Cladding which did the 2-way shuffle

A cladding system designed to accommodate differential movements between an aluminium frame and metal-faced insulation-cored cladding panels experienced gradual displacement of building components as the gaskets snaked their way along the grooves between shuffling panels. 

The panels, being small, elongated less on heating than the relatively long frame sections.  The connection between the two was a combination of shelf brackets and clamps, with polymer gaskets inserted tightly into grooves between the panels to complete the weather-sealing.  Long continuous gaskets ran horizontally; vertical gaskets were shorter, and discontinuous at each horizontal joint. 

When the system heated up and expanded, the panels and vertical gaskets tended to move upwards.  When it cooled, the panels and gaskets contracted but did not uniformly return to their original positions.  The consequence was a gradual displacement of parts of the system relative to one another.  This opened gaps at the butt joints between horizontal and vertical gaskets and, in places, drove the vertical gaskets into the horizontal gaskets, deforming them.  Those panels on the elevations which received most sunshine moved progressively out of alignment.

The design was intended, by avoidance of rigid fixings, to allow reciprocal movements without distress.  But this lack of rigidity allowed each reciprocal movement to cause slight relative displacements in the panels and gaskets, the accumulation of which over time reduced weather resistance and marred appearance.

Sir Walter Scott, Guy Mannering, ch. 37, 1815:

A lawyer without history or literature is a mechanic, a mere working mason; if he possesses some knowledge of these, he may venture to call himself an architect.

Lead Roof Corrosion

A recent investigation revealed an oversight in roof design.  The construction under investigation had wide lead gutters behind masonry parapets.  These gutter formed part of the roof and are in effect cold decks over thick thermal insulation.  Other parts of the roof were provided with interstitial ventilation following current guidance.  The gutters were not.

The natural durability of lead under normal conditions is due to the formation of protective insoluble salts which are formed on the surface. Moisture and carbon dioxide in the atmosphere combine to form weak carbonic acid and this reacts with bright metallic lead during periods of rain or overnight dews to form the normal grey patina typical of lead roofs. This thin continuous surface layer protects the metallic lead from further attack. On the underside of lead sheets these protective layers may not form.

Architectural Acoustics

The third most common complaint of defects in buildings is noise. Architectural acoustics is the study of applying sound control within and between buildings. An early well recorded application of architectural acoustics is in opera house design. More recently it has been applied to both new and renovated concert halls. This has much to do with the quality of sound rather than noise suppression which is critical to the design of multi-occupancy building and city centre living. Dwellings and business premises may both generate significant noise and suffer from noise intrusion. The design of workplaces has often to contend with the potential effects of noise on health. Architectural acoustics includes room acoustics, the design of recording and broadcast studios, home theaters, and listening rooms for media playback.

Season's greetings



With thanks to all who have worked with us in 2011 we wish you a properous and happy new year

THE DUTY TO REVIEW DESIGN

There is case law which suggests an architect or engineer has an ongoing duty to review their design.

The architect is under a continuing duty to check that his design will work in practice and to correct any errors which may emerge.  It savours of the ridiculous for the architect to be able to say: ‘True, my design was faulty but of course, I saw to it that the contractors followed it faithfully’ and to be enabled on that ground to succeed in the action.[1] 

There is authority that duration of the duty continues beyond practical completion until the works are truly complete.[2]

PERSONAL AND COMPANY LIABILITY

Individuals who are members of companies may, through their actions, create liabilities – both on the companies and on themselves.  This is true also of individuals who work for partnerships.

Insurance policies will generally be taken out by companies or partnerships rather than by individuals.  These policies, which protect the companies or partnerships, will not necessarily automatically provide the same protection to the members of the companies and partnerships – whether they be principals, employees or owners. 

For this reason, some professional organisations advise and/or require their members to be expressly covered by the insurances taken out by the organisations for whom they work.  Even where this is in place, the insurance cover is unlikely to extend to protect individuals when acting in their own capacity rather than on behalf of their company, etc.

Therefore, professionals who give advice not in pursuit of a commission given to the organisation with which they work may expose themselves to liabilities for which the insurance taken out by the company or partnership offers no protection.