How a floor finish can fail: A case study

The screeding contract for the recent screeding project for the new sports hall and changing area at Uxbridge College was taken up by a screeding contractor on behalf of the main contractor. The screed used was FlexiDry F2/14 day dry.

Sports Hall

The screed was laid to perfection. But when moisture tests were carried out in the main sports hall at the end of the thirteen day period by the screed contractor, it was found that the moisture content in the area that was screeded the last was higher than what was expected. With time being a constraint for the project, the Principal contractor was under pressure to come up with a quick solution, and it was decided that DPM be applied on the 650 sm area. The premature tests done for a screed with a 14 day drying period ultimately led to this decision that resulted in causing considerable additional expenditure to the client, as the application of DPM is highly expensive, and costs more than screeding itself.

Changing Areas

Moisture problems were noticed in the floors of the changing areas as well. It was found that the vinyl finish on the floors had bubbled and lifted, and it was removed for closer examination the substrate. Upon examining, it was seen that the adhesive was considerably wet and had even turned milky. As a result, it was decided to conduct a Tramex moisture test in the presence of the Floor Screeding Contractor, Screed Manufacturer, the Principal Contractor and the Floor Finishing Contractor. The moisture test showed that the screed was a CM 1.6% and the latex 3%, and the adhesive was clearly wet as well.

The screed was found to be dry. But the problem could have occurred to a number of reasons ranging from entry of water into the vinyl, application of the vinyl finish before the drying of the latex, problems with the adhesive or even leakage of water into the screed during construction. However, it was not possible to point out the real cause as the floor finishing contractor had not ensured that the screed was tested before laying the final vinyl finish on the latex coat.

Conclusion

It should always be ensured that an accurate method of moisture testing is followed and the results recorded without fail, before the final floor finish is laid.