Condensation on the windows

[Roger Gunkel]

Couln't agree more. If you seal up the windows or have dg & keep them shut you will still produce moisture & it has to go somewhere.

We have the solid fuel stove on 24/7 (now I have learnt how to keep it in!) & always keep several windows open.

When it is really cold we shut the bedroom windows before bed & they are streaming in the morning - we just leave them open all day & they soon clear.

 

I am not disagreeing with your point of view, as it works for you, but I feel you are missing an important point. By living on your boat you are constantly producing moisture which is carried in the air in your boat. At night and on cold days, as parts of the interior drop in temperature more than others, windows in particular, the moisture is going to condense out on the cold surfaces. By opening the windows at night or in the day, you are increasing the flow of air through the boat, which will replace some of the moist air assuming the outside air is drier. More noteably the air temperature in the boat, particularly near the windows will also be lowered, making the difference in temperature between the glass and the air flowing over it much less. This means that more of the moisture will still be held in suspension rather than condensing.

 

This is fine if you are happy to keep the inside temperature nearer the outside temperature, but if you want to maintain a much higher boat temperature, you need to keep the moisture in suspension by removing as many cold surfaces as possible. If you double glaze the windows, you won't move the moisture somewhere else, you will just keep it in suspension. If there are other cold surfaces such as the back hatch, then it will still condense there, so try insulating that as well and any other exposed surfaces, but make sure that you maintain normal ventilation needed for stoves and appliances etc. To help remove the moisture, open the boat up during the day when temperatures outside are higher, and circulate fresh air then.

 

Modern houses do not suffer condensation in the same way as a boat because there are few cold sufaces for it to condense on and they are better insulated. In addition, there is a larger volume of air in a house, which will absorb more moisture. If you remove more moisture in a boat at source then you will also ease condensation. Use a low power extractor fan if possible to help disperse steam from cooking, the same over a shower to take the steam straight out. Make sure you open windows when cooking etc and try to dry towels and clothes outside of the boat.

 

Roger

[tomandsophie]

I am considering putting the clingfilm-type-stuff on our bedroom windows. However, a couple of things are making me hesitate:

1. We have hoppers on the windows and the bits that hold them stick out past the window frames. These hopper holder bits are riveted on so I don't think I can remove them. Will the film stretch tight over them?

2. We had a friend-of-a-friend look after our boat for three months while we were away travelling and, on our return yesterday evening, although she had looked after the boat very well she had not had the windows open (we usually have them all a little bit open all the time for extra ventilation) and there are some small patches of mould on the wooden lining around the boat. If we put the clingfilm stuff on the windows then I guess this problem could be made worse by the lack of ventilation.

[stickleback]

I want some insulating fabric - quite thin - which I can cut and stick onto the underside of the back hatch using flexible plastic magnets. Any ideas as to where I can get some??

 

Stickleback

[ChrisPy]

I am considering putting the clingfilm-type-stuff on our bedroom windows. However, a couple of things are making me hesitate:

1. We have hoppers on the windows and the bits that hold them stick out past the window frames. These hopper holder bits are riveted on so I don't think I can remove them. Will the film stretch tight over them?

2. We had a friend-of-a-friend look after our boat for three months while we were away travelling and, on our return yesterday evening, although she had looked after the boat very well she had not had the windows open (we usually have them all a little bit open all the time for extra ventilation) and there are some small patches of mould on the wooden lining around the boat. If we put the clingfilm stuff on the windows then I guess this problem could be made worse by the lack of ventilation.

Seems that you need to maximise your ventilation while keeping the windows closed and insulated. If your high level vents are fully open you are half-way there. You can buy mushroom vent liners with extractor fans incorporated, which gives you forced draught ventilation. Or simply fit a computer fan in the hole.

 

I want some insulating fabric - quite thin - which I can cut and stick onto the underside of the back hatch using flexible plastic magnets. Any ideas as to where I can get some??

 

Stickleback

what is 'insulating fabric'?

you could line the hatch with thin polystyrene or bubble wrap and then cover it with a lining material - plywood or fabric.

[Roger Gunkel]

I am considering putting the clingfilm-type-stuff on our bedroom windows. However, a couple of things are making me hesitate:

1. We have hoppers on the windows and the bits that hold them stick out past the window frames. These hopper holder bits are riveted on so I don't think I can remove them. Will the film stretch tight over them?

2. We had a friend-of-a-friend look after our boat for three months while we were away travelling and, on our return yesterday evening, although she had looked after the boat very well she had not had the windows open (we usually have them all a little bit open all the time for extra ventilation) and there are some small patches of mould on the wooden lining around the boat. If we put the clingfilm stuff on the windows then I guess this problem could be made worse by the lack of ventilation.

 

Hi Tom & Sophie, nice to see you back on the forum.

 

I covered fitting this film double glazing on a recent thread, but can't remember what the thread was called. I think that the film would probably split if taughtened up over your hoppers, the other problem could be that even if it didn't split, the hopper could provide a cold bridge between the two layers reducing the efficiency. Could you perhaps drill out the rivets, then use self tappers when you want to replace the hoppers.

 

I am looking at replacing my film, with 3mm clear acrylic at about £16 per window, which can be made easily removeable and reuseable, useing turn buttons to hold it in place against a rubber edging.

 

Just edited to say that the double glazing film won't increase your mould problems, providing you have adequate ventilation elsewhere. Your mildew will be due to other cold surfaces condensing the moisture and trapping it. You can further insulate cold areas and make sure that areas where you have the damp have improved ventilation, perhaps during the day. They are only going mildewed because they are staying damp.

 

Roger

 

I want some insulating fabric - quite thin - which I can cut and stick onto the underside of the back hatch using flexible plastic magnets. Any ideas as to where I can get some??

 

Stickleback

 

Try this link to a company that does various plastic and insulating products. Their expanded foam sheet with whipe clean surface might be what you are after, Insulation

 

Roger

Edited December 23, 2008 by Roger Gunkel

[bluegreencanal]

I am considering putting the clingfilm-type-stuff on our bedroom windows. However, a couple of things are making me hesitate:

1. We have hoppers on the windows and the bits that hold them stick out past the window frames. These hopper holder bits are riveted on so I don't think I can remove them. Will the film stretch tight over them?

2. We had a friend-of-a-friend look after our boat for three months while we were away travelling and, on our return yesterday evening, although she had looked after the boat very well she had not had the windows open (we usually have them all a little bit open all the time for extra ventilation) and there are some small patches of mould on the wooden lining around the boat. If we put the clingfilm stuff on the windows then I guess this problem could be made worse by the lack of ventilation.

We had very wet windows and it was pretty cold so did the clingfilm double glazing on the larger lower part of the window not the top openeers as they stick out too much. It made a big difference.

 

However we also have problems in the wardrobe and kitchen cupboards which are below the water line. I have to empty and dry them periodically.

 

I find a hairdryer quite effective.

 

Have thought about putting carpet in the lower cupboards.

[Lady Muck]

Have thought about putting carpet in the lower cupboards.

You will probably end up with mouldy carpet.

 

How I deal with it is:

 

All blankets and out of season clothes go in pack bags (those ones that you squash flat that gets the air out of the garments) Under my bed I have those boxes of crystals that soak up moisture (can be bought from Lakeland or camping shops) - you need to remember that these are there and check/ replace/empty them once a month, otherwise they'll overflow. I have ones in my wardrobe that are crystals in yellow bags - they can be dried out in the microwave and reused.

I store these blankets in packbags under the bed, in plastic boxes, but they aren't hard, solid sided boxes, they are mesh to allow for air circulation.

 

Re the windows, I've just used rolled up towels, it only really starts to drip alot when the temperature is below freezing. I have very flush fitting blinds which keep these in place.

[Roger Gunkel]

However we also have problems in the wardrobe and kitchen cupboards which are below the water line. I have to empty and dry them periodically.

 

I find a hairdryer quite effective.

 

Have thought about putting carpet in the lower cupboards.

 

I sympathise with you on the condensation problem in low level cupboards. Unfortunately, although the hairdryer may well dry up the condensation, you are simply warming up the air so that it can absorb more moisture and temporarily heating the cold surface so that moisture doesn't condense back onto it. As soon as it cools down again, the problem will repeat itself. You have got to:

 

1) remove the cold surfaces, - lining with carpet will help considerably.

2) reduce the moisture content in the air - produce less moisture by boiling less water, just heat what you need, try to dry towels etc outside, keep the bilges as dry as possible

3) improve ventilation - this will help to bring dryer air into the boat and remove moister air. Try especially to allow air to circulate through closed areas such as cupboards, wardrobes, under bed areas etc by adding ventilation openings and if you have adequate power, perhaps even low power, cheap computer case fans in cubboard and bed bases to circulate air.

 

Air will always contain moisture, especially in a small volume like a boat, the trick is to reduce the amount of moisture as far as possible, then keep it in the air and not on your walls and windows, by reducing the temperature difference in the surfaces.

 

Hope some of that helps,

 

Roger

[johnjo]

You will probably end up with mouldy carpet.

 

How I deal with it is:

 

All blankets and out of season clothes go in pack bags (those ones that you squash flat that gets the air out of the garments) Under my bed I have those boxes of crystals that soak up moisture (can be bought from Lakeland or camping shops) - you need to remember that these are there and check/ replace/empty them once a month, otherwise they'll overflow. I have ones in my wardrobe that are crystals in yellow bags - they can be dried out in the microwave and reused.I store these blankets in packbags under the bed, in plastic boxes, but they aren't hard, solid sided boxes, they are mesh to allow for air circulation.

 

Re the windows, I've just used rolled up towels, it only really starts to drip alot when the temperature is below freezing. I have very flush fitting blinds which keep these in place.

Surely that puts it straight back to where it was absorbed from in the first place, don't it?

[Neil TNC]

We find that every morning and at other times to the windows are streaming. What do you do to stop it?

 

N

 

As others have said, ventilation will get rid of it...but to save heat, not everybody does. We use a large industrial squegy thingy, which is just the height of our bus windows. One scrape and the water is all in the drain channel. This method aslo saves getting the windows messy using rags and such.

[8 Ball]

Hi all. I must say that Roger Gunkel has it 100% correct. The condensation wont "find somewhere else" it is all around you, and the only way to stop it from forming into visable water and rotting your window ledge etc is simply to remove it directly from the air.

 

I have had no problems at all. There is no condensation on my windows. My low level cupboards are dry. Under my bed is dry.

 

To achieve this is as RG said. The insulating 'hairdry on' double glazing on all your windows during the winter (which I got from Robert Dyas). The other real simple thing is to use damp traps around your boat. These contain generally calcium oxide which takes dampness from the air and condenses it into water which it holds in a container. Every couple of months (in the winter) just empty out the water replace the little packet and hey presto. From many pound shops you can buy a 'one use only' container which you just dispose of complete when the lower part of the trap is holding that water. Two traps for a pound normally. The reusable ones can be found in most chandlers and all the usual BnQ type places ....Others stores are available ! :-)

 

I have traps around my boat. Under the floor of the wardrobe, under my bed, under my sink in the bathroom, under my sink in the galley, behind my settee (as its quite cold down there) and one under the well deck in the gap before the gas locker.

 

My side hatch and bow doors provide all the flow of air when I want to ventilate fully.

 

As they say...... Job done. Nil damp.

 

Dry boating !

[mrsmelly]

We find that every morning and at other times to the windows are streaming. What do you do to stop it?

 

N

 

If its a boat it should have portholes not windows. Less surface area = less condensation and less glass area to lose heat thro thats a fact, go on a portholed boat I bet its always warm like mine.

[NB Alnwick]

If its a boat it should have portholes not windows. Less surface area = less condensation and less glass area to lose heat thro thats a fact, go on a portholed boat I bet its always warm like mine.

 

Certainly, we do not see any condensation on 'Alnwick' - but then we also have excellent insulation.

[Roger Gunkel]

If its a boat it should have portholes not windows. Less surface area = less condensation and less glass area to lose heat thro thats a fact, go on a portholed boat I bet its always warm like mine.

 

You could also argue (not that I ever would) Portholes=Less light, restricted view, closed in feeling. Go to a windowed boat with insulated windows, I bet its always warm like mine

 

No offence intended mrsmelly, just to say there is always an alternative equally valid to most points of view

 

Roger

[Neil TNC]

If its a boat it should have portholes not windows. Less surface area = less condensation and less glass area to lose heat thro thats a fact, go on a portholed boat I bet its always warm like mine.

 

You wait till you get to Ireland!

[mrsmelly]

You could also argue (not that I ever would) Portholes=Less light, restricted view, closed in feeling. Go to a windowed boat with insulated windows, I bet its always warm like mine

 

No offence intended mrsmelly, just to say there is always an alternative equally valid to most points of view

 

Roger

 

Correct I agree, it takes all kinds. A good one though if other owners have not tried them yet I have the fab looks of portholes but Mr Hudson bless him fits as an option, glass prisms in the roof which throw loads of light in even with their small size and you dont get the free shower arrangement with them like with harry Houdini and his hatches.

[sueb]

Correct I agree, it takes all kinds. A good one though if other owners have not tried them yet I have the fab looks of portholes but Mr Hudson bless him fits as an option, glass prisms in the roof which throw loads of light in even with their small size and you dont get the free shower arrangement with them like with harry Houdini and his hatches.

Our houdini hatch is over the shower

Sue

[Username]

Further to this... We've been living on our NB for nearly a year now. We get condensation on the windows, like most others seem to. However, yesterday, I noticed a line of drip marks in the bedroom, running down from beloe the gunwhale. We took the lining, wood and insulation panels out to have a look see what was causing it, and the inside of the steel superstructure was damp all across behind the insulation. The water was coming from below the window. It was coming out at the point it was purely because there was a drilled hole, with no screw in it, in the wood panel at that point. I'm assuming this is condensation leaking down behind the wall panels. What do we do about it? Do other people get this? We wonder if the window is leaking slightly? Our windows have a sort of metal gutter thing at the bottom, should this feed water to outside? I don't really know what I'm looking for!

 

I haven't yet dared to look behind the panels elsewhere on the boat - not least because it took hours of unscrewing and drilling out rivets to look at the bit we did!

 

The NB is only 2 years old. The inside of the steel shell seemed to have some lines of lumpy bits of corrosion - would this be expected?

Help!

Cat

[Ex- Member]

Further to this... We've been living on our NB for nearly a year now. We get condensation on the windows, like most others seem to. However, yesterday, I noticed a line of drip marks in the bedroom, running down from beloe the gunwhale. We took the lining, wood and insulation panels out to have a look see what was causing it, and the inside of the steel superstructure was damp all across behind the insulation. The water was coming from below the window. It was coming out at the point it was purely because there was a drilled hole, with no screw in it, in the wood panel at that point. I'm assuming this is condensation leaking down behind the wall panels. What do we do about it? Do other people get this? We wonder if the window is leaking slightly? Our windows have a sort of metal gutter thing at the bottom, should this feed water to outside? I don't really know what I'm looking for!

 

I haven't yet dared to look behind the panels elsewhere on the boat - not least because it took hours of unscrewing and drilling out rivets to look at the bit we did!

 

The NB is only 2 years old. The inside of the steel shell seemed to have some lines of lumpy bits of corrosion - would this be expected?

Help!

Cat

 

If there are any areas where insulation isn't in good contact with the steel it will condensate. If your boat has been sprayfoamed then this shouldn't occur, but if insulation like we have being Rockwool you have to insure full contact to the steel everywhere.

 

First off what insulation do you have.

 

It's possible water is leaking down from a window, but windows should have a drip away that guides water outside the window.

 

What type window?

Edited February 16, 2009 by Julynian

[Username]

The insulation is just sheets of polystyrene type stuff.

The windows do appear to have things that let the water out of the gutter, to the outside. They're damp below the gutters though.

Help/advice muchly appreciated!

 

Edit: Having just gone to look at them, it's a particular point that seems to collect damp/water. They've got curved corners to the gutters, but square corners to the actual wooden frame, and water collects in the gap between the square corner and the rounded corner. Kind of hard to explain - imagine this <c sort of thing, but with the c and the v shape pushed together - the point of the v gets damp. It's worse in the bedroom than anywhere else.

 

Is it really bad to have the insides of the steel wet? What do we do about it? We dried it off when we took the panals off, and have been making sure the boat si better ventilated, which has helped as far as the windows are concerned, but will the dampness behind the insulation dry off?

 

Is it possible to retrospectively foam fill behind the walls?

Edited February 16, 2009 by Username

[Bones]

The insulation is just sheets of polystyrene type stuff.

The windows do appear to have things that let the water out of the gutter, to the outside. They're damp below the gutters though.

Help/advice muchly appreciated!

 

Have you checked that the drip things are clear of obstructions?

[Username]

Have you checked that the drip things are clear of obstructions?

 

Having just read through this topic, I am just about to The gutters don't seem to have much/any water in, though, and yet the windows are still damp beneath.

[Ex- Member]

Unfortunately polystyrene can cause problems like this if not fitted well, it needs to be tight against the steel, it's ok as insulation goes but needs to be fitted extremely well, some even glue it to the steel to ensure no gaps between it and the steel occur and use tinned spray foam to get to awkward bits. You need to check if the poly is loose fitting or flapping about. It should be 2 inches thick also. The condensation if it is that could be emanating from elsewhere and ending up in the place you have found it. If the poly is loose in the area you have found at the moment, it would be wroth checking it elsewhere. You can check under the floor also, if it's wet then again it could be the condensation dripping all the way down the steel sides. Also check the bilges at their loest point for water.

 

Hopefully though it is an isolated patch.

[sueb]

Did you have the boat built for you and who built it?

Sue

[alan_fincher]

If it's only just started occurring after 2 years, and has not happened previously, I'd be doubtful this is a problem of poor insulation. They seem to show up pretty quickly from new.

 

The symptom, (so far as I can understand it), is entirely consistent with what happens if a leak develops between the window frame and cabin side.

 

If small amounts of water get in, then freeze, as in this recent cold snap, then that can further force the two surfaces apart, letting more water penetrate.

 

Often windows are bedded on to a silicone sealant, and, whilst this works well in many cases, in others it seems to be a point of failure. Our resident engineer reckons he has seen any number of windows removed where the silicone still has a good bond to one surface, but none to the other.

 

Do you know what sealant, mastic, or sealing strip has been used between window frame, and cabin, please ? Are the windows secured with visible fastenings ? Screws, or rivets ? Some people have stopped leaks by removing each screw in turn, and refitting smeared in sealant......... It's worth seeing if screws are loose, and can be nipped up tighter. (If you find any brass screws in alloy window frames, this is also "bad", as bimetallic corrosion can cause the window frame to get eaten away at that local point, also ultimately resulting in it not being properly held).

 

Have you still got the linings out, or can they be easily removed again ? If so, take the boat to a water point, and hose the window heavily. If it's correctly fitted, no water should end up inside. (Close any toplights first, though! )

 

It's usually reasonably easy to remove a leaking window, and to reseal underneath, but this isn't the best time of year to do it by choice.

 

Alan