was the case, that would get the score
zero. If the buildings were of delicate structural form or buildings
sandwiched between modern framed buildings, which themselves are
much stiffer, and perhaps itself the building has one or two more
significant openings, that would make it somewhat more vulnerable,
so it would get the score of one. Then, in cases where the buildings
which, by their own structural form, will tend to concentrate
all of the movements in one location, that is potentially of more
concern and that would get the score of two. That is how the sensitivity
of the structure in terms of the overall way it might respond
gets scored. Then, on the right-hand side there is a separate
grouping which is to do with the sensitivity to movement of particular
features within the building and again the scoring system is applied
so that, in cases where there were no particular sensitive features,
if that judgment was made, there would be a score of zero. If
there were brittle finishes, for example, faiences or tight-jointed
stonework which are most susceptible to movement, even small movements,
and difficult to repair, then they would be given the score of
one. If there were finishes, and this is a most important point,
which, if damaged, would have a significant effect on the heritage
of that building, for example, cracks through frescos, that kind
of example, that would get the higher scoring of two. The whole
purpose of this additional sensitivity scoring for listed buildings
is to take into account the heritage aspects of the buildings
in question. I was going to ask, Mr Mould, if we could perhaps
go back to that front-sheet example for 17-25—
4142. Just before we do, my Lord, Lord Colville,
put the question just before the short adjournment in relation
to cornicing and we see that that, I think, is a feature which
would fall to be considered on the right-hand side of the table.
(Professor Mair) Yes, that is correct.
4143. Insofar as it was a particularly sensitive
feature, it would fall within the right-hand side of the table,
and one can see that the most vulnerable, if I can put it this
way, category in relation to the right-hand side of the table,
category two, focuses upon elements which are of significance
to the heritage of the building. Do you see that?
(Professor Mair) That is exactly correct.
4144. MR MOULD: I do not know if you
feel able to comment on this but if one was focusing, for example,
on a building which had corniced ceilings is it right that one
of the questions one would need to ask as to where the existence
of that feature placed the building in this table, would be whether
that element of the building was or was not of importance to its
heritage value?
4145. (Professor Mair) Yes, I think what
you are asking me is the significance of the difference really
between the category one and the category two for the right hand
column, for finishes?
4146. Yes.
(Professor Mair) I think that if there
was something that was identified clearly as being part of the
heritage of the building, such as a very important fresco or some
feature like that, which was an identified aspect of its heritage,
and if that was present then that would be appropriate to be scored
under the category two.
4147. But the corollary is, if one thinks of
buildings of more than a certain age cornice ceilings are a relatively
typical feature of many buildings older than the 20th century,
for example, and features of that kind, which, if you will, are
no more than typical, the question would need to be asked, would
it not, whether such features, albeit present in the building
under consideration, did or did not merit any higher, for example,
than category one in this table?
(Professor Mair) Yes, they would not merit
any higher category than category one and arguably they could
even be in category zero.
4148. MR MOULD: I am raising points which
are moving towards the expertise of Alan Baxter, but I think it
is helpful to flag these points up with the Committee and I am
grateful to you for your assistance on that.
4149. LORD YOUNG OF NORWOOD GREEN: Yesterday
there was a lot of focus from one of the Petitioners, Mr Wheeler,
on the fact that he questioned, if you like, the integrity of
the assessment that had been made, the scores, because there had
not been in every case an internal survey. When I look at this
background document and how you allocate the scores it would seem
to be that that is necessary. But that may be an assumption too
far that I am making; can you clarify that?
4150. MR MOULD: My Lord, forgive me,
but we are going to come on to explain the significance of the
inspections that we carried out with this process in a very few
moments. Would it be convenient to deal with it that way because
we have a logic here and I would like to stick with it, if we
may? If we have not dealt with it to your satisfaction when we
come to it, then by all means we will deal with any further points
arising.
4151. CHAIRMAN: If you have not dealt
with it by the time you come to the end of Professor Mair's evidence
I am going to ask anyway.
4152. MR MOULD: I did not think we would
get away with it!
4153. LORD YOUNG OF NORWOOD GREEN: And
it will be more penetrating!
4154. MR MOULD: I am very grateful for
that indulgence. Professor Mair, I took you a little out of your
way, for which I apologise, but I hope it was helpful. Now we
want to go back to page 58, is that right?
(Professor
Mair) That is right.
4155. Is that right?
(Professor Mair) That is the page, I think
just briefly, and then I think we will need to go on to another
one. This is the summary page—we will go into more detail
shortly—for this particular structure, which results in
the total score of one, there essentially being three elements—the
predicted damage category from the calculation of the engineering
strain, the tensile strain; and then the other two categories,
the sensitivity of the building as a structure and then the sensitivity
of features or finishes.
4156. If we look at the top of the page and
with our minds cast back to the table you showed us a moment ago,
in relation to the left hand side of the table we can see under
the heading "sensitivity of structure" the score of
one given there and an explanation for that. Then as regards to
the right hand side we can see the issue of sensitivity in particular
of features and finishes is dealt with, a score of nil. And we
know that Lord Young wants us to explain how that is arrived at
given the level of inspection that was undertaken. So we go on
then to page 58.[30]
(Professor Mair) The heading of this page is
"historic buildings and features" and this really sets
out a lot of the details of the building in terms of its heritage.
It first and most importantly makes the point that the date of
the building is 1723—we see that four lines down—which
sets the scene for the experts who are assessing the type of building
and its vulnerability to movement. The very fact that it is 1723
immediately flags up that we are talking here about early Georgian
buildings. A bit further down you see other important features.
The site of the building is important; it is shown here to be
three stories plus cellars, plus the weavers' attics. You cannot
quite see those in the photograph but above the building there
is an attic as well—or there are attics along the building.
Then in much more detail—and I will not go through all of
what is written here—this is the assessment of the building
in terms of its description of what kind of building it is—any
special features, how it has been constructed—and below
that paragraph you will see the title, "significant or potentially
vulnerable features", and there are various points listed
down here about that.
4157. MR MOULD: Just in relation to the
question of height, Mr Wheeler had a point on that yesterday.
Can you explain to the Committee what are the significant factors
as regards height for the purposes of this assessment?
4158. CHAIRMAN: These are all things
you can see from the outside, are they? I would expect so.
(Professor
Mair) These are principally the things that could be seen from
the outside, that is correct, yes.
4159. LORD BROOKE OF ALVETHORPE: Yesterday
it was claimed that the report did not in fact give the true height
of the building and that this would have an impact that was not
being recognised.
(Professor
Mair) I can comment on that. I think actually that comment was
made about this row of buildings, if I am not mistaken.
27 Crossrail Ref: P23, 17-25 Wilkes Street, listed
Building Assessments, Phase 3 Iteration 1 Reports, Mott MacDonald
(TOWHLB-XR5A-056) Back
28
Crossrail Information Paper D12-Ground Settlement, Table 1, http://billdocuments.crossrail.co.uk
(LINEWD-IPD12-011) Back
29
Crossrail Information Paper D12-Ground Settlement, Table 2, http://billdocuments.crossrail.co.uk
(LINEWD-IPD12-012) Back
30
Crossrail Ref: P23, 17-25 Wilkes Street, Historic Building and
Features, Mott MacDonald (TOWHLB-XR5A-058) Back
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