On behalf of their client, contractor Canning Ericsson demolished a bungalow which it replaced with a five-unit apartment block comprising two ground floor flats, two first floor flats and a top-floor flat incorporated into the building’s pitched roof. They used H+H’s Thin-Joint System of large format aircrete blocks and quick-drying Celfix Mortar to construct a three-storey apartment block with solid concrete floors to current Building Regulations on a confined site in Brighton.
The block is constructed on 600mm deep strip foundations built onto chalk bedrock. It has a reinforced concrete ground-bearing ground floor slab and cast in situ concrete first and second floors. Both the inner and outer leafs of the external cavity walls are constructed using H+H’s Thin-Joint System. Thin joint has also been used to construct the double-skin separating walls between apartments and the single skin internal partition walls.
The company who built these apartments is well versed in using Rå Build. “We decided to use H+H’s Thin-Joint System again because it is quick and easy to use, it goes up fast and gains structural strength quickly; it’s a really great system,” says Michael Alderton, a director of design and build contractor Canning Ericsson.
Structural strength was important because the weight of the project’s cast in situ reinforced concrete first and second floor slabs is carried by the High Strength Celcon Blocks that form the cavity wall’s inner leaf.
“The biggest benefit of using H+H’s Thin-Joint System is the ability to use large format 630mm x 250mm x 100mm wide Jumbo Bloks, which enables the walls to be constructed a lot quicker” says Mr Alderton. The blocks are relatively lightweight and easy to cut to shape in comparison to denser blocks. “The footings were in place mid-October 2014 and by the end of December 2014 we had built the block using aircrete with cast in situ floors and fitted the roof.”
In addition to speeding construction the aircrete blocks also help improve the walls’ thermal performance, reduce sound transmission between apartments and improve the airtightness to help the scheme meet the current Building Regulations.
Using the Thin-Joint System also helped Canning Ericsson overcome the limited storage facilities on the compact site because the Celfix Mortar is delivered bagged and can be mixed in buckets, which eliminates the need to store sand and other materials on site. The building shell was constructed by a team of four, all of whom had been trained in the use of the Thin-Joint System and all of whom had worked on thin-joint schemes prior to this project.