Building on Gasworks Site

A few members of the Society's Executive Committee were pleased to accept a private invitation to visit the former gasworks site in Duke Street being developed by Persimmon Homes. The invitation arose from my use of a photo on the front cover of the July Newsletter of one of the newly completed blocks of flats there.

The visit was particularly illuminating at this stage because of the valuable re-use of what must have been the most contaminated site in Ipswich. The general public - and I suppose most Society members - are keen to see as much residential building as possible on brownfield sites. And this site couldn't have been any browner! Cyanide and cadmium were only two of the many dangers there. It is therefore very gratifying to discover that Persimmon, one of the country's biggest house builders, should see this as a viable commercial challenge. In fact 90% of their work is on brownfield sites.

From the rooftop of their current site office, it was possible to appreciate the enormous amount of work that has gone into decontaminating the site. You can get some idea of this still from Patteson Road alongside the site, although as that side will be the next part to be built on you need to go soon. When we made our visit in August there were great heaps of cleaned soil being regularly turned over, as one does a compost heap. When ready, this soil will be spread over the site. Only the very worst of the polluted material was taken away, although that still necessitated over 4,000 large lorry movements to remove it to a special dump in Bedfordshire. If the whole site had been cleared of contaminated materials that would have taken 150,000 lorry journeys.

Much of the decontamination was by bio-remediation: the addition of wood bark enabled microorganisms to break down some of the pollutants. Further cleaning of the site is still going on with water under high pressure forced through the soil, the impurities being collected in big sunken tanks. Much of the concrete on the site has been crushed and will be used to help restore levels.

The environmental benefits of the clean-up are already noticeable in the river. There is no longer a seeping of black sludge from the site into the river and Wet Dock. Such environmental improvements used to attract Government financial support - what used to be called "gap funding" . But that is no longer the case, although there is some tax relief for a developer's expenditure (£3m for this site). And the Local Authority can relieve the developer of such a big site of his obligation to contribute to the cost of new or enlarged schools - which Ipswich Borough Council has done.

Because of possible flooding, all the more likely owing to global warming, this site like all the others around the port will not have residential accommodation at ground level, where car parking and shops will be located. The buildings themselves ought to be stable since we learned that the pilings can be as deep as 25 metres where necessary! Another interesting aspect of the development is the use of factory-made units for some walls and even complete bathrooms. There ought to be more scope for prefabrication, but it appears there still isn't enough take-up of these possibilities nationally for industry to develop really profitable production lines. However, the selective use of prefabricated units must have helped Persimmon to speed up the erection of their first two blocks of flats which were begun little more than six months ago and now are occupied.

It won't be possible, of course, to judge the appearance of the whole development until it is complete with its restaurant, its grassy spaces and trees and its bigger blocks of flats on a vast podium at the waterfront. That will be in about five years time. But thanks to the clear and enthusiastic explanations of Managing Director, Andrew Jay, we were able to appreciate that this most difficult site in the town is being put to good use for the future.

NEIL SALMON