Limescale Airing Cupboard on Ceiling
Three central heating pipes ( one assumes) enters the expansion tank in the loft above from the airing cupboard.
A brown condensation stain has developed on the ceiling below the expansion tank with brown limescale crusting.
The stain appears to be old ( it is dry now) and the system has since had a water softner system installed. The whole system is fairly new ( 2018)
This is a house I am buying, and the vendor was not forthcoming on the stain.
Is this is major concern?
Thank you.
Replies from 2 tradespeople
The brown, limescale-crusted stain on the ceiling below the expansion tank is likely from a past leak, possibly due to a faulty float valve or condensation, and it's not necessarily a major concern if the system has since been upgraded with a water softener. However, the vendor's lack of disclosure is a red flag, and it's worth investigating further to ensure the issue is resolved and to understand the extent of any past damage
The brown stain and limescale crusting you’ve described under the expansion tank suggest there was a past leak or overflow, likely from the central heating system’s feed and expansion tank. This isn’t uncommon, especially in older or open-vented systems, and it could have been caused by something as simple as an overflowing tank due to high pressure or a sticking ball valve.
The fact that the stain is dry and hasn’t worsened suggests it was a historic issue, not an active one. The installation of a water softener may also indicate the previous owners were addressing hard water problems that can contribute to limescale buildup. Given that the heating system was installed in 2018, it’s relatively modern, which lowers the chance of a serious ongoing problem — but it doesn't rule one out entirely.
Still, a brown stain with crusting could mean there’s been corrosion at some point, or that overflow water sat there long enough to leave mineral deposits. While this isn’t necessarily a major concern, it would be sensible to:
Ask your surveyor to check the tank, pipework, and ceiling from above for signs of corrosion or ongoing leakage.
Confirm whether the system is sealed or open-vented (open systems are more prone to this kind of issue).
Consider having a heating engineer inspect the expansion tank setup to ensure everything is in good condition and compliant.
It’s not necessarily a deal-breaker, but it is something worth clarifying before exchange — especially since the vendor was evasive about it. If there are no signs of active leaks or corrosion, and the engineer is satisfied, you’ll likely be fine. But if you see fresh staining or the tank isn’t properly maintained, it could point to longer-term neglect.
