A Little bit about me...

I'm a Structural Engineer, specialising in conservation, at Hurst Peirce + Malcolm in London. I don't wear tweeds, am not particularly "cultured" and I'm not that old, but I do care passionately about the conservation of old buildings. I am a Chartered Structural Engineer, a member of The SPAB (formerly on the founding committee of the reborn Berks, Bucks & Oxon Regional Group), a Friend of SAVE Britain's Heritage and have recently completed a PD Diploma in conservation at West Dean College, with a view to achieving CARE accreditation. I hope to give you regular updates on my trials and tribulations as well as some insight into projects I am involved with and things I believe in.

Be patient with me - I'm no writer and I'm normally up to my eyeballs at work........

All views expressed here are my own.

Hurst Peirce + Malcolm, Celtic House, 33 John's Mews, Holborn, London WC1N 2QL

07854 624692 - richardsalmon9@gmail.com


Sunday, 3 July 2011

Phoenix from the flames

This Grade II listed barn in North Norfolk dates back, at least in part, to the late c16, but is now quite a complex of bolt-ons of varying dates. It has been partially converted for use as a private function room and is held under lease along with the adjacent, but separately listed farmhouse.

The fire started externally in the open-sided lean-to (cause remains disputed) and apparently lasted approximately two hours until extinguished by the Fire Brigade. During this time, the fire had spread into the main barn, damaging sections of the main barn vaulted roof (lower slope on fire side, upper slope on opposite side), as well as entirely gutting the lean-to roof itself.

We were appointed to design and project manage the reinstatement, liaising directly with the Insurance Loss Adjusters and local Conservation and Building Control departments.

On contacting the Conservation Officer, we were advised that so long as reinstatement works were "like-for-like" they would take no further interest. A little surprising I have to say. Perhaps he thought I knew what I was talking about! We did stick with the like-for-like philosophy as far as possible but had to deviate when an existing structural detail was found not to work, or in the case of the low level windows where we replaced some ugly 1980's windows with something more appropriate (seeking listed buildings consent as we went along, of course).

Fires can be devastating, but quite often, if caught early enough, apparent damage can look much worse than it is and much can be salvaged. Large old timbers for instance will char to a certain depth and then stop, with the charring zone actually protecting the sound timber beneath. We did calculations to prove that the chunky original trusses and some of the larger purlins were still man enough to work, even on a reduced section size. Once again, traditional construction proves to be quite resilient.

One thing to beware of though, is just how wet things get after the Fire Brigade do their thing. Some of the building elements took a full 9 months to dry out properly.

See below some annotated photos showing before, during and after repairs.

An archive photo of the barn before the fire. During the repair project it was discovered that the building had suffered a very similar fire event about 20 years before, meaning some elements of structure had already been replaced.

The lean-to roof completely gutted. The timber posts were charred, but could safely be re-used as the depth of charring was not significant.

Charring to lower slope rafters and wall plate. In most locations the wall plate was thick enough to save, but most of the rafters were too deeply charred to remain useful.

A shot showing the extent of damage within the main barn.

What we considered to be one of the original barn "windows". Unglazed, with hardwood rhomboidal mullions, it was very disappointing when we finally decided it could not be saved due to a combination of deep charring and historic beetle damage. We commissioned new slow-grown softwood matching frame with recessed glazing (as subsequently agreed with the conservation dept)

New slow-grown softwood lower rafter sections scarf-jointed to the remaining upper rafters and with renewed peg joints to connect to purlins. Note the de-charred truss rafter in the foreground.

The results of the first attempt at removal of charred and sooted timber surfaces. Started without our approval, we managed to stop this mechanical clean before too much damage was done! Always a philosophical argument whether to leave and consolidate charred timber surfaces as part of the building's history. The decision was made for us here!

A structural strengthening plate added to one truss member where charring added to the problems of this already weak section.

A repaired repair - this truss had previously been strengthened by splicing, but the fire damaged the splice so had to be replaced.

The main barn roof completed. New members blended into existing and given a coat of breathable stain. Ceiling relined in a light board with natural insulation and breather membrane added above. We also added a fire break between the main and lean-to roofs to ensure the same thing could not happen again.

Inside the lean-to: Our own 'forensics' showed that the monopitch trusses had the usual mortice and tenon connections, but were held together with Glasgow nails rather than pegs, so we replicated this. The repointed areas of wall show where the existing mortar had one a strange hue of pink and was crumbling away (flint and bricks showed no signs of damage). Note the new low level windows, a bit less "chunky" than those they replaced.

The lean-to from the outside, all new apart from existing posts and pantiles (reclaims used to replace those broken in the fire).

2 comments:

  1. Your restoration of that house, especially when you repaired the lean-to roof, is simply astounding. You even strengthened it to make it last. I hope many generations get the chance to see that antique but resilient piece of history.

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    Replies
    1. Thank you Vernice, for you kind comments. Yes, these buildings are more resilient than we give them credit for, but we also must look after them.

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