29/04/2016
Nicolas Collins, Area Sales Manager - Property, Sika UK You work in a London Borough housing department and are responsible for a large concrete residential social housing block whose exterior is severely in need of a major overhaul. However you have a mix of owner-occupier and council tenants who are not keen to leave and a very long housing waiting list, renovation will take months but demolition and rebuilding will take years. What are you going to do?
Concrete Repair of High Rise Buildings
It’s an inescapable fact of life that budgetary concerns drive many council planning decisions but this is not always a bad thing - sometimes the best decisions come from expediency. And despite the old adage that it is cheaper to rebuild from scratch than repair ageing buildings, this is not often the case when it comes to demolishing a high rise block in dense urban areas - including the emotional and physical ramifications of decanting hundreds of occupants. Many of those residents don’t want the upheaval and cost of moving, and some are even very fond of the buildings they call home.
At the same time demand for housing in London is increasing exponentially, so minimising time spent on remedying works is a big factor. Housing waiting lists are getting longer with an increasing population and more people moving to London from all corners of the globe. As a rough guide if a full exterior overhaul takes a year it will take two years for a demolition and rebuild which adds to the case for refurbishment.
So in the light of the cost of rebuilding combined with the need to minimise downtime, cash-conscious local authorities are instead tending to constantly refurb the exterior of existing concrete buildings. However an approach of patch repairing spalled concrete as it occurs is nowhere near as effective as achieving a fundamental long-term fix which can save money in the long run.
Concrete Repair vs Demolition Costs
The cost-effectiveness of renewal over demolition is shown by the fact we are being asked by London Boroughs to do more and more renewal and refurbishment of high-rise blocks. There have been cases where demolition has been considered but once a client has looked at the reality of how much it would cost and the necessary programme time they have thought twice. Hundreds of millions are currently being spent across the whole of London on renovating these assets with Boroughs facing more challenges like Southwark and Tower Hamlets being allocated considerable resources.
Boroughs go through different phases of activity based on when they get their budgets from the GLA but when they get it they certainly look to spend it wisely. A lot of clients are looking to buy into comprehensive longer term solutions we can provide to extend their buildings’ life cycle significantly. With a full specification concrete renovation including our Total Corrosion Management technologies being applied we can extend our standard 10 year guarantee up to 20 years.
Sika‘s concrete repair and protection solutions are designed to rehabilitate and restore concrete surfaces back to their original quality. The extensive range includes concrete repair mortars, anti-corrosion coatings, corrosion inhibitors, reinforcement corrosion protectors and embedded galvanic anodes.
Residents don’t want disruption – even grit blasting the exterior of concrete buildings can be too disruptive so we often have to look at jet washing instead. However the disruption caused by a demolition is far more of a challenge. As well as council flats, a lot of residents own leases or even the freehold, giving them an intense personal investment in these buildings, some of which are listed.
A major benefit of exterior renovations can be delivered far more simply than the essential concrete repairs themselves. Coatings used for a renovation can not only provide an overall protection layer or coordinate with existing surface, they can also use colour to transform a grey concrete edifice. A recent example is the Four Squares Estate in Southwark which includes four 10 storey blocks which we coated in white resulting in a far less aggressive impact on the skyline than their former grey.
Sikagard ElastoColor is particularly suited as a final protective coating for concrete facades, its anti-carbonation treatment provides a high quality yet economical water-based, acrylic coating to protect against weathering and ageing. However it is also available in virtually any colour, freeing up planners and designers to create a vivid aesthetic statement if required.
Lastly, refurbishment and renovation of an existing asset is much better from a sustainability standpoint than knocking it down and starting from scratch with new materials. Even more importantly, sustainability of communities can be enhanced in underprivileged areas as a result of visually refreshing tower blocks and creating a more appealing environment. They can be a component of genuine urban regeneration.