Page 20 - Parquet International luglio 2014

IN DEPTH ANALYSIS
When glue unglues
The amount of adhesive used is important, but the laying method adopted for the particular type of plank and laying surface is just as vital
MAURO ERRICO
Ibecame involved (again) in a legal dis- pute that could have been easily avoid- ed. Just a bit of common sense, and above all, knowledge of the technical characteris- tics of the materials used would have been sufficient. The floor under dispute was an approx. 22 mm thick single-layer parquet floor of a type of wood described in Stan- dard “UNI EN 13226:2004 - Wood flooring - solid parquet elements with grooves and/or tongues”, a product that we may de- scribe as important in terms of quality, and especially in terms of format. The type of wood in the floor was Oak (Quercus Spp), and it was laid onsite in shipdeck pattern from the main entrance to the every room for a total 350 square meters.
Problem: the parquet becomes unglued
The wood flooring in question was laid on two floors in two adjacent properties that were undergoing a well-planned and well- executed renovation. The first thing I did
was to visually check the floors, room by room, with daylight striking the floor both in front and behind.
This parquet had been laid onsite with the total gluing method using a bicomponent synthetic adhesive over a fresh traditional concrete support surface cast more than 6 months prior to the laying of the floor. I was informed that the parquet installer had rightfully conducted a check on the humid- ity levels still present in the concrete, but not whether he had adopted the electric or the chemical reaction testing method. A water- base varnish with low environmental im- pact was provided as the protective treat- ment for the surface.
The problem was that in both properties, many areas of flooring gave off hollow thud- ding sounds when struck with the correct instrument, a 500 g stiff plastic mallet. This phenomenon does not leave much room for doubt, and nearly always signals the de- tachment of the elements in wood from the support surface.