Condensation in the attic... damn you!

elchanco

Hi,

I’ve been battling against condensation in my attic since last winter! From reading posts on boards, I am not the only person with this headache!

I advised my neighbours and they also were shocked to have the same problem. Now, I know we are experiencing freezing temperatures which increases the problem. I checked my attic last night and it was dripping from the felt like rain!

The insulation will probably have to be replaced (insulation is now damp) when the weather improves.

I installed two vent tiles in the north side of the roof which did not solve the problem?

Any suggestions much appreciated.

Is it possible to use a de-humidifier in the attic?

Can you replace the felt to a breathable material?

Is the builder liable to fix this problem, since they never installed adequate ventilation for the attic? the house is 3years old..

Regards
El

corribfitz

Hi All
After only just joining boards.ie im learning so much about condensation in attics. My house is 25 years old and i now know how important ventilation is, as i had pvc soffit fitted 7 years ago and upon checking them recently there was 2 false vents fitted front and back with no hole cut in the old timber soffit,that plus no ridge tile vents was a receipe for distaster.Im now going to insulate my attic with knuff insulation plus get new soffit vennts and 4 tile vents and hopefully that will stop the condesation in my attic. I would like someone if they could please tell me for definite can i use polythene as a vapour barrier as there is a lot of conflicting views.( My ceiling boards have foil on them between the joists
Thanks to anyone who can help
Cheers Ken

OB1CAN

Good morning All,

I find this post most interesting... Maybe someone might be able to help us all .... Maybe a roofer ??

I've just got a new roof fitted to my 80 year old house...

The roofer fitted new latts , a felt (which I'd hope would be breathable) , and new slates.

But when I've been up in the attic in the last few days ... There are droplets all over the inside of the felt....It's not dripping onto the insulation but more looks like the droplets you'd get on the inside of a tent....It's only when you touch the felt do the droplets fall and wet the insulation.

So ,.. Is the condensation normal ?

How do I combat it if it is not ?

Any help would be greatly appreciated.

Thanks

RKQ

corribfitz wrote: »

I would like someone if they could please tell me for definite can i use polythene as a vapour barrier as there is a lot of conflicting views.( My ceiling boards have foil on them between the joists

Yes, but retro fitting a 500 guage vapour barrier is extremely difficult to get 100% airtight. Much easier in a new build.

In your case you have foil backed plasterboard, which may act as a barrier - you might need to run a bead of mastic along each side of each joist.

• Check where the warm air is getting into your attic - around light fittings & access hatch door.
• Ensure good ventilation at eaves - 50mm clar air gap between underside of felt & top of insulation.

gsxr1

As RKQ has said. It is very important to promote airflow.

Get onto your hands and knees . Use a plank across your joising to kneel on and make sure you have clear airflow from soffit to attic.
Your builder might have pushed your attic insolation to far into the soffit area and blocked the air flow



Also check from the outside of the house to see if there are vent holes in the soffit. There should be plenty.

The heat of your house is reaching your felt. You could well have substandard or poorly fitted fiberglass insulation. These conditions are easy to fix and well within a DIY enthusiasts skills .

Maybe if you took a few photos of your attic and posted them here we could be of more help.

qc3

This will give you some ideas of how to prevent condensation in the attic.

http://www.associatedcontent.com/article/980728/tips_for_preventing_attic_condensation.html?cat=6

gsxr1

qc3 wrote: »

This will give you some ideas of how to prevent condensation in the attic.

http://www.associatedcontent.com/article/980728/tips_for_preventing_attic_condensation.html?cat=6

thats interesting one about your gutters. Would not have though of that.

cork1

something else i saw being done recently was if you have gables rather than a hip roof you can drill a 100mm hole in each gable and put a vent in it to allow more air in the attic space. also when your checking your insulation make sur eyou have a draft excluder on the trap door or else you will feel a gust coming down around it.

RKQ

Great picture / diagram grsx1, it really helps explain a lot.

I'd agree with cork1, if you have a detached house with gables then drill 100mm diameter hole in each gable, opposite each other, to increase air flow.

Condensation is usually only noticeable when the temp drops to zero or below. Especially on roof with traditional blak sarking felt. This cold weather is usually still / wind free - like the last few weeks, so there is like air movement.

This condensation is usually more visible on the cold side of the roof, where the sun doesn't shine during the day.

paddles

is this what's causing the black felt stuff to peel away in the attic roof? only noticed this t'other day..
if it's not one thing thses days...

gsxr1

paddles wrote: »

is this what's causing the black felt stuff to peel away in the attic roof? only noticed this t'other day..
if it's not one thing thses days...

sarking felt falls apart as it gets old. The heat of the summer hardens it over time. It gets very fragile.
Its terrible stuff to be honest.

its a pretty big job to replace as you roof will need stripped. Tiles, battons then the felt.

just leave it. If its not leaking leave well alone.

wheeliebin

The temperature in your attic has been close to freezing for the last couple of days if its insulated properly. The air has been 100% humid and when you change the temperature quite quickly the dew point changes and you will get droplets. There has been very little wind to premote good airflow. Just make sure the insulation at the edges does not block airflow. A handy way of creating a gap is to use corryboard the stuff political billboards plastered on every lampost are made of. These can be cut to the width of your rafters and slotted between the felt and insulation making sure you will always have air fow and not stuffed with insulation. They have hollow channels in the middle from top to bottom.

corribfitz

To each and everyone that resplied to my post, Thank you all My insulation looked like it was past it sell by date so that and the trap door was letting heat up in to the attic.Im now sorting these out and with the new soffit vents and tile vents i hope to have a condensation free attic

Cheers and Thanks again

RKQ

Glad to help in any way I can. Good look with the works.