The project entailed –
Acid Stain and seal lobby areas – 3500ft2
Resurface and Acid Stain two rest rooms – 1000ft2
Time allotted – 4 days (Start Thursday morning and finish it by Monday morning)
Project crew – 5
We had planned in such a way that it was all doable in 4 days and nights. As we all know there are always surprises on every project. When we inspected the project site on Wednesday evening, we got a big surprise. The concrete surface that was to be acid stained in the lobby area was NOT concrete…it was gypsum concrete! This contractor who was new in the decorative concrete business did not realize that the gypsum concrete and regular concrete are different and gypsum cannot be acid stained. (I guess you understand now, why I am not mentioning the name of the contractor).
Since walking away from the project was not an option, we decided to resurface gypsum subfloor with a micro-topping ( Skraffino Regular & Superfine Super Fine ). There were two big challenges with resurfacing –
- Additional cost of resurfacing 3500ft2
- Time restriction
The availability of Skraffino SF was not an issue because the products were available in the company warehouse that was located in Cleveland, OH.
To minimize the additional cost of resurfacing, to speed up the application process and to give a smooth surface, we decided to spray the Skraffino SF. By spraying Skraffino SF we were able to
- minimize the cost of additional products required (because spraying increases the coverage rate by at least 1.5 times)
- resurface 3500ft2 in 3.0 hours (1 coat) and
- achieve a very smooth surface (without any trowel marks)
Needless to say the project was completed in allotted time period and as you can see from the pictures the floor looks great. For an additional cost of $0.48/ft2, the contractor was able to give their customer what he promised and still make good money.
Please let me know if you are interested in information like – step by step process (with time periods for each step), acid stains and sealers used, etc. I did not want to bore the readers with this trivia.
Lesson learned from this experience: Concrete resurfacing is the best way to acid stain gypsum sub floors and one can get great results by spraying the micro-topping. Please note spraying is a good option for large areas and when you already have a smooth (level) surface. Since this floor was very smooth (gypsum sub-floor installer did a good job), one coat of Skraffino SF was sufficient.
More and more contractors are adopting this process on self leveling concrete. Most of the self leveling concrete products (those I know), do not give good results when acid stained. Of course they look very good when dyed and sealed. Moreover self leveling concrete surfaces look plastic (for lack of any other words). The best solution is to spray Skraffino Superfine. Recently, Hudson Concrete Contractors in NYC used this process (self leveling concrete plus spray) for 18,000ft2 in Martha Stewart’s corporate office in New York City. The floor preparation and self leveling this area took almost a week but spraying the whole area was done in ONE DAY!
I know you want to see the pics…unfortunately we are not allowed to take the pics (if you are in the NYC and want to take a look at the floor, please contact me). The floor has typical New York look…different shades of grey.
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