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

Saturday, 1 December 2012

In a nutshell

Some of you will know by now that I am moving on in the new year, to one of the oldest and most highly respected consulting engineering practices in the country (and who specialise in conservation). Yes, I will have to commute into London again, but so be it. This was too good an opportunity to turn down and I'm looking forward to jumping into the deep end again (best get revising over Christmas!).

Given the imminent move from RDT to Hurst Peirce + Malcolm , just in case it's my last scribble here, I thought I'd post a quick photo-essay of our most recent piece of involved conservation work; a shop unit in Chesham, Bucks. This was a particularly good example of a project presenting a range of issues facing the conservation engineer in practice. Conservation "in a nutshell" if you will, from an adjoining owner that wouldn't repair his own rotting timber frame wall (can't elaborate as Party Wall negotiations ongoing), to all manner of impermeable finishes, to a real mish-mash of iron, steel and timber alterations to unravel.

This Grade II listed, three storey building, according to the official listing dated back to c.1740, had been converted to a shop at ground floor in Victorian times (at which point the entire front fa├žade timber frame was removed and replaced with rendered brickwork) with the two upper storeys in residential use until the fairly recent past.

Our client had only recently bought the building freehold. Having been born there, he felt somewhat philanthropic towards the sorry state it was in, but was in for a bit of a shock when the repairs, estimated at £75k by his commercial surveyors, turned into a bill in excess of £250k once the full horror was uncovered.

Unfortunately, ill health put an end to any long-term plans our client may have had, but not before we were able to make the building weatherproof and structurally stable. (See annotated photos below)

Hopefully, I will be able to continue writing posts from time-to-time, but this will obviously depend on company policies and the amount of spare time I get.......

Photo from the 1920's (nicked from the Cheshammuseum.org.uk website). Our building is on the right-hand side of this old roadworks, yes, roadworks scene.

The entire roof had been covered in this "turnerised" coating: A reinforced bituminous sheet material, painted to try and match the old tile colour. Just laid straight on top of the old tiles. Presumably sold as a 'maintenance free' solution, I would personally like to shoot in the nether-regions whoever it was that allowed this to happen. Horrible stuff....

Leaks in the so-called protection coat in the rear valley gutter led (eventually) to the partial collapse of the roof structure (the point at which we got called in)....

..... but not before water had been penetrating the building fabric for many years (upper floors uninhabited even with retail premises at ground floor). A wide variety of fungi greeted us on our first inspection.

Not satisfied with trying to waterproof the roof, someone had also tried to waterproof the external walls with cement render too. Result: Complete loss of original timber framing in places where render had cracked, let water in, but not out again.

Took a while to figure out what was going on here. Eventually found an original lower purlin was being asked to carry the load of a more recent cross beam (installed to support original upper purlins instead of resolving actual racking roof problem) and had snapped as a result. Existing door frame below seemingly happy to carry all the load, one way or another....

An ingenious one-sided forged iron joist hanger. Probably would've been ok had the end of the joist not started to rot away.

Some of the steelwork used to support the original timber frame allowing the open space for the shop unit below. Although it looks quite puny, this back-to-back channel arrangement was found to be perfectly capable of supporting the required load from above.

As much as I hate to admit defeat, this particular original purlin had been so badly eaten away that even the historic  steel strapping wasn't enough to save it this time.

You can't always rely upon the description in a listing, as many buildings were not inspected internally at the time of original listing. As noted above, the listing states that the building dates from c.1740 - You should have seen the Conservation Officer's eyes light up when presented with the stripped back remains of what we agreed was probably a c.1550 hall-house. (Upper floors inserted during c18th, we think)

Here is more of the original timber framing with wattle & daub infill panels.

The saddest loss for me was the failure, due to rot, of one of the original tudor cross-frame principal rafters. Here are the remains being used to help model its replacement in new air-dried oak (lucky find by the carpenters at a local timber yard).

Despite the need to replace the one failed purlin, we found just enough guts left in this (and other) original wind brace(s) to be able to keep it.

Both supported purlins at the frame junction had rotten ends. Here the carpenters  are preparing a new oak shoulder  to support the scarfed ends of both purlins (cut back clear of the extents of the wet rot). Note also more original wattle & daub infill.

A new jowl-post fitted in the rear wall, before being worked down to size-match the original lost section (The valley gutter beam had also rotted beyond repair and it's replacement was to be fitted to the jowl in due course).

Finally sorted out the earlier noted mess of timber. New lower purlin and wind braces installed and existing cross beam now hung by specially forged steel stirrup strap.

After repairing the rear wall timber frame and brick infill, breathable wood fibre insulation boards are being fitted in readiness for a new lime render finish.

We completed the external shell and internal structural stabilisation works, but unfortunately at this point our client 's health deteriorated and he called a halt to the project. Sad to see the building up for sale before being able to get it back into use, but at least we have 'stopped the rot' quite literally and sincerely hope that a buyer is found soon to put the building back to use....


  1. Fascinating article. Good to see that it's been saved in the nick of time.

  2. Are you available for consultations? We are the relatively new owners of an early medieval hall house in Surrey and want to ensure we are updating using respectful materials and that we are not overlooking work that needs to be done sooner rather than later (ie slipped purlin and an upper floor bedroom with quite wonky, scary plaster issues). Please reply if you are able to hyorkston at gmail dot com. Thank you!

  3. Well, I would like to suggest that if the roofs of the house is leaking then you renovate or repair the house by doing acrylic render or plastering which would stop the roof leakage.
    cement rendering sydney | textured rendering Sydney

    1. Sorry, but noooooo!!!

      It's exactly treatments like that that lead to the problems in the first place and certainly not appropriate for historic buildings.

      This search for maintenance free solutions has done much more harm than good.

      Solid wall buildings were built to "breathe". Acrylic or cement coatings just lock in moisture.

  4. Looking at your photos, you have a big job to be do. I guess the strength of the metal strap has diminished over time, which is why it can’t hold the purlin up to that time. I hope the building is already back in use as of this time.

    < Carl Patten >

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    Please continue to write more because it’s unusual that someone has something interesting to say about this. Will be waiting for more!

  6. Carl,

    Yes there was much to do due to past problems, but the building is now safe. Still not sure if its back in use. I will have to find out.


    Thank you. Its my passion as well as my job so I'll do my best to keep blogging!

  7. plasterer surrey
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