Walcot Yard, Bath

OVERVIEW:

The surrounding area was being redeveloped into residential housing. Lawson Group were awarded the project to remove asbestos and hand demolish a disused mill building in Walcot Yard, Bath.

CHALLENGE

Lawson Group would have to coordinate and devise a programme for multiple activities at this site. An asbestos report had found evidence of Asbestos Containing materials (ACMs) located under the floorboards and inside a bricked-up room. Loose Asbestos Insulation Board (AIB) panels were also found to be in the building.

Enabling works would also have to include the building of a supporting wall, laying down of a piling mat and the demolition of the building would have to be carried out by hand. All this would take place in a residential area, so consideration to the general public and environment would have to be taken.

SOLUTION

All the loose AIB debris and AIB panels were carefully removed and bagged immediately. When the AIB was too big to bag, it was double wrapped in 1,000-gauge polythene, red bags and marked accordingly.

Contaminated waste was removed from the enclosure by way of the baglock. It was singularly bagged within the enclosure, wiped clean and vacuumed with Class ‘H’ vacuum cleaners, then they were passed into the baglock. Once in the middle section, the waste was double-bagged. It was then removed via the pre-agreed waste route to the waste van. At the end of the removal, the work area (including waste route) and equipment were thoroughly cleaned using low-dust techniques. Any visible asbestos or suspicious debris on the waste route was removed.

Prior to dismantling the enclosure, an independent analyst carried out a four-stage clearance. After the analyst had passed the visual and air tests, operatives then proceeded to take down the enclosure and bag the 1,000-gauge polythene as waste. This was double-bagged and carefully disposed of as asbestos waste.

Once the site had been decontaminated, then the soft strip and hand demolition of the building could take place. Stairs within the building were used for access to the first floor and plywood sheets were laid on the timber floor for protection. Using a tower scaffold for access to the building, the operatives started removing the roof tiles and timbers. The tiles were passed to operatives on the first floor and were stacked on the scaffold ready for removal. Care was taken not to overload the scaffolding. Once the roof tiles had been removed, a reciprocating saw was used to cut out the timber into manageable sizes, these pieces were passed to operatives on the first floor. All waste was removed via the access scaffold and then placed in a 40-yard bin outside the building.

Following the removal of the roof, the walls were removed using hand-held tools. As the walls were reduced in height, the hardcore was removed to the scaffold using wheelbarrows.

A rubble chute was attached to the scaffold and all hardcore was deposited down it for safe disposal.

The tower scaffold was relocated to the ground floor, the first-floor floorboards and timbers were then cut out using reciprocating saws and removed from the building. Much of the work on the ground floor continued in a similar vein to that previously above.

Now that the building had been removed (apart from one middle wall), all obstructions had been removed and the height of all walls reduced – a block wall was required to be built in two locations along the adjoining walls. Foundations were dug out using a 7-tonne excavator with bucket attachment. Once the concrete had been poured, scaffold was installed. The block wall was built course by course up to the underside of each steel beam in both areas. Slate was used to dry pack the beam. Once works had been completed, all scaffold was removed. Once the walls had been built, the remaining middle wall could be removed. A 7-tonne excavator was then used to remove the slab and foundation from site.

Finally, the piling mat construction could start and 6F2 crushed concrete was brought onto site. Each load was spread out to a depth of 150mm and compacted with a twin drum roller. As the levels of the piling mat changed across the site, each gradient was battered back to ensure safe access.

RESULT

All asbestos was safely removed, and the building was carefully hand demolished ready to handover to the client.

To find out more on how Lawson Group can help with your next demolition or asbestos removal project, call 01793 782000, email enquiries@lawsongroup.co.uk.