Insulating a Boat to Prevent Condensation

[MustyBoat]

Hi all,

 

Our boat (52" widebeam) gets really bad condensation, to the point where the water is dripping down the walls. The walls are wooden and have started to swell.

 

When we had our windows upgraded to double glazing (old windows still available for sale btw!) in order to fix this problem, we found that the walls are not insulated in any way.

 

What I'm asking is that a) does anyone know a reliable boat builder who could rip out all the walls and thoroughly insulate them, and b ) is this definitely going to solve the problem?

 

Thank you!

Edited January 28, 2014 by MustyBoat

[Captain Fizz]

Is there any insulation in the boat, what about the roof.

Who did the original fit out?

[Dave_P]

This why forum members often go to great lengths to convince newcomers to have a proper survey. I would imagine the fit out was a DIY job since surely no professional boat builder would do this?

 

MustyBoat: you don't say where in the country you are. There's respected boat builders all over who could do this work, but probably not at short notice. I would also recommend you get you boat surveyed properly asap in case there's other issues which need attending to.

 

I'm sorry I'm bearing bad news and I don't want to scare you needlessly, but an uninsulated widebeam smacks of serious cost-cutting and/or incompentance in the fit-out. You need to know the whole situation with this boat.

[Grace and Favour]

Hi Mustyboat,

 

In addition to the other questions above - - how old is the boat?

What form of heating are you using?

 

And, one of the essential conditions of reducing condensation - is that of keeping the boat really well ventilated. - During the day we keep at least half a dozen portholes open, and a hopper window, an often the rear door is ajar too.

[MustyBoat]

Hi all,

 

The boat was built in 2004. We are in London. Yes we had a full survey done in 2011 when we bought the boat, with no problems regarding to this highlighted problem.

 

Dave P - unfortunately I'm pretty sure the guy before us fitted it out himself..

 

We heat using a stove and stove fan too, as well as an electric radiator on a timer in the corridor and another in the bedroom which is sometimes on in the evenings before bed.

 

In regards to ventilation, we are guilty of closing the ventilators when it is cold, as it is at the moment and we do not have hoppers open either.

 

Thanks!

[Dave_P]

I'm no expert on this but I would have thought you should have a claim against the surveyor, and/or the seller? It strikes me that insulation is a prerequisite on a boat like this? Maybe someone else knows better?

 

For anyone who is currently looking - ask about insulation and do your research! I was able to have a look at the insulation on mine by crawling into the front locker under the cratch with a torch and i could see the insulation - just!

 

For info: There's 3 main types of insulation used on boats.

 

1. Spray-foam, the most popular. Good insulating properties and relatively easy to apply. It gets into all the small cracks and should avoid issues with cold spots. Just make sure the boat builder has applied to to a sufficient thickness.

 

2. Polystyrene sheets. Used to be more popular than it is now. Needs to be well installed with the seperate panels fitting snugly. If done properly, it works pretty well.

 

3. Rockwool. This can be awkward nasty dusty stuff to put in but has one big advantage over the others - it's unaffected by heat. This means it won't melt if you need to do any welding on your hull, which could lead to a cold spot forming with the other two options.

 

I'm sure there's boats out there with all sorts of other forms of insulation.

[The Bagdad Boatman (waits)]

One possibility is insulating a small section at a time using either Kingspan which is very good. Wadding which must be covered both sides with a vapor proof barrier. There is a super efficient material available but uber expensive. Fill any small gaps with blow foam.

[koukouvagia]

 

3. Rockwool. This can be awkward nasty dusty stuff to put in but has one big advantage over the others - it's unaffected by heat. This means it won't melt if you need to do any welding on your hull, which could lead to a cold spot forming with the other two options.

 

 

 

Far better than Rockwool is slab insulation. The slabs knit together to eliminate gaps and they hold in place by friction. There's also a lot less horrible itchy dust flying around.

This picture also shows the vapour barrier - absolutely essential otherwise the insulation will get sopping wet.

 

[Stilllearning]

Hi all,

 

The boat was built in 2004. We are in London. Yes we had a full survey done in 2011 when we bought the boat, with no problems regarding to this highlighted problem.

 

Dave P - unfortunately I'm pretty sure the guy before us fitted it out himself..

 

We heat using a stove and stove fan too, as well as an electric radiator on a timer in the corridor and another in the bedroom which is sometimes on in the evenings before bed.

 

In regards to ventilation, we are guilty of closing the ventilators when it is cold, as it is at the moment and we do not have hoppers open either.

 

Thanks!

Do please remember to leave some ventilation, we don't want to hear of more boaters being found dead through CO2/CO poisoning...

Not wanting to scare you or anything!

[MustyBoat]

Thanks so much, all! I will bear in mind what you say about ventilation and the pic of the insulation is perfect - just what I need.

 

Does anyone know someone in London who would be willing to do this work?

[Grace and Favour]

Hi all,

 

The boat was built in 2004. We are in London. Yes we had a full survey done in 2011 when we bought the boat, with no problems regarding to this highlighted problem.

 

Dave P - unfortunately I'm pretty sure the guy before us fitted it out himself..

 

We heat using a stove and stove fan too, as well as an electric radiator on a timer in the corridor and another in the bedroom which is sometimes on in the evenings before bed.

 

In regards to ventilation, we are guilty of closing the ventilators when it is cold, as it is at the moment and we do not have hoppers open either.

 

Thanks!

I have to say that I'm frankly amazed that there's no insulation for such a recent boat - even if the laddo did fit it out himself..

 

And the surveyor didn't spot it either?? - - Phew!

 

Whilst it may increase your fuel bills slightly - get as much ventilation as you can - (it can be quite bracing!) - open windows at each end of the boat, don't block the mushroom vents, and keep every ventilator open 24/7.

 

I can't recommend a fitter for you I'm afraid - but I'm sure that others will.

 

Get quotes from different fitters, as well as the best quality insulation you can - (the insulation material is the cheapest part of the refitting job I suspect!)

[smileypete]

We heat using a stove and stove fan too, as well as an electric radiator on a timer in the corridor and another in the bedroom which is sometimes on in the evenings before bed.

If you heat with electric on shoreline then an electric dessicant dehumidifier, like the Meaco DD8L Junior or the 'DD122FW-Simple' which comes under a few different names, will probably be a great help in the meantime...

 

cheers, Pete.

~smpt~

[David Mack]

For info: There's 3 main types of insulation used on boats.

 

1. Spray-foam, the most popular. Good insulating properties and relatively easy to apply. It gets into all the small cracks and should avoid issues with cold spots. Just make sure the boat builder has applied to to a sufficient thickness.

 

2. Polystyrene sheets. Used to be more popular than it is now. Needs to be well installed with the seperate panels fitting snugly. If done properly, it works pretty well.

 

3. Rockwool. This can be awkward nasty dusty stuff to put in but has one big advantage over the others - it's unaffected by heat. This means it won't melt if you need to do any welding on your hull, which could lead to a cold spot forming with the other two options.

4. Kingspan or Celotex sheets. Same material as sprayfoam, but guaranteed thickness, and better insulation than polystyrene. Has foil facing which acts as a vapour barrier. Use aerosal spray foam to fill any gaps and tape joints with the proper foil tape.

[station tug]

i used to be corgi lpg qualified many years ago so when i worked my ventilation out for my fit out i had double of what i actually needed for the new bss regs..if i were you id use kingspan boards..theres a company called seconds ahead who deal with all of kingspans seconds they deliver nation wide it will save you a fortune.......please please please give your self to much ventilation....if your boats properly insulated decent ventilation will make your life so much more pleasent.......

[NorthwichTrader]

I was taking a look at the vapour barrier above...is this essential on foam sprayed boats? I've got around a 1cm air gap behind my boards ( then the foam spray, of course), and thought this would be fine?

I was tempted to fill the gap with recycled plastic insulation roll, but thought that could potentially hold any condensation and make things worse?

[peterboat]

Years ago we had our old cottage insulated with urethene balls they were blown in between the plasterboard and internal walls. it made a huge difference I wonder if something similar could be done with the OPs boat this would remove the need to dismantle the interior. Its just a thought and I could see difficulties but its maybe possableP

 

Peter

[koukouvagia]

I was taking a look at the vapour barrier above...is this essential on foam sprayed boats? I've got around a 1cm air gap behind my boards ( then the foam spray, of course), and thought this would be fine?

I was tempted to fill the gap with recycled plastic insulation roll, but thought that could potentially hold any condensation and make things worse?

In the pic. in post #8 there is a gap between the vapour barrier and the slab insulation because the hull of the boat is not vertical, whereas the wooden lining is. (The reason for this is that I wanted to have the wood below the gunwales at 90 degrees to the floor). Since no warm, moisture laden air can penetrate the vapour barrier the insulation material remains bone dry despite the small air gap between the vapour barrier and the slab insulation. There must be no gaps in the vapour barrier.

 

One thing to bear in mind is to extend the vapour barrier below the level of the insulation. In some conditions, when it is very hot and humid inside and very cold outside, condensation does collect on the cabin side of the plastic sheet, but runs off harmlessly down into the bilge.

 

Also every last square inch of metal must be insulated. If you miss a bit out you'll be surprised how much condensation can accumulate. Whereas this might not be so serious with spray foam insulation, slab insulation or rock wool will simply absorb the moisture gradually turning it into a soggy mess.

[NorthwichTrader]

Do you think I need a vapour barrier, then, or would the painted wood lining serve the same purpose?

[koukouvagia]

Do you think I need a vapour barrier, then, or would the painted wood lining serve the same purpose?

I've never heard of anyone doing this on a boat, but if you google "vapour barrier paint", you'll see there are plenty of products on the market that claim to do this.

[junior]

As far as I'm aware, what insulation is fitted is a major thing to check on the survey. At first I was going to ask you to put the name of your surveyor out there so people could avoid, but perhaps the best thing is just to ask that you never recommend him to anyone else looking for a surveyor in your area.

[Neil2]

I don't think there's any doubt whatsoever that lack of insulation is causing the problem, I can't imagine what it must be like trying to keep an uninsulated WB warm in the winter. Lots of NB's have poor insulation but you can get away with it because of the much reduced volume of air.

 

Regarding the survey - this highlights a point made many times on the forum ie there are surveyors and surveyors, but I suspect the guy that did it will hide behind his T&C's which usually have an escape clause regarding stuff concealed in bilges and behind linings.

 

As for the solution - wasn't there a thread on here ages ago about injecting insulation or did I dream it? I have a feeling Blackrose and possibly Julynian have some direct experience.

 

Apologies to everyone if I have misremembered this but thought I'd mention it as it would be the most practical solution.

 

 

 

 

I think this is the thread I was thinking of

 

http://www.canalworld.net/forums/index.php?showtopic=61790&hl=insulation

[Alastair]

Do please remember to leave some ventilation, we don't want to hear of more boaters being found dead through CO2/CO poisoning...

Not wanting to scare you or anything!

Actually, the OP should be scared. Very scared.

 

CO poisoning is really no joke, there are several deaths a year from it.

 

Leave your ventilation open. Apart from the CO risk, if you are closing it off then you will increase the condensation problem.

[Rob@BSSOffice]

Leave your ventilation open. Apart from the CO risk, if you are closing it off then you will increase the condensation problem.

 

... and heavy condensation can be one sign of carbon monoxide in the environment.

 

Please do unblock the ventilation. The stove will be burning up the oxygen in the boat and it will start kicking out even more CO as the combustion efficiency diminishes due to the lack of oxygen. A vicious spiral can ensue.

 

You can check how much is needed using this calculation

2200 x (U) the input rating of all unflued appliances, in kilowatts

+650 x (Berths) the number of persons for which the accommodation space is designed

+550 x (H) the nominal output rating of open-flued solid fuel appliances, in kilowatts

+ 440 x (F) the input rating for all other open-flued combustion appliances, in kilowatts

= Total XXXXX mm2, the recommended minimum ventilation which should be split approximately 50/50 between high and low level vents

 

There can easily be 100x the concentration of carbon monoxide in stove combustion gases compared with LPG burners.

 

When there is seriously insufficient ventilation, it is not the sort of issue to let ride or 'eventually get around to' tackling.

 

 

 

edited for layout improvements

Edited January 31, 2014 by Rob@BSSOffice

[smileypete]

Though good ventilation will dilute a modest amount of CO, I think the best defence is a well maintained stove AND flue, and at least 2 CO alarms of different make, one with an LCD readout of CO levels.

 

A stove that's ticking over uses a suprisingly small amount of air, the CO problems occurs when combustion gases escape into the cabin somehow, which can be through various different and unexpected routes.

 

ETA: I do think CO alarms are trouble free enough these days to be requirement of the BSS for solid fuel stoves and maybe gas fridges too.

 

cheers, Pete.

~smpt~

Edited January 31, 2014 by smileypete

[Sir Percy]

Having gutted the boat, I've just finished painting the bilge and sides up to the gunwale. Went to check on drying, and what I thought was a horizontal shadow line on the side turned out to be where condensation started at the water line, going down to the bottom. Don't know why I was so surprised, but explains why there was so much rust that I had to remove when starting work. The old insulation was rockwool. No vapour barrier used.

 

For the sides from gunwales down, plan to use battens and expanding foam, and then Celotex faced with ply panels. Celotex should provide the vapour barrier.

 

Any recommendations on foam? Looking at Soudal Flexifoam and Bond-It Megafoam.