265cos_The architecture of the White Picket Fence.

The picket fence is a type of timber fence often used decoratively for domestic boundaries, distinguished by their evenly spaced vertical boards, the pickets, attached to horizontal rails. The white picket fence came to symbolise, particularly in the US, the ideal middle-class suburban life: the nuclear family with its 2.4 children, a dog, a station wagon, a large house and peaceful living. With his film Blue Velvet, David Lynch deployed the picket fence as a visual ploy to subvert suburban living as “stultifying at best, soul-poisoning at worst. The visual monotony of a given neighborhood’s cookie-cutter architecture becomes a predictable stand-in for the unthinking conformity of the community’s expectations, as well as the narrowness of the denizens’ dreams and desires.”

265cos_Brick walls, slate roof

The materialisation of our Costa Street project in Peckham is merely a contemporary interpretation of the traditional two-storey semi-detached house. Formally this was a central entry, with framed windows and a pitched roof;  materially, brick walls and a slate roof.

265cos_ slate v brick

Slate (roofs) and brick (walls) are ubiquitous building materials in London and thus can readily facilitate planning consents through ‘normalcy’. On the other hand the architect in her quest for innovation is always asking: how can I contribute something new to the dialogue between brick and slate? She did a quick mock-up… TBC

072hin_FROM CARVING TO CASTING: MAORI HERITAGE SPEARHEADS THE WAY FORWARD

Keywords:
  • xylothic conversion
  • taiaha
  • inclusive Māori carving

Amin Taha_15 Clerkenwell Close as three short films.

     

265cos_Bob Parkin talks firefighting

How are fires fought in high-rise blocks?

The deadly blaze at the 24-storey Grenfell tower block in west London has shocked the UK. Fire services around the world have to deal with blazes in high-rise blocks, so what lessons have been learned?

Firefighters arriving at the scene of a high-rise fire would normally set up a base about two floors below the actual fire, says Bob Parkin, an ex-firefighter turned safety consultant. This allows them to set up entry control points, so firefighters going to fight the blaze can be recorded, and crucially, have their breathing apparatus checked so it’s clear how much time they can spend in a dangerous, smoke-filled area. The amount of time each person can spend fighting the fire is limited by the amount of air available – so any minutes spent climbing up into a building with equipment is precious fire-fighting time wasted. “You’re going to use a considerable amount of air going up the 10 floors, so because of that and various other things, they will set up the control point two floors below the fire,” Mr Parkin says. Once they are able to go in, the immediate focus, if people are reported to be trapped in the building, would be on rescuing them, rather than firefighting, and the firefighters would carry minimum levels of equipment for that reason, he adds. “They will have to fight their way in, in some instances, but they will take chances when people’s lives are at risk, without a doubt.”

But the situation faced at Grenfell Tower in London would have been extremely difficult, Mr Parkin says, because the fire was able to spread so rapidly, and appeared to engulf nearly the entire building. Having to get 20 storeys up to rescue people in that situation “is just unbelievable”, he says. Without extra air supply for the person rescued, the journey back out of the building would be extremely dangerous.The fire brigade would also have had to operate from a very low level in the building because of how far the blaze had spread, and there were concerns that the building might collapse. https://www.bbc.co.uk/news/uk-england-london-40273714 We now asked Bob to look at a small block of flats made from CLT. Surprisingly CLT solid wood elements are more fire-resistant than is generally assumed. CLT panels have a moisture content of approx. 12%. and so if CLT is exposed to fire, and thus to an elevated supply of energy, its temperature rises and the water molecules embedded within start to evaporate at approx. 100 °C. At temperatures above 200-300 °C, these chemical compounds decompose in a process known as “pyrolysis” (whereby gas emissions from combustible components in the wood burst into flame), gradually spreading along the wood, leaving a charring area behind it. This char layer is formed from the carbonaceous residue of pyrolysis, which burns, generating embers. This layer’s properties — in particular, low density and high permeability — act as heat insulation and protect the underlying, undamaged wood. This results in a carbonised surface which protects the internal CLT layers which have not yet been exposed to fire and although in a fire, solid wood constructions become charred on the surface, the process of pyrolysis and the behaviour of wood can actually be predicted (unlike steel or concrete constructions). Through the properties of pyrolysis and the ability to form a char layer, the building material, wood, has inherited its fire resistance from nature itself. By contrast, steel constructions, for example, require additional fire protection measures. The environmentally-friendly building material offers unique features when exposed to fire, which means that CLT elements have a high level of fire resistance.

265cos_TOOL OF THE MONTH: FREUND MASTERCUT SLATE CUTTER

Who would have thought cutting slate could be so easy? I start to think a whole generation of architecture students at NCKU Taiwan making slate models. Marvin will make a slate model of our Costa St project, by way of example. 

Tramezzino: a triangulated sandwich panel?

The tramezzino is a: triangular Italian sandwich with the crusts removed and are popular and inexpensive. The origin of the tramezzino can be found in (Caffè Mulassano) in Turin where I worked for Andrea Bruno Architetto and where I also met both la Juve and Lingotto.  The tramezzino I understand to be a halfway, between breakfast and lunch but also between the triangle and the regular polygon. I like triangles. It reminds me of Polynesia as triangulation in navigation gives 3-point geo-spatial fixity. What happens if we triangulate the fibre cement sheet cladding on our proposal by cutting along the diagonals?

265cos_WHAT’S THE SECRET ABOUT SECRET FIXINGS?

“Look mum, no hands!” Secret fixing is the architectural equivalent of riding your bike with no hands. That’s really not so difficult when actually “Look mum, doing a wheelie” is far more daring. Your hands are on the bike but the bike is being propelled at a balanced crazy angle. Even better is a rodeo-like one-handed wheelie. Trying to implement difficult architectural geometries made me question whether it is then necessary to complicate matters with the economic overlay of secret fixing which often requires curtain walling ‘cassette cladding’ diseconomies to create material strength through extruded depth. One could secret fix though through bonding: a triumph of the chemical over the mechanical. Or is it? How do the insurers / warrantors assess the fixation risk? Mechanical could puncture a waterproofing membrane for example. SuperGlue was promoted when I grew up as ‘one drop holds a tonne’ but these were laboratory conditions promoting tensile not shear strength. And who says the contractor applies the correct amount when cost cutting quantities increases profit? The name’s Bonded, James Bonded? Doubtful when he still uses a mechanically propelled weapon. So let’s keep it simple: a mechanical face-fixed stainless steel screw is relatively low-tech ‘8-bit solution’ for an easy fix without the need for an ‘Approved Installer’> given the affordability crisis affecting house building in London I am convinced this is the way forward.    

265cos_CLADDING RUSHES

As much as brick corbelling is of innovative interest and fits the brick context, brick doesn’t stack up. In terms of weight, 22,000 bricks @ 2.4 kg per brick means the cladding would weigh 50 tonne and increase pile loads even before we cladding one considers Ancon bracket shelving @ 6kg/m). A lighter cladding system would reduce pile loads from say 10kN/m to, for example slate, to 2kN/m. In terms of time, assume 500/day given a good brick layer corbelling = 44 days * 1.5 risk = 66 days but let’s say 2 months… plausible if the programme was split into parallel interior and exterior works). So what are the cladding alternatives? Cor-Ten? Good fit in terms of contextual robustness but proprietary Cor-Ten systems at first glance could be Kingspan’s curtain walling. Not cheap at £100/sqm supply doubling to £200/sqm installed = £70k. Also the Kingspan system is a say 1.5mm thick biscuit tin fitted as a ‘cassette’ on a curtain walling system. Many of such systems look like commercial warehouse façades. Ask Kingspan if there CNC system allows for large 2m high panels say supported internally by a timber cross member to avoid the biscuit tin from denting. Plywood? Our House on Motiti (in New Zealand) was made in 1996 utilising 12mm thk rough faced WBP type ply. How does it look 20y later? Will ask the client who still lives there today… Visual degradation, say due to surface discolouration as evident in Lynch Architect’s Greenwood Road house, could be attended to by staining so how did Motiti perform in terms of water tightness? And how could it inform self-building in London? I see the House K – Tham & Videgård Arkitekter also used plywood so it seems it could work in a European environment. I believe the Dubbel Huis by MVRDV was also plywood clad as was David Adjaye’s Electra House. So using the filmic equivalent of a ‘rush’ deploying blending raw fast techniques, in this case Tham & Videgård, our project in Peckham might, fenestration not pertaining, might look like: