Boat insulation: Armaflex vs closed cell foam?

Tim Good

Tim Good

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I’m replacing the polystyrene in thenroof of the coachroof with a better insulation in preparation for a trip to high latitudes.

Now most people recommend Armaflex but it’s incredibly pricey. £150 for just 3sqm.

Now you can also buy online stuff that looks the same and calls itself sound proofing. It’s still closed cell foam and appears to be the same but way cheaper.

Are we just paying loads for the Armaflex name?
 
I’m replacing the polystyrene
[/QUOTE]
Yes wise too.
Burns like crazy and releases toxins.
.
Used a propane powered flame / diy soldering kit for copper pipes to ignite insulation before fitting to our steel sailboat.
The polyurethane foam we used claimed tgo be fiore retardant.
.
It was,
then after it was installed the foam was sealed with 3 coats of bathroom paint which has I believe anti fungal qualities for use in wet spaces.

The paint was used to
enhance fire resistance.

The pu foam was blown in by a contractor.
 
Yes!
We insulated our previous boat with sheet closed cell foam. It is similar to the camping mats you can buy. We used 3 layers of 6mm on the cabin roof and 2 layers on the hull. We bought it in 8’x4’ sheets. It made a huge difference to the warmth of the boat and made the Dickinson Diesel heater far more effective.
We then covered it with vinyl
 
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Insulation is a long way down our refit jobs list... but when we get there, I’ve been contemplating eBay as a source of closed cell vehicle insulation. The bigger sellers (e.g. ‘car-insulation-uk’) claim to provide UK fire certification, which would be my main concern.

We plan to insulate our entire 42ft boat above the waterline, so camping mats or flooring won’t cut it (or remain economical at that scale). Armaflex and similar are just unviable, as the OP suggests.

My main concern with the eBay/Amazon varieties is that they all seem to be self adhesive. I’m not sure how this would hold out, especially with hotter days/climes?

If anyone can source similar fire retardant closed cell foam, without the adhesive, that would be my favoured solution (with Hawke House adhesives).
 
dankilb said:
Insulation is a long way down our refit jobs list... but when we get there, I’ve been contemplating eBay as a source of closed cell vehicle insulation. The bigger sellers (e.g. ‘car-insulation-uk’) claim to provide UK fire certification, which would be my main concern.

We plan to insulate our entire 42ft boat above the waterline, so camping mats or flooring won’t cut it (or remain economical at that scale). Armaflex and similar are just unviable, as the OP suggests.

My main concern with the eBay/Amazon varieties is that they all seem to be self adhesive. I’m not sure how this would hold out, especially with hotter days/climes?

If anyone can source similar fire retardant closed cell foam, without the adhesive, that would be my favoured solution (with Hawke House adhesives).
Click to expand...

The main issue I’ve found with some of the foam online or on ebay is that isn’t opencell or if it is closed, its rigid.
 
...some are foil faced and other plain foam. But all seem to be adhesive, whereas I’d prefer to glue it myself.

I might use the eBay adhesive type where they’d be above panels that make up the ‘ceiling’ and a hawke house product with their recommended adhesives for any areas of headlining glued direct to GRP (some of which have compound curves etc).

Whether the adhesive type would hold up in lockers etc. is the outstanding question for me. I’ve heard it suggested that additional adhesive can be added to self-adhesive surfaces. Apparently spray on contact adhesive works.
 
Ive used the 10mm foil faced self adhesive and it often comes unstuck but the surface is as sticky as when it was new. Maybe it needs a very smooth shiny surface to stick properly ?
Have also found the spray glue fails after a year or two, maybe spray glue needs to be a good brand rather than cheap supplies ?
 
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I used 5mm foil faced closed cell insulation on the inside of the walls of my hot tub to improve it's energy consumption, I also used rockwool packed and sealed in heavyweight plastic bags to fill in the awkward shaped spaces around the tub as the blown foam looked more like someone had just farted it in :)
All in all the spray on adhesive on the sheets of insulation gave up after about 18months, the tub is in quite hard conditions with the water in the tub getting up to 40c while the outside is -15c but the insulation works well and I can maintain a 28c temp with just running the circulation pumps for an hour or so every day, the heat generated by the pumps trapped in the "box" means I only have to heat the tub a little when we want to use it.
 
samsonioni said:
Try Plastazote. Fireproof, bendable, closed cell, not expensive. Worked brilliantly for me.
Click to expand...
Good tip. Looks like the ‘-FR’ suffixed versions are flame retardant. I could only find a price with a minimum order of 15 sheets (30m2), but that worked out about £15 per metre, so not bad for something that looks quite ‘high grade’.

It calls itself a ‘block foam’ though, so I wonder how well it would conform to curves etc.? Any experience of adhering it to compound curves?

You hear of all kinds of ‘proper’ adhesives failing when exposed to the heat of the sun on GRP mouldings and the general rigorous of ‘marine environments’ so it doesn’t surprise me to read that the vehicle type adhesive foams come unstuck.
 
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