Dymatec Blog

London Cutting: removing a 4,000m3 slab of concrete

14 months, 10,000 tonnes of concrete and 1,000 diamond blades and cores. Just a few of the big numbers associated with the Grosvenor Place demolition project located a stone’s throw from Buckingham Palace in London.


The brief? To remove the basement slab of a five storey building in one of the most prestigious addresses in the capital to allow for additional below ground construction to convert the property into a brand new private hospital.

No easy task, especially considering the thickness of the concrete and the need to retain the majority of the slab to support the building.

Dymatec was retained as the exclusive supplier to contractor London Diamond Drilling, advising on and providing all the blades and cores needed to complete the works, a total of 1,000 over the 14 month life of the project.


The plan of attack was to remove an 8m wide section around the entire perimeter of the basement slab. The perimeter had to be removed in sections to allow for steelworks to construct the structural support needed to hold up the main facade, which was to remain intact. 8m of concrete at a time was removed with the concrete slab varying in thickness from 1m to 3.5m with a significant quantity of 32mm rebar throughout.


As well as being a significant quantity to remove, 4,000m3 in total, the concrete was also extremely hard as it was packed with dense black flint, which meant that only the fastest diamond cores and blades would be able to power through it.


To tackle this tough, unrelenting concrete, Dymatec recommended the SDF P20 diamond blade and supplied over 70 of these blades in varying sizes during the project. This powerful high performing blade, manufactured solely by Dymatec, was the only solution to combat London’s challenging concrete.


The plan was to tracksaw the entire perimeter up to 1.1m deep and all the cross cuts into sections. However, this was only possible where the concrete was shallow enough. Anything deeper than 1m had to be stitch drilled. To facilitate this process, Dymatec supplied over 900 Turbo S cores.


Once the perimeter of the concrete slab had been removed, the slab was peppered with 212mm diameter holes so it could be broken up using a 8” hydraulic burster. Only when this was complete could a team come in and break up the slab using Brokk 500 and 260.


During the 14 months it took to cut and drill the basement slab, Dymatec were on site at least once a week, collecting used cores and blades, returning them to their UK headquarters in Bedfordshire to retip and repair them, before delivering new and refurbished consumables back to the project. In addition, Dymatec’s Sales Manager David Hibbert visited the project once every two weeks, to ensure the products were performing as they should.


To ensure the works stayed on programme, and that tracksawing stayed ahead of the steelworks team, London Diamond Drilling were on site between six to seven days every week during this demanding project.


Work has now started on casting the new concrete slab for Grosvenor Place, with the construction of the new building expected to last a couple of years.