MAN ON A MISSION:
Architectural Cladding Association chairman Stephen
Maddelena is determined to prove to contractors the
time and cost savings possible with precast.
Precast's share of the cladding market
is growing, but not as fast as Architectural Cladding
Association chairman Stephen Maddalena would like.
He tells Will Mann why dyed-in-the-wool attitudes
are holding back its wider uptake.
The economics of precast cladding add
up to anyone with a basic grasp of a balance sheet,
but Stephen Maddalena still has a job selling it
to the wider construction industry.
"We're fighting against the traditional
way of building things," says the managing director
of precaster Marble Mosaic. "Architects want
to design every job so that one stone has to be laid
on top of the other, and those are the only kind
of jobs that most main contractors know how to build."
Changing times
Change is in the air though. "We're
starting to see contractors who are more switched
on to precast's benefits," says Maddalena, who
chairs the Architectural Cladding Association (ACA).
"The likes of Sir Robert McAlpine,
Bovis Lend Lease and housebuilder St George - where
the construction team is ex-Lovells - all use precast
widely.
"We are currently working on a
project in Piccadilly Circus where there are obviously
major access issues and the main contractor told
the client: 'We won't build this unless it's precast.'"
Precast's share of the cladding market
is still relatively small, probably between £50m
and £100m, which is only around 2% to 3% of
the whole cladding market. Growing that share is
Maddalena's mission at the ACA.
Members first
The association is one of construction's
smaller trade bodies, with only three other members
besides Marble Mosaics: Techrete (UK), Trent and
Belgian firm Decomo. Redland Precast of Hong Kong
is an international member.
But the slim membership is partly
due to the exacting standards set by the ACA; aspiring
members must be not only manufacturers, but also
designers, constructors and hauliers. Demonstrating
the point, outside Marble Mosaic’s Weston-super-Mare
factory there are three lowloaders, three 30ft trailers,
plus three other, shorter trailers. For bigger jobs,
40-footers are hired in, Maddalena adds.
The £6m turnover Marble Mosaics
was founded 100 years ago in Bristol, but in the
past decade or so, the company has gradually spread
it's workload around the country. Funnily enough,
Maddalena's first job in the capital was the facade
for CJ's own offices - and it still looks in pretty
good nick, 20 years on.
At present, key markets for precasters
are residential apartment blocks, student accommodation,
commercial offices and retail centres.
"The rebirth of the town centre
has been great for us," says Maddalena. "Retail
centres lend themselves to precast because speed
of construction is of the essence for the client,
and they want minimal disruption to the surroundings.
They tend to be large work packages too, and there
are quite a few more in the pipeline.
"Precast cladding generally works
best on schemes with 500m2 of facade. Below 250m2
and you're not going to get economies of scale."
Cladding costs
The cost of precast cladding starts
at around £275/m2 'on the wall' for recon (reconstructed
stone) panels, give or take 10%, says Maddalena.
Brick- or tile-faced panels are around the £300
mark, with high-quality stone like Portland in the
region of £400/m2 to £500/m2.
"But the point is," he adds, "this
doesn't factor in savings on the other trades necessary
when the facade is constructed in situ. You won't
need any bricklayers, which are a scarce resource
at the best of times.
"And you won't need any scaffolding
either - and in places like the City of London that's
very important to both clients and main contractor.
They want precasters who can come in on a JIT basis."
This means the precaster has to take
on a fair degree of risk. "Our yard in Weston
is a buffer between my economic production and deliveries
to site," Maddalena explains. "The lead-in
we typically require is eight weeks for design development,
then 12 weeks for the manufacturing. With stone there's
a longer lead-in, if we're sourcing Chinese granite,
for example, it might take us three months to obtain
the materials.
"But we can give a main contractors
certainty of supply, which they might not get with
bricklayers."
Looking ahead, Maddalena sees plenty
of scope for further technological advance in the
precast cladding sector.
"In future, there's no reason
why we shouldn't be casting in services," he
says. "We're already taken a step towards that
by casting in air vents.
"We're also supplying more and
more panels fitted with insulation, which has been
driven by Part L.
"And the manufacturing process
itself is becoming more sophisticated; Techrete has
just invested £3.5m in a new UK plant that
features an automotive industry-style Carousel system."
Geared for delivery
The precast cladding sector is geared
up to deliver if the wider industry is prepared to
give it a chance.
"A lot of our business is secured
by negotiation with those who realise the direct
and incidental benefits of precast cladding," says
Maddalena, "but not enough contractors evaluate
what we have to offer early enough. We are presented
with a number of schemes that have been designed
for traditional construction, and we then have to
adapt them for precast.
"But if we'd been involved earlier,
the scheme would have been more buildable, cheaper
and safer.
Cladding Bristol fashion
A few miles up the M5 from Marble
Mosaic’s Weston-super-Mare factory, there's
a classic example ofthe kind of project Maddalena
would love to do much more of.
The office development. in a busy commercial
area of Bristol, was designed specifically for precast
by architect Stride Treglown, largely in recognition
of the need for a speedy construction programme and
the potential for access problems with an in situ
scheme.
Wates is constructing the office for
developer RokEagle and the facade features 210 precast
panels.
The recon panels have a coarse textured
surface below second floor level, and a smooth acid-etched
finish above, giving a Portland stone 'look' - though
Maddalena points out the end result is not porous
and will weather much better than natural stone.
The panels also have insulation fixed to their internal
face to enhance their thermal performance.
Thirty-eight of the panels have a
framed and glazed window cast into a 5.75m x 2.5m
aperture, and the risk of the glass breaking during
transportation is carried by the precaster, Maddalena
reveals. The windows are fitted into the aperture
by a glazing contractor, who sets up in the corner
of Marble Mosaics' yard.
"We did have some problems with
this, mainly because the framing system wasn't fitting
into the panel apertures," says Maddalena, "but
in some respects, this demonstrates the advantage
of precast - we were able to sort the problem out
in the yard, rather than when it was on the building."
Wates has been installing between four
and six panels-a-day on average, mostly using the
site's 80t tower crane. The only facade the tower
crane could not reach was the north elevation, which
meant bringing in a mobile crane with a 4t lifting
capacity. This caused the only disruption to the
surroundings during the facade installation, forcing
the closure of the adjacent road for a day.
The panels are attached to the building
via bolted connections, which engage in channels
in the main concrete frame. Their weight is supported
by stainless steel corbels, which are cast into each
panel.
The bearing points of the panels are
adjacent to the building's structural columns. This
dispenses with the need for midspan loading which,
as Maddelena points out, would be necessary with
brickwork or blockwork.
Once the panels are on the building,
the facade is weatherproofed with the application
of polyethylene cord in the 18mm to 20mm gaps between
the panels, then a mastic seal on top. This is applied
by abseilers.
"We've only started using them
relatively recently," says Maddalena, "and
they're quite expensive compared to the window cleaner
cradles we used before. But they're very quick, which
is the key factor on a site with limited access. "
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