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.

Insurance Cover for Construction?

It is sometimes not enough merely to see that insurance is in place, it is important also to know what is covered by that insurance.

An example of inappropriate insurance came to light when a major building-products manufacturer undertook the role of main contractor in remedial works to a refurbishment project.  Their building system and materials had been used for the refurbishment work, but performance when finished was flawed.  Believing the faults lay in the site work, not in their products, they undertook to confirm this to the building owner by implementing repairs. 

They ably set about correcting the installation.  This done, the work failed.  They had created an excellent test bed for a relatively new product.  By minimising workmanship error and having full control over design and materials, they had ensured there was a full-sized example of their building system, which was correctly set up and exposed as intended to the elements.  This was a much more robust way of evaluating the system than the laboratory tests and computer modelling upon which all had hitherto relied.  The failures were limited and allowed specific flaws in the computer modelling to be identified, with benefits for the future development and use of the system.

Building over the boundary

A development in Worcester was hemmed in by surrounding properties.  For maximum return, the development was taken to the very edge of the legal boundaries.  To prevent dispute, the foundations were designed not to cross the boundaries into the land of those neighbouring owners who were opposed to the development.  This created difficulties in construction. 

The site team did not appreciate the significance of this aspect of the design, particularly as the legal boundaries were to them nought but invisible concepts passing though muddy excavations. In constructing a basement, the builder ran the bottom layer of concrete wide of the site boundaries.