Earlier perceptions that the cavity around the steel frames in steel frame properties should be 'open' thus allowing structures to breathe and to deter erosion, can now be shown to be false.
Recent works in Bristol have now proven the injection of foam into buildings of this type will save an awful lot of capital outlay where repair works are happening.

A case history:-

"I bought an 80 year old Dorman-Long (steel frame concrete section construction) back in the 80's. We had a very bad problem with condensation on the walls, so having had foam CWI in my previous property, we had the walls injected with Everwarm cavity foam insulation and needless to say it solved the problem completely.
Over the past 6 months my local authority have been repairing properties the same construction as mine that are experiencing problems with the steel frames corroding.
When I spoke to a council official telling him what I had done to my property, his reaction was that I had done more damage to the steel in my walls, as you need air in cavities to circulate to keep the steel from rusting away.
Well I could not agree or disagree, but logic told me that if you had something warm next to a cold appliance, it will keep it warm, thus preventing problems.
I decided to look further at the steel frames in my property, so I engaged an engineer to investigate. After inspection, very little damage to the steel was found. The Council then hearing about this asked if they could see for themselves, which they did, stating that they would have to re-write 'The Manual' on foam insulation to steel properties because of the preservation that they'd found."

Contents of a letter sent by a satisfied customer at Sylvan Way, Sea Mills, Bristol. ( Name and address given if more information is required )

In the letter from the highly regarded structural engineer

"Because on this island we live with wind driven rain, there is naturally a tendency for most people to think only in terms of "it's wet outside". The introduction of cavity protection in the mid nineteenth century was a great improvement over houses constructed with solid brick walls. For nearly a hundred years it worked well because the interior was well ventilated with open fires, ill fitting doors and windows and chimneys. By the mid twentieth century great attention began to be given to reducing ventilation, more commomly called draughts. At much the same time we started putting things in the cavity, apart from cavity ties - that had often caused problems. Some forms of insulation were injected that provided a passage for the moisture from the outer leaf of brickwork to come through to the interior. The introduction of steel framing into the cavity obviously called for some protection and painting has not proved adequate.
Attention has continued to concentrate on keeping the wet on the outside to stay outside. But in modern times probably for most days of the year, inside of the house is warmer and moister outside. The warmer the atmosphere the more moisture laden air will pass through to the cooler atmosphere in the cavity. The net result is that the cavity is under attack from both inside and outside.
An empty cavity will allow the moisture laden atmosphere to circulate and deposit its moisture on those surfaces that are cooler. But where the cavity is filled with an impermeable insulation that keeps the cavity warm - and any steel in the cavity warm - and also prevents the circulation of moisture laden air depositing its moisture, then the steel is unlikely to be corroded.
That's my experience with the many steel framed buildings that I have inspected."

(Name and contact given on request)

In Bristol the properties where steel structures were repaired, external wall insulation was applied, still leaving a 75mm 'open' cavity.
After a costly outlay per property, problems of condensation are now occurring where, because of the open cavity the steel frames are remaining cold, and where the cold frame meets the warm internal wall - Result: Condensation!
All these problems can be resolved by injecting Protectorfoam into the cavity walls of such like properties. Cavities even as small as 40mm can be injected.

More information on the installation process can be found here and the details of insulating benefits of ProtectorFoam can be found here.