Sarking and Wall Wrap
Wall wrapping / Sarking
The concept of sarking around the exterior of a timber framed wall has been around for a long time and has existed in various forms (tar-paper, Sissalation, Thermofoil, Tuff-stuff, Gladiator wrap, wall wrap, Tyvec, Enviro-seal, Proctorwrap etc.).
Installed from bottom to top it acts as a weather protecting membrane. The concept is a light-weight barrier to protect the structure from the ingress of the elements that may prove detrimental to the integrity of the construction. It is also important that the membrane can allow for the various moisture build-ups that occur such as “leaky house syndrome”.
The sarking as such does not offer a whole lot of insulation performance even though some types have reflective foil facings. There are all sorts of grades and variations on the basic concept and care needs to be taken to comply with whatever the exterior skin’s manufacturer recommends. Breathable membranes are essential for many composite claddings and most timber cladding suppliers insist on ply-cladding or Thermo-craft permeable paper membrane to prevent uneven moisture distribution and potential ‘cupping’ of weatherboards or shingles.
In brick-veneer construction, sarking offers an excellent retention barrier for other forms of bulk insulation that might be fitted between studwork. The sarking / light-weight barrier ensures the integrity of the cavity from framing to external brickwork.
With a timber framed structure the material is run continuously along a wall and stapled in place. Windows and doors are “cut-out’ after, and some extra spot-fix clips will help hold the material secure. In steel-framed construction it is necessary to use screw fasteners in lieu of staples.
With Steel Framing it is necessary to have a thermal break separating the Sarking from the frame. This can be achieved by the addition of a tape or by using products such as Insulmist.
Light weight claddings are more likely to be fastened to battens over Tyvec or Proctor wrap to allow for proper air movement behind facade.