Attic Internal Felt Condensation Advice/Help

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Hi all,

I am looking for some advice\guidance please.

We purchased our house a few years ago and it’s a detached four bedroom built in the 70’s with a very shallow height attic.

These are fitted around the eaves in places for external ventilation.

upload_2021-12-26_21-18-46.png



We had the tile roof replaced two years ago. I also increased the insulation in a part of the attic, boarded it and started using it for storage. Prior to this I was not using it to store anything.

Earlier in the year I noticed severe condensation on the inside felt of the attic when it’s cold etc.

I noticed I had pushed the insulation in some places up to the edges of the eaves, so I moved this back off the eaves in case it was the root cause but unfortunately it made no difference.

A roofer advised it looked like the roofer who replaced the roof has used non-breathable felt which won’t help and suggested placing a few cuts in the roof felt under the ridge tiles to allow more ventilation. If that didn’t make a difference then consider fitting some roof tile vents.

A few months later now the winter weather has returned the condensation is still present but to a lot less degree. Hopefully the picture below provides a good example and also shows how shallow the height of the attic is.

upload_2021-12-26_21-18-58.png



To combat the condensation further I am thinking of having roof vent tiles fitted as a next step, however before I did would like to seek some advice and thoughts please.

From what I read on line some sites suggested it can be impossible to remove condensation entirely, so am I flogging a dead horse so to speak?????

Secondly I don’t have an extractor fan in the bathroom so I am aware that the bathroom becomes quite steamy and that will be getting released into the roof. Therefore wondered if this could be the cause of the condensation and I should bring forward getting the bathroom suite done??????? The condensation built on the roof felt does not appear to be solely above the bathroom though.

Any advice, suggestions or tips on what feel should do next would be appreciated.

Thanks in advance.
 
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andyhuk, good evening.

In no particular order, some ideas??

Depending on how many vents there are in the eaves?? insert some more.
Ensure that the eaves are really clear of any residual glass wool that will stop the air flow.
Open up the felt laps, insert small bits of timber, this will lead to more venting, do as many of these as you can.

When using the bathroom, if you have one open a window for [say] 10 Mins after use, this will go a long way to off set not having a bathroom extract.

All above, easily DIY-able, and cheap to fulfill.

Ken.
 
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Wedge some polystyrene in the laps.

Sort your bathroom extract out

Top up insulation to 300mm if not already
 
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Thanks for advice so far.

There are quite a few vents in the eves already.

Will make sure make better use of window ventilation in the short term and sort out a bathroom extractor longer term.

I will also look at fitting some internal felt lap vents which look easy enough to fit.

Alternatively do you think would be better to get tile vents fitted by a roofer?
 
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I wrote something in reply but then re-read your original post and realised what I wrote didn't apply. Sorry.
 
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andyhuk, good, morning.

Suggest one thing at a time?

OK Just now it is warm so the condensation may ??? not develop.

If it were me, I would install the polystyrene [or what ever spacers] in the laps, leave for a while, wait for a cold snap and start to check to see if that has assisted, or indeed eliminated the problem.

If the issue persists and is just as bad then I would consider further [at a cost £££ ] action.

Ken.
 
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The bathroom extracting directly into the loft is a major cause. Your bathroom extract needs to go outside. The setup you have you can get a roof tile vent fitted and then duct the fan to the vent. I had roof tile vents fitted and it has stopped condensation in mine. Ours is a 1930s house with original felt so its definitely not breathable. We have no eaves vents either. You'd get away with the eaves vents you have and roof tile vents high up on each pitch of the roof or roof vents on the ridge. The idea is cold air comes in at the eaves and then blows up and out of the roof high up or at the ridge. The air flow takes the moisture with it. Il warn you tho it makes the loft absolutely freezing. If I'd had my roof done recently and they didn't put breathable felt in and some sort of ventilation in the eaves/on the ridges I'd be fuming. With all the insulating we have to do now ventilation is so important to combat condensation
 
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Michaelsf90, good evening.

In the original post it states.

"Secondly I don’t have an extractor fan in the bathroom "

Ken
 
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Sorry I thought it said an extractor fan that vents steam into the roof. Sorry my mistake. Like everyone else has said keep the window open and bathroom door shut when showing. An extractor is the best bet. Also drying clothes on radiators is a big one for condensation in winter. We got a dehumidifier this year and the condensation in our loft has totally gone. We only put it on when cooking or drying clothes on radiators. It's like when the house gets overwhelmed with moisture. Maybe yours is the same
 
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