superstructure thermal insulation Q

[vas]

evening all,

almost over upholstering the bow cabin, got to do some little tidying up and putting everything together.
However, I want to insulate the "ceiling" so to speak of the whole cabin which in effect is the bow sundeck, plus the side decks to the bow.
Now, Versilcraft originally used 30mm thick rigid strips of expandable polystyrene. That's the white stuff, flexes a bit, rubs into small round balls 4-5mm in dia. Not highly regarded for its thermal properties.

The two options I'm considering are:

A.
Dow Styrofoam 50mm thick. That's extruded polystyrene foam in rigid slabs. You can cut with a Stanley knife, not easily squeezed between the frames. Generally messy.

B.
Rockwool 50mm thick 300kg/whatever (i.e. the dense one) Easier to handle and squeeze in place. Probably slightly better thermal insulation properties due to less cold bridges left behind after fitting.


Yes, I know as I present the options, B is a clear winner (and I've got 2-3 slabs leftover from my house rebuilt 8yrs ago in the garage doing nothing...)
The Q is, any reason I shouldn't use Rockwool there, anything else better, cheaper, more efficient, etc?
BTW, main concern is protection from the heat and not the cold.

I did investigate the reflective films and all that theory with bubble wrap on either side, but the problem is that its rather dense framing (250-300mm centres) and I need to find a way to get the hot air escape from between the 12mm ply sundeck and the reflective film.

ideas?

cheers

V.

 

[MrB]

I had a sample of insulation sent me yesterday and i'm very impressed with it. They do insulation and sound deadening for exterior and interior use, non combustable and with Microban. Maybe worth a look.

http://www.armacell.com/WWW/armacell/INETArmacell.nsf/standard/B8367F773A73C70A8025778C003728C7


NB* I have no connection with this company*

 

[rbcoomer]

Have you looked at Celotex? Although I've not used in a marine environment, I've used this in lofts and it's very effective: http://www.insulationexpress.co.uk/Product.asp?gclid=CJTKvoC0rr0CFY_ItAodZXwAvg Don't know if you can get there or not? If you cut approx 1mm oversized, you can wedge in and it's rigid enough to stay - even in large areas.

 

[vas]

thanks for the suggestions,

MrB, armaflex (at least in Greece) is only available for pipe insulation (or duct insulation) Browsing through the resources available, couldn't find slabs for my needs

Robin, didn't even know Celotex, definitely not available in Volos, will check if I can get in Athens, but the idea of the foil means I pay more and wont get the proper functionality of the foil due to placement restrictions (as explained in my first post)

Any other ideas?
Ah, and any reason for NOT using rockwool?

cheers

V.

 

[lambohill]

Hi Vas, here in chilly Ireland / uk we use the following in order of performance;
1. PUR board such as Kingspan or Celotex as mentioned earlier. This is generally foil faced, but it is regarded as the best 'thin' insulation.(also available bonded to boards.)
2. Extruded 'dark grey';polystyrene. About 30-40% thicker than PUR to get same results, but better value for only modest increased design thickness.
3. Rockwool. Cheap and cheerful, but you can get it into difficult spaces, so we tend to use it in difficult access situations and where we have plenty of space as it requires about four times the thickness of PUR to achieve same performance.
5. Glassfibre. Like rockwool thermally etc, but cheaper and needs kept dry, useless once wet.

Negative on Rockwool is its relatively low performance / thickness and some v. similar quilt products do not like dampness.

 

[rbcoomer]

thanks for the suggestions,

MrB, armaflex (at least in Greece) is only available for pipe insulation (or duct insulation) Browsing through the resources available, couldn't find slabs for my needs

Robin, didn't even know Celotex, definitely not available in Volos, will check if I can get in Athens, but the idea of the foil means I pay more and wont get the proper functionality of the foil due to placement restrictions (as explained in my first post)

Any other ideas?
Ah, and any reason for NOT using rockwool?

cheers

V.

Hi Vas,

The advantages of Celotex would be weight & cost (about 1/5th of Styrofoam). I used a 25mm thickness for loft and wedged at the lower edges of the rafters, leaving an air-gap above. Rockwool is ok I suspect, but would it absorb/retain any moisture/condensation? (I have it in between sterling board and corrugated roof on workshop and it does absorb water if there's any ingress!)

Hopefully you'll get some more suggestions...

Regards,

Rob

 

[MrB]

thanks for the suggestions,

MrB, armaflex (at least in Greece) is only available for pipe insulation (or duct insulation) Browsing through the resources available, couldn't find slabs for my needs


V.

I don't know if that "OEM applications" tab was on the Greek site http://www.armacell.com/WWW/armacell/INETArmacell.nsf/standard/6212EAB1DC817AB5802576CE004B1F89

Maybe worth a call and see if they can send you some samples to try?

 

[Dill et Bound]

+1 for Celotex.. If you can get it.
About 35 years ago I was involved in the building of 6 Oil Rig support craft. Use for transporting staff.. for the Persian Gulf.
They were Steel.
However they had Aluminium superstructures.
When they arrived in the workshop you could not believe what had been done to insulate them.
They had used a sprayed on, 2 part foam that had been applied to about 4 to 6 inches thick all over the deck heads and superstructure sides.
It all had to be cut back to the frames, with old saws, and fitting the services,ie wiring etc was a nightmare.
However it was brilliant insulation for that heat.
Now I am not suggesting going down to your local DIY store and purchasing 50 cans of spray foam,but as Rob says Celotex, which is basically the same in sheet form will I am sure do a great job.
There is also another type of sheet foam called Wedi Board, Tilers use it, but I am not sure of its insulation properties..

 

[rustybarge]

Hi Vas,

A very strong caveat: If you push sheets of foam insulation up between the frame, condensation will form behind the styrene, then drip down on your head while you are sleeping.

When i was building my boat a very nice fellow boat owning neighbor used to drop by for a chat about my boat project, he always said 'you're going to spay insulation on the ceilings aren't' you?' Never understood why he kept on repeating it!!!
Of course with one thing and another, I was in such a rush to get the boat launched that I decided to use foam sheets pushed up between the frames, I thought ' that will do fine, it's exactly the same insulation qualities as spray on'

As you can guess, I have regretted not using spray on foam ever since. To do it now i would have disassemble the wooden ceiling.
Also remember a very small temperature difference between the outside temp and the inside temp will produce gallons of condensation.......:ambivalence:

Hey Vas, 'you are going to use spray on foam aren't you?'

 

[Dill et Bound]

Yes Vaz use the spray foam.
Even back then they must have known about condensation problems.

 

[vas]

Hi Vas, here in chilly Ireland / uk we use the following in order of performance;
1. PUR board such as Kingspan or Celotex as mentioned earlier. This is generally foil faced, but it is regarded as the best 'thin' insulation.(also available bonded to boards.)
2. Extruded 'dark grey';polystyrene. About 30-40% thicker than PUR to get same results, but better value for only modest increased design thickness.
3. Rockwool. Cheap and cheerful, but you can get it into difficult spaces, so we tend to use it in difficult access situations and where we have plenty of space as it requires about four times the thickness of PUR to achieve same performance.
5. Glassfibre. Like rockwool thermally etc, but cheaper and needs kept dry, useless once wet.

Negative on Rockwool is its relatively low performance / thickness and some v. similar quilt products do not like dampness.

thanks LH,

1. doesn't seem to be easily obtainable down here, may have to go to Athens (and I'm NOT!)
2. yes, fine but difficult to handle, cut, fill gaps, best avoid!
3. true λ=0.04 compared to λ=0.02something for the fancy ones.
5. definitely avoid due to your last point, well aware of this issue.

Now, I do think you are talking from a completely different perspective from up north
I don't want insulation to keep me warm in the winter (I'll be at home 400mt away from MiToS with a fireplace and GCH )
I want to keep the cabins and salon/lower helm cool/bearable during July -Sept. Best I've recorded last year with the boat on the hard was 46C IIRC

Hi Vas,

The advantages of Celotex would be weight & cost (about 1/5th of Styrofoam). I used a 25mm thickness for loft and wedged at the lower edges of the rafters, leaving an air-gap above. Rockwool is ok I suspect, but would it absorb/retain any moisture/condensation? (I have it in between sterling board and corrugated roof on workshop and it does absorb water if there's any ingress!)

Hopefully you'll get some more suggestions...

Regards,

Rob

I don't know if that "OEM applications" tab was on the Greek site http://www.armacell.com/WWW/armacell/INETArmacell.nsf/standard/6212EAB1DC817AB5802576CE004B1F89

Maybe worth a call and see if they can send you some samples to try?

MrB, Greek companies under severe recession don't quite work as you'd expect. No way I'd get a dealer sent me samples of material. Most likely wont even have any in stock and I'd pay in advance to get it...

+1 for Celotex.. If you can get it.
About 35 years ago I was involved in the building of 6 Oil Rig support craft. Use for transporting staff.. for the Persian Gulf.
They were Steel.
However they had Aluminium superstructures.
When they arrived in the workshop you could not believe what had been done to insulate them.
They had used a sprayed on, 2 part foam that had been applied to about 4 to 6 inches thick all over the deck heads and superstructure sides.
It all had to be cut back to the frames, with old saws, and fitting the services,ie wiring etc was a nightmare.
However it was brilliant insulation for that heat.
Now I am not suggesting going down to your local DIY store and purchasing 50 cans of spray foam,but as Rob says Celotex, which is basically the same in sheet form will I am sure do a great job.
There is also another type of sheet foam called Wedi Board, Tilers use it, but I am not sure of its insulation properties..

thanks will check for polyurethane flex slabs - not that I've seen any down here.

Hi Vas,

A very strong caveat: If you push sheets of foam insulation up between the frame, condensation will form behind the styrene, then drip down on your head while you are sleeping.

When i was building my boat a very nice fellow boat owning neighbor used to drop by for a chat about my boat project, he always said 'you're going to spay insulation on the ceilings aren't' you?' Never understood why he kept on repeating it!!!
Of course with one thing and another, I was in such a rush to get the boat launched that I decided to use foam sheets pushed up between the frames, I thought ' that will do fine, it's exactly the same insulation qualities as spray on'

As you can guess, I have regretted not using spray on foam ever since. To do it now i would have disassemble the wooden ceiling.
Also remember a very small temperature difference between the outside temp and the inside temp will produce gallons of condensation.......:ambivalence:

Hey Vas, 'you are going to use spray on foam aren't you?'

RB, NO definitely WONT spray foam!
as noted to LH, it's summer use I'm after, so highly unlikely to have condensation issues in July in the med.

If I wanted to use foam I'd have to do it before upholstery, If I do it now I'll make a mess of the lot


Went to a shop specializing on that sort of thing and had a look at this http://www.metaxiotis.gr/en/1-Προιόντα/sort-products/B.2 Mineral with ECOSE Technology. Looks like nicely weaved rockwool, and they do a version with a reflective alu foil (on one side). My gap is 52-55mm so it looks like I'll get a roll of 30mm thick foiled one so that I can have a 20mm gap between the 12mm ply and the insulation. Price is under 4euro/m2 whereas a ricofon (sp?)type of insulation with a better λ value works up to 18euro/m2.

So looks like it's going to be this unless I find some foam slabs going cheap.

cheers

V.

 

[rustybarge]

I'll get a roll of 30mm thick foiled one so that I can have a 20mm gap between the 12mm ply and the insulation.

Not too sure about the weather in Greece, but here in The S. of France it can get quite cold in the winter.
If you leave an air gap in the insulation the change in temp will cause severe condensation. If I had to guess you may run into trouble because plywood does not offer much insulation.

I think the rockwool would get wringing wet after a cold winter.

 

[vas]

Not too sure about the weather in Greece, but here in The S. of France it can get quite cold in the winter.
If you leave an air gap in the insulation the change in temp will cause severe condensation. If I had to guess you may run into trouble because plywood does not offer much insulation.

I think the rockwool would get wringing wet after a cold winter.

It can get as cold as it wishes in the winter, I'll be at home
Good thing with rockwool compared to glasswool is that once it dries it's all up and running, good as new (especially as it's flat and not upright)
If I get my facts right, no occupation, no heating means no condensation in the winter. So I'm fine.

cheers

V.