Beadboard for Hull Insulation?

[patrickstickler]

I'm about to insulate my boat throughout and was going to use extruded foam (XEPS) but have a source of essentially free 1/2 inch beadboard (MEPS) that I'd prefer to use to save on expenses.

I've read, though, that the bonding agent in beadboard can absorb water over time and am wondering (a) how big a risk that really is in this particular application, and (b) whether that was a problem with earlier formulations but not with the current stuff.

I anyway intend to paint over the insulation with a water based latex in most areas, and am thinking that between the contact cement on the hull side and the paint on the other side, that may serve to sufficiently minimize any absorption that otherwise might occur.

Eh?

[hellosailor]

Do you mean beadboard, the "beaded" wood molding often used below chair rails? Or beadboard, the styrofoam bead material? If the latter, there are spaces between the beads and yes, that can and will trap moisture and mildew.

[Faster]

You'll have a difficult time fitting a 2 dimensional material to the compound curves of the hull cleanly enough to simply paint it over.

If it's not closed-cell foam you will eventually accumulate moisture in that area.

We lined certain areas of our hull with the closed cell foam pads that campers and kayakers use in their tents, and covered it with planked ceilings - has worked well and looks good too.

[patrickstickler]

Originally Posted by Faster

You'll have a difficult time fitting a 2 dimensional material to the compound curves of the hull cleanly enough to simply paint it over.

If it's not closed-cell foam you will eventually accumulate moisture in that area.

We lined certain areas of our hull with the closed cell foam pads that campers and kayakers use in their tents, and covered it with planked ceilings - has worked well and looks good too.

What thickness did you use? I can get 5-6mm closed cell foam rolls for about the same price as the XEPS, per square meter, but was expecting I'd need about 10-12mm (about 1/2 inch) of insulation being in Finland (will be living aboard year-round).

[scottyt]

another option for insulation is called reflectex iirc. it is basicly bubble wrap with a mylar layer on one side and plastic on the other. it is pretty cheap and very easy to work with. if you hit up a hvac company they use it for duct insulation you might be able to get lots of off cuts for free.

as was said hiding it is the hard part, you will have better luck with strips of wood than any sheet goods.

[Faster]

Originally Posted by patrickstickler

What thickness did you use? I can get 5-6mm closed cell foam rolls for about the same price as the XEPS, per square meter, but was expecting I'd need about 10-12mm (about 1/2 inch) of insulation being in Finland (will be living aboard year-round).

It was 1/2 inch thick.. in either case you can double up if you need to add the thickness. While it depends on the curvature of the hull you may be able to cut rigid foam to fit, but it will need covering up. Still, closed cell foam is a must.

Anyhow we glued some kerf-cut battens, also 1/2 thick to the hull vertically and filled the spaces between with the foam.. then applied 1/4 x 2 inch battens horizontally, screwing them to the vertical glued-on ones. At the extremes of curvature some shaping and trimming was required for a nice visible fit, and a bit of stain and varnish and it was done.

It was a small area in the aft berth where originally all there was there was a cushion. See the result on the far side of the berth in the pic below.

[patrickstickler]

Originally Posted by Faster

It was 1/2 inch thick.. in either case you can double up if you need to add the thickness. While it depends on the curvature of the hull you may be able to cut rigid foam to fit, but it will need covering up. Still, closed cell foam is a must.

Anyhow we glued some kerf-cut battens, also 1/2 thick to the hull vertically and filled the spaces between with the foam.. then applied 1/4 x 2 inch battens horizontally, screwing them to the vertical glued-on ones. At the extremes of curvature some shaping and trimming was required for a nice visible fit, and a bit of stain and varnish and it was done.

It was a small area in the aft berth where originally all there was there was a cushion. See the result on the far side of the berth in the pic below.

OK, I'll just go with the XEPS, which is 15mm thick (.6"). The cost of the extra adhesive to do multiple layers of the 5mm camping foam would make that option alot more, and probably the XEPS has a better R value anyway.

Thanks.

[mbsl98]

Originally Posted by Faster

Anyhow we glued some kerf-cut battens, also 1/2 thick to the hull vertically and filled the spaces between with the foam.. then applied 1/4 x 2 inch battens horizontally......

Faster,
Where can one purchase the "battens" like you used (the sort of business, not a particular place in BC)? And just what is teh proper description of them when I go shopping? That is just what I am thinking of for some interior trim upgrades.

Thanks,
Mike

[saillife]

Any sort of cabinet shop or hardwood store can make battens like that for you. As for a description you just want 3/8" by whatever width you like....
Best of luck,
Brian

[Faster]

Originally Posted by mbsl98

Faster,
Where can one purchase the "battens" like you used (the sort of business, not a particular place in BC)? And just what is teh proper description of them when I go shopping? That is just what I am thinking of for some interior trim upgrades.

Thanks,
Mike

They are available in any wood moulding/lumber stores, called battens or sometimes door stops, but they don't always have both corners rounded. Alternatively you could mill them yourself with a table saw, a router, and planer/sander.. if you have access to those you'd save a lot of money.

Cedar is lightweight, looks nicest,and closest to teak when stained and varnished.. these are just fir/hem with stain etc...