Boiler Heating Pipes making my floors sweat and home damp

[Alison123]

Hi Everyone

I would be very grateful for any help or advice or if anyone has experienced this problem?

I live in a top floor flat of a 1900s building that was converted in the 70's.

When I moved in for the first couple of years my flat was bone dry and then suddenly it all changed - my flat was damp, my bed sheets were damp and my washing didn't dry completely anymore - I even got mould on my washing. Long story short I discovered that when the floors became damp with condensation exactly matched when the heating went on for the neighbours in the ground floor flat - to the point where if they went on holiday I enjoyed a bone dry flat again.

I spent years trying to work out how that was in any way possible - I never worried the neighbours at the time as they were in their 70s and I didn't want to worry them. Then in about the middle of 2023 it all stopped and my flat was just dry all the time.

In January 2024 I was having a cup of tea with my ground floor neighbour when he hold me that he had made an extraordinary discovery - that the heating pipes from his flat ran up and over the flat beneath me and that he had as a result re-routed them so that the pipework all remained within his flat.

Which is why my flat had become a wonderful dry home.

Then in March of this year I went away for the weekend and when I came back my flat was unbelievably damp with condensation - really damp sheets, really damp floors, really miserable.

It took me about a week to realise that it was the ground floor heating pipes again - they have a wall that faces the first floor landing and even though they were away it was really hot to touch (they have on the odd occasion not switched off their heating when going away - I appreciate they get cold, they are in their 70s).

It took me a while to pluck up my courage but after waking up one morning and putting my feet on my extremely condensation damp floor (I have videos of my leaving hand prints) - I sent them an email, I didn't say that I knew that they had re-routed their heating back to beneath my floor again, and it was very non-commital as I didn't want to be accusatory or cause offence. I did explain though that my flat was very damp, my sheets were very damp and that it was miserable. I guess I hoped it would ***** their conscience as they know I have really quite bad arthritis and osteoporosis and that they might just re-route things back again as a result.

My hopes were dashed when they sent me back an email denying that their pipes ever ran above their flat and the husband came up and refused to accept that it was anything other than a fault with my flat (even though I explained that it was sporadic and not all the time and that it matched when their heating came on). When I said that I had felt the heat from the pipe in the wall on the first floor landing and this alone ran up to above the flat beneath mine and no further he went quiet.

Naively I thought that would be enough and that evening waited hopefully for a dry evening so when the damp started spreading back into my flat I was so upset and when I went down to feel the pipe behind the wall on the first floor landing and find the wall now cold I was even more upset.

So I guess that I have to approach the problem from my flat - is there anyway of locating the pipes beneath my floors to prove that they are my neighbours heating pipes? Once found is there any way to stop them from causing my floorboards to develop condensation on the surface and create truly dreadful unbearable damp in my flat??

It's a living nightmare - once the floors are damp, everything is damp - is there anything that can be done to control the situation from my flat as it's clear my neighbours don't care and don't want to help.

Very many thanks indeed for any advice or help.

Best wishes
Alison

 

[Chuck]

This sort of question is tricky to answer without visiting the property but, in most cases, condensation is due to a combination of poor ventilation and lack of heating.

So, to inform our speculation:

What type of heating system(s) are we dealing with? (Panel radiators, underfloor, etc?) What sort of boiler(s) provide the heating?

How is your flat ventilated? Where/how do you dry clothes? How much water do you boil cooking, etc. Are there fans installed in the kitchen and bathroom? Do you make sure that the kitchen and bathroom doors are kept closed to prevent water vapour migrating into the rest of the flat?

Are there one, or more, expansion tanks for the boilers in the roof above you? Is there any evidence of a water leaks on walls or ceilings? Has someone checked recently that any storage/expansion tanks in the roof have properly fitting covers?

It is possible that your flat is, in fact, humid / damp a lot of the time but you don't notice until your neighbour puts their heating on and some of the surfaces warm up as a result. These will then evaporate adsorbed water which then condenses on the colder surfaces.

You might wish to get a humidity+temperature meter you can put in the worst affected area(s). By keeping an eye on this you can get a handle on what you need to do to get the humidity down to below the dew point, at which point everything should dry out. An indoor digital hygrometer of the type I have in mind will cost somewhere in the range £15–£35.

 

[Alison123]

This sort of question is tricky to answer without visiting the property but, in most cases, condensation is due to a combination of poor ventilation and lack of heating.

So, to inform our speculation:

What type of heating system(s) are we dealing with? (Panel radiators, underfloor, etc?) What sort of boiler(s) provide the heating?

How is your flat ventilated? Where/how do you dry clothes? How much water do you boil cooking, etc. Are there fans installed in the kitchen and bathroom? Do you make sure that the kitchen and bathroom doors are kept closed to prevent water vapour migrating into the rest of the flat?

Are there one, or more, expansion tanks for the boilers in the roof above you? Is there any evidence of a water leaks on walls or ceilings? Has someone checked recently that any storage/expansion tanks in the roof have properly fitting covers?

It is possible that your flat is, in fact, humid / damp a lot of the time but you don't notice until your neighbour puts their heating on and some of the surfaces warm up as a result. These will then evaporate adsorbed water which then condenses on the colder surfaces.

You might wish to get a humidity+temperature meter you can put in the worst affected area(s). By keeping an eye on this you can get a handle on what you need to do to get the humidity down to below the dew point, at which point everything should dry out. An indoor digital hygrometer of the type I have in mind will cost somewhere in the range £15–£35.

Hi Chuck

Thank you so much for your reply - I really appreciate it.

The heating pipes running beneath the floors here are the pipes related to the heating in the ground floor flat and separate to mine - it's unfortunately just the way the house was converted into flats (lots of issues that we have all discovered if any of the flats have done any work!) - the ground floor heating pipes run up from their flat and through the void beneath my floors / above the middle floor flat. I wouldn't have known about this if it hadn't been for the ground floor neighbour actually telling me that he had discovered the way the pipes had been run and how he had re-routed the heating (which is when my flat returned to being completely dry until March of this year).

I have an extractor fan in my kitchen and a dehumidifying fan (vent axia) in my bathroom and my flat was bone dry with no damp issues until the neighbours in the ground floor moved in (and I absolutely stress that this is not meant as a reflection on them - they are just living their lives and feel the cold and so have their heating on very high). I have turned their heating on on occasions when they have been coming back from being away and it's set at 26. I can always tell when they are away and haven't left their heating on / if they have gone out for the evening and turned the heating off as my floors begin to settle back and they and the flat begin to dry out again.

The attic and roof are checked regularly by the Managing Agent so no leaks and the thing I loved most about my flat was the sheer dryness of the place - my bedsheets were never damp and the flat was always dry. For a year and a half from about mid 2023 to March of this year my flat was completely dry - and it was during this period that my neighbour told me that he had re-routed the heating in his flat so that it didn't go beyond the perimeters of his flat.

This year when the flat suddenly returned to being excessively damp again, I tried everything because I hadn't clicked it was the hot pipes under my floor again, I put the heating up high and then opened the windows to allow the damp out - all that happened was the bed sheets were hot as well as damp / I put all the fans on in the flat and opened all the windows for hours but the damp never left the floor and my sheets never recovered. It was only when my neighbours returned from holiday about 2 weeks after the damp returned that the flat started having periods of being dry again and that I clicked that they had re-routed their heating back to its original setting...

It's a difficult situation but if I could locate their pipes underneath my floorboards from the surface to pinpoint them maybe I could so something to stop the issue in my flat - put down an extra layer of insulation or something - I just don't know how to solve this situation and it's especially hard as my neighbour has now denied that the pipes run up from his flat. If he won't acknowledge this or that he re-routed the heating previously then I can't hope for any help from him.

Thank you for the recommendation re the humidity+temperature meter - maybe that will help me pinpoint the pipes??

Best wishes
Alison