Why does mould come back even after repainting?+
Because the stain is the symptom of something else. Mould takes hold where a surface stays damp for long enough: condensation on a cold wall, a thermal bridge, water getting in from outside, a room that is never aired. Repainting covers the mark but touches none of those conditions, and the problem comes back. The first step is to work out where the moisture is coming from: as long as that remains, no finish can do the job of insulation or a repair.
How can you tell condensation from rising damp?+
By looking at where the stain is and when it appears. Condensation forms on the cold spots of the room (external corners, behind furniture pushed against the wall, around windows, on the ceiling) and shows mainly in the cold months, when there is vapour indoors and the wall is icy. Rising damp starts from the bottom instead, with a continuous band climbing up from the skirting that stays even in summer, often with crumbling plaster and whitish salt deposits. They are two problems with two different remedies: confusing them means treating the wrong place.
Does anti-mould paint solve the problem?+
No, and it is worth saying clearly. An anti-mould paint contains active ingredients that hinder the growth of the fungus on the surface: it is a help that works on the last layer. If the wall keeps getting wet (through condensation, a thermal bridge, water getting in), the mould finds a way back. Finishes of this kind make sense after the cause has been dealt with, as the final layer of work that has already been done.
Is airing the room enough to prevent mould?+
It helps a lot, but it is not always enough. Changing the air takes out the vapour produced by cooking, showers, drying laundry and breathing, and reduces condensation on cold surfaces: it is the first thing to do and it costs nothing. It falls short where the wall is cold because of how it is built, or where water comes from outside: there the vapour is only one of the sources, and the problem remains even with the windows open.
Do the site visit and the quote commit me to anything?+
No. The site visit is there to look at the wall with our own eyes: to understand what state the substrate is in, whether there are cracks, damp or old finishes to remove, and which steps are really needed. Only then can a quote be put together that stands up. Until that point there is no commitment to make.
How much does mould treatment cost?+
It depends on which of the four causes lies underneath, and that is the reason we do not give a figure over the phone. Treating a wall with surface condensation is one job; rising damp or water ingress are another category, and often call for another trade. The figure comes after the diagnosis, because it is the cause that decides the work. The site visit with the diagnosis is free.
What if you find it is not a problem you can solve?+
We tell you, and we do not take the job. Rising damp, water coming in from the roof or a terrace, a leak from a pipe: these are jobs of a different kind, and painting over them means paying twice. In that case we leave you a written note of what we found and who it is worth turning to: we have trusted professionals we refer cases to, and we point you to them in person, case by case.
Can the work be done in winter?+
Yes, and it is also the time when the problem shows best: condensation is a winter phenomenon, and a wall that looks fine in summer tells the truth in winter. Temperature and humidity readings taken in the cold season say far more than the same readings taken in August.
In a rented home, who pays?+
It depends on the cause, and that is why the diagnosis matters more than the quote. As a rule mould is a defect of the property and falls on the landlord, who must hand over a home fit for use; it falls on the tenant when it depends on how the property is lived in, for example rooms never aired or laundry dried indoors. We do not decide who is right: we establish the technical cause and put it in writing, which is the document both sides need.
