Help! My garage drips!

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Nessa
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Help! My garage drips!

Post by Nessa » Thu Feb 12, 2009 3:53 pm

Whilst at first this request may appear to have nothing to do with boats, it does, of course, have everything to do with boats, because there is nothing quite so valuable to the restoration enthusiast as their garage or boat shed.

Having waited for seven long months to move into our new house and then to move Aggie (heh) to his/her new home so work can continue, I now find that the concrete garage that should have been the new boat shed has a severe condensation problem. In the morning it is almost as if it is raining in there, so clearly no boat work can be done because the wood be wet, marked etc.

Knowing that gentlemen of a certain age tend to have a fondness for, and inexhaustible knowledge of, sheds, garages, workshops etc, I am hoping for some pearls of wisdom....

(Sorry about the verbosity of this post; I am reading Jane Austen as befits a lady such as myself!)
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Rupert
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Re: Help! My garage drips!

Post by Rupert » Thu Feb 12, 2009 4:39 pm

I had the same problem with my corrugated iron roof/plastic in my last house's boatshed. What worked tomporarily to catch the drips was to hang plastic sheeting up and empty the puddles out when no boat is underneath. The current garage has a bedroom above it, and that seems to work...
I'm guessing the only real answer is insulation.
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Ancient Geek
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Re: Help! My garage drips!

Post by Ancient Geek » Thu Feb 12, 2009 4:42 pm

What I can tell you to NOT to use is any form of Parafin or liquid fuel heating an electric heater for a greenhouse will reduce the condesation, and not cost much to run.
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Re: Help! My garage drips!

Post by Nigel » Thu Feb 12, 2009 6:10 pm

Hi Nessa,

ventilation should help but it sounds like a problem with the roofing material. From what is the roof made?

Nigel

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Re: Help! My garage drips!

Post by Michael Brigg » Thu Feb 12, 2009 7:45 pm

Ventilation, ventilation and more ventilation. If you cant do that then use a dehumidifier.

Heating will make it worse.

Condensation is caused when warm air (which will carry more moisture) is cooled down by a cold wall/window/ceiling. The cooled air then cannot carry the same humidity, (lower partial pressure of H2O at lower temparature) resulting in condensation. (ie 100%humidity at 0'c is actually "drier" than 10% humidity at 60'c, or thereabouts, I'm sure you get the picture.)

Heating your garage will simply speed up the transfer of water from the source to the window or wall as the warmer air will carry a greater quantity, and a blow heater will move the warm moister air towards the cold walls. Condensation in a warm unventilated room will only stop when there is no more moisture.

So where is all that water coming from??

Your garage possbly has no damp course or an unsealed concrete floor, both of which may allow ground water to get in, or may be connected to the wall cavity of the main house in which case warm moist air from the house will come into the garage if there are insufficient air bricks, a common building fault.

Adequate ventilation will

a) remove moist air before it causes condensation, and

b) allow colder drier air in from ouside to aid evapourative removal of the condensation. Also

c) If the garage air is the same temparature as the walls/ceilings/windows, then condensation will not occur.

If you want a warmer garage without condensation you will need to add 2' glazing and insulate the walls and ceiling and possibly seal the walls (if no damp course) and floor, or make an effective "greenhouse" within the garage by lining it with insulation or a plastic tent.

Finally of course, Flat roofs like the double skins of a 445 described by Laser tourist can hide a multitude of sins.

What did your pre purchase structural survey say about it? (or have you only got the "buyer's pack?")
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neil
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Re: Help! My garage drips!

Post by neil » Thu Feb 12, 2009 8:41 pm

Bloody workshop roof is the bane of my life. I put a roof on a cow shed about 9 years ago to make the workshop, and extended it so I could easily get a Flying15 in. The roofing sheets were gaurenteed for 7 years. They lasted 6. Finally got a new roof on a few weeks ago. This one is belt and braces. 11mm OSB then roofing membrane topped off with powder coated Box section galvanised. The roof is ventilated and the workshop is the driest it's ever been - and a pleasure to work in, even has an ipod dock and wireless broadband now I know the dripping roof won't interfere with the electrics

I was going to put clear sections in the roof, gald I didn't as this is a main cause of condensation. Damp has never been a problem, the running water from the roof was - this even led to internal guttering - don't do this.

If it's the roof it needs to be sorted. Let us know what the material is and/or post some pics.
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Nessa
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Re: Help! My garage drips!

Post by Nessa » Fri Feb 13, 2009 10:52 am

The roof is white (does it always snow in Cambridgeshire?) and also white under the snow, it appears to be some kind of corrugated plastic - quite sharp edges, but pretty flexible. It seems to be quite well fitted, but there does seem to be a wooden strip - about 8" between the top of the concrete and the wood, though this may just be cladding, and the garage also has a metal up and over door, also a snug fit. There is a wooden side door and we plan to drill some small ventilation holes along the top of this. There is also a small window which is either perspex or plastic. The floor is also concrete, but I can't inspect it closely because it is covered in boxes etc!

Nik (foolishly) insists on wanting to keep the mr2 in my boat shed, so we are probably going to either extend it with some kind of wooden structure, or eventually build a spearate structure to store a boat, but all this will take time and I am anxious to be able to get back to work on the 14 ready for when it might be warm enough to consider epoxy.....I want to sail the thing, not just have it as an ongoing project!
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Re: Help! My garage drips!

Post by Ancient Geek » Fri Feb 13, 2009 10:59 am

Meanwhile lots of good boats have been built in polytunnels.
Simples.

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Nessa
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Re: Help! My garage drips!

Post by Nessa » Fri Feb 13, 2009 11:18 am

Indeed, and there is a huge proliferation of empty ploy tunnels in these parts....I am keeping my ears and eyes open... :shock:
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Re: Help! My garage drips!

Post by Nigel » Fri Feb 13, 2009 12:06 pm

Hi Nessa,

the wooden cladding is a good candidate for ventilation. You can pick up cheap plastic louvred vents at places like B&Q - just cut a big hole behind them and screw them on. Fit a couple on each side and you have a through draught.

If that does not do it, replacing the roof is the next step but obviously a lot more cost.

Re another boatshed, B&Q online used to sell prefab steel framed carports. Otherwise, if there is a Costco near you they do a massive really heavy duty steel framed canvas garage pretty cheaply.

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Re: Help! My garage drips!

Post by Pat » Fri Feb 13, 2009 2:28 pm

Yes the Costco one is brill. They are plastic covered not canvas with zip doors and ours, known as "the tent", has stood nearly two years through gales and snow and sun and rain. Fat Merlin's in there at present with space to spare.
Cost was about £130 plus some big heavy weights from the scrapyard to help keep it down and we also screwed some tying eyes into the garage wall for it.

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