By Dave Doherty and Phil Romah, Tego Systems
When it comes to adhering flooring materials to concrete substrates, there are numerous hurdles to overcome, and much important research to be completed for a successful installation. Let’s put aside the environmental (HVAC/Humidity) issues and focus on the concrete itself. This includes concrete that is below-, above- or on-grade. This is not all inclusive.
New Concrete
- Is there a proper moisture barrier beneath the slab?
- Was the concrete placed correctly?
- Was the concrete allowed to cure properly?
- Is there an admixture in the concrete itself to assist in curing that may be deleterious to the adhesive bond?
- Is it Lightweight Concrete? This is important regarding In-Situ testing.
- Is it hard troweled and therefore mainly non-porous?
- Is there a chemical moisture barrier adhered to the surface (new and existing)?
Existing Concrete
- Were there previous moisture problems or flooring failures?
- What was the previous flooring material?
- What type of adhesive residue is on the surface of the concrete?
- Was the previous adhesive removed mechanically or chemically?
- What was the space previously used for? Consider a machine shop that contaminated the slab for decades with oil and other contaminants. These types of mill-type buildings are being converted all over the country.
Q: The old flooring has been down for many years and didn’t fail. Do I still need to test for moisture?
A: Yes. Just because the older material(s) didn’t fail does not factor into the moisture testing requirements for the new material or patching compounds:
- Many older flooring materials contained asbestos which is resistant to moisture and would not be a comparison to today’s materials/backings.
- Older adhesives were solvent-based, which were not as susceptible to moisture related degradation.
- There could be a major construction site nearby, or other environmental factors that may have inadvertently changed the water table beneath the slab.
The Flooring Contractor must test for the two major causes of adhesive failure – Moisture and Alkalinity, while following proper ASTM and Manufacturer standards. Concrete is naturally alkaline and moisture vapor brings this to the surface. This killer combination is a major factor in flooring failures around the world.
Bottom line – do your homework and test, test, test. Look at the installation with a wider scope. Be sure to carefully document the test results. This is an inexpensive insurance policy.
iStock photos courtesy of Tego Systems
