# Water dripping from roof in attic



## Neil_Ireland (28 Dec 2009)

Hi,

I was working on my pc when I could hear some water dripping, I opened the attic door and noticed it was wet on the inside and there is water dripping from the inside of the roof. Some of the insulation around the door is damp.
No rain for the past day but it was cold last night -2 I think.

Does this mean the attic is not vented properly, it's a new house.

Thanks.


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## Neil_Ireland (28 Dec 2009)

Just had a better look up in the attic.

There are droplets of water on the inner lining of the roof, seems to be only on the north facing part of the roof.

Is this anything to worry about?

Thanks,
Neil.


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## eamonn123456 (28 Dec 2009)

Check out a couple of recent posts on this.


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## Towger (28 Dec 2009)

Neil_Ireland said:


> Is this anything to worry about?


 
Yes. Lack of ventilation, leak in roof, ceiling not sealed (warm air entering attic), or the builders favourite venting bathroom etc extraction fans directly into the attic. etc etc


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## onq (28 Dec 2009)

Neil, this is your second house post.

Yes, this could point to inadequate ventilation.

Do you have disconnected vents or downlighters in the ceiling?

Did you have this house inspected by a surveyor or architect before you bought?

ONQ


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## Neil_Ireland (28 Dec 2009)

Towger said:


> Yes. Lack of ventilation, leak in roof, ceiling not sealed (warm air entering attic), or the builders favourite venting bathroom etc extraction fans directly into the attic. etc etc



No leaks that I could spot. Hotpress etc is sealed and the extractor fans are ducted to wall vents.



onq said:


> Neil, this is your second house post.
> 
> Yes, this could point to inadequate ventilation.
> 
> ...



My second post yes, the first being the settling cracks.
No downlighters or disconnected vents from what I can see.

I only had a snag completed before the purchase.


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## onq (28 Dec 2009)

Neil,

If you click on my nic [ONQ] or eamonn123456's, click on the "statistics" tab and search for "all posts by" you'll see several recent posts about this problem.
Failing thsi you cna use the search engine with keywords like "condensation" "interstitial" "ventilation" et cetera.

Read up on what's posted so far and revert here with any queries.

Basically in certain conditions, yes, moisture droplets can form on the underside of roofing felt.
This usually doesn't affect the felt, but can affect the insulation it drips onto.
Usually the incidence of moisture doesn't cause dripping off like this.

If this is only occurring local to the roof above attic door consider sealing around it and insulating the back of it.

ONQ.


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## Neil_Ireland (28 Dec 2009)

Thanks onq 

I'll do some reading.

The water droplets are on the north facing side of the roof. Not isolated to above the attic door, this is sealed and insulated.


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## roker (30 Dec 2009)

I have notice my attic is wet on the inside of the roofing lining/felt below the tile, My house is 7 year old has vents in the soffits and a aluminium damp seal on the ceiling board,
Could a de-humidifier be put in to the attic during cold spells?


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## Neil_Ireland (30 Dec 2009)

roker said:


> I have notice my attic is wet on the inside of the roofing lining/felt below the tile, My house is 7 year old has vents in the soffits and a aluminium damp seal on the ceiling board,
> Could a de-humidifier be put in to the attic during cold spells?



Same as I am seeing.

Thanks to some advice from onq here I have sorted out my water storage tank insulation. The insulation should go all the way to the floor of the attic, mine did not.

Heat was prob getting into the attic space because of this, will keep an eye on things and see if there is any improvement.


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## eamonn123456 (31 Dec 2009)

Neil_Ireland said:


> Same as I am seeing.
> 
> Thanks to some advice from onq here I have sorted out my water storage tank insulation. The insulation should go all the way to the floor of the attic, mine did not.
> *
> Heat was prob getting into the attic space because of this, will keep an eye on things and see if there is any improvement.*



That kind of low level of heat getting into the attic would be fairly negligible I would have thought and in any case would tend to reduce condensation I would have thought.


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## Neil_Ireland (1 Jan 2010)

eamonn123456 said:


> That kind of low level of heat getting into the attic would be fairly negligible I would have thought and in any case would tend to reduce condensation I would have thought.



What do you recommend Eamonn?


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## eamonn123456 (1 Jan 2010)

I wish I knew! but just letting you know that insulating the tank is unlikely to solve it.


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## Bob_tg (1 Jan 2010)

onq said:


> Did you have this house inspected by a surveyor or architect before you bought?



Would a standard survey have caught this kind of thing?  I've always wondered about surveys.  A surveyor I used before did not even go in to the attic.  They are full of disclaimers and only seem to spot the obvious.


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## onq (1 Jan 2010)

Neil_Ireland said:


> Same as I am seeing.
> 
> Thanks to some advice from onq here I have sorted out my water storage tank insulation. The insulation should go all the way to the floor of the attic, mine did not.
> 
> Heat was prob getting into the attic space because of this, will keep an eye on things and see if there is any improvement.



These are two different but related issues.

1. Allowing heat from below to rise in a controlled way to prevent the water tank freezing.
2. Reducing water vapour in the air sufficiently enough to let the ventilation provided clear away moisture forming on cold surfaces.

The relationship is that warm air holds more moisture, ready for deposition on a surface which is below dewpoint temperature.
Unless you know everything about the building physics of a space its difficult to predict what effect correct tank insulation may have.

Factors to consider might include:
i) Will the increased heat in the tank water lead to a greater rate of evaporation into the attic space?
ii) Will the closed cell insulation board above the tank prevent movement of the evaporate enough to ensure there is no greater contravention?

This is an extreme, and somewhat marginal, example.
Such issues may be irrelevant to well vented older houses regardless.
The effects of attic venting may be more of an issue with sealed, highly insulated homes.
If that is the case, do not be surprised to see matters like this rearing their heads more often.

Yes, there are sealed systems for heating [still needing an expansion tank IIRC] but AFAIK the main  tank volume cannot be sealed.
It has to allow for draining at a rapid rate and filling at a less rapid rate, which would displace air in any sealed tank volume.
If it were sealed, it would probably need an external supply air or some sort of diaphragm system.

As you can see, its not a simple science.



ONQ.


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## Neil_Ireland (1 Jan 2010)

It's cold today, as cold as the day I first noticed the droplets and there are none forming now. I'll keep an eye on it.

ONQ, I checked the rest of the attic and the foil back plasterboard covers the entire attic. Seems to be about a 3 or 4 inch vent gap around the eaves too. That's all I could see so far.


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## onq (1 Jan 2010)

Neil_Ireland said:


> It's cold today, as cold as the day I first noticed the droplets and there are none forming now. I'll keep an eye on it.
> 
> ONQ, I checked the rest of the attic and the foil back plasterboard covers the entire attic. Seems to be about a 3 or 4 inch vent gap around the eaves too. That's all I could see so far.



3 or 4 inches? That seems excessive if its a continuous vent.

The width for a  continuous vent serving an "open" attic i.e. with no dormers or conversation is 10mm or less than half an inch.

Where the attic is  converted [the rooms follow the roof totally] or it has dormers [partial conversion with small attics to the side and above] the continuous widths need to be 25mm or 1 inch at the eaves and 5mm at the ridge.

Here is TGD F:

http://www.environ.ie/en/Publicatio...ng/BuildingStandards/FileDownLoad,1647,en.pdf

Diagram 6, P.11 refers.

ONQ.

[broken link removed]


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## roker (1 Jan 2010)

I would be interested to know if the problems is greater with Tru-tone/slate type tiles. I would think that the older cement type roofing tiles would absorb the water and allow the roof to breath


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## roker (2 Jan 2010)

My storage tank and heating tank has been mounted about 6 feet up in the loft, on a timber frame, I don't know why, but it is imposible to lag it or keep it warm. Is there some new logic for doing this? possibly better pressure for the shower, should I get a plumber to relocate it above the hot press.?


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## jeananne (3 Jan 2010)

I have noticed several small damp patches on plasterboard in attic partial conversion near ( but i think unrelated to ) velux window in our 7 year old house - this has happened in the last week and I assume has something to do with the very cold weather and condensation...
Checked out attic insulation and discovered one area between rafters, about 5 feet in length had no insulation at all ( I've filled in the gap with some spare ) and also in the main attic the extractor fan from the infrequently used ensuite vents directly into the attic space !!! 
Is this a big deal and can I fix it by attaching a hose and directing the extractor air to a nearby vent in the eves ???
Also while i'm up there should i cover the 2 large water tanks and if so with what ?
Thanks


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## onq (3 Jan 2010)

roker said:


> I would be interested to know if the problems is greater with Tru-tone/slate type tiles. I would think that the older cement type roofing tiles would absorb the water and allow the roof to breath



Hi roker,

I understood that the previous poster's problem was that there was condensation on the underside of the felt.

The felt is the first thing rising warm moist air meets - i.e. before it could hit the underside of cement/clay tiles it would condense on the felt.

ONQ.


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## onq (3 Jan 2010)

roker said:


> My storage tank and heating tank has been mounted about 6 feet up in the loft, on a timber frame, I don't know why, but it is imposible to lag it or keep it warm. Is there some new logic for doing this? possibly better pressure for the shower, should I get a plumber to relocate it above the hot press.?



This is unusual in my experience, but aren't you lucky to have such a high loft - plenty head height for a conversion!
Water pressure may have been a factor originally, or simply the builder/plumber thinking he was doing you a favour by raising it up to give you storage area below, without realising the problems this might bring.

Modern pumped showers will do away with cold pressure issues assuming you have enough pressure from the HWC in the hot press.
Thus you could relocate, making sure you also relocate your overflow pipes [as well as supply pipes] and any associated header tank for the HW/heating system.
I would advise that you should only use a certified plumber for a job like this as there may be other issues not immediately recognisable from your post above.
You would them proceed to leave no insulation under the tank in its new position and continue the insulation layer from the ceiling below up the sides of the tank and install an insulated cover.

However you could also leave as is, dropping lightweight timber posts from the tank to ceiling level and wrapping the four cornered perimeter they form in quilted insulation or fixing rigid insulation to them to form a duct up which heat could rise.
You would be removing insulation from the ceiling just below this, naturally, and surrounding the tank sides and installing an insulated tank cover also.

FWIW

ONQ.

[broken link removed]


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## onq (3 Jan 2010)

Hi Jeananne,

Answers interspersed below:



jeananne said:


> I have noticed several small damp patches on plasterboard in attic partial conversion near ( but i think unrelated to ) velux window in our 7 year old house - this has happened in the last week and I assume has something to do with the very cold weather and condensation...


It may not be unrelated to the velux - they can cause pockets of dead air to be created above and below them by the trimmer rafters interrupting the continuous 50mm air gap there should be above any insulation following the slope of the roof.

Here is a link to Part F to help explain that 

http://www.environ.ie/en/Publicatio...ng/BuildingStandards/FileDownLoad,1647,en.pdf 

Dia 6 P. 11 refers


> Checked out attic insulation and discovered one area between rafters, about 5 feet in length had no insulation at all ( I've filled in the gap with some spare ) and also in the main attic the extractor fan from the infrequently used ensuite vents directly into the attic space !!!
> Is this a big deal and can I fix it by attaching a hose and directing the extractor air to a nearby vent in the eves ???


It depends on whether or not this vent was intended to receive a hose - it should have a facility to receive a circular hose or clip a connector into place.
It may have been added to help vent the attic in which case attaching the hose would prevent this - in that case, no, not a good idea.


> Also while i'm up there should i cover the 2 large water tanks and if so with what ?
> Thanks



Solid insulation board is usually used for a cover, and quilted insualtion is usually used for the sides.
Cover and surround them but keep the underside of them clear of insulation. 

Unfortunately the problems you describe are all too common in the building industry. Deadlines within which to complete works stages, rolls of insulation not being delivered or even being pilfered off sites mean that problems not addressed can get covered up by even the most well-intentioned contractor.

At the risk of veering wildly off topic there are new developments coming down the pipe which will affect us all.

[broken link removed]

Sorry for the ridiculously long URL, but that's the way it came.


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## RSMike (4 Jan 2010)

Attic space needs to be ventiltated properly.

If no special roof tile vents are present, you need soffit ventilators every 600mm along each side of the roof and there needs to be clear air from the soffit ventilators up into the attic space, if the space is filled/over-packed with insultaion this will render the ventilators useless.

Basically, air draughts need to flow in one side of the roof, up and back down exiting the other side, This will keep your attic nice and dry.

If ventilators are not fitted, or not enough are fitted ( you really do need one every 600mm), it need not be a huge job to retrofit them.
I have first hand experience of having this problem and fixing it in my garage.

Previous post:
http://www.askaboutmoney.com/showthread.php?t=99202


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## roker (4 Jan 2010)

Thanks ong for the reply. Sorry gone off the damp problem slightly. The shower is a mixer tap on the bath, The other shower is an electric shower with water from the mains via a pressure regulator. I think I will lower the tanks over the hot press and for maintenance purposes also. It was 2.6°C in the loft last night and -1° outside.

Is it necessary to have the primary circuit header tank the same hight as the main header tank? or would it be easy to convert to a sealed sytem for the primary circuit?


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## jeananne (4 Jan 2010)

Thank you onq for that very comprehensive reply.
 I thought the damp patches were unrelated to the velux because they follow one horizontal line extending between 1 foot and 4 feet away from the actual window, at a height that is 2/3 way up the velux (it looks like the condensation is running off along a joint/beam???) I'm hoping that the missing insulation being filled in might rectify the condensation there as it was in the side attic off that room...
Re. the vent in the soffitt in the upper attic I'd say it's definately there to ventilate the attic as it is the only vent on the high gable end of the house and there is a corresponding one on the other gable...so I better not divert the extractor fan air that way. Might try to get the builder involved, but it's 7 years since he finished so that will be a long shot (well he's a nice man, and probably not too busy right now !!! ).


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## onq (4 Jan 2010)

jeananne said:


> Thank you onq for that very comprehensive reply.
> I thought the damp patches were unrelated to the velux because they follow one horizontal line extending between 1 foot and 4 feet away from the actual window, at a height that is 2/3 way up the velux (it looks like the condensation is running off along a joint/beam???) I'm hoping that the missing insulation being filled in might rectify the condensation there as it was in the side attic off that room...
> Re. the vent in the soffitt in the upper attic I'd say it's definately there to ventilate the attic as it is the only vent on the high gable end of the house and there is a corresponding one on the other gable...so I better not divert the extractor fan air that way. Might try to get the builder involved, but it's 7 years since he finished so that will be a long shot (well he's a nice man, and probably not too busy right now !!! ).



Hi Jeananne,

The important thing is to maintain the 50mm ventilation gap above/behind  the insulation to carry air laden with water vapour away before condensation can form.

You also need to try and check the passage of water vapour into the space in the first place.

Your assessment of the progress of the moisture may be the correct one, and this is turn may suggest there is not a continuous 50mm air gap.

Without opening up, I cannot advice further but purlin supports should ve under that rafters and the air gap is usually along the top two inches of rafter.

HTH

ONQ

[broken link removed]


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## roker (4 Jan 2010)

Just to report back. The weather must have been really exceptionally humid during the last few days causing condensation. I noticed that the downstairs toilet cistern which is fed directly from the house main supply, was condensing water so bad that it was running down and across the tiled floor, I never saw this before, we thought at first that one of our guests was missing the pan. This has now stopped as the weather became dryer. Of course this has shown up faults in many people’s attic installation which now require drying out and fixing. I found that the builders had installed the insulation over the soffit vent which I am in the process of fixing, they also took the ducting from the extractor to the soffit vent and no further, so it is not exactly going outside. (not sure how to do this yet) do these vent just click into the plastic soffits? I have also the freezing tank problem to fix. Thanks "onq" for all your advice


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## elchanco (5 Jan 2010)

roker said:


> I noticed that the downstairs toilet cistern which is fed directly from the house main supply, was condensing water so bad that it was running down and across the tiled floor...
> 
> ...they also took the ducting from the extractor to the soffit vent and no further, so it is not exactly going outside. (not sure how to do this yet) do these vent just click into the plastic soffits?


 
My extractor is installed in the same way as described... I would be interested in other alternatives?

I experienced the same over the weekend with the toilet.. never seen this before!


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## jeananne (5 Jan 2010)

Thanks again onq.


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## onq (5 Jan 2010)

elchanco said:


> My extractor is installed in the same way as described... I would be interested in other alternatives?
> 
> I experienced the same over the weekend with the toilet.. never seen this before!



Turn on the heat in your Bathrooms/Toilets.

The body of the cistern is most likely below dewpoint.

This is may be due to the temperature of the water in your attic tank.

HTH

ONQ


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## onq (5 Jan 2010)

roker said:


> Just to report back. The weather must have been really exceptionally humid during the last few days causing condensation. I noticed that the downstairs toilet cistern which is fed directly from the house main supply, was condensing water so bad that it was running down and across the tiled floor, I never saw this before, we thought at first that one of our guests was missing the pan. This has now stopped as the weather became dryer.


The issue is possibly exacerbated by the temperature of the supply water dropping - I've certainly noticed drop in temperature of the [potable] cold water tap in the kitchen as the cold spell continues.


> Of course this has shown up faults in many people’s attic installation which now require drying out and fixing.


Just remember that these are extreme conditions and that matters will tend to improve.
The cold causes even the normal amounts of vapour-checked water vapour in attics to condense on surfaces which are above the insulation and so have become very cold because of the extended cold spell.
I would be a little concerned about the ability of damp or wet fibreglass to dry out properly and this should be monitored.
Rockwool should reputedly have less of a problem.


> I found that the builders had installed the insulation over the soffit vent which I am in the process of fixing, they also took the ducting from the extractor to the soffit vent and no further, so it is not exactly going outside. (not sure how to do this yet) do these vent just click into the plastic soffits?



No, these shouldn't be vented to soffits usually as a bare minimum you could get bad smells around the house.

Also check these are simple vents and not foul pipe discharge stacks taken insude to keep a "clean look" on the building elevations.
For stack discharge vents the end of the pipe need to be a 900mm above windows nearer than 3000mm.
Usually these extract to a vent pipe through the roof or a vented slate or tile - a specialist item.

Here is TGD Part H of the Building Regulations:
http://www.environ.ie/en/Publicatio...ng/BuildingStandards/FileDownLoad,1649,en.pdf
Diagram 5 Page 8 refers.

For ordinary steam or WC vents through a cold attic you have to remember that warm air rises and the surface of the flexible duct can get cold so making the volume of air hit the top of a curved duct on its way to the eaves is just inviting the water vapour in it to condense and run back down the ducting both ways.

I've seen examples of such ducts going down into the cavity walling resulting in smells coming into the house.

Straight up and out is the best way.

In relation to the soffit vents ensure you keet a 50mm clear gap from them into the attic proper - don't just clear insulation from the vents.


> I have also the freezing tank problem to fix.



Well, you should be an expert from all the advice posted.


> Thanks "onq" for all your advice


You are all very welcome - no point letting a difficult situation become a crisis due to lack of knowledge and I am always happoy to stand correct also - the most dangerous assumptions are based on obsolete information.

ONQ.

[broken link removed]


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