Insulation for a Wooden Boat

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alb40

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Over the summer, i constructed a new roof on my boat from plywood and then covered it in epoxy with a layer of matting.

Im a liveaboard, so now its heading fast into winter, i was thinking about insulating the roof somehow to help keep the heat in.

There is a gap of about 20 - 25mm between the roof, and the headlining inside, which is just a thin plywood which i then painted.

So question is, what is suitable to put in the gap? I was thinking about using some expanding foam, or some loft insulation type material, but im concerned that i might trap dampness in there, and lead to replacing the roof (again)

Any ideas? Or should i get a thicker coat? /forums/images/graemlins/blush.gif

Thanks, Alex.
 
I would suggest a thicker coat!

You need the air to circulate in a wooden boat or you will be encouraging damp. Personaly I would not suggest having the ply headlining either.

I have thin strips of mahogany (about 2" wide and 1/4" thick) fastened to the frames inside the hull. This stops bedding getting damp if touching the side of the boat, but also allows air to circulate.

This is possibly not much help, but I really wouldn't use insulation as your fears are correct.
 
Expanding foam might give moisture problems. Loft insulation is not much use in such a narrow gap. You could try some aluminium covered bubble polythene if you can get it. The stuff they sell to go behind domestic radators might do. Of course it might still trap moisture!
 
I think my original plan might stick then - get a bigger heater!

The ply headlining does contain some vents BTW, and I left a small gap around the edges, which keeps that ventelated, so there are no current problems with damness there.
 
A good quality tent over the Boom and cockpit will keep all dry and the cold wind out if brought down to the ships side.
Try to get the type of material used for curtains on the side of waggons and trailers its similar to spray hood material but better. We have used the jib on occasions in the past if it was blowing a hooley and it kept us nice and snug especially on the pick or a swinging mooring in Bray Harbour Alderney.
 
I have a wheelhouse on the boat, so there is no cover, but I have covered the cabin in a tarpualin as I didnt get round to finishing the painting to the top over the summer. It does help retain some heat, but its only thin, so maybe a proper cover would be better.
 
got to agree with the other replies... but

i'd go for thermal insulation from your local builders merchants.. you can get it in various thicknesses, it's class zero for flammability (it won't burn... and yes i've tried), it's got foil on both sides, so you could epoxy the underside of the roof, then allow to set then epoxy the panel in (moisture shouldn't be a problem if you don't already have leaks... and i'm guessing you don't)

it's easy to work with nice and light, and can be bent/formed to curves.

guy near me is using it on the inside of the hull on his Bertram, looks a neat and effective job.

i will be using it on the inside of my hull, as it gives a firm surface for carpet and such to be glued over as a finish.

hope this helps. steve.
 
Heres an idea, get hold of some of the thick bubble wrap like they use for big packaging, its about 1" thick. Put a layer or two over the outside of the cabin tops then tarp over. Much less likely to cause rot problems than permenat insulation on the inside but just as effective.
 
I've got a heavy canvas cover that goes over the whole topsides, held down by 5litre bottles. It significantly improves the temperature on board, the whole boat is warm not just next to the wood stove.
 
Re: How about insulating paint?

I'd agree about restricting air flow causing problems if there are leaks, but with a ply top there should not be any.

In a situation like this, liveaboard, constantly cooking, washing, even just breathing, condensation will be a major problem, and this is going to be particularly bad on the underside of the coachroof. This is very difficult to resolve. However, a rule with water is It Must Go Somewhere and if atmospheric water vapour is not vented out it will condense on cold surfaces. It's not practically possible to sufficiently ventilate a boat to get rid of all the vapour, so you have to deal with condensation. If it don't condense out on the deckhead it will on the inside of the hull; this should be less of an issue as it will hopefully have a clear run to the bilge.

On the other hand living with constant overhead drips is torture. As well as this I've seen cases where condensation running down the coachroof has rotted the ends of the beams where they fit into the beamshelf.

The traditional solution (other than ten layers of clothes) is the huge coal stove but this works by drawing in air and shooting it up the chimney; unfortunately the places condensation likes to form tend to be out of the way of the airflow in my experience, so your ankles freeze and your head still gets dripped on.

On balance I'd have to say that for weekend/hobby boat leave it uninsulated and ventilate it well, but for a long-term liveaboard in UK waters I think you'll have to insulate the overheads somehow. (Particularly if the female of the species is to be induced to remain on board.) Whatever you use it will have to be fitted in such a way that no air can reach the cold surface otherwise you will trap moisture, which is to be avoided.

Personally I think if someone could come up with a simple, genuine solution to this they could make quite a lot of money. FWIW I think one solution would be to fit some sort of foam-core sandwich cabin top, but that's really only possible at major refit time.
 
Re: How about insulating paint?

[ QUOTE ]
I'd agree about restricting air flow causing problems if there are leaks, but with a ply top there should not be any.
.

[/ QUOTE ]


!!!!!!!!!!

Anywhere - and I mean anywhere there is anything passing through a ply deck - whether it be a bolt, or the forehatch - there is potential for a leak.

And a wooden boat absolutely must have air flow through it. My Eventide was nicely sealed up when I bought her - no ventilation apart from in the heads, and everything absolutely running with condensation, mould and mildew kept coming up everywhere, and she smelled musty after a few days unopened.

A vent in the forehatch, and another in the washboards has cured 90% of it, and she smells sweet when I open up now however long it has been since I was last aboard.
 
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