Bratislava, SK
Section 01
The challenge
Damp rising from the massive stone masonry in the basement of the south wing of Bratislava Castle. The walls showed heavy salt efflorescence and the gradual degradation of the historic plasters. In places, surface layers had begun to separate, and the damp was undermining the structural integrity of the adjoining stone elements. Previous attempts at damp-proofing using traditional methods — electro-osmosis, surface water repellents — failed to produce a sustainable result. Furthermore, the stone masonry, over a metre thick, could be neither sawn nor demolished.
Section 02
Why WetBRICK®
WetBRICK® was approved by the Monuments Board of the Slovak Republic as a reversible intervention that does not alter the visible fabric of the masonry. The gel is injected into Ø 18 mm holes in a single horizontal line at the base of the wall. No demolition, no cutting, no structural intervention. Once complete, only discreet plugs remain in the masonry, which are made good as part of routine maintenance. For a UNESCO-protected building, this non-invasiveness was decisive.
Section 03
What happened next
Six months after injection, damp levels in the monitored probes fell by 60–70%. After one year, the application of Epasit® WTA renovating plaster followed. The walls now show stable dryness, and salt efflorescence has not returned. Bratislava Castle has incorporated this procedure into its long-term methodology for damp-proofing historic masonry.