Page 28 - Parquet International December 2013

ON FIELD
A SURVEY
“Site” survey
After removing at least three of the par- quet boards, it was found that the first and the third boards had no “fixing nails”, while the second had 4. Further- more, the following floor structure was observed:
1) polyethylene sheet laid under the par- quet surface and on top of the counter floor;
2) the counter floor consisting of wood- en elements (spruce) 90/95 mm wide with a variable space (distance from centre) between the various strips, ranging from 50 mm to about 55 mm;
3) the initial joists consisting of 2 single wooden elements with flexible cou- pling, positioned about 450 mm apart;
4) wooden sleepers with nominal dimen- sions of 93 mm wide and 80 mm high (the official measurements were 100/ 120 mm wide and 60/80 mm high);
5) polyethylene sheet laid directly on the raw concrete floor with the heating sys- tem pipes clearly visible on top of this.
With regard to the temperature of the par- quet flooring and that in the “air gap” cre- ated by inserting the wooden sleepers, the investigations found no negative or unexpected values, including the dy- namic balancing of hygroscopic wood as foreseen by UNI EN 1264-1/2/3/4. However, when it came to the question of how the parquet sports floor had been “nailed”, it was found during the inva- sive investigation that the wooden ele- ments had been nailed in an approximate manner, not in line with the technical doc- umentation received (in particular, the specifications in the installation instruc- tions drawn up by the manufacturer and attached to the DIN V 18032-2:2001-04 certification dated 28-02-2005). For ex- ample, there were no nails in two of the three boards and the “nails” used were inappropriate for the intended use of the sports floor. Indeed, nails of the wrong size had been used, incapable of with- standing the envisaged stress: 1.2 x 40 mm long with a 1.8mm head instead of
Moments from the invasive investigation:
the picture below showing the only board of the three examined that actually
has any nails. Two photos
on the right clearly showing the floor structure.
the recommended 2.2 mm x 40 mm long nails with a 7mm head.
Only after the invasive investigation was it possible to detect the lack of nails in the two of the boards examined. Whilst it is certainly true that such a small number of boards cannot be considered repre- sentative of the entire floor, one can as- sume that the practice to simply “nail down the boards from time to time” had been repeated right across the surface giv- en the observed dynamics of the way the blocks “had grown apart” several times and in a “random” manner.
Without prejudice to these findings, there are currently no sector-specific regulations regarding the installation of wooden parts to be nailed down giving the precise di- mensions of the nails to be used (nor were there any at the time of the technical in- spection), yet contrary to what is usually the case, the fact that there were technical documents with specific installation in- structions from the manufacturer means that precise elements do, in fact, exist that allow one to assess the causal link.
All suspicions therefore
fall on the “NAILING”
From the findings of the technical in- spections, one can safely state that not enough importance was paid to how the boards should have been nailed down when the sports floor was being laid, a crucial oversight given the high levels of stress and strain (attrition) that such floors are subject to.
Moreover, after reading the manufactur- er’s installation instructions, provided with the certification from DIN CERTCO
of Berlin (DIN V 18032-2-2001-04 dated 28-02-2005, the whole bundle having been given to the customer), it is evident that the people responsible for fitting the floor did not follow some of the basic techni- cal instructions.
The invasive investigation has clearly af- forded us the chance to discover some technical deficiencies that form the prob- able cause of the problem. R