Concrete – How Not to Repair It – 1

The Golden Lane Estate has some magnificent concrete – use of concrete is one of the architectural features of the estate.

Being 60+ years old it needs repair.  To date the City of London has not made a good god of it.  For example, in the case the defective concrete has been cut out and sloppily filled, without any attempt to incorporate the aggregate (gravel) that gives the surrounding concrete its character or to match the concrete.

Sometimes repairs have been abandoned half way through as in the example where the steel reinforcements have been exposed and treated with special paint but the hole left unfilled, while other have been filled in un-matching mortar.

Concrete repairs should normally be in a softer mortar than the surrounding concrete. Where they are harder the repair doesn’t expand and contract slightly as is needed and the repair eventually, cracks, separates and falls out. In this example the repair has cracked all round in less than three months, so started the process of falling out. The cornet is the wrong colour and texture and has been smeared around the repair creating a messy repair as well as one that is destined to fail.

Here is another unsightly botched repair completed in 2013.

Whilst for this repair black waterproof paint and some kind of mastic has been used – and is failing.

These repairs – and many others like them are spreading across the estate. If this were a listed stone building those charged with repairing it would try to match the stone they used in repairs. At Golden Lane Estate there appears to be a cavalier attitude that any sort of repair is good enough.