foil bubble insulation / radiant barrier ??

[onionbargee]

anyone know anything about this stuff, i'm insulating a steel n.b right now, i have a load of it i was given left over from a building site, but it looks like it has no place in a boat, i'm guessing its radiant barrier , and not insulation as such ?

 

i have loads of celotex board going in, so if i don't use it i'm not bothered, is it any use to me ? under the floor ?

[Grace and Favour]

have used foil bubble insulation in between the two surfaces of our wheelhouse (detachable) roof

 

I was able to use 4 layers of double bubble (luvly jubbly!)

 

It has made an enormous difference - we don't even get condensation on the inside of the roof now - - (and in winter we used to get a layer of ice).

 

So yes - put it in between the Celotex and your lining

[Ex- Member]

It isn't insulation as you suggest and is no better than any other insulation at the same thickness. I posted this on another thread earlier in response to someone suggesting a layer of this stuff was equal to 50mm of polystyrene.

Many have been duped by this nonsense, bubble foil is no better than any other insulation at the same thickness, in fact it isn't even an insulation material. The R values for this product are highly misleading, as an insulation it is actually only R-1 if you calculated it as an equivalent to proper insulation. If you want to know some truth about this product I would read hear. It certainly wouldn't be applied on my boat even if it was cheap. It does have it's uses and is a decent enough product for certain applications as this website points out.


http://www.just-insulation.com/productselection.html

And your assumption it's unsuitable for boats is also correct.

ETA

Cellotex is good stuff fill the cavities full of it and seal gaps with spray foam, I would also use it on the floor and with hindsight I wish we had done so even if only thin sheets between floor joists. Also when you cut off the spray foam flush with the surface tape over with Aluminium tape which will ensure the vapour barrier, I also taped over timber battens.

Edited May 9, 2013 by Julynian

[onionbargee]

link gets me back to this page !

[Ex- Member]

link gets me back to this page !

Apologies, try this

 

http://www.just-insulation.com/productselection.html

 

Scroll down to

 

Are there downsides to bubble foil insulation?

Edited May 9, 2013 by Julynian

[onionbargee]

Anyone want a load of bubble foil ?

[Ex- Member]

Anyone want a load of bubble foil ?

 

Although people pay stupid money for this stuff, so e-bay it

 

This you tube clip explains the scam regarding R values, the Irony is that in certain conditions if you remove the bubble wrap from the foil, the foils reflective element of the product works better without the bubble and it could be purchased at a fraction of the cost of the stuff glued to bubble wrap , you couldn't make it up really could you

 

[smileypete]

Having a layer or two of bubbles, or foam, or quilt between 2 foils definitely is better than a single layer of foil, unless the laws of physics have changed recently.

 

But more importantly it helps prevent or reduce the risk of condensation buildup on one side of the insulation. Somehow the guy in the video selling foil omits to say that, wonder why?

 

Anyway for OB it might be best to use the Celotex board firstly, and if there's not enough to go round use the bubble foil where it works best, and if there's lots then layer it up where poss as GnF has done.

 

cheers, Pete.

~smpt~

Edited May 10, 2013 by smileypete

[Ex- Member]

Having a layer or two of bubbles, or foam, or quilt between 2 foils definitely is better than a single layer of foil, unless the laws of physics have changed recently.

 

But more importantly it helps prevent or reduce the risk of condensation buildup on one side of the insulation. Somehow the guy in the video selling foil omits to say that, wonder why?

 

Anyway for OB it might be best to use the Celotex board firstly, and if there's not enough to go round use the bubble foil where it works best, and if there's lots then layer it up where poss as GnF has done.

 

cheers, Pete.

~smpt~

 

Having a layer or two of bubbles, or foam, or quilt between 2 foils definitely is better than a single layer of foil, unless the laws of physics have changed recently.

 

But more importantly it helps prevent or reduce the risk of condensation buildup on one side of the insulation. Somehow the guy in the video selling foil omits to say that, wonder why?

 

Anyway for OB it might be best to use the Celotex board firstly, and if there's not enough to go round use the bubble foil where it works best, and if there's lots then layer it up where poss as GnF has done.

 

cheers, Pete.

~smpt~

Hi Pete

 

That's the point though this stuff only works when used in a large air cavity and then it's the air in that cavity actually making up the r value, but the reflective value works better in that situation. If the the foil is close to anything other than proper insulation like celotex then it's less efficient. Bubble wrap is not insulation.

 

Used in I tight cavity it is no better than any other insulation at the same thickness but it's prone to condensate. I certainly wouldn't consider it from what I've read from reputable sources.

 

Like you say celotex would be far superior.

 

If you go to a proper insulation dealer you might be able to get Celotex in really thin sheets between 6 and 20mm. When they make it in the factory it's formed in giant blocks and then sawn to required thickness usually 50mm + sheets, they skim a thin layer off the top first to have a perfectly square & flat surface for foil adhesion and there's usually always a thin bit left on each block, they still cover these thinner slices in foil both sides and they use these thin sheets on the tops and bottoms of pallet loads to protect the edges of all the good sheets. Most dealers keep this stuff and often sell it off cheaper. Our whole boat is lined with 10 to 12mm Celotex on top of 50mm Rockwool, I paid around a fiver a sheet 8x4, sheets are often creased though and torn foil, but buy a decent roll of foil and patch up.

 

Keep your eyes open though some dealers just throw it out but then it's usually broken down into smaller pieces and disposed of in bins & skips.

[Alastair]

I've used it in older boats - it works well applied under floorboards, tacked to the floorboards. Reduces drafts while still allowing air circulation next to the skin of the hull.

 

Also use it behind radiators and heating pipes - reflects heat back into a room.

 

Saying it "isn't insulation" is clearly nonsense. Go outside and lie down on some cold concrete for 5 min. Now try it with a layer of the silver bubble wrap below you. There is more than a slight difference.

[Ex- Member]

I've used it in older boats - it works well applied under floorboards, tacked to the floorboards. Reduces drafts while still allowing air circulation next to the skin of the hull.

 

Also use it behind radiators and heating pipes - reflects heat back into a room.

 

Saying it "isn't insulation" is clearly nonsense. Go outside and lie down on some cold concrete for 5 min. Now try it with a layer of the silver bubble wrap below you. There is more than a slight difference.

 

Clearly you've been duped too, as you clearly don't understand the difference between reflective materials and materials that prevent the transfer of heat. The experts in the field are the ones saying it's not insulation and aluminium foil isn't insulation either.

 

Reflecting heat isn't insulation.

[Alastair]

I followed your link and read it.

 

Nothing in there says bubble foil isn't insulation. In fact, it explains where it is appropriate to use it (funnily enough, it's the situation I described but in a house rather than a boat).

 

Two products. Both slow down loss of heat. They work by different methods (one reflects heat, the other slows transmission). End result is the same. Slowing down loss of heat. I call that insulation.

 

There is much better insulation to use than bubble foil. Sprayfoam has definite advantages. There are also situations where bubble foil is suitable.

[Ex- Member]

I followed your link and read it.

 

Nothing in there says bubble foil isn't insulation. In fact, it explains where it is appropriate to use it (funnily enough, it's the situation I described but in a house rather than a boat).

 

Two products. Both slow down loss of heat. They work by different methods (one reflects heat, the other slows transmission). End result is the same. Slowing down loss of heat. I call that insulation.

 

There is much better insulation to use than bubble foil. Sprayfoam has definite advantages. There are also situations where bubble foil is suitable.

 

Blimy, I just hope you don't fit insulation for a living. I would do some more research if I were you.

[smileypete]

Blimy, I just hope you don't fit insulation for a living. I would do some more research if I were you.

 

Now now, toys back in pram!

 

Thing is that R value measures conductive heat loss, so it's not really appropriate for bubble foil type stuff on it's own unless it's part of a built up construction. I expect the more reputable foil insulation makers give all the details of this to back up their claims.

 

Anyway it's not that hard to make a 'hot box' from offcuts of Celotex, then test different insulation out and see how it does.

 

ETA Something else to bear in mind is that the the cheaper foil type stuff doesn't deaden sound at all well compared to insulation boards, but that shouldn't be a problem if it's used under floor or in conjunction.

 

cheers, Pete.

~smpt~

Edited May 10, 2013 by smileypete

[onionbargee]

Seeing as the boards i have are foil covered i can't see any use for the bubble wrap.

 

in my opinion spray foam iv'e seen is usually thinner than an inch , and despite what they sat foam insulation gets better up to over 300mm thick, as is used in some super insulated houses now, so i wouldn't bother with it unless they can garentee thickness.

Edited May 10, 2013 by onionbargee

[Ex- Member]

Seeing as the boards i have are foil covered i can't see any use for the bubble wrap.

 

in my opinion spray foam iv'e seen is usually thinner than an inch , and despite what they sat foam insulation gets better up to over 300mm thick, as is used in some super insulated houses now, so i wouldn't bother with it unless they can garentee thickness.

 

Hi Onion

 

Bubble wrap could sweat/condensate, that's why there are many problems with certain type installations and manufacturers claims about foil wrap have been disproven world wide.

 

A good optimal thickness for spray foam is 50mm 2 inch, as you go thicker from this you gain very little additional insulation value even up to 300mm thick, but 500mm gives you 90% insulation I recall.

50mm is what should be aimed for and more importantly should be applied evenly all over.

 

This is why Celotex k/span etc is a good option glued to the hull and spray foamed in with aerosol & gun and sealed in with alloy foil. If I were to ever to it again it would be in this manner.

[onionbargee]

just what i'm going to do, though my sheets are 40mm, i might double up, up to the gunwales.

[Ex- Member]

just what i'm going to do, though my sheets are 40mm, i might double up, up to the gunwales.

 

 

Good idea, I used some thicker celotex on top of the Rockwool below the gunwale, but I wish I had done more though, although the boat is lovely and cosy and stays warm with just 1kw of heat at just a couple of degrees, I could have done even better, once you've lined out though it becomes too late to add more insulation easily. With hindsight I was just being a tight arse.

 

There are some things not worth scrimping on, and insulation is top of the list, put as much in as you can afford, at the end of the day it saves money long term and will pay for its self over a few years.

 

If you get 80mm thick under the gunwale, that's pretty much there around 95% efficient just over 3 inches. As you'll see from the chart, even adding 4 more inches will only gain another 5%

 

Bear in mind also you have reflective properties in the foil, and sealing it all with foil ensures a good vapour barrier although it's not so important with urethane products.

 

 

 

[onionbargee]

i got a shed load off a demolition site for a tenner to the foreman, no shortage. Taping all the seams with foil tape, and filler foaming all the gaps, DPM behind all the battens.

 

what do you reckon for the floor ? Iv'e plenty of headroom, as i'm only 2 slabs high on the ballast. I could use the bubble foil ?

[Ex- Member]

i got a shed load off a demolition site for a tenner to the foreman, no shortage. Taping all the seams with foil tape, and filler foaming all the gaps, DPM behind all the battens.

 

what do you reckon for the floor ? Iv'e plenty of headroom, as i'm only 2 slabs high on the ballast. I could use the bubble foil ?

 

 

If you can get celotex under the floor all good and well. I laid 3x2 joists flat on steer bearers, I could have easily placed celotex between those timbers at 50mm thick. Again I now wish I had, ok heat rises, but the floor is quite cold and where we have a natural cherrywood floor laid in boards it's surprising the draught that rises through the butted joints, I should have insulated and also tongue & grooved the cherrywood.

 

We use a good quality rug in the winter which solves the problem, but of course insulation laid in the first place would have saved all the hassle. I would say the 40mm thickness you mentioned would amply suffice for the floor, remember though some ventilation needs to come from the bilges, good air circulation is important also. We can draw cold air from the bilges which blows up behind the fridge, We also have fans under the bed which keeps the sleeping area aerated and fresh. Just 4 inch comp fans, 2 under fridge and 2 under bed 0.1 amp each I think.

[Alastair]

This is why Celotex k/span etc is a good option glued to the hull and spray foamed in with aerosol & gun and sealed in with alloy foil. If I were to ever to it again it would be in this manner.

The glue to the hull and spray foamed in is absolutely vital.

 

All insulation has a dew point somewhere in it (the point at which temp drops enough that the hot air cools so that the moisture condenses). Sealed (eg spray foamed) insulation doesn't suffer from this as it isn't moisture-permeable.

 

It is absolutely essential that the insulation is sealed to the hull completely. If it isn't sealed, then it's better to have less insulation and more air flowing next to the hull.

[davey b]

You should be aware (if not already) that there are two levels of this silvered bubble wrap. B&Q do some stuff for about £15 for 15m x 600mm & screwfix have something that looks similar for about £100 for 25m x 1m.

 

We've used the cheap stuff as a liner between the spray foam and the ply wood before the decorative layer (t&g ash). It does make a slight difference, if only by bridging or filling drafty gaps. I wouldn't pay the higher price.

 

 

It stops them stealing your thoughts, too!!!