Preparing the substrate for raised floors

Preparation begins with a precise elevation survey . The subfloor level is measured at multiple points, checking for any unevenness, depressions, or slopes. This allows us to determine the final elevation of the finished floor and how it connects with other rooms, landings, entrances, elevators, windows, and fixtures.

The ideal subfloor for a raised floor is solid, flat, and clean . Screeds that are too dusty, have loose particles, or have old adhesives or loose coverings must be fixed before installing the feet. In some cases, a self-leveling screed is necessary to minimize unevenness, especially on very large surfaces.

A key aspect is moisture management . Raised floors, especially those with chipboard cores, do not tolerate damp screeds or rising damp. Therefore, residual moisture is measured, any leaks are checked, and specific vapor barriers or primers are applied if necessary. In the case of basements or critical situations, this check must be carried out with particular care.

At the same time, the distribution of the systems in the plenum is planned: electrical cables, data cables, HVAC pipes, and ducts. The raised floor must not become a "disorganized container," but an organized space, with preferential passageways, carefully designed access points (turrets, boxes, columns), and free spaces for future modifications. Any technical walkways or additional supports for large-section conduits are also defined at this stage.

The subfloor is then thoroughly cleaned : dust, scraps, construction debris, nails, or rebar should not be left in the plenum, as they could hinder the adjustment of the feet or generate noise and vibrations during operation. Once the structure is installed, access to the area below will be less immediate, so this is the right time to tidy up.

In spaces where traditional flooring and raised floors coexist, preparation includes considering level transitions : ramps, finishing profiles, thresholds, and flush solutions with doors and windows. It's important to avoid unexpected steps or abrupt visual changes that compromise the perception of continuity.

Only after checking the dimensions, support, humidity, and utilities does it really make sense to begin installing the feet and structure. Skipping this step means burdening the system adjustments with problems that should have been resolved earlier, with the risk of ending up with a "floating" floor that isn't perfectly stable.