Monolithic terrazzo has many years of successful history as cement terrazzo system. These systems are traditionally placed directly onto a prepared structural concrete slab.
CONCRETE JOINTING: SETTLEMENT & CRACK CONTROL
Concrete has been the standard flooring substrate in the commercial construction industry for many years. The concrete industry has developed many industry guidelines and recommendations to minimize cracking.
Cracks in concrete are a result of any number of issues, including volume change during the curing process, load deflection, settlement cracks and cracks induced from thermal stresses, which are typically due to non-climate controlled environments during the construction process. While shrinkage cracks, which account for most concrete cracking, become static once the volume change from curing is complete, any crack has the potential to become a dynamic, moving crack under thermal and load movement stresses. To accommodate dynamic loading, slabs should be designed for maximum deflection of L/360.
The details contained herein provide general information to use as a starting point for detailing site conditions that frequently occur on monolithic terrazzo projects.
They represent generally accepted practices of terrazzo contractors and suppliers across the United States under typical circumstances. These details do not replace the direction or advice of an architect or engineer regarding a specific project or for specific project conditions. The architect or engineer must specify movement joints and show location and details on drawings.
It is not the intent of this guide to make movement joint recommendations for a specific project. For your particular project(s), you should consider contacting an NTMA Contractor Member in your area to discuss details that many be most applicable for a given circumstance/location.
To mitigate cracking and curling in concrete at thin set cement terrazzo areas follow recommendations in ACI 360R-10.
- Terrazzo divider strips must precisely follow the concrete joint – even if crooked.
- Terrazzo divider strips are not flattening or leveling devices. They must adhere tightly to the concrete.
- Tooled edges on concrete joints are not to be used at areas to receive thin set cement terrazzo systems.