As the site was in a built-up area, environmental consideration regarding noise, vibration and dust would have to be given to residential and commercial neighbours as well as local footpath users. The three main structures were a mixture of single, two and three storey buildings as well as a block of garages and built from a combination of brick, concrete and wood. Tarmac, slab and footings would also need removing from site and care would need to be taken to remove asbestos slabs in accordance with regulations. The site would have restricted access due to its location.
Works were divided into two phases commencing with the soft strip of the three main buildings on the site. Phase one consisted of the primary soft strip and asbestos removal from the Phoenix Day Centre, Bourne Lodge and Wren Centre buildings. Highly experienced Lawson Group operatives used hand tools to remove the non-structural, loose fittings and fixtures of the buildings – this included furniture, doors, door frames, skirting, suspended ceilings, floor coverings and plasterboard timber partitions. All materials were removed in a controlled manner and segregated.
Any asbestos products found within the buildings were removed in accordance with the asbestos site survey.
Phase two involved demolition of all the main structures including the garage blocks in accordance with the plan and as agreed with the client. Care would have to be taken as works would be in the vicinity of live gas and electric services. A 360° tracked excavator with a hydraulic pulveriser attachment was used rather than a percussive attachment in order to reduce noise and dust emissions on the site. Deconstruction of the sites used a top down methodology removing timber, steel and concrete roof structures ready for processing and recycling.
The methodology for the demolition works commenced on the structure nearest the front of the site and continued towards the rear. The works were carried out in accordance with the NFDC guidance bay by bay in a methodical manner, ensuring that the buildings were stepped back. Care was taken to ensure the structural integrity of the buildings was maintained at all times.
Throughout the demolition process, Dust bosses were used for dust suppression to ensure environmental expectations were met. A crusher was used to process the arisings to a specification as agreed with the client.
As with all projects, Lawson Group used their own machinery and plant to complete the works.
The site was handed over the to client on time and within budget for the next phase of development. All environmental factors were catered for successfully for the benefit of local residents and businesses.
Acol Crescent, Ruislip (with Bourne Court)
Bourne Court was a project that ran in tandem with a second demolition of separate buildings located across the road in Acol Crescent. Both sites were owned by the same client and separate methodologies were prepared for each. The buildings on the Acol Crescent site were of a traditional construction with brick and block walls and a combination of pitched tiled and a flat roof. The buildings served as a former day care centre in Ruislip and were to be demolished as part of a redevelopment scheme involving a new three storey building for social housing. The two existing buildings were to be soft stripped, have cement bonded asbestos removed, followed by the demolition of both structures in line with agreed methodologies with the client.
Loose contents from within the structures, including furniture, appliances and general waste were removed by hand in a controlled manner and arisings managed in accordance with the Site Waste Management Plan. Door frames and skirting boards were removed by using bar and sledge hammers. Only operatives who had received class two asbestos training undertook removal of the asbestos products. Dust suppression systems were positioned within the working area and used to wet the roof sheets before and during the removal.
A 360-demolition excavator with a grab attachment was positioned at the rear of the structure, all voids in the ground such as manholes and sewers were back filled to ensure the ground was suitable. Deconstruction of the structures commenced by removing the roofs to the end of the buildings, these were removed by the excavator and materials generated were stock piled away from the demolition area. To minimise the environmental impact of general dust to neighbouring residential communities, a dust suppression system was set up near the excavator. Using a hydraulic grab attachment, the roof purlins were lifted out, this exposed the under cloaking around the edge of the roof. The asbestos supervisor monitored the work at all times.
Once the roof had been removed on each building, the grab was positioned over the top of the wall, each grab was lowered to ground level. A handheld killer sprayer was used to wet the brick and any asbestos cement products that were present. A fully trained operative carefully moved each brick and picked out pieces of asbestos and placed them in asbestos bags.
The site, along with Bourne Court, was cleared on time, within budget and handed back to the client ready for the next stage of development.