Hi,

I am guessing that standard home insulation is not the normal for boats due
to trapped moisture and mold.

What should I use and where should I buy from?

thanks
marshall

Assuming you're insulating the boats living space (as opposed to the
refer / ice box)?

Yes, the Big Box home stores often have extruded polystyrene. (These
[nominally 2 x 8 or 4 X 8 sheets] are 'rigid foam' not at all like the
'cotton candy' fiberglass batting you may be thinking of, and are
available in thicknesses from 1/2 to 2" at your favorite home store).
There are two manufacturers: Dow's 'blueboard' and Owens Corning pink
'Foamular'.

Extruded polystyrene will not absorb moisture over time, and has the
same 'R' value on day one as on day N times 1.

Other 'foams' - and there are many (!) - may have a higher insulation
'R' value, but may not be as suitable on a boat because they're
somewhat hygoscopic and their insulation value will decrease over
time.

Extruded P. will 'melt' like the Wicked Witch of the West if it comes
in contact with solvents (Acetone, rubber cement, polyester resin), so
attaching it to a hull side (for example) may take a little
creativity.

MW

On 10 Feb, 01:05, "MarshallE" wrote:
Hi,

I am guessing that standard home insulation is not the normal for boats due
to trapped moisture and mold.

What should I use and where should I buy from?

If a metal boat you cannot go far wrong with PU 2 component spray
foam. Get the professionals in or buy Handi foam -but it is not much
cheaper.
http://www.luxe-motor-kei.co.uk/inte...e/image31.html

Your solutlion depends on the boat. Your choices are sprayed PU, styrofoam
sheet and rock wool. If the boat is metal, preventing condensation is the
overwhelming requirement to prevent corrosion, so a vapor barrier is also
needed. Please remember that sprayed PU is NOT closed cell so it absorbs
liquid. It is terrible to remove and in fire, the fumes are deadly. The same
is true for polystyrene, but it does not absorb liquid and contact cement
melts the foam. Rock wool is the best for large boats that require more than
3 in. of insulation. It can come with an infra-red and vapor barrier and it
is easy to replace if it gets wet. Additionally it has the best R rating as
well. It does not outgas, nor does it create deadly vapor in a fire.
Steve

"MarshallE" wrote in message
...
Hi,

I am guessing that standard home insulation is not the normal for boats
due
to trapped moisture and mold.

What should I use and where should I buy from?

thanks
marshall

There is also Soundown for engine rooms.
Depending on whether you are insulating against cold/heat or noise.
http://www.soundown.com/

"MarshallE" wrote in message
...
Hi,

I am guessing that standard home insulation is not the normal for boats
due
to trapped moisture and mold.

What should I use and where should I buy from?

thanks
marshall

Reflectix, the shiny, aluminized bubble wrap can be good for some
insulation applications. Used often in window shades in hot climates.
I've heard of folks adding it into their cabin-tops when replacing
headliners. If carefully glued and taped, it's also a vapor-barrier.
It is actually aluminum-coated, leaving black marks on things it rubs
against, and might be of some concern for galvanic interaction with
other metals.

Aaron
www.navagear.com - the gear and gadgets blog for cruisers
s/v Sweet Destiny