The Unifix lightweight cement board system for exterior facings is the most conventional rain screen system. It is detached and spaced out from the insulated structure of the building. This spacing permits ventilation, which ensures the following:
Evacuation of infiltration water (coming in from the junctions with other materials of different expansions, such as the window frame and door frame, moldings and other facing materials, construction joints, errors in workmanship, etc.). This infiltration is amplified by positive pressure on the wall, created by winds or sudden squalls.
PermaBase® will not rot, swell or deteriorate in the presence of moisture, while gypsum board products are susceptible to moisture issues if it reaches the core.
The building envelope is always in movement caused by expansion, contraction or by wind pressures.
To absorb these natural movements, we recommend expansion joints placed a maximum of 4.6 meters (16 feet) apart, at major corner openings, in joints of each floor, where dissimilar materials are joined together (e.g. concrete slab and cement board) and where there is a significant change in elevation of a wall surface.
No, the same people that install gypsum boards can install PermaBase without any special tools or practices. The rough side of PermaBase® can be cut with a utility knife and no pre-drilling is necessary.
We recommend the use of a screw with a very large trumpet head, which will press the board firmly against the mounting studs or furring, thus avoiding any vibrations. Also, in very humid areas and/or for exterior use, the use of an anti-corrosive, high performing screw is highly advisable (do not use drywall or galvanized screws there!).
Yes, mainly due to its low water absorption and because it is rot-proof. Furthermore, after the jointing operation is done, it can be exposed to the elements for a few months before being finished with the final finishing product. But, before installing the finishing to PermaBase® (e.g. acrylic coatings, stucco, tiles, etc.), we recommend that you clean the surface (a smooth brush and water or just a water jet will often do) to remove dust, dirt, efflorescence or pollution that could be present due to its long exposure.
PermaBase® is more versatile, faster to install and just as moisture resistant as block wall construction. It also reduces the cost of the other trades, such as plumbing and electrical, since it is a stud wall system.
PermaBase Dek® functions as a support board and/or cover board for the insulation. It also functions as a support board for approved membranes such as ballasted systems, liquid membranes and mechanically fastened membranes. PermaBase Dek® will not swell or rot in the presence of moisture and has a high indentation strength to protect the insulation and support the membrane.
The chemical and physical composition gives it a very low water absorption, which explains its great dimensional stability. Therefore, it cannot be damaged by great differences of temperature. On top of that, PermaBase® is rot-proof. The armature used has a special treatment against alkalis contained in the cement. PermaBase does not stop solidifying itself as the years go by (like any concrete does).
These facts demonstrate the long life of PermaBase®, as seen in the field and in the laboratory during accelerated aging tests. But the most evident proof is the fact that PermaBase has been proven in Canada, a country with the most drastic changes in weather in the world.