In March 2025, Teknoprogetti Engineering was commissioned by the school administration — following formal approval by the competent authorities — to carry out a campaign of instrumental investigations on the timber structure of a school building under construction in the Municipality of Frassinoro (MO). The entire elevated structure is built with prefabricated Cross-Laminated Timber (X-Lam) panels. During construction, the Site Supervisor and the Works Director had visually detected moisture on several load-bearing elements: the problem had to be quantified before finishes covered everything.
The critical issue with timber structures is this: a wet X-Lam panel can appear perfectly intact on the surface even when moisture has already reached the core of the section. Visual inspection alone is not enough — instrumented testing is required.
We carried out the campaign on 20 sample elements — columns, walls, portal beams, ridge beams, floor boarding — for a total of 31 Resistograph measurements, supported by sclerometric tests and electrical moisture readings, in accordance with current UNI standards.
The moisture data confirmed localised anomalies: on the window jamb exposed to the elements, in the area below the sill, we measured 39.6% — well above the reference threshold for a building under construction. On the floor boarding, in contact with straw infill saturated with water from infiltrations through the not-yet-completed roof, values ranged between 28% and 38%.
This is where the Resistograph came in: a 3 mm drill bit penetrated each element for the full depth of the cross-section, continuously measuring resistance to penetration. The result — all 31 measurements — showed constant, homogeneous profiles with no drops in the curve that would indicate rot, voids or layer separation.
The diagnosis was clear: infiltrations had increased moisture locally, but biological decay had not had time to compromise the internal structure of the panels. No structural elements needed replacement. The Works Director was able to prescribe targeted controlled drying measures and monitoring, avoiding invasive intervention and additional construction time.
High moisture in timber is a signal that cannot be ignored — but it is not automatically structural damage. The difference lies in correct instrumental diagnosis.
→ Read the full technical guide: methodology, standards, operational checklist and the complete results from the Frassinoro case.
