Here's something I haven't done before in 15 years of blogging - a report on a visit deliberately posted 52 weeks late.
This weekend is Heritage Open Days weekend, with thousands of buildings open across the country (generally everywhere except for London). Last year I went on a visit to one such building - or set of buildings - in Watford, but decided not to blog about it because
a) most of you wouldn't be very interested
b) none of you could repeat the experience until next year
That same set of buildings is open again tomorrow, for a special Open Day, which takes takes care of b). Unfortunately a) remains true, but I'm going to blog about it anyway, because since when has that stopped me, and one of you might decide to go.
The Building Research Establishment is based in Garston, just north of Watford, and has been there since 1925. Set up by the government, its purpose was to investigate building materials and building methods to provide factual support for the construction industry. If you've ever wondered who first studied the behaviour of reinforced concrete in floors, or developed the British Standard for bricks, it was them. In 1972 BRE was merged with partners investigating timber and fire prevention, and in the 1990s the organisation was privatised, so exists today as a sort-of-independent trust. But its key purpose remains health and safety, checking that buildings don't burn too quickly or fall apart, as well as a strong focus on environmental sustainability.
If you visit tomorrow, here's what you might see.
Testing the Bouncing Bomb: The success of the Dambusters attack owes much to secret preliminary work in Garston three years earlier. Barnes Wallis needed to determine the weight of explosive needed, where precisely to hit the wall and at what angle, so a scale model of the Mohne Dam was constructed across a small stream in the grounds to test that out. To properly mimic its construction two million tiny bricks were used, each about half a cubic centimetre in size, and laid in situ over several wintry weeks. A sequence of explosive charges was then deployed underwater, each a different distance from the face of the dam, and by the tenth bang the structure was terminally damaged.
Testing of further models happened elsewhere, notably at the Road Research Laboratory in Harmondsworth, and Garston's broken model lived on as a wartime secret. Visitors to the Open Day can see it tomorrow - a peculiar weir in the woods, cut through by a trickle of water. There'll also be a really interesting 30 minute presentation indoors about the history of the Mohne Dam raids, including archive drawings and rare test footage. It was really interesting last year, anyway.
Structures Lab: When you have buildings to test, you need a big building to test them inside. This large concrete bunker fulfils that aim, with considerable capacity in which to build multi-storey towers, smash things, shake things, and generally test materials on a large scale. No photos during your scout inside, sorry, because there might be commercially sensitive projects erected within. But several buildings you use daily, maybe even live in, stand safely because of standards established after experimentation in Garston.
Wind tunnel: No photos here either, but what a facility. BRE has what's essentially a giant fan in a tube, capable of firing a 120mph blast of air at whatever's placed in its way. Usually that's a scale model of a new building at roughly 1/250th normal size, placed on a board showing its surroundings, to check for dangerous vortices, updraughts or gusty corners. On the Open Day tour you'll see several of these architectural models, handmade on site, plus get the chance to go up the ladder and stand in the blast (at less-than full whack). [video]
Anechoic Chamber: Or, possibly the quietest room in Britain. All of its surfaces are covered by metre-long wedges of expanded polyurethane, twenty-two thousand in total, which almost completely absorb all sound. Stepping inside this giant grey room was like entering a spiky padded cell, and all the more peculiar for bouncing gently on the net that covers the equally spiky floor. I didn't experience perfect echo-free conditions because the door was open... and you won't experience the ageing chamber I stood in last year because they've built a new room since. But if you've ever wondered how manufacturers confirm the decibel level of hairdriers and other electrical equipment, it's by hiring spaces like this. [video]
Burn Hall: This building's been in the news recently as it's where tests on tower block cladding have been carried out in the aftermath of the Grenfell Tower disaster. BRE has been at the heart of fire research for years, including many of those public information films you'll have seen where a match or smouldering cigarette turns a sofa, and then an entire room, into a blazing conflagration. The Burn Hall's not on the self-guided tour route this year, nor was it last year, but it's reassuring to know that such an infernal facility exists.
Innovation Park: With an eye to climate change and the future, BRE opened this village of full-scale demonstration houses in 2005. Various sustainable methods of construction have been used, and several specialist materials and technologies are showcased within, the idea being that architects and industry professionals can visit to get ideas on how to build better. For the lay visitor it's still fascinating to wander around a series of empty homes and wonder whether you'll ever live anywhere so forward-looking. [video]
Timber Library: Imagine a library not for books but for book-sized specimens of timber. This 'Xylarium' contains thousands of different types of hardwoods and softwoods, each with subtly different properties, and was especially useful in pre-internet days for architects and builders to choose the right material for the right job. It's still the largest timber library in the world, and utterly charming, but also potentially endangered should budget cuts ever condemn this woodpile for the chop.
And also: Step inside Bucknalls, the Victorian mansion the government bought up in 1925, where the heritage chaps'll be hiding away. Throw your kids onto the bouncy castle for a different kind of structural testing. Pop into the staff cafe for a drink and a nice lunch. Wander the leafy grounds of what's usually a highly restricted site.
To visit the Building Research Establishment Open Day tomorrow you'll need to register to attend, which is easier than it looks, and print out a sheet which tells you how to get there. Doors open at 10 and close at 4, and the weather forecast looks better than the washout I experienced last year. The whole day's organised by staff volunteers who've given up their Saturday to attend, so deserve a decent audience... should you be in the area, or fancy a fascinating look round somewhere important you'd never normally go.