5.1 Coating /Rendering
The proprietary coating systems consist of polymer-modified cement renders, which must be finished with an acrylic texture and paint. The proprietary coating manufacturer’s instructions and application requirements must be followed at all times.
*(Available to download from the QT website) In most cases these coating systems must be applied by an approved applicator. High profile or heavy texture finishes can minimise surface imperfections or glancing light concerns. Light coloured coatings are recommended. Polymer-modified cement renders must not be applied over sealants or control joints.
5.2 Pre – Coating System Inspection
Check all internal and external corners are formed correctly and have good straight lines. Check the first horizontal course, and panels above rooflines have a good clean bottom line. Check weep holes have been installed in the first horizontal course. With a 1.8m spirit level check for variations greater than 3mm in the QT EcoSeries Wall Panels, especially where panels butt together. If variations are found, take the appropriate remedial action eg. rasp to an acceptable level, or re-fix the offending panels. It is important to eliminate large variations, as they may appear under critical or glancing light conditions. If the internal lining has not yet been installed, advise the building supervisor that internal wall lining cannot be installed using nails as the knocking vibrations will transfer through the frame and crack the render coatings (hairline cracking).
Hence internal lining must be screwed. After the inspection has been completed, application of the base coat can begin.
5.3 Application of a Polymer Modified Render Base Coat
Trowel an even coat of polymer-modified cement render over the entire QT EcoSeries Wall Panel, embed QT FullMesh into the wet Render, overlapping joints by 100mm minimum. Allow to firm and then screed and or float to a flat and level finish. The purpose of this coat is to even out the substrate and the porosity of the QT EcoSeries Wall Panel. 150mm wide x 300mm long strips of QT 45° Mesh are also required to be set into the base coat at 45° angle across the corner of all windows and door openings into wet render. Do not render or texture over control joints. The above is a generic guide only.
Refer to the proprietary coating manufacturer’s instructions for a detailed description of application. Any proprietary coating system specified must meet or exceed the performance criteria of the BCA.