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-   -   Possible alternative to Reflectix? (http://www.sailnet.com/forums/gear-maintenance/87316-possible-alternative-reflectix.html)

Jgbrown 05-12-2012 02:51 AM

Possible alternative to Reflectix?
 
Space is at a real premium in my boat(Alberg 30) but I am trying to insulate the V-berth. Funds are a bit tricky too, and I came across an article talking about attic insulation, and the lack of benefit vs expense of the bubble wrap/fiber fill reflective vapor barriers.
I found a single sided reflective barrier for a good price, double sided for not much more. 110 and 128$ for a 4'x250' roll. (vs 142$ for a 50' roll of reflectix)
The article also talked about the lack of radiant benefit unless there was an air space on one side of the foil, but on the hull side it would be more about the vapor barrier I think?
This plus 3/8" or a 1/2" of Volara closed celled foam sandwiched in between two layers like on frugal mariner would take up little space, and might give me a decent boost in condensation avoidance, and heat retention.
I could then do the fiberglass panel, and/or a mahogany ceiling.
Attic Foil Radiant Barrier - 48" Wide Radiant Barrier Foil - Solid/Vapor Barrier

Foam Insulation, Padding, Closed-Cell Foam - Volara

sea_hunter 05-12-2012 06:52 AM

When I redid our coach house paneling I glued a layer (1/4") of foundation insulation/vapor barrier between the teak paneling and FG. $60 for a bundle from Home Depot.

-OvO- 05-12-2012 11:20 AM

Re: Possible alternative to Reflectix?
 
I've gone down this road a few times myself and concluded that the bubble wrap is only useful under some very carefully constrained conditions. what you want is either the closed-cell foam (cheap) or aerogel (def not).

mitiempo 05-12-2012 11:59 AM

Re: Possible alternative to Reflectix?
 
This link might be interesting Capt'n Pauley's Virtual Boat Yard -- Projects Galore!!!: Installing Insulation in Your Boat

I am insulating with both Reflectix and closed cell foam. In the V-berth my boat has vertical beams glassed in that are 1" thick. I am using a layer of Reflectix, a layer of 1/2" closed cell foam and another layer of Reflectix. The V-berth is probably the most important area as when sleeping you have a lot more body heat close to the hull than in other parts of the boat which often have lockers between where you sit and the hull.
I don't think Reflectix is that effective by itself but it would help on the inside of a cabin top that is balsa cored.

As described on the Frugal Mariner site there are 3 types of heat loss and one type of insulation can't eliminate all 3.

I have a neighbor with a Spencer 35 that is insulated with 1/2" closed cell foam - it was done over 20 years ago - and it is one of the warmest boats I have been on in cold weather. The boat was built in the 60's and other than the 1/2" foam the only insulation is a thick hull.

Jgbrown 05-12-2012 01:05 PM

Re: Possible alternative to Reflectix?
 
This would be the same triple layer, the volara is closed cell foam. The only difference is bubbles in the reflective barrier, eliminating those since they aren't as effective as the closed cell foam and having the vapor barrier/reflective layer without them, more room and money for foam, or slightly thinner overall after all three layers

mitiempo 05-12-2012 01:18 PM

Re: Possible alternative to Reflectix?
 
1 Attachment(s)
The attic radiant barrier foil is not much less expensive than Reflectix. And there are places on the boat that may not have the available room for the Volara - in these places Reflectix can be used by itself.

I have used Ethafoam which is closed cell and similar to Volara in price.

The air space is needed in conjunction with the foil barrier to create a radiant barrier.

From the attic foil link:

mitiempo 05-12-2012 01:24 PM

Re: Possible alternative to Reflectix?
 
I just checked Home Depot and Reflectix is $142 for a 48" x 50' roll! I have a roll this size that I bought last year for about half this amount.

Jgbrown 06-10-2012 01:20 AM

Re: Possible alternative to Reflectix?
 
Quote:

Originally Posted by mitiempo (Post 870452)
The attic radiant barrier foil is not much less expensive than Reflectix. And there are places on the boat that may not have the available room for the Volara - in these places Reflectix can be used by itself.

I have used Ethafoam which is closed cell and similar to Volara in price.

The air space is needed in conjunction with the foil barrier to create a radiant barrier.

From the attic foil link:

Then what good is reflectix, when people are putting it behind closed celled foam it is basically only a vapor barrier at that point? I agree for the places where spacing is hard, but for the most part, it seems like they were saying on frugal mariner that it was ok to have it touch the surfaces of reflectix(same as attic liner?)

mitiempo 06-10-2012 01:25 AM

Re: Possible alternative to Reflectix?
 
1 Attachment(s)
Jeremy

From the Frugal Mariner:

Jgbrown 06-10-2012 01:55 AM

Re: Possible alternative to Reflectix?
 
I remember that. What I don't get is where the difference is. They are both doing the same thing, one with bubble wrap, one with closed celled foam. If it doesn't work touching hull or foam without bubble wrap, why would it work any better with bubble wrap?
If reflective materials only work with air gap, the frugal mariner version doesn't work? If they work without it, then closed celled foam(skipping the bubble wrap) makes more sense anyways since it has a better R value. Or am I missing some extra property of reflectix?


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