Question:

• Why do building interior contractors in Vietnam excessively use self-adhesive fiberglass mesh tape and putty compound (for masonry construction) to flush joint screwed-up concealed grid gypsum ceiling and drywall partition ?

   

Answer:

• To perform gypsum wallboard joint treatment with perforated paper tapes, drywallers must be well trained both theoretically and practically in several months, whereas self-adhesive fiberglass mesh tapes are purposely designed and produced for handy people called Do-It-Yourselfers, not for professionals. In short, anybody can use self-adhesive fiberglass mesh tapes since they are easy to use, what you have to do is to bond it to the board joints, and leave it there. The following step, applying jointing compounds to the joints in several coats, are for painters !!!

   

• Calcium carbonate (CaCO₃) based putty compounds are easy to use as their drying time is very long, normally up to 2-3 hours after the dry powder is mixed with water, thus suitable for unskilled workers, those who have not been trained or already trained but not exposed long enough to practicing. When completely dry, calcium carbonate based putty compounds are porous, soft, easy for sanding, thus helps workers saving their working time; however these products have very poor anti-cracking strength in comparison with gypsum plaster based jointing compounds (CaSO₄.1/2H₂O).

   

• Obviously, the magnified effect of using unskilled workers plus inappropriate materials has resulted in poor quality gypsum drywall and ceiling systems with lots of joint cracks !!! Recently, in Vietnam, due to several reasons, some house owners have bad impressions with very short life time of gypsum drywall and ceiling systems. Meanwhile in North America, Australia, New Zealand, etc. where most houses are built up with timber frame, which seem much less strong compared to traditional houses in Vietnam, often made of brick walls and reinforced concrete floors - columns - beams, drywall partitions and ceilings lined with gypsum wallboards are long lasting with normal service life time up to 40-50 years.

• In brief, due to the lack of profound knowledge about specialty products in the gypsum industry, most of enterprises in Vietnam involved in the building industry often specify and/or use inappropriate products for gypsum drywall and ceiling systems.