WDO in a 100 year old apartment in wet area

[Enid]

Hello everyone,

On inspection, a 100-year-old apartment in Lisbon, Portugal showed evidence of a Wood Destroying Organism infestation in the stairwell: 1-2mm holes in the wood and slope to the stairs, but no powder visible (the area is high traffic and frequently cleaned).

In the apartment itself, 1-2mm holes were also observed and the joist is likely infested, too, as evidenced by a slope, or sag to the floor (see pictures). Again, there were no signs of active infection but also no reason to believe that it isn't active.

An investigation by a structural engineer was recommended to determine that the joist does not need replacement or sistering. However, the owner of the apartment does not want to remove any flooring prior to selling it, so it is impossible for the engineer to conduct a through inspection.

The building is old and ornate, and replacing a joist or two would be major work, including working with a plasterer. If you were the buyer (me) would you decide against a purchase or do you feel that with proper moisture control, the building will reasonably hold up for many decades? (It has already made it 100 years.)

Thanks!

Enid