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New felt flat roof mould inside and dripping wet!


 
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leecollins

from United Kingdom

Joined: 17 Dec 2009
Posts: 4
Location: Dorset,
United Kingdom

PostPosted: Thu Dec 17, 2009 5:25 pm Reply with quote

Hi all,
Would really appreciate some advice here from the pro's, myself and some neighbours had our garage block re-roofed back this summer, they were felted before but had not been maintained for over 15 years, all the joists and decking boards had completely rotted and fallen through. We had it done this year, new timber joists, boards and three layer felt torch on fitted, however i have noticed inside the the underside of the new boards are dripping wet and covered in green mould. The neighbours garages are the same, but not as bad. The inside floor of all the garages were soaking wet before the new roof was fitted due to old collapsing and some even had trees growing inside them. Can someone shed some light on what has happened here or what should/could have been done to prevent this? I have taken some photos for you to see, The felt on top of garages doesn't have any obvious signs of damage and was done by a recommended company.


Any help much appreciated.
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Chukka63

from United Kingdom

Joined: 14 Oct 2009
Posts: 903
Location: United Kingdom
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PostPosted: Thu Dec 17, 2009 6:29 pm Reply with quote

is there any ventilation in the garages??
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leecollins

from United Kingdom

Joined: 17 Dec 2009
Posts: 4
Location: Dorset,
United Kingdom

PostPosted: Thu Dec 17, 2009 6:34 pm Reply with quote

Chukka,
There is no ventilation in there, where abouts should it be/go and what would it be like a pipe through the roof or something??

Thanks..
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Chukka63

from United Kingdom

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PostPosted: Thu Dec 17, 2009 7:03 pm Reply with quote

sorry,ignore my first post.i was assuming there had previously been a ceiling in there but then realised there probably wasnt.

if the building is reasonably air tight then you would still need more ventilation than you currently have.possibly via air bricks
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LeadFarmer

from United Kingdom

Joined: 27 Mar 2009
Posts: 246
Location: Yorkshire,
United Kingdom
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PostPosted: Fri Dec 18, 2009 11:28 am Reply with quote

First things first, I am not a roofer. Nor do I have any knowledge of roofing, but Im wondering if the whole block of garages is suffering from damp? Are they situated in the shade?

I would have assumed that there should be 3 or 4 air bricks somewhere between the ground level and the damp proof course. I guess you could easily fit some if there arent any. Just knock out a brick in each corner and fix in a plastic air brick from B&Q.

Just my thoughts, although Im probably wrong.
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freddymercurystwin

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Location: Devon,
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PostPosted: Fri Dec 18, 2009 12:50 pm Reply with quote

It either needs ventilation or there are leaks throughout the roof. One or the other no mystery. Assuming it is not leaking, as mentioned stick some air bricks in but at high level not at ground level, they need to be up high to vent any moist warm air that rises within the garage before it condenses on the underside of the roof. Again as briefly mentioned this assumes there is not some other funadmental thing going on like a higher ground level to the rear or similar and penetrating damp.

To make it really clear, what level are the ground levels surrounding the garage.
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leecollins

from United Kingdom

Joined: 17 Dec 2009
Posts: 4
Location: Dorset,
United Kingdom

PostPosted: Fri Dec 18, 2009 4:57 pm Reply with quote

Thanks for the replies guys keep them coming please!

I'll try and explain the best i can, the property at the rear of the garages (where the fence is) the fence is fitted at the gardens ground level, so there is a higher ground all the way behind all of the garages, when the roof was stripped, the rear of the garages wall was about 1m wide, there was an outer retaining wall made from breeze blocks, an inner wall (the rear wall of garages) built from breeze blocks and the gap between them roughly 600mm was filled with concrete! I don't think there was any tanking or anything. The pics of the fence the bottom half look to be soaking wet all along? The rear wall of garages isn't wet just freezing cold, any more thoughts on this, i have inserted some more pics of the garages after they had just been finished, is the roofer at fault for this do you think or is it a design fault?
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leecollins

from United Kingdom

Joined: 17 Dec 2009
Posts: 4
Location: Dorset,
United Kingdom

PostPosted: Fri Dec 18, 2009 5:04 pm Reply with quote

Here are some pics when it was finished back in summer, there has never been any ventilation even when built new years ago.
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LeadFarmer

from United Kingdom

Joined: 27 Mar 2009
Posts: 246
Location: Yorkshire,
United Kingdom
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PostPosted: Fri Dec 18, 2009 5:52 pm Reply with quote

It looks like the roofs fall is from the rear (where the fence is) to the front.

Should the felt have been laid the other way around, from side to side rather than from front to back?
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Chukka63

from United Kingdom

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PostPosted: Fri Dec 18, 2009 6:06 pm Reply with quote

might pay you to tank the walls that are touching the soil at the back.must be loads of damp coming through those bricks,unless tanked on the outside.
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nandou

from United Kingdom

Joined: 25 Nov 2010
Posts: 1
Location: Surrey,
United Kingdom

PostPosted: Thu Nov 25, 2010 9:23 pm Reply with quote

leecollins wrote:
Hi all,
Would really appreciate some advice here from the pro's, myself and some neighbours had our garage block re-roofed back this summer, they were felted before but had not been maintained for over 15 years, all the joists and decking boards had completely rotted and fallen through. We had it done this year, new timber joists, boards and three layer felt torch on fitted, however i have noticed inside the the underside of the new boards are dripping wet and covered in green mould. The neighbours garages are the same, but not as bad. The inside floor of all the garages were soaking wet before the new roof was fitted due to old collapsing and some even had trees growing inside them. Can someone shed some light on what has happened here or what should/could have been done to prevent this? I have taken some photos for you to see, The felt on top of garages doesn't have any obvious signs of damage and was done by a recommended company.


Any help much appreciated.


Hello,
I have got exactly the same problem in a very similar garage.
Would you be so kind and tell me what is the cost of renovating such a roof.
And also Is it possible to renovate only one garage in a block of garages or all of them have to be redone?

Thank you!
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MainsMan

from United Kingdom

Joined: 28 Nov 2010
Posts: 5
Location: Londonderry,
United Kingdom

PostPosted: Wed Dec 01, 2010 12:16 am Reply with quote

Im no expert either mate, but I'd want to know how the fence edge of the roof's are protected from ground runoff. I'd guess that rain/moisture is getting under the roof around the fence area and penetrating your garages that way.

My next guess is that from the back wall (fence height) to below the foundations of the garages should also incorpaorate an impermaeable layer to prevent this higher level moisture getting into your garages.

Or you slice off some of the ground to leave a gap between your gargages and the fences, so water cant run directly into them.

The fact you mentioned that in less than 15 years service, peoples rafters where crumbling to the floor, would say to me that theses garages suffer from a major water problem, namely the runoff from higher ground.
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