Insulation

I'm a tiny bit suspicious of those silver multi layer foil insulation products. I'm not saying that they don't work, but it is noticeable that unlike other insulation materials they do not actually tell you what their R value is. They couch their performance in terms of "equivalent to...." which is a bit strange. Kingspan don't go on about what depth mineral wool their products are equivalent to, they just come straight out and tell you the R value.
Reading up on the 'Triso Super 10' it requires 25mm air gap on either side, so that gives a total thickness of 60mm, plus your finished surface on top. I can't help feeling that this particular method of installation is part of how it achieves its claimed performance, so just sticking it onto the hull might not do the exact same job as sticking on 210mm of mineral wool would achieve (which, btw, is the same performance as you would get out of 105mm of closed cell polyurethane)
 
Kelpie said:
I'm a tiny bit suspicious of those silver multi layer foil insulation products. I'm not saying that they don't work, but it is noticeable that unlike other insulation materials they do not actually tell you what their R value is. They couch their performance in terms of "equivalent to...." which is a bit strange. Kingspan don't go on about what depth mineral wool their products are equivalent to, they just come straight out and tell you the R value.
Reading up on the 'Triso Super 10' it requires 25mm air gap on either side, so that gives a total thickness of 60mm, plus your finished surface on top. I can't help feeling that this particular method of installation is part of how it achieves its claimed performance, so just sticking it onto the hull might not do the exact same job as sticking on 210mm of mineral wool would achieve (which, btw, is the same performance as you would get out of 105mm of closed cell polyurethane)
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I agree entirely. Having bought some of that foil covered bubble wrap stuff I used it on my heater ducting but it needed several layers to stop the warmth coming through to the outside. That was getting expensive so I tried using some ordinary bubble wrap which I had lying around and it was just as effective. The felt pipe wrap from plumbers merchants was the most effective, but obviously prone to waterlogging.

As you say, the claims for the foil stuff are suspiciously vague, and having tried it and compared it I can see why
 
Kelpie said:
I'm a tiny bit suspicious of those silver multi layer foil insulation products. I'm not saying that they don't work, but it is noticeable that unlike other insulation materials they do not actually tell you what their R value is. They couch their performance in terms of "equivalent to...." which is a bit strange. Kingspan don't go on about what depth mineral wool their products are equivalent to, they just come straight out and tell you the R value.
Reading up on the 'Triso Super 10' it requires 25mm air gap on either side, so that gives a total thickness of 60mm, plus your finished surface on top. I can't help feeling that this particular method of installation is part of how it achieves its claimed performance, so just sticking it onto the hull might not do the exact same job as sticking on 210mm of mineral wool would achieve (which, btw, is the same performance as you would get out of 105mm of closed cell polyurethane)
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I renovated my house a few years ago and read up a lot on insulation. There were some very heated threads on a few green building forums as to whether these multi foil products are any good. As far as I could gather they are effective, if, and it's a big if, they gave the air gap you mention but also are 100% sealed to air. If not then their performance is piss poor. Also their usual method of installation is battens, for the air gap, and staples. Neither very good to keep it air tight. I think they are popular as they are easy and take less space.
 
I also don't have a lot of faith in the metal foils. They may be good for radiant heat in an engine bay in combination with conventional insulation but not for general insulation. I too have done extensive research from a domestic point of view but marine applications have specific requirements. For instance I am still not sure how you deal with the bilges?
 
Aren't (some) Sadlers double skinned with a layer of foam, below the waterline? That would suggest that there's nothing inherently wrong about insulating below the waterline. I presume the difficulty is in preventing condensation and bilge water from soaking into the insulation, but for your new build you could conceivably do what Sadler did and seal it all away under a layer of fibreglass.
Good quality closed cell foam might be a good idea, as well, seeing as it shouldn't absorb any water.
 
Kelpie said:
Aren't (some) Sadlers double skinned with a layer of foam, below the waterline? That would suggest that there's nothing inherently wrong about insulating below the waterline. I presume the difficulty is in preventing condensation and bilge water from soaking into the insulation, but for your new build you could conceivably do what Sadler did and seal it all away under a layer of fibreglass.
Good quality closed cell foam might be a good idea, as well, seeing as it shouldn't absorb any water.
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Thats a possibility and if the GRP was only beneath the waterline it wouldn't add up to too much additional weight in a place that is problematic. It would, however, not add much structurally and cost significant time and money. It may also fail at some point and provide a void for water to sit in. I tend to be more of the 'keep it exposed' mindset so that if there is an issue you can fix it with minimal disruption. I don't mind cosmetic detailing but grp is pretty permanent unless you get our the angle grinder. I will think more about this, however, as it may be useful when integrating fuel and water tanks to afford them some insulation. The only alternative I can think of is to run the insulation at the level just below the cabin sole. That way it would not be in the bilges but would maintain a continuous wrap around the living accommodation. I will need to do more research into the pros and cons.
 
Kelpie said:
Reading up on the 'Triso Super 10' it requires 25mm air gap on either side, so that gives a total thickness of 60mm, plus your finished surface on top. I can't help feeling that this particular method of installation is part of how it achieves its claimed performance, so just sticking it onto the hull might not do the exact same job as sticking on 210mm of mineral wool would achieve (which, btw, is the same performance as you would get out of 105mm of closed cell polyurethane)
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Any insulation board or material used to enclose a heated space should have a ventilated air gap above it. It is nothing to do with improving R values (although each surface does add a bit), it is mainly to do with avoiding interstitial condensation. That is why the foil types and rigid boards should have taped joints to limit vapour passing through and condensing when it meets dewpoint. If you use Kingspan board at sarking level (i.e. over the rafters) you should counterbatten to create a 50mm airgap. Building regs permit Triso and the regs also demand a ventilated air gap in any 'warm roof' situation regardless of the product used.
 
I think you can use a breathable membrane and not have a ventilation gap. But that's a little OT for a boat forum :)
 
Keith-i said:
Any insulation board or material used to enclose a heated space should have a ventilated air gap above it. It is nothing to do with improving R values (although each surface does add a bit), it is mainly to do with avoiding interstitial condensation. That is why the foil types and rigid boards should have taped joints to limit vapour passing through and condensing when it meets dewpoint. If you use Kingspan board at sarking level (i.e. over the rafters) you should counterbatten to create a 50mm airgap. Building regs permit Triso and the regs also demand a ventilated air gap in any 'warm roof' situation regardless of the product used.
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Yes but regs are put together by fools. If you ventilate your insulation then it doesn't realy work. Much better to have vapour control layers or simply to use insulation that doesn't allow water ingress. You also need a trickle vent on a triple glazed window!!
 
pmagowan said:
Yes but regs are put together by fools. If you ventilate your insulation then it doesn't realy work. Much better to have vapour control layers or simply to use insulation that doesn't allow water ingress. You also need a trickle vent on a triple glazed window!!
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Exactly. Control where water vapor condenses and you do not need ventilation in the layers. I put an inverted flat roof on my office. There's no air gap as the water vapor cannot penetrate beyond the first taped layer of foil
 
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