Moisture guides
Guides to understand damp walls, saltpeter and condensation
Practical content to identify symptoms, distinguish causes and prepare a diagnosis before renovation work.
The guides are organised by symptoms, causes, affected rooms, possible solutions and diagnosis. The aim is not to make a final diagnosis online, but to help you prepare a clear request and avoid unsuitable works or equipment.
Symptoms
What you can see on the wall or in the room.
Wallpaper
Peeling wallpaper: is humidity to blame?
Peeling wallpaper can be a sign of moisture contained in the wall, linked to rising damp or water damage.
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Paint
Flaking paint: should you suspect wall moisture?
Paint that blisters or flakes may be linked to moisture evaporating inside the wall. Repainting too quickly may hide the problem.
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Plaster
Crumbling plaster: a possible sign of moisture in the wall
Crumbling plaster can be caused by moisture evaporating from within the wall. The cause must be understood before any work.
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Saltpeter
Why does saltpeter come back after cleaning?
Saltpeter may reappear if the source of the moisture is not treated. Key points for understanding the phenomenon before redoing a wall.
Read the guide →Damp wall
Damp wall before repainting: what should you check?
Repainting a damp wall too early may hide the problem. Here are the checks to make before decorative finishing work.
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Damp band
Damp band at the bottom of walls: a sign of rising damp?
A damp band at the foot of a wall, sometimes with a white border, may indicate rising damp. How to interpret it.
Read the guide →Saltpeter
Saltpeter on walls: causes, risks for the building, what to do
Saltpeter on a wall often signals moisture that needs analysis. Possible causes, impacts on the building, and the right steps before works.
Read the guide →Causes
The possible origins to distinguish before treatment.
Mold
Gray/black mold and condensation: what should you understand?
Gray or black mold in corners, on upper walls, or behind furniture is often linked to condensation. Careful reference points.
Read the guide →Rising damp
Capillary rise: signs, causes and treatment
Understand capillary rise, its visible signs, and why a diagnosis matters before any treatment for a damp wall.
Read the guide →Condensation
Condensation in a house: cautious causes and solutions
Condensation can cause mold and discomfort. Understand the possible causes before choosing an air-treatment solution.
Read the guide →Water damage
Water damage: damp walls and drying before renovation work
After water damage, the structure can remain saturated. Why drying matters before render, paint, or wallpaper.
Read the guide →Infiltration
Water infiltration in a wall or leak: how can you tell the difference?
A damp mark can come from infiltration, a leak, or rising damp. Guidelines to distinguish these causes before treatment.
Read the guide →Rooms
Contexts where moisture behaves differently.
Cellar / basement
Cellar / basement damp: what should you check?
A damp cellar or basement may be due to the air, the walls, or a water event. Key points before equipment or renovation work.
Read the guide →Bedroom
Moisture in a bedroom: signs and possible causes
Mold, odor, condensation, or damp walls in a bedroom: how to think it through without overdiagnosing.
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Humidity in a bathroom: condensation or a wall problem?
Mold, blackened joints, flaking paint: moisture in a bathroom often comes from the air, sometimes from the wall. How to reason about it.
Read the guide →Ceiling
Ceiling damp: infiltration, condensation, or water damage?
A stain or mold on the ceiling can come from infiltration, an upstairs leak, or condensation. How to orient the diagnosis.
Read the guide →Interior walls
Humidity on interior walls: where should you start?
Cold interior walls, stains, salt deposits, or flaking paint: how to distinguish condensation from building-related damp before treatment.
Read the guide →Solutions
The families of possible responses according to the cause.
Choosing the right solution
Dehumidifier or wall treatment: what is the difference?
A dehumidifier treats the air; a wall solution treats a cause present in the building. The two approaches do not address the same need.
Read the guide →Dehumidifier
Home dehumidifier: when is it useful?
A dehumidifier can help with humid air, but it does not replace treatment of the cause of a damp wall.
Read the guide →Basement dehumidifier
Cellar / basement dehumidifier: choose without getting it wrong
For a cellar or basement, the dehumidifier must be chosen according to the use, the volume, and the cause of the moisture.
Read the guide →Treatment
Damp wall treatment: which solution for which cause?
A damp wall can come from rising damp, condensation, or water damage. The treatment depends on the identified cause.
Read the guide →Diagnosis
Guides to prepare a request, a quote, or a professional discussion.
Older buildings
Moisture in an older house: mistakes to avoid
Older buildings must be understood before they are corrected. Hiding the effects can worsen the issues or waste time.
Read the guide →Humidity level
Home humidity level: how should it be interpreted?
A humidity reading must be interpreted with the room, the season, and visible symptoms. Guidelines to avoid jumping to conclusions.
Read the guide →Diagnosis
Home damp diagnosis: process and value
Why start with a damp diagnosis before choosing a solution for walls, air, or water damage.
Read the guide →Professional
Damp treatment company: how to choose?
Choosing a damp-treatment company means checking its approach: diagnosis, cautious claims, and a solution suited to the cause.
Read the guide →Quote
Damp treatment quote: what information should you prepare?
To request a damp treatment quote or damp diagnosis, prepare the symptoms, photos, municipality, and building context.
Read the guide →Mold / fungi
Mold or dry rot: when should you seek a professional opinion?
Not all dark stains are the same. Understand when visible fungal growth requires a qualified inspection, without an online diagnosis.
Read the guide →Next step
Prefer showing your walls rather than reading?
Request a diagnosis. Describe the issues you have noticed and the construction period.