Steel hull isolation: alternatives to foam?

Hi Majay,

Insul-Coustic on Fenton road in Ottawa sells Armaflex products. There is also a distributor in Montreal.

Cheers,
Mark

 

To which product does this refer Brent?

 

Thanks for the info, Mark. It's going to be one hell of a job to get it out of there... it's on the deckhead, ceilings...all over the place.

 

All foams that come in spray cans.

 

Apologies in advance for slight thread hijack.

Is there a good insulation alternative that is lighter than Armaflex for those of us who have to be weight conscious?

While I'm not advocating polystyrene as boat insulation, Armaflex will be slightly thicker and more than twice as heavy for the same insulation value, which is a bit off-putting for an expensive product.

Of course this will be slightly offset by the fact that elastomeric foams can be used without an inner lining in some areas, while PS or PU foams cannot.

Suggestions?

 

Foams that can't be sprayed in get heavy condensation behind them, regardless of any attempts to get a vapour barrier , leading to serious corrosion.
A friend said he was quoted $2500 to get his 36 footer spray foamed , but found he could buy a kit and do it himself for $1500. It will be interesting to see how it works out.
The foam comes in a couple of pressure cans, which look like propane bottles.

 

Sorry Brent for contradicting.

Armaflex does NOT allow condensation between foam and hull! It was designed and produced to avoid exactly that. And it has proven to be the best stuff available for this purpose, though it is by far the most expensive too.

Regards
Richard

 

How do you guarantee airtightness around the edges? I was never able to achieve it, nor have others I know, who tried everything.

 

It does´nt need to be airtight. A few square centimeter of open surface in the entire hull do´nt build up condensate to worry about.

More important is to seal the frames (usually with a thinner covering) before one applies the hull insulation. You otherwise have the condensate on the full length of the frames, collecting in the bilge.

Regards
Richard

 

I have found that an uninsultated piece of steel the size of your little fingernail wil drip like a faucet if it is not covered.
That is extremely hard to accomplish without spray foaming.

 

Yesterday it had to be airtight..............

now a cm² drips like a faucet.........

may I repeat:
A few square centimeter of open surface in the entire hull do´nt build up condensate to worry about.

A adult person of about 75kg or 150 pounds, sweats out more then one liter of water at night. That humidity gets assimilated in the air and wood and decoration textiles in your stateroom, is then transported outside with every sufficient ventilation.

Do you really assume the 20ccm of water which can drip from a 10 cm² open surface over one day cannot?

 

I am considering an insulating paint; the kit comes with a sprayer. One coat to control condensation and then add sheet insulation as needed for more radiant or sound insulation. Has any one done this. The boat is aluminum.

 

Not to worry about , unles the drip is directly over your bunk, or your books , or your clothes, etc etc.
As it only takes a 2 degree difference in temperature to get condensation , it woud take enough ventilation to make the inside air the same temperature as outside to avoid condensation.
I have several friends living aboard in BC who thought they could solve the condensation problem with lots of ventilation. It rained harder inside their boats than outside, and during cold snaps the boat was coated inside with a layer of solid ice, except over the heater, where it rained constantly.
I made the same naive asumption in my early 20's . No one could tell me otherwise. Boy, what a miserable winter that was.
Since I spayfoamed ,I have lived aboard comfortably in many BC winters for 34 years

 

The stainless pipes on my cowl vents used to drip condensation ,so I used the insulating paint on them . It stopped the drip in normal conditions , but not while cooking. It has nowhere near the insulating abilities advertised, but it helps a bit.
Will it work enough to let you use sheet foam over it ?It would be nice if it did, but your guess is as good as mine. I'd say 50/ 50 chance of it working.

 

Even that won't avoid condensation. The water is often colder than the air, which turns any uninsulated, or insulated but not airtight, steel below the waterline into a fairly efficient water condenser, kind of like a giant dehumidifier.