From symptom to the right product — site diagnosis and matching solutions
In most damp complaints the real problem is not the product but the diagnosis. In a building that has been diagnosed wrongly, even the best product fails. This guide is built around distinctions you can make on site, by eye.
| SYMPTOM | WHERE IT APPEARS | DIAGNOSIS | SOLUTION |
|---|---|---|---|
| A horizontal line parallel to the floor, 0.5 – 1.5 m, with white salt above it | At the base of the wall, in every season | Rising damp | D101 → W101 |
| Black mould in upper corners, on the ceiling, around windows | In winter, in a heated room | Condensation | Ventilation + thermal insulation |
| A local, irregularly bounded wet patch that grows over time | Along a pipe run | Plumbing leak | Repair the plumbing first |
| A stain that grows after rain and fades as it dries | External wall, under the roof | Facade / roof leak | Facade repair |
| Widespread damp and dripping on a below-ground wall | Basement wall and foundation | External water pressure | N102 (± E101/G101) |
| Pressurised water is running | Crack, joint, tie-rod hole | Active leak | N111/N112 → N102 |
The decisive question: does the problem disappear completely with the season? If it is never visible in summer it is most likely condensation — injection is not the answer. Rising damp varies in intensity with the season but never disappears entirely.
Once rising damp is diagnosed, the solution depends on what the wall is made of. Chemical injection needs a capillary network; reinforced concrete does not have one.
| WALL TYPE | STATUS | NOTE |
|---|---|---|
| Solid brick, stone masonry, mixed masonry | Suitable | D101 injection — the most efficient case |
| Pumice block, aerated concrete, adobe | Suitable | D101; calculate consumption from the upper values |
| Perforated brick | Conditional | D101; the plaster must be renewed first |
| Very thick (>60 cm) or cavity section | Conditional | D101 from both sides; a survey is essential |
| Reinforced concrete wall, column, foundation | Not suitable | Injection does not work — NK130 |
| Mixed structure (masonry + reinforced concrete) | Conditional | D101 + NK130 planned together |
Why it matters Rising water leaves the salts it carries at the surface. These salts are hygroscopic — they draw moisture from the air. Even after injection has stopped the water from rising, the salt left in the wall keeps drawing moisture; the surface stays damp and the new plaster blisters within a few months. D201 converts those salts into water-insoluble compounds and breaks the cycle. It is applied after injection and before plastering.
| SCENARIO | PRODUCT CHAIN | NOTE |
|---|---|---|
| Basement, masonry wall, no sign of salt | D101 → W101 | The most common domestic case |
| Basement, masonry wall, efflorescence present | D101 → D201 → W101 | Skip the salt step and the plaster blisters |
| Ground floor, reinforced concrete wall | NK130 | Injection cannot be used |
| Mixed structure — masonry wall + concrete column | D101 → W101 + NK130 | Both methods together |
| Historic building, surface must not be touched | NK130 | Where no holes may be drilled |
| Dripping and active flow on a basement wall | N111/N112 → R101 → N102 | Stop the water first |
| No access behind the wall, leak present | G101 curtain injection → N102 | Where excavation is impossible |
| Water coming through tie-rod holes | N112 → R101 → N102 | Not N111; the void has to be filled |
| Inner face of a water tank | R101 → N102 | For potable water: 7 days + disinfection |
Condensation is a building-physics problem; a chemical barrier does not solve it. Ventilation and thermal insulation are needed. The wrong recommendation costs both money and trust.
There is no capillary network; the solution does not spread and no barrier forms. These elements need NK130.
If hygroscopic salt remains, the surface stays damp and the new plaster blisters. Where there is efflorescence, D201 is mandatory.
Running water washes out mortar that has not set. Stop the flow first with N111 or N112.
The two get confused. N111 is a dry powder — for pressurised point leaks. N112 is a kneadable mortar — for filling voids.
If only the injection is done and the surface is not renewed, the existing damp and salt keep coming to the surface. The customer never sees the result.
These ten questions give you everything needed to prepare a quotation. Where you cannot be certain, send a photo of the wall with its dimensions and ask our technical team.
Send a photo of the wall with its dimensions; our technical team will propose the right product chain within 24 hours.
