Part 3: Execution
This section is important in specifying the scope of work, quantitative installation methods and requirements, and the sequence of work relative to the respective installation products. Protection of materials should be pointed out, indicating the requirements and limitations in terms of material storage, environmental conditions for material storage and during installation, and protection of the completed work.
Often, what is missing from this section is the QC plan. The QC plan should be written to outline the sequence of work and the requirements of the respective products being used. The plan should require the QC inspector to verify the material’s manufacturer’s directions are met in terms of storage, its use during application, and during curing.
The QC plan should verify relevant industry standards are being met, for example, achieving 95 percent thin-set contact between the tile and the substrate in a wet application, or ensuring movement joints are installed every 2.4 to 3.6 m (8 to 12 ft) in an exterior application. It should be required for freshly installed tiles to be pulled-up, to verify and document the thin-set mortar coverage, and then immediately re-install them. This takes little time and effort by the installer and is what the standards say the installer should do periodically. The QC inspection should be done quantitatively when possible. For instance, for every 4.6 m2 (50 sf) tile installed, three tiles shall be removed to verify they substantially achieved the required 95 percent thin-set mortar coverage. A laser thermometer can also be used to document the temperature of the substrate or materials not exceeding 32 C (90 F). The movement joints being placed every 2.4 to 3.6 m (8 to 12 ft) should also be documented, as well as the closed-cell polyethene foam backer rod being used and installed correctly with the appropriate ASTM C920 traffic grade sealant.
The lack of installer supervision and QC adds to the construction industry’s shortage of qualified labor. Without the supervision and oversight, the labor continues to do things wrong, which perpetuates the same mistakes and problems. A QC plan that is not only written clearly and comprehensively, but also implemented by a qualified inspector with installation experience and knowledge, becomes the best remedy to ensure a successful installation. The installers end up being trained on how to properly perform the work as per the industry standards and per the manufacturer’s directions, which follows them to their next job.
