AWS - Acoustic Wall Strap "Making it easier for timber frame to gain more Code credits and points" Dr. Sean Smith, Building Performance Centre, Napier University
STRUCTURAL FEATURES A gradual evolution has been taking place in separating wall strap design in the last decade from the original 30x2.5mm flat strip, but the groundbreaking new Cullen AWS is a quantum leap in this regard, both in terms of acoustic and structural performance. The unique AWS design possesses twice the load transfer capability of conventional separating wall straps, which means double the wall racking resistance of adjacent timber frame units can be utilised in racking calculations on attached dwellings. This can result in less need to resort to additional sheathing layers or dense nailing to overcome racking problems.
ACOUSTIC FEATURES With the introduction of the new Code for Sustainable Homes it is more important than ever for developers to locate solutions which go beyond simply satisfying the minimum requirements of the Building Regulations. The new Acoustic Wall Strap (AWS) is the first acoustically engineered strap, which makes it easier for timber framed houses to gain credits for enhanced levels of sound insulation between dwellings. Specifically the AWS-75 is targeted towards the achievement of 4 credits under the Code. Increasing strap length increases the isolation, sound insulation performance and the potential for Code credits.
PERFORMANCE SWL is 1.7kN in compression and tension
IMPORTANCE OF CAVITY SPACING BETWEEN TWIN STUDS “The AWS is the only wall strap that ensures correct cavity width is maintained. This is extremely important as other standard ties are dependent on site measurement. Errors in site measurement can lead to a significant reduction of up to 10 dB in overall airborne sound insulation performance.” Dr Sean Smith, Building Performance Centre, Napier University
Reducing horizontal impact noise transmission from sockets, switches and cupboards. Improving sound insulation against horizontal impact noise from plugs being inserted into sockets, wall mounted switches, doors and cupboard doors closing is a key feature which many clients wish to have within their homes. The above graph illustrates the effective improvement by using the Cullen AWS versus standard separating wall straps and ties. Collectively over this important sound frequency range the AWS has been found to improve impact noise insulation by 25 dB.
