Plain-English answers to the questions we get asked most, written by the team that actually installs and services these systems, not a copywriter guessing. For the full evidence, calculator and printable cheat sheet, see The Healthy Home Humidity Guide.
Soft, dark or cracked timber means decay, and the cause is nearly always water. How to read the signs, what to fix first and when a specialist is needed.
WindowsBlack mould on window seals and frames is usually condensation, not a faulty window. Trickle vents, wiping and ventilation, from free fixes up to a system.
RentingWhat GOV.UK says a landlord must repair, what tenants can do themselves, and how to involve Medway Council if nothing happens, in four steps.
Everyday CausesWhy a night of breathing leaves bedroom windows wet, and a four-rung ladder from free habits to mechanical help.
PestsSilverfish, booklice and dust mites are clues to damp and humidity. Read the signs, cut the moisture, and know what a dehumidifier can and cannot do.
FurnitureA sofa, bed or bookcase pushed flat against an outside wall holds a pocket of cold, still air behind it. That is where mould starts. Here is what to move and what to check.
Cold spotsMould back in the same place every winter? How cold spots form at lintels, reveals and corners, and a four-rung ladder from free checks to a surveyor.
FloorsBlocked airbricks and poorly ventilated timber floors can make a ground floor smell musty. Check the vents, find the water, and know when to call a specialist.
HumidityWhat indoor humidity is healthy? Learn the 40-60% band, why 50-55% is a sensible target, what it does for mould and dust mites, and what it cannot do.
DiagnosisThree kinds of damp look alike but need different fixes. Use this four-rung ladder to tell rising, penetrating and condensation damp apart before you spend.
Everyday CausesWiping condensation and cleaning a small mould patch: the routine the guidance suggests, which products it prefers and when to stop.
Everyday CausesWindows streaming once the heating goes on? Work up a four-rung ladder from free readings to fixes, and learn when a dehumidifier will not help.
LeaksDamp patch under a gutter or after rain? Work up a four-rung ladder from a free walk-round to repairs, and learn when a dehumidifier will not help.
LeaksDamp patch after rain on an outside wall? Work up a four-rung ladder from a free look at render and pointing to repair, and when a dehumidifier will not help.
Cold homesA cold home is a damp home, and rising bills make it hard to do the obvious thing. Here is what costs nothing, what support exists, and what to avoid.
Soft furnishingsMould on a carpet, curtain or sofa is harder than mould on a wall. What to clean, what may have to go, and how to stop the damp that caused it.
InsulationNew damp patch after cavity wall insulation? Work up a four-rung ladder from free checks to the guarantee and a surveyor, and when a dehumidifier will not help.
Everyday CausesMusty smell in a wardrobe or cupboard? A four-rung ladder from free checks to proper fixes, plus when a dehumidifier helps and when it does not.
Everyday CausesWet windows every morning? Learn what window condensation means, which rooms matter, and a four-step ladder from free habits to a proper fix.
MouldBlack mould in the corner of a bedroom is usually condensation on a cold wall. Follow this four-rung ladder to clean it safely, fix it and stop it returning.
Roofs and LoftsDamp roof timbers, wet insulation or a musty loft? Learn what causes loft condensation and how to fix it, in four rungs from cheap checks to specialist help.
VentilationIs your extractor fan doing anything? A four-rung ladder to check, clean, upgrade and ventilate properly so steam leaves the house instead of settling on walls.
Older PropertiesStains, salts or peeling paint on a chimney breast usually point to one of four causes. Work up a four-rung ladder from capping to specialist repair.
Older PropertiesSolid walls, sealed-up fireplaces and draught-proofed sash windows all change how moisture behaves in an older terrace, and why the fix isn't the same as for a modern estate house.
Everyday CausesA load of wet washing can put litres of water vapour into the air of a small house. Here's what actually helps, and what just moves the problem to a different room.
Doors and heatDamp air drifts from the kitchen and bathroom to the coldest room in the house. Which doors to close, which rooms to warm, and a ladder from free checks to a surveyor.
RoofsA new patch after roof work can be a missed leak or loft condensation. Match the patch to the weather, then work from free checks up to a specialist.
MonitoringA hygrometer shows what your air is doing. Where to put one, what to log for a week, how to read the pattern and when a reading points to a leak instead.
DiagnosisTreatment only works on the right kind of damp. Read the pattern, log the humidity and know what to ask a surveyor before you pay for work.
SmellsA musty smell with nothing to see is often mould behind furniture, wallpaper or carpet. A four-rung ladder to find it safely and cut the moisture feeding it.
BathroomsA stain next to or under a bathroom is often a leak, not condensation. A four-rung ladder to check the seals, tell the signs apart and fix the source first.
Looking for help near you? See the areas we cover around Chatham.