Ra Build meets the need for speed

H+H’s Rå Build method has been used by design and build contractor Canning Ericsson to speed construction of a three-storey apartment block on a confined site in Brighton.

Canning Ericsson was already familiar with the advantages of H+H’s Rå Build method of large format aircrete blocks, the Thin-Joint System and quick-drying Celfix Mortar having used the modern construction method on several of its previous schemes.

“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, director of Canning Ericsson.

Aircrete’s 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 Thin-Joint Blocks that form the inner leaf of the building’s external cavity wall.

Construction speed was important to the contractor. “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 Code for Sustainable Homes Level 3 criteria.

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.