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How to tackle the damp???? Any ideas??? Thanx


lucyboatgirl

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Hi you lot. Happy New year!

I am on-board a little twenty foot grp river cruiser and it is getting very damp. I am trying to fix the leaking Windows which I will get finished next week. But even without leaks it still gets very damp. Lots of moisture in the air. Any advice? Some mornings the whole ceiling is dripping from condensation (I guess). Is it worth getting a dehumidifier would you think? Anyone got any experience of this? Someone said to me it was pointless because your on the water so there's just too much moisture in the air anyway.

If you have any advice or experience with this please let me know what you tried or would advise?????? It's starting to get me down seeing all my books wrinkle up and my clothes all damp. Thanks you lot. Thanks for any help you can give me x x x x x x x x x x

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If you were talking about a steel narrow boat with its inside heavily insulated with Rockwool, polystyrene or sprayfoam, and then wood lined, the stock answer is that if you keep it well ventilated, and try to avoid sources of moisture, (whether drying clothes or steaming saucepans), then condensation can be minimised.

However, I rather fear that if your 20 foot GRP river cruiser is much less well insulated, those answers may not be sufficient.

How much insulation and lining do you have inside the GRP skin?  If the answer is "not very much", then I rather fear you will find this hard to solve, unless there are ways of adding the insulation it may currently lack.

EDIT:

Also, depending on exactly what type of boat you have, I'm guessing you are actually occupying a fairly small space, even if it were just one person on board.  Our bodies are, of course, all generators of moisture, and hence potentially of condensation, and I suggest the smaller the volume of air you are in, the more concentrated any condensation problems are likely to be.

How is the cabin space heated, please, (assuming it is)?

Edited by alan_fincher
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Sounds pretty grim! Insulation helps, as a short term fix if you don't have shore power the moisture traps you can get will absorb some, as will bowls of table salt. 

Perhaps you could try as a temporary measure stapling a blanket to the roof trim? 

What's your method of heating? Gas heaters can produce lots of condensation

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Hey Alan thanks for this reply, even if it's not what I want to hear. I have no idea how much insulation my boat has. But I'm guessing by the amount of moisture the answer is 'not very much' oh dear. Can you think of anything that might help alleviate it? Or is it just a matter of Lear ing to live with it? Thanks x

Hey Harry, I hots a solid fuel stove. It does dry the place out when I get her up to temp. Do you think those moisture traps might be worth trying ? Or just a waste of time? Thanks x

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I think you need to find out how much insulation you have.  Assuming the cabin is lined with something, is it possible to gain an impression by how "fat" the entire combination of outer skin, anything in the middle, and inner skin is, by looking at thickness at windows, vents, or doorways?

It's hard for anybody to advise, (not just me!), until we have some idea of what you currently have. (Pictures would be good).

In the worst case, if you are actually looking at the GRP from the inside, (i.e. there are no other layers), then I would say that gluing some kind of insulating layer straight to that might not look pretty, but would probably help a lot.  However it's probably best that advice about what to use comes from people more experienced with GRP boats than I am.

The fact that the stove is solid fuel is at least good news.  Other alternatives can create more problems, but assuming safely installed, a solid fuel stove will generally help suck moisture out and send it up the chimney.   However with poor insulation, the more you heat the boat, then possibly the worse the condensation will be, as the temperature difference to the cold skin of the boat will be greater.

As you say, none of this is what you need to hear, but it is probably necessary to b quite realistic about what you are faced with and what it might be possible to do.  Several on the forum have lived on small GRP boats, so their input might be more useful than mine.

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:unsure: Poor you Lucy, damp is not fun.

I'm afraid I can't offer much in the way of good advice but I do use those moisture traps in my little caravan over the winter and they can make a difference.

I use Ecozone room dehumidifiers, not only do they seem to do the best job but they are refillable so I don't have to throw out the plastic bits I just but the slightly cheeper refills. 

I've also used cups of salt, but while the salt did absorb moisture it wasn't as good as the Ecozone thingies.

The draw back to these dehumidifiers is that in a small space they are clutter and might spill - the Ecozone ones can be emptied with out loss of use unlike others.

So, no they might not be a waste of time but neither will they be a long tern solution.

I do hope some one gives you some better advice than I have.:blush:

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We have a couple of the Unibond Aero moisture traps on board and they do collect quite a bit of moisture over the winter months. It won't cure your problem but it might help.

You need to ventilate the space and provide a dry source of heat.

Getting a window vac might help as well.

Whenever we are onboard our cruiser we keep the windows and hatches cracked open to provide lots of ventilation in the cabin and keep condensation at bay. It doesn't mean the cabin is cold either. We have two of us breathing and creating moisture in a 23ft hull and we don't get any condensation problems in the cabin.

Make sure your bilges are dry as well.

ETA: there are the moisture traps we use:

http://www.wilko.com/insulation/unibond-aero-360-moisture-absorber-450g/invt/0286745

Edited by Naughty Cal
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I have to say that when i had my 20 foot Shetland for two years I kept that on the water but I can't say I noticed a huge amount of condensation. I didn't live on my boat to be fair but I was on it every day. I had a fan heater during the winter months as I did have a mooring with electricity but in the summer I didn't need anything. The walls of my boat didn't have any insulation it was just the plastic. I had even stripped the hessian, that Shetland used to cover the inside of their boats, because the glue had deteriorated. I also had a gas cooker and a kettle both of which produced condensation but I did not have a problem.

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1 hour ago, lucyboatgirl said:

Hey Alan thanks for this reply, even if it's not what I want to hear. I have no idea how much insulation my boat has. But I'm guessing by the amount of moisture the answer is 'not very much' oh dear. Can you think of anything that might help alleviate it? Or is it just a matter of Lear ing to live with it? Thanks x

Hey Harry, I hots a solid fuel stove. It does dry the place out when I get her up to temp. Do you think those moisture traps might be worth trying ? Or just a waste of time? Thanks x

I think insulation is the way to go, maybe try something like the stuff on this link which can be moulded to the shape of the boat

http://www.ebay.co.uk/itm/CAMPERVAN-VAN-FOIL-INSULATION-FOAM-DEFENDER-SOUND-PROOFING-DEADENING-CARPET-T5-6-/272084102902?_trksid=p2385738.m4383.l4275.c10

Edited by 13-10
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I used to use moisture traps on my first boat - same as Naughty Cal and they did okay.

For my present bigger boat I found last winter the moisture traps were not sufficient and I bought  a Meaco DD8L dehumidifier which works very well - the interior is dry as a bone. But that might be a bit over the top in a small boat.

https://www.appliancesdirect.co.uk/meaco_8l_desiccant_dehumidifier_electronic_control_dd8l/version.asp

When you are on the boat your very presence will create moisture . I would suggest trying the moisture traps and some heating such as an oil filled radiator and don't be afraid to open a window to  allow air to circulate  - especially  when you stay aboard overnight.

 

 

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As a quick fix heating is the way to go, I'd suggest a fan assisted cheramic heater like:

https://www.ebay.co.uk/itm/Sealey-CH2013-Ceramic-Fan-Heater-1500W-230V-2-Heat-Settings-with-Thermostat/122239112882?epid=2254805304&hash=item1c7604d6b2:g:mZkAAOSwfpVZEjmi

as it would be easy to find a place for it and the fan will stir the air so condensation will have less chance to build up. Test in store first so it's not too noisy. Lots of small things you could do to help the situation, pre dry clothes under the hood, wrap anything that may store humidity in plastic, make sure your ventilators are open so the heat can take the damp out.

 

 

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12 hours ago, Naughty Cal said:

We have a couple of the Unibond Aero moisture traps on board and they do collect quite a bit of moisture over the winter months. It won't cure your problem but it might help.

You need to ventilate the space and provide a dry source of heat.

Getting a window vac might help as well.

Whenever we are onboard our cruiser we keep the windows and hatches cracked open to provide lots of ventilation in the cabin and keep condensation at bay. It doesn't mean the cabin is cold either. We have two of us breathing and creating moisture in a 23ft hull and we don't get any condensation problems in the cabin.

Make sure your bilges are dry as well.

ETA: there are the moisture traps we use:

http://www.wilko.com/insulation/unibond-aero-360-moisture-absorber-450g/invt/0286745

I have one of these in the bedroom above the bed, they do collect a fair bit over the weeks of winter, for the cost they are worth it, get a couple i would advise,

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14 minutes ago, Dave Payne said:

I have one of these in the bedroom above the bed, they do collect a fair bit over the weeks of winter, for the cost they are worth it, get a couple i would advise,

They are very good for the price. They seem to collect far more moisture then the types that have the crystals and are far more stable and unlikely to spill.

We initially started with one but seeing how much moisture it was collecting bought another one. 

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A few thoughts on damp.

Condensation (damp) occurs when damp air meets a cold surface, and this is inevitable.  So things you can do -

1)  Eliminate the cold surface - this can only be done by insulation and if the insulation you use is not damp proof (eg mineral wool), then it will slowly get soggy and stop working.  So either use a damp proof insulation or put a damp proof membrane over it.

2)  Reduce the amount of water in the air - water comes from evaporation (eg washing drying, cooking etc) so get rid of wet activities.

3)  Any form of heating that releases water into the boat - such as mobile paraffin or LPG heaters - is going to give you lots a damp.  

3)  Lack of ventilation will allow the air to get wetter and wetter, so replacing warm damp air, with colder outside air will help, though it will cost more in heating.

Solid fuel stoves are good, as they both heat the air, but also discharge some of the damp boat air together with any water from burning wood etc up the flue.

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57 minutes ago, Chewbacka said:

A few thoughts on damp.

Condensation (damp) occurs when damp air meets a cold surface, and this is inevitable.  So things you can do -

1)  Eliminate the cold surface - this can only be done by insulation and if the insulation you use is not damp proof (eg mineral wool), then it will slowly get soggy and stop working.  So either use a damp proof insulation or put a damp proof membrane over it.

2)  Reduce the amount of water in the air - water comes from evaporation (eg washing drying, cooking etc) so get rid of wet activities.

3)  Any form of heating that releases water into the boat - such as mobile paraffin or LPG heaters - is going to give you lots a damp.  

3)  Lack of ventilation will allow the air to get wetter and wetter, so replacing warm damp air, with colder outside air will help, though it will cost more in heating.

Solid fuel stoves are good, as they both heat the air, but also discharge some of the damp boat air together with any water from burning wood etc up the flue.

Depending on what 20ft cruiser the OP is in there may well be a lot of windows which will be difficult to insulate!

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2 minutes ago, Naughty Cal said:

Depending on what 20ft cruiser the OP is in there may well be a lot of windows which will be difficult to insulate!

But if moored up for a while, some form of insulating 'blanket' like you see on some camper vans across the front screen may help.

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Hi all, we are planning our boat fitout and are keen to have the best insulation to avoid damp as far as possible and be as efficient as we can. Seems like good quality steel and insulation are worth the investment upfront in the long term! Anyway, we're really appreciate your advice on what works and what could give the best result. For example, is it work doing spray foam + a layer of rock wool, or some sort of painted coating + spray foam? Anything else innovative out there that's worth considering? 

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21 hours ago, lucyboatgirl said:

Hi you lot. Happy New year!

I am on-board a little twenty foot grp river cruiser and it is getting very damp. I am trying to fix the leaking Windows which I will get finished next week. But even without leaks it still gets very damp. Lots of moisture in the air. Any advice? Some mornings the whole ceiling is dripping from condensation (I guess). Is it worth getting a dehumidifier would you think? Anyone got any experience of this? Someone said to me it was pointless because your on the water so there's just too much moisture in the air anyway.

If you have any advice or experience with this please let me know what you tried or would advise?????? It's starting to get me down seeing all my books wrinkle up and my clothes all damp. Thanks you lot. Thanks for any help you can give me x x x x x x x x x x

I had a 20ft Norman cruiser and damp was a problem when I first got it. There were several causes.Leaking windows,leaking canopy,leaking deck fittings,water in the bilges,and also a roof leak.The Norman has a double skin cabin roof and water from a roof leak can run anywhere in the boat.

Investigation with a helper and a hose should help you track down most leaks,but be aware that where the water is coming in on the inside is not always where it is entering on the outside.Also it can take some time for the water to percolate through.

It can be a painstaking process,finding leaks,but worth the effort.

To minimise condensation [when all leaks have been fixed] line the cabin inside with cheap thin carpet sticking it on with Evostick and ensure that the bilges are always dry.

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52 minutes ago, FoxLovesCrow said:

Hi all, we are planning our boat fitout and are keen to have the best insulation to avoid damp as far as possible and be as efficient as we can. Seems like good quality steel and insulation are worth the investment upfront in the long term! Anyway, we're really appreciate your advice on what works and what could give the best result. For example, is it work doing spray foam + a layer of rock wool, or some sort of painted coating + spray foam? Anything else innovative out there that's worth considering? 

Our boat is spray foamed, nice and warm in winter and just as importantly for me, cool in summer.  However you need to make sure you specify the thickness you want and make sure they do it.  I've seen boats where large areas of foam are only about 10mm thick and in patches even thinner, this will not give you what you want.

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11 minutes ago, Chewbacka said:

Our boat is spray foamed, nice and warm in winter and just as importantly for me, cool in summer.  However you need to make sure you specify the thickness you want and make sure they do it.  I've seen boats where large areas of foam are only about 10mm thick and in patches even thinner, this will not give you what you want.

Great advice, thank you! What thickness would you recommend?

Edited by FoxLovesCrow
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1 hour ago, FoxLovesCrow said:

Great advice, thank you! What thickness would you recommend?

I've just stripped out all of the ceiling insulation polystyrene layers then the roof board on my live-aboard....leaks and condensation running from different places so easier to strip back, scrub and re-insulate.....a product I quite liked the look of and bought was thinsulate and will have this plus a membrane layer and then the ceiling material.....not cheap but seems easy to handle, flexible and good quality......I hope it matches expectations.

Just an option as can't comment on personal results yet still prepping but ready to start refitting soon.....great customer service though...Marine Industrial in Norfolk.

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2 hours ago, FoxLovesCrow said:

Great advice, thank you! What thickness would you recommend?

I told them I wanted it (the spray foam) within 6mm (quarter inch) of the battens that the lining is screwed to.  I did agree that if they went over thick (which they did in a quite a few places) I would cut it back flush.  I used a new sharp bread knife and it took me a couple of days and a few bin bags of trimmings.

Edited by Chewbacka
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2 hours ago, Furness said:

Investigation with a helper and a hose should help you track down most leaks,but be aware that where the water is coming in on the inside is not always where it is entering on the outside.Also it can take some time for the water to percolate through.

Wayne cooked up a good way of finding a leak in his roof. He glued a plate below where the water was entering the boat and ran an airline to it. He then crawled around on the roof with soapy Water looking for bubbles. Eventually he found a pinhole several feet away. 

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14 hours ago, Chewbacka said:

I told them I wanted it (the spray foam) within 6mm (quarter inch) of the battens that the lining is screwed to.  I did agree that if they went over thick (which they did in a quite a few places) I would cut it back flush.  I used a new sharp bread knife and it took me a couple of days and a few bin bags of trimmings.

Ah yes, we watched a video by Journo with Jono where he had a bit of a mission with sorting out inconsistencies with the foam. Patience is a virtue! What stage are you at with your boat now? 

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