Widdrington Station, Northumberland

New homebuilder Grainger Homes is benefiting from a timesaving three-in one solution by using Leca® lightweight expanded clay aggregate (LWA) to provide infill, insulation and a gas ventilation layer for new homes built in the North East.



Widdrington Station Northumberland. Methane Gas Ventilation

New homebuilder Grainger Homes is benefiting from a timesaving three-in one solution by using Leca lightweight expanded clay aggregate (LWA) to provide infill, insulation and a gas ventilation layer for new homes built in the North East.

The developer has embarked on a further phase of 34 new homes at Widdrington Station, Northumberland, using Leca LWA Insulation Fill as an underfloor fill, which is easy to install and gives a proven reduction in overall costs.

Stocks of Leca LWA Insulation Fill, which is manufactured by expanding clay at high temperatures, are delivered direct to site and installed as part of the foundations of each new home by Grainger Homes’ flooring subcontractors Lumsden & Carroll, of Newcastle upon- Tyne.

Because there is no need for compaction, Leca LWA, which weighs five times less than traditional aggregates, is simply tipped into place, allowing follow-on work to commence immediately.

Using Leca LWA in 10-20 mm grade as both hardcore and insulation they are able to infill the sub-floor of five homes and complete them by pouring a concrete slab in only two hours.

Additionally, to comply with planning regulations for former mining areas, they are also able to provide for the safe discharge of any methane gas by using Leca LWA’s free draining characteristics to provide a gas ventilation layer. This involves leaving small weep holes in the brickwork at sub-floor level and installing a gas-proof membrane before the pouring of the floor slab, removing the need for a secondary ventilation system.

So far, Leca LWA has been used in more than 50 Grainger Homes properties and the solution is producing positive cost benefits when compared with the alternative of constructing conventional suspended floors with added insulation and provision for ventilation.

Explains Neil Sarin, contracts manager of Grainger Homes: “Previously we were putting down stone, followed by sand, then a layer of polystyrene insulation, followed by a concrete slab, which took three people and a machine, now we can achieve the same with one person and a machine, so the labour saving is significant and the overall time taken is reduced.

“The savings have been proven and this is now our standard specification for all floors.”