The Tower

Contract	The New Armories Building and Annexe, Tower of London
Value
Client	Historic Royal Palaces
Employer	Lister Beare

One of our most prestigeous projects was the refurbishment of the New Armories building and the construction of a new catering annexe on the site of the old Irish Barracks.

The New Armories was built as a storehouse for weapons and provisions shortly after the restoration of the monarchy under Charles II. It was completed in November 1664 at a cost to the royal purse of £ 4000. Since then it had been through a number of changes of use is was now to be converted into banqueting, conference and exhibition space, together with attendant offices and a considerable amount of mechanical services to be crammed into the roof void.

Our brief included

Assessing the load capacity of the oak floors by visual grading and load testing
Lowering the ground floor and forming service ducts.
Infilling the existing stair openings while forming new stair and lift shafts.
Restoring the floor structure around a previous partially removed chimney.
Providing a new deck for mechanical services in the roof space.
Constuction of a podium for a large stone fresco.
To survey all structural elements as they were exposed during building works, advise on any remedial works needed and coordinate with the services designer.


Oak floor beams	Beam ends	Drawing dated 1717
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The new catering Annexe, containing kitchens and more services, is located on the far side of the Ballium wall, the inner ring of the Tower's defences. The two had to be connected by enlarging an existing arrow slot and an opening formed in Victorian times. The new structure is steel framed with a pre-cast concrete ground floor and timber first floor, roof and walls. To minimise the likelihood of a clash with any Archaeoligical remains the number of columns has been minimised and the floors cantelevered out to keep clear of the Ballium wall foundations. This required a large transfer structure within the roof space. The intermediate columns were replaced with hangers from these roof trusses.


End elevation	Internal framing	Drawing extract


Roof hanger connections
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To avoid disturbing any archaeological remains we originally proposed supporting the Annexe on a raft. The client was nervous about possible settlements however and so we switched to isolated pile groups.

Needless to say the Archaelogy had a very major impact on the works and we had a team of Archaeologists on site full time. This did not stop problems arising however. Often these were questions of interpretation - to a layman the distinction between remains that can be readily discarded and those that are sacrosanct seemed muddled. To be cynical it often seemed to have more to do with HRP's business requirements than the historical worth of the relics. We did however maintain excellent relations with the archaeological staff throughout the project and received a letter of commendation at the end recognising the great efforts we had made to ensure that all possible historical remains were preserved intact.

The most problematic area in archaelogical terms was undoubtably the Annexe foundations. We knew that we were likely to encounter foundations from the old Irish Barracks as well as remains from previous eras. The client was unwilling to carry out an archaeological dig before the start of the contract so all our designs and drawings had to be based on the results of a desk study and surface survey. While these were reasonably accurate in themselves, we found that there were far more remains in the ground than anticipated. We found ourselves inspecting archaelogical pits, re-designing foundations and watching piles being bored the same day. Only a couple of isolated pile caps were unaffected, all other elements in the ground had to be re-designed in this frantic ad-hoc manner.