Condensation on Inside of Loft.

[RP66]

Not sure if this is the correct place to ask this question, my appologies if not.

Went up into my loft yesterday because we seem to have a mouse scratching around up there, and found that there was condensation on the inside of the roofing felt. Is this normal.

The condensation was along one side only the other being dry.

We moved here 3 mths ago and therefore have not been in the loft before.

Bungalow is 11 years old has wall insulation and very thick insulation in the loft.

Thankfully it does not appear to drop and make the insulation damp.

Any comments please.

 

[stem]

Warm damp air is getting into your loft and condensing on the cold surfaces. All you need to do, is find where the damp air is coming from. Here are some culprits.

1. Bathroom extractor fan duct has become disconnected from the fan so the warm damp air from the bathroom is being blown into the loft.

2. The cold water storage tanks for the central heating or hot water are getting warm and don't have close fitting lids allowing moisture to escape from the tank or vent pipe.

3. Your house is particularly steamy because washing is dried on radiators, or continual bathing/showering etc and somehow this moisture gets into the loft. Is the loft hatch a good fit? are there gaps where pipes pass from the house into the loft? perhaps from an airing cupboard where washing is dried. Is the loft sufficiently ventilated?

4. There are lots of rats up there all breathing heavily!

 

[JohnD]

//www.diynot.com/forums/viewtopic.php?t=160032

You're a month late with this one.

 

[nm1270]

I have the same problem on one side only of my loft which coincidentally is the side directly above my bathroom.The heating has also been on since October so I guess all that heat and steam had only one direction to go...up!In my case the felt and loft insulation was soaked from wall to wall and my bathroom ceiling marked from the dripping moisture.
You could try a little cost free DIY SOS as I have,I've slotted some small slats of wood inbetween the felt where it overlaps to allow air into the attic and create ventilation.

 

[JohnD]

Very unlikely to be "coincidentally"

I hope you also reduced the source of excessive steam (see my link and stem's post).

If anyone is in the habit of draping wet washing about the house or over radiators, it will always be damp and no-one can help you

 

[RP66]

Thanks Stem,

Bathroom extractor fan duct has become disconnected from the fan so the warm damp air from the bathroom is being blown into the loft. .

Had a look this morning and this is what the problem was.

 

[JohnD]

Thanks stem

I have stolen your idea for the future!

 

[mointainwalker]

@ FMT

HEy, Freddy, look at this !

"

The heating has also been on since October so I guess all that heat and steam had only one direction to go...up!In my case the felt and loft insulation was soaked from wall to wall and my bathroom ceiling marked from the dripping moisture.

"

 

[freddiemercurystwin]

Hi MW,

Has nm1270 got an extractor fan and is it working/connected? Has his bathroom got a window etc? Does he have adequate ventilation in the loft? How many other threads are there on here with saturated insulation in this location?