Condensation in loft affecting Model Railway Layout

[Prairie_5542]

Hi,

Hope anyone can help me out with a problem I have in my loft.

During the cold weather we have been having recently, there has been quite a lot of condensation on the inside of the felt in my loft. This in turn then drips down onto my model railway boards causing damp and mould on the top. The water is brown and sticky and also has caused the track to become green in places. A bit like when a battery becomes wet.
:cry:
I have a water tank in my loft which the layout has been built over (with removable section to gain access). Also there is a smaller tank next to the water tank, which has hot water in it. This smaller tank used to let off steam until I made a cover for it and this has now stopped.

The condensation only appears to be on one side of the loft and not the other.

When I'm up in the loft I do tend to have a small heater on.

Every time there are the drips of water on the felt I have to wipe dry.

The roof rafters are becoming wet because of this, with one in particular becoming a grey/oily colour. The black roof felt has overlaping layers. Recently I have put 'clips' to allow a gap in between these to allow air to flow out through them.

There were a couple of holes in the felt, and the damp/mould on the boards seemed worse in these areas.

What I would like to know is- 1. How to stop this condensation? 2. Is it made worse with having a heater on in there? 3. How to get rid of the damp/mould from the boards? Anything else to help me in this matter?

Thanks for reading.

 

[455driver]

What sort of heater is it, if its a calor gas type the output from them is heat and water vapour.
This could be the source of the condensation and it will mainly be on the side of the roof away from the sun (colder).

 

[Prairie_5542]

What sort of heater is it, if its a calor gas type the output from them is heat and water vapour.
This could be the source of the condensation and it will mainly be on the side of the roof away from the sun (colder).

Hi,

Thanks for your reply 455driver. The condensation is mainly on the Southern side of the loft where we get most of the sun. I have two heaters. One is a small fan type heater, which blows hot air around. The other is a normal electric heater with an option to blow the air. These aren't positioned any where near the condensation.

I never have these on when I'm not in the loft.

The condensation always appears everyday. The loft hatch is kept closed at all times. It's a mystery why it happens and its very annoying!:roll:

 

[455driver]

Is there sufficient ventilation up there, people do tend to seal lofts up but there needs to be reasonable ventilation, with the hot water tank up there there will be a (small amount of) water vapour up there anyway and if the loft is sealed it wont have anywhere to go and so will just build up.

Also because the base boards and other stuff (we all have "stuff" up there) there will be causing still air that wont help either, maybe try leaving the hatch open and putting a reasonably powerful fan (no heat) up there to move the air around a bit to see if it gets any better.

Another idea would be a dehumidifier but lets try the easy/ cheaper stuff first.

 

[Prairie_5542]

Is there sufficient ventilation up there, people do tend to seal lofts up but there needs to be reasonable ventilation, with the hot water tank up there there will be a (small amount of) water vapour up there anyway and if the loft is sealed it wont have anywhere to go and so will just build up.

Also because the base boards and other stuff (we all have "stuff" up there) there will be causing still air that wont help either, maybe try leaving the hatch open and putting a reasonably powerful fan (no heat) up there to move the air around a bit to see if it gets any better.

Another idea would be a dehumidifier but lets try the easy/ cheaper stuff first.

Thanks for that. That is a thought. The only problem I have with leaving the hatch open is that it makes the house cold. I have put clips in to separate the roof felt to let a bit of air through/escape. Any idea how to remove the damp and mold from the baseboards? Thanks.

 

[gazthomas]

I agree, get yourself a dehumidifier.

 

[Prairie_5542]

I agree, get yourself a dehumidifier.

gazthomas Thanks for your reply. Any cheap ones out there, the cheapest I could find was from Argos for £49.95!

 

[Lewisham2221]

gazthomas Thanks for your reply. Any cheap ones out there, the cheapest I could find was from Argos for £49.95!

You could try a damp trap. They sell them in most of the pound shops and also Wilkinson that I know of. It's basically a plastic container with some crystals in the top. They absorb the moisture which then gathers in the bottom of the container and depending on the type you either throw it away and replace it when full or empty the water out and replace the crystals.

 

[Prairie_5542]

You could try a damp trap. They sell them in most of the pound shops and also Wilkinson that I know of. It's basically a plastic container with some crystals in the top. They absorb the moisture which then gathers in the bottom of the container and depending on the type you either throw it away and replace it when full or empty the water out and replace the crystals.

Thanks for that I'll have a look around!
--- old post above --- --- new post below ---
Any ideas how to get rid of the damp and mould from the boards?

 

[Nick W]

I would definitely agree with the suggestions to get a dehumidifier. They aren't cheap but they work very well and I'm sure will be cheaper than buying moisture traps in the long term. I believe you may be able to empty the dehumidifier into the hot water tank with a hose (water from a dehumidifier is not safe to drink so it mustn't go into the cold water tank) but check with an expert.

Once you get a dehumidifier, running it on the full setting for a day should remove any damp from the layout. You can then run it continuously on the lowest setting which prevents any further damp.

A heater will reduce the level of condensation as hot air can store more water. But it would cost more electricity than a dehumidifier. Ultimately it doesn't really solve the problem - water is getting in and not getting out.

 

[455driver]

Any idea how to remove the damp and mold from the baseboards? Thanks.

Afraid not, sorry.

One possibility would be to gently rub the area with a mild disinfectant of your preferred choice to kill off the mould but cannot guarantee the results, best try it out on an inconspicuous area first.

I am sure others will be along with better recommendations soon.

 

[ATW Alex 101]

I had the same problem in my garage loft when I had a model railway up there and I pinned lots of rubble sacks to the roof and that seemed to do the trick. If anybody does that, just be careful when removing them just incase a lot of water builds up between the roof and the bag. Remove one end gently and just let the water pour into a bucket.

 

[Trog]

What is need to stop the damp is ventilation.

Clear out any air bricks, make sure that the insulation on the loft floor does not touch the sarking felt in the eves, fit vents in the horizonal board between the board with the gutter fixed to it and the wall.

Cover both the cold water tank and the central heating header tank.

 

[DaveNewcastle]

Thos puzzles me -

Also there is a smaller tank next to the water tank, which has hot water in it. This smaller tank used to let off steam until I made a cover for it and this has now stopped. . . .

If it introduces steam into the room's air, then I'm curious to know if it is an intentional opening in the water circuit, a pressure relief valve presumably. The 'cover' won't contain the pressure and steam will still be enterng the room from the hot water heater's tank.

Perhaps that valve should be vented via an adequately rated pipe to a point outdoors?
A dehumidifier may be an elaborate means to try to capture that damp air being released from the hot water heater.

 

[Prairie_5542]

Thos puzzles me -If it introduces steam into the room's air, then I'm curious to know if it is an intentional opening in the water circuit, a pressure relief valve presumably. The 'cover' won't contain the pressure and steam will still be enterng the room from the hot water heater's tank.

Perhaps that valve should be vented via an adequately rated pipe to a point outdoors?A dehumidifier may be an elaborate means to try to capture that damp air being released from the hot water heater.

There is what seems to be an 'overflow' pipe that goes from the header tank to outside. It is approximately 6-7ft long!

 

[youngboy]

Hi all,this is my first post it feels a bit cheeky jumping straight in on this topic but if i can help i will.
When you say you have two tanks in the loft is one of these the hot water cylinder (copper) ??
The way I see it you have cold air on the outside and warmer air inside hence the condensation build up, this could also be made worse if you have the DHW cylinder there because this will be adding to the warm air.
to eliminate the problem you will either have to do as trog says and ventilate as much as possible to create an even temperature or insulate as much as possible by adding kingspan or rockwool between the trusses and board them over. You can also buy plasterboard with insulation attached and board the whole roof internally with this.........youngy.

 

[Prairie_5542]

Hi all,this is my first post it feels a bit cheeky jumping straight in on this topic but if i can help i will.
When you say you have two tanks in the loft is one of these the hot water cylinder (copper) ??
The way I see it you have cold air on the outside and warmer air inside hence the condensation build up, this could also be made worse if you have the DHW cylinder there because this will be adding to the warm air.
to eliminate the problem you will either have to do as trog says and ventilate as much as possible to create an even temperature or insulate as much as possible by adding kingspan or rockwool between the trusses and board them over. You can also buy plasterboard with insulation attached and board the whole roof internally with this.........youngy.

Welcome!We all have to start somewhere with posts!LOL! Thanks for your comment!! The only problem I've got is I need the room in between the trusses for head room when sorting out the layout etc!

 

[DaveNewcastle]

There is what seems to be an 'overflow' pipe that goes from the header tank to outside. It is approximately 6-7ft long!

Good. That presumably is an overflow. But that doesn't explain how steam is being released into the room.

I agree with the other posters advising proper ventilation, but it could be possible that the entire problem can be dealt with a its source - the steam being released from the heater tank. That can only manifest itself in one way - condensation.

So, from where is the steam being released?

The cover you made to contain it won't get rid of the airborne water vapour, though may accelerate its cooling. What happens to the water vapour when it reaches the cover? Does it just fall as water droplets?

 

[Prairie_5542]

Good. That presumably is an overflow. But that doesn't explain how steam is being released into the room.

I agree with the other posters advising proper ventilation, but it could be possible that the entire problem can be dealt with a its source - the steam being released from the heater tank. That can only manifest itself in one way - condensation.

So, from where is the steam being released?

The cover you made to contain it won't get rid of the airborne water vapour, though may accelerate its cooling. What happens to the water vapour when it reaches the cover? Does it just fall as water droplets?

Thank you for your reply. The steam did come off the hot water tank every time that water went into it. The cover I have made for it is a silver sort of 'insulation' type material that I have cut into a circular shape to fit in the grove near the top of the tank. Then on top of this there is a black 'sack' with insulation in it. This then covers the top.

 

[youngboy]

Thank you for your reply. The steam did come off the hot water tank every time that water went into it. The cover I have made for it is a silver sort of 'insulation' type material that I have cut into a circular shape to fit in the grove near the top of the tank. Then on top of this there is a black 'sack' with insulation in it. This then covers the top.

Hi Prairie, am confused the two tanks in your loft are they both square plastic tanks ??? somewhere in the house is there a DHW cylinder made of copper or is the steam you see coming from a copper pipe which is hanging over the plastic tank ??

 

[Wyvern]

The large cold cistern is the header for the household hot water supply. The smaller cistern will be the header for the central heating system. Both should have overflow pipes leading outside.

 

[Prairie_5542]

The large cold cistern is the header for the household hot water supply. The smaller cistern will be the header for the central heating system. Both should have overflow pipes leading outside.

Hi Wyvern;1348763. I have a big rectangle shaped water tank that holds cold water (could be made out of asbestos!). A pipe comes off of this into a smaller circular shaped water tank, which is hot (for the hot water or central heating). You are correct, both have overflow pipes that lead outside.

 

[Wyvern]

THe large one will be for the hot water supply, the small one for the central heating system. They are separate because besides being stale the central heating sytem will have descaling and corrosion inhibiting additive in it (Fernox for instance).

It would seem therefore to be a traditional indirect non-pressurised system, therfore OK to cover the tanks. Indeed under modern Building Regulations they both should have snug-fitting covers each with a pressure vent fitted with a mesh to prevent the creepy-crawlies getting in, and the overflows should have similar mesh traps.

Fitting these should help with excessive amounts of humidity in your attic.

Fitting a complete new roof would be a bit extreme but to complete the subject modern felts are waterproof but breathable to get rid of condensation which is a major problem with present-day draught-proofed houses.

 

[Scottw]

I too have the same problem,but I think I've fixed it...
When I boarded out the attic,I put the excess fibreglass into the Eve's to stop the draft......mistake....,after reading this post I thought about ventilation and when I checked ,the Eve's had corrugated plastic in to AID ventilation.
Think you need good ventilation .

 

[W.Tregurtha]

What is need to stop the damp is ventilation.

Clear out any air bricks, make sure that the insulation on the loft floor does not touch the sarking felt in the eves, fit vents in the horizonal board between the board with the gutter fixed to it and the wall.

Cover both the cold water tank and the central heating header tank.

12 entries and finally the correct one. If anywhere is damp it's due to no or insufficient ventilation. End of.

 

[youngboy]

12 entries and finally the correct one. If anywhere is damp it's due to no or insufficient ventilation. End of.

Not always, I've been to jobs many times were the damp has been caused by tiles and slates slipping, or lead flashing missing.

Condensation is not the same as damp !!