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A ceiling stain is worst when the AC runs hard
A ceiling stain grows during the hottest weeks, when the air conditioning runs almost constantly, and has nothing to do with rain. The water is coming from the cooling system or from condensation on cold surfaces in the ceiling void.
Waterproofing
Active ingress during rain is prioritised. Tracing and permanent repair are scheduled once the source is identified.
Call nowRequest an inspection on WhatsApp01LIKELY CAUSES
What usually sits behind this symptom, and what tells one cause from another.
Condensation on uninsulated ducts or pipes in the ceiling void
Droplets on cold surfaces; insulation missing or split.
Condensate drain blocked or poorly graded
Water standing in the drain line or tray.
Warm, humid air leaking into a cold ceiling void
Gaps around ceiling penetrations; condensation on the slab underside.
02BEFORE ANYONE VISITS
What you can safely check.
- Note whether the stain grows with AC use rather than rain.
- Check whether it is near an indoor unit or along a duct route.
- Look for dripping from grilles or access panels.
- Reduce the cooling setpoint slightly to see if the stain slows.
03WHAT WE MEASURE
We open the ceiling access, inspect duct and pipe insulation, test the condensate drain, and check for humid air paths into the void. Moisture readings and the pattern of wetting confirm whether it is condensation rather than a waterproofing failure.
04IN A VILLA
Villa ceiling voids carry long cold ducts and refrigerant pipes under hot roofs. Where insulation is missing or damaged, the surfaces sweat continuously in summer — and it looks exactly like a roof leak on the ceiling below.
05THE FIX
Which repair, and when.
Continuous condensation wets ceiling boards and insulation and can lead to mould in the void.
Reinsulate ducts and pipework
Cold surfaces are sweating.
Clear or regrade the condensate drain
The drain is blocked or poorly laid.
Seal air leaks into the ceiling void
Humid air is reaching cold surfaces.
06Typical villa waterproofing work
Quoted after survey — always
Cost is driven almost entirely by what the tracing finds and how much has to be lifted to reach it. We do not price waterproofing over the phone, because a number given before the source is located is a guess.
07QUESTIONS
- Do I need roof waterproofing?
- Not if the stain follows AC use rather than rain. This pattern points at the cooling system or condensation.
- Why does it only happen in summer?
- That is when ducts are coldest and the air outside them is most humid.