A system solution that offers a fail-save method of complying with Part E in modern construction, negating the need for pre-completion testing, has won Robust Detail accreditation for Monarfloor Acoustic Systems, the Icopal subsidiary.
Monarfloor Bridgestop high-performance membrane prevents acoustic bridging commonly caused by a mortar build-up at the base of the cavity within separating party-cavity walls, and also can act as methane and radon barriers or protect such barriers from the damage that can occur when site operatives remove the mortar from the base of the walls.
It does this by isolating both masonry leaves of the cavity party wall from mortar collecting on the raft or continual foundation. Where the slab has been split and a gas barrier installed, the Bridgestop membrane ensures the integrity of the gas membrane from potential damage.
With 70% of new build now on brownfield sites where contamination may require raft foundations or gas barriers, the Bridgestop system is proving invaluable to housebuilders, developers and structural engineers because it enables all lightweight and dense block RD masonry party cavity walls (currently nine in total) to be built off rafts and continuous slabs.
John Foster, technical director for George Wimpey North East, said: “We’re using Bridgestop for the improved test results in all current and future instances of party walls where rafts are required.”
Bridgestop is laid in the cavity between the separating walls and folded around to bridge the gap at the base. Acoustically-resilient wall ties hold it in place with a special cap on the first course of brickwork. A second layer can also be used if required and held in place by new wall ties on the second course of brickwork.
Bridgestop’s properties have high acoustic damping to absorb more sound energy and reduce structural flanking, performing approximately 4-5dB better than solid walls and 2-6dB better than standard Robust Detail E-WM-4 walls.
In addition, only one coat of render instead of two is required as well as standard plasterboard (8kg/m²) instead of 12.5kg/m² for solid Part E solution walls, saving 4.5kg/m² of gypsum-based board per m².
Dave Baker, Robust Details’ chief executive, said: “The introduction of a high acoustic performing solution for a range of dense and lightweight blockwork type cavity walls suitable for use with raft foundations has been on the wish list of many housebuilders and developers for some time."
The Bridgestop system was developed by a joint venture between Monarfloor/Icopal and the Build-ing Performance Centre (BPC) at Napier University in Edinburgh.
Dr Sean Smith, depute director at the BPC, said: “This solution results in a greater range of options for housebuilders for Part E in their separating wall designs and given the blockwork and concrete industry wider scope in the increasing brownfield site market.”
Pictured from left: Monarfloor Acoustic Systems’ general manager Paul Levie, Robust Details’ chief executive Dave Baker and Monarfloor product development manager Lee Nichols.