Berth condensation

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nimbusgb

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Been discussed many times before. My boat suffers badly from condensation under the matresses during cold weather.

Ventilation is the key as is insultion under the bunk. I have just come across a material called ecomat. http://www.camperlands.co.uk/eco-mat-breathable-groundsheet.html I'm going to line the bunks with this to try to aid ventilation and air circulation. I paid £9 per running metre so at 3.60 sq m it's no great investment but a hell of a lot cheaper than the stuff sold by the marine industry.

I may put a couplr of space blankets under the matting to improve insulation too.
 
I can't see what you're hoping to achieve with the EcoMat, unless you provide some means of ventilation in the boards under the bunks - in which case you won't need the EcoMat anyway! My bunk boards have lots of 1" holes drilled in them, and I don't seem to get condensation problems (and I sleep on the boat in the depths of winter).
 
On our last boat I cut peg board to the shape of the berths and then put 1"X1" battens underneath that, just screwed through. Theses sat on top of the original berth tops. Never had any condensation under the cushions. Got the peg board on 8X4 sheets from Alloway timber. Pretty sure that most timber merchants will do it or can order it. Cost was a weekends drinking fund.
 
I've seen better ventilation material in bedding / matress stores than Ecomat. Also much cheaper than the chandelry swindles.
 
pvb said:
I can't see what you're hoping to achieve with the EcoMat, unless you provide some means of ventilation in the boards under the bunks - in which case you won't need the EcoMat anyway! My bunk boards have lots of 1" holes drilled in them, and I don't seem to get condensation problems (and I sleep on the boat in the depths of winter).
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Ah but you have a HR, well insulated, with unvarnished berth boards with hundreds of vent holes. Not everyone is so fortunate.
 
pvb said:
Don't know about insulation (the hull is solid GRP), but any fool can chop loads of holes in their bunk boards!
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I seem to remember a YM boat test of an HR a couple of years ago. The author was at a loss to explain why the berth board had holes in them, thought to be a very odd scandinavian idea.
 
Capillary matting & Insulation

We suffered from a lot of condensation under our berth in the aft cabin. First thing was to fit insulation (roll of foil/foam) above the water tank underneath the berth. Second step was to install capillary matting under the berth.

Very cheap solution and it has worked for us, no signs of damp now and we usually had small puddles before.

We had used capillary matting for at least 10 years on our previous boat to solve similar problem in the fore cabin. However, we only live on the boat 6-7 months and winter ashore.
 
Mistroma said:
We suffered from a lot of condensation under our berth in the aft cabin. First thing was to fit insulation (roll of foil/foam) above the water tank underneath the berth. Second step was to install capillary matting under the berth.

Very cheap solution and it has worked for us, no signs of damp now and we usually had small puddles before.

We had used capillary matting for at least 10 years on our previous boat to solve similar problem in the fore cabin. However, we only live on the boat 6-7 months and winter ashore.
Click to expand...

Yup that was my thinking.
 
Mistroma said:
We suffered from a lot of condensation under our berth in the aft cabin. First thing was to fit insulation (roll of foil/foam) above the water tank underneath the berth. Second step was to install capillary matting under the berth.

Very cheap solution and it has worked for us, no signs of damp now and we usually had small puddles before.

We had used capillary matting for at least 10 years on our previous boat to solve similar problem in the fore cabin. However, we only live on the boat 6-7 months and winter ashore.
Click to expand...

Does the capillary matting wick the condensation from under the bunk cushion & onto the board or does airflow prevent condensation appearing under the bunk altogether?
 
We have tried coconut matting, a plastic/wire mesh mat and holes in the locker tops. They all work to some extent but after 15 years of experimentation the prize goes to IKEA bed slats, so far the best and cheapest solution.
 
V1701 said:
Does the capillary matting wick the condensation from under the bunk cushion & onto the board or does airflow prevent condensation appearing under the bunk altogether?
Click to expand...

I doubt that it is airflow as the matting is quite thin and not very permeable to air without help from a fan. I've always assumed that it just spreads the moisture so finely that it evaporates because the surface area is so massive.

It worked on single berths on our previous boat and one of those had a high wooden side. That was the berth where condensation was most noticeable until we put down matting.

There's a water tank under one side of a double berth on our current boat and bottom of cushion was always very wet. The other side was only slightly damp. I reasoned that insulating the tank might help by keeping temp. in the area under the mattress above the dew point.

It seems to work and we didn't have any problems afterwards. Matting might have been OK without insulation but it was cheap and easy to fit underneath the wooden cover.

I imagine that the Ikea stuff would also work but cost of £130 for 2 items puts me off. They'd also be too narrow as the berth in my aft cabin is 2m x 2m. So I'm happy to stick with my cheap solution. In fact, we repeated the exercise on the fore cabin before leaving Scotland last year. That berth is almost never used but we sorted it out just in case we needed that berth.
 
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