John Norman looks at a construction material we might describe as being the Marmite of building solutions.

Ipswich Star: The new loos at Bawdsey - Bawdsey being famous for its role in the history of radar. Picture: JOHN NORMANThe new loos at Bawdsey - Bawdsey being famous for its role in the history of radar. Picture: JOHN NORMAN (Image: Archant)

For the past 50 years a type of steel has been produced that has a remarkable quality: it goes rusty (nothing unusual about that!) but does not deteriorate.

That is, once the surface has a thin coat of rust, the core of the steel plate remains, and retains its strength.

COR-TEN is a registered trade name for what is technically known as weathering steel, designed to eliminate painting. The steel produces a stable rust-like appearance after exposure to the weather.

To illustrate the steel in use, there are two public works of art you might be familiar with: The Angel of the North alongside the A1 in Gateshead, and the Fulcrum, just outside Liverpool Street Station, as you walk towards Broadgate.

Ipswich Star: The extension to St Augustine's Church. What do you think? Picture: JOHN NORMANThe extension to St Augustine's Church. What do you think? Picture: JOHN NORMAN (Image: Archant)

Numerous major buildings and other structures around the world have used weathering steel to great architectural effect, and occasionally with some controversy.

Odense University in southern Denmark is known by students and staff as Rustenburg (the rusty castle).

In Ipswich, Handstanding on Downham Avenue, which was featured in the article about the public art at Ravenswood, is made from this steel.

It is a statue of a man balancing on one hand on top of what appears to be a wartime pill-box.

This week we are looking at other local uses of weathering steel, particularly where it has been used as a building material and especially where its use has created adverse comment.

One of the most appropriate uses locally is on the new toilet block adjacent to the transmitter building at Bawdsey.

The main building has just undergone a major refurbishment to restore it to something like its wartime appearance and to enable it to fulfil its function as a museum dedicated to the development of radar.

With the expected increase in the number of visitors a new toilet facility became essential and this “rusty” steel box has exactly the right attributes to fit in alongside the rough concrete and common-brick main building. A very appropriate use of weathering steel.

Alternatively, if you happen to be walking along the quay in Woodbridge this summer, look out for the redevelopment and new public square formed on the former Whisstocks Boat Yard.

This space is destined to become a major asset to the town, not least because of the museum and boat-building shed which have been incorporated into the development.

Take a look at the building on Tide Mill Way, behind the proposed chandlery. A solid building (without windows) clad externally in weathering steel. It’s not on the quayside – not as prominent as it could have been. It is, however, an industrial material cladding on an otherwise uninteresting building.

The building that has really caused me to write this article, and which has probably created more comment locally than even the disused Odeon cinema, is the extension to St Augustine’s Church, Felixstowe Road.

Actually, the new extension is alongside Bucklesham Road, which, with its more expensive housing, is even more controversial.

The extension is an activity space attached to the church, with kitchen and toilets.

Users of the building are full of praise, commenting positively on the difference between this extension and the previous one.

Their comments, however, apply to the function and internal form of the space, not its appearance.

The challenge for the architect in designing a building for this location was choosing a material to fit in alongside the existing church.

Unlike the medieval churches (in flint), or those of the late Victorian period (soft red brick), St Augustine’s was erected between the wars – finished in cement render which doesn’t age well.

Thus, an extension in modern brickwork would have shamed the existing building.

COR-TEN is probably the most durable of the alternative cladding materials and should outlast the host structure.

The great advantage of weathering steel in this location is that it will mellow and the extension will almost disappear between the trees.