Eco-friendly Earthquake Resistant Wall Framing
“Frame Saver” has been created by Winstone Wallboards and has multiple benefits. Walls are essentially seismically stronger more thermally efficient and also cheaper due to a significant reduction in the amount of timber used.
It is not often that improvements are actually cheaper than the status quo. That’s what is called a winner.
Replacing triple or stud-block-stud arrangements at wall junctions with ‘frame saver’ metal angles, means less timber is used increasing the thermal efficiency of the external envelope and increasing seismic resilience by securely locking plasterboard corners to a single metal angle. This results in better energy efficiency through more insulation and less thermal bridging due to less timber.
Further cost savings are achieved as only one instead of two Handibrac bottom plate anchors are required at corners. Another benefit is reduced risk of quality of finish imperfections as many mechanical fasteners into timber have been removed. Also included are new wall to ceiling details with some similar benefits. There is no impact a relation to NZS3604 or building code compliance as the standard is silent on junction details and the Frame Saver details provide better than code performance.
Following the Canterbury Earthquakes all external framing in Bob Burnett Architecture houses has been a minimum of 140mm wide with a RAB (Rigid Air Barrier) instead of the normal 90mm wide with building wrap. (Internal walls remain 90mm thick).
This adds only a surprisingly little extra cost to the build and provides multiple benefits. Additional Earthquake and windload resistance is one benefit with another obvious benefit of the larger frame cavity being the ability to install thicker insulation, providing a better thermal performance meaning a warmer more energy efficient home is achieved. Wall insulation is up to R4.0 with fibreglass and R3.2 with Wool. The RAB makes the house more air tight and hence insulation works better.
Dwangs can be removed completely or if dwangs are desired for whatever reason they can be installed vertically on the inside face allowing continuous insulation without thermal bridging. In either case, another benefit is there is no drilling of holes required to run plumbing, electrical or other services.
More recently BBA begun using LVL (laminated veneer lumber) for 140 frames which is both stronger and more sustainable than traditional solid timber. Waste is minimised as all of the tree is used due to LVL being made from laminated log peelings and finger jointing of timber.
All these innovations add up to achieved bracing that is at least double code requirements and in some cases up to 3 to 4 times code. The result is greatly improved earthquake resilience providing safety, security and peace of mind, combined with superior warmth and energy efficiency and a healthy low running cost home that is environmentally sound.