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Rockwood or 25mm Kingspan


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https://www.ebay.co.uk/itm/Gold-Laminate-Floor-Underlay-Heat-Insulation-Wood-Acoustic-Flooring-Imperfection/183835644609?var=691480826714&_trkparms=ispr%3D1&hash=item2acd7552c1:m:mkSMd3c7aSw3pVIjSlLch7w

 

Ive used this under floor in a campervan recently seems slightly better than the foil options mentioned. I decided against spray foam as was under the impression it would be expensive as a DIY option 

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15 minutes ago, Rose Narrowboats said:

 

Probably because even the article you quoted accepts it has an R value of 1 when in direct contact. Other reasonable sources quote 1.1.

 

25mm Polystyrene has R value of between 0.6 and 0.7, so that extra 3mm of insulation has almost trebled the total insulation value.

 

Kingspan has an R value of 1.1 - but it seems it is generally accepted that it degrades with age and is equivalent to polystyrene after 10 years.

 

Sprayfoam has an R value of 1.2(ish) which is fine and dandy until you want to get at a rivet or do a welding repair.

 

 

No, expanded polystyrene has an R value if around 3.8-5 for 25mm (depending on density and temperature). Polyurethane sheets (kingspan etc) about 6. So you would have got a very similar benefit from adding 3mm of kingspan (although to be fair, that would be tricky!).

 

You are quoting R values for things like spray foam, without specifying the thickness. 25mm sprayfoam is around 4 to 8 depending on exactly what it is.

9 minutes ago, TheSaintlyOne said:

https://www.ebay.co.uk/itm/Gold-Laminate-Floor-Underlay-Heat-Insulation-Wood-Acoustic-Flooring-Imperfection/183835644609?var=691480826714&_trkparms=ispr%3D1&hash=item2acd7552c1:m:mkSMd3c7aSw3pVIjSlLch7w

 

Ive used this under floor in a campervan recently seems slightly better than the foil options mentioned. I decided against spray foam as was under the impression it would be expensive as a DIY option 

Yes more expensive than kingspan sheeting or rock wool, but much quicker. You don’t necessarily have to DIY, it can be messy! But you can get a man (person) in to do it. Depends on whether your time costs money or is free! 

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3 minutes ago, nicknorman said:

No, expanded polystyrene has an R value if around 3.8-5 for 25mm (depending on density and temperature). Polyurethane sheets (kingspan etc) about 6. So you would have got a very similar benefit from adding 3mm of kingspan (although to be fair, that would be tricky!).

 

You are quoting R values for things like spray foam, without specifying the thickness. 25mm sprayfoam is around 4 to 8 depending on exactly what it is.

Apologies - I've just amended my post to clarify I was talking about 25mm of sprayfoam.

 

Your research has obviously thrown up some very different figures to mine.

 

Source for the expanded polystyrene (who recently took over our local supplier, Warren Insulation): https://www.insulationshop.co/25mm_polystyrene_insulation_eps_70.html

 

Source for the Kingspan: https://www.insulationshop.co/25mm_thermawall_tw55_pir_insulation_board_kingspan.html

 

Source for the sprayfoam: http://www.puservices.co.nz/polyurethane-spray-foam

 

I've seen the wiki page claiming up to R-6 for sprayfoam, but haven't seen any installers claiming it.

 

Based on having pretty well all types of insulation across the hire fleet over the years, there's no doubt sprayfoam is the most effective, but on a cost/benefit analysis the polystyrene/foil bubble wrap combination has been most satisfactory for this particular project.

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34 minutes ago, Rose Narrowboats said:

Apologies - I've just amended my post to clarify I was talking about 25mm of sprayfoam.

 

Your research has obviously thrown up some very different figures to mine.

 

Source for the expanded polystyrene (who recently took over our local supplier, Warren Insulation): https://www.insulationshop.co/25mm_polystyrene_insulation_eps_70.html

 

Source for the Kingspan: https://www.insulationshop.co/25mm_thermawall_tw55_pir_insulation_board_kingspan.html

 

Source for the sprayfoam: http://www.puservices.co.nz/polyurethane-spray-foam

 

I've seen the wiki page claiming up to R-6 for sprayfoam, but haven't seen any installers claiming it.

 

Based on having pretty well all types of insulation across the hire fleet over the years, there's no doubt sprayfoam is the most effective, but on a cost/benefit analysis the polystyrene/foil bubble wrap combination has been most satisfactory for this particular project.

I was looking at Wikipedia. https://en.wikipedia.org/wiki/R-value_(insulation)
But now I see it’s quoted in bloody American units! R-value per inch (ft2·°F·h/(BTU·in))

So one thing is clear, one has to be careful with units! I think we will find that the foil bubble wrap is quoted in American units at around 1.


Anyway, common sense says that 25mm of expanded polystyrene (even the high density stuff designed for under foot that you linked to) has got to have a lot more conductive insulation value than 3mm bubble wrap (remembering that the foil bit adds absolutely nothing to the conductivity element). Getting late I’ll have another look tomorrow for consistent units!

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1 hour ago, Sir Percy said:

Also careful to use the word 'foil' rather than 'bubble-wrap'. If you've used some bubble-wrap to lag your calorifier, the bubbles would have been the only thing providing some benefit.

It was the foil covered bubble wrap stuff sold in DIY shops as insulation. And claiming near magical properties!

Edited by nicknorman
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Kingspan or its equivalent is better than the rockwool, seen to many soggy boats because of badly installed rockwool, whereas  the foil gives a vapour protection as long as its sealed, I have sprayfoam and thinsulite on the back third of the boat, and double thinsulite on the front two thirds, the stern is warmer plus it gives better vapour protection to the steel. Rockwool is cheaper than kingspan, I have just paid 16 squids a sheet but it is the better product even on your fibreglass roof

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An easier to fit DIY insulation is 3M Thinsulate.

 

https://www.amazon.com/Thinsulate-Acoustic-Thermal-Insulation-SM600L/dp/B074XLDV58

 

My boat is insulated with it. It is almost, but not quite as good a thermal insulator as sprayfoam, and a much better acoustic insulator.

 

It is gkued to the steelwork with a tacky spray adhesive and easily removed should localised welding is necessary. 

 

Not cheap though.

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4 minutes ago, cuthound said:

An easier to fit DIY insulation is 3M Thinsulate.

 

https://www.amazon.com/Thinsulate-Acoustic-Thermal-Insulation-SM600L/dp/B074XLDV58

 

My boat is insulated with it. It is almost, but not quite as good a thermal insulator as sprayfoam, and a much better acoustic insulator.

 

It is gkued to the steelwork with a tacky spray adhesive and easily removed should localised welding is necessary. 

 

Not cheap though.

Mine is stuck to the steelwork and to the woodpanels so its double thickness,, the owner went over the top on this boat I think

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I did mine with 50mm celotex stuck to the steel then taped all joints with foil tape then an air gap before the ply lining, to the op please don't use mdf anywhere on your boat as when it gets damp it will swell up, I know it's more money but use wbp ply.

Ps my boat keeps its best a long while after the fire goes out with little condensation.

Edited by Neil Smith
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Boater next to us during fitout stuck Celotex or Kingspan (can't remember which) to the steel shell, sealed joints with aerosol foam then stuck 6mm ply on that, the result was very solid, it felt like a brick wall if it was thumped. 

 

ETA: Bear in mind the roof and cab sides were 3mm steel and were quite 'boingy' when thumped hard before. 

Edited by nb Innisfree
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9 hours ago, peterboat said:

Kingspan or its equivalent is better than the rockwool, seen to many soggy boats because of badly installed rockwool, whereas  the foil gives a vapour protection as long as its sealed, I have sprayfoam and thinsulite on the back third of the boat, and double thinsulite on the front two thirds, the stern is warmer plus it gives better vapour protection to the steel. Rockwool is cheaper than kingspan, I have just paid 16 squids a sheet but it is the better product even on your fibreglass roof

How does rockwool make for a soggy boat?

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1 hour ago, Neil Smith said:

 , to the op please don't use mdf anywhere on your boat as when it gets damp it will swell up, I know it's more money but use wbp ply.

Ps my boat keeps its best a long while after the fire goes out with little condensation.

This ties in very well with the thread on Kitchen units. and if you use the right MDF it's far better than any plywood as far as moisture is concerned 

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41 minutes ago, BWM said:

How does rockwool make for a soggy boat?

Because it allows vapour through to the steel skin which then condenses. The rock wool absorbs the water becoming soggy. Especially if there are any air voids between the rock wool and the skin.

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I know the OP does not seem to want warnings of potential problems BUT .......

 

Many GRP topped narrowboats seem to have wooden handrails screwed through the GRP. This gives a number of potential leak points. On older boats the handraiols ofetn rot so the screws fall out/loosen and leak.

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1 hour ago, matty40s said:

 

It would be even less work if you got a lady in to do it, far less tea would be drunk.

But more time spent chatting!

 

No doubt I will get a row for gender stereotyping because whilst one is allowed to point out the flaws in stereotypical men, one is not allowed to do the the same for women!

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22 hours ago, nicknorman said:

Because it allows vapour through to the steel skin which then condenses. The rock wool absorbs the water becoming soggy. Especially if there are any air voids between the rock wool and the skin.

Genuine rockwool is hydrophobic and will not absorb water, the horticultural variety has to be treated to do so. 

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1 hour ago, BWM said:

Genuine rockwool is hydrophobic and will not absorb water, the horticultural variety has to be treated to do so. 

 

Indeed, I once had a sample of genuine Rockwool  sitting in a glass of water on my desk for a week and it didn't absorb any moisture. 

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23 hours ago, Tony Brooks said:

I know the OP does not seem to want warnings of potential problems BUT .......

 

Many GRP topped narrowboats seem to have wooden handrails screwed through the GRP. This gives a number of potential leak points. On older boats the handraiols ofetn rot so the screws fall out/loosen and leak.

My issue with the original post was not the warning or information provided as that was very helpful but with the doom and gloom walk away and spend your money elsewhere unessacary part of the post  but thanks I do appreciate the advice about fibreglass tops 

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On 25/10/2019 at 10:16, BWM said:

How does rockwool make for a soggy boat?

Because it allows vapour to pass straight through it condense on the shell and then drip onto the wood below = soggy boat, as others have said rockwool doesnt absorb water but it does go flat and so doesnt work as well

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Google the insulation values of kingspan and Rockwool and you will see there is no contest. 

 

In my opinion Rockwool should never even be considered for a space restricted and damp application like a boat. Its a low efficiency insulation and absorbs damp, then it sags away from the framing, in bad cases it disintegrates and falls down into a pile of mush at the floor or gunwale level. 

 

Also remember that every additional mm of thickness you fit will reduce your future fuel bills, and once its fitted its practically I possible to change. 25 mm of PU foam board is a bare minimum of insulation thickness , it wouldn't even be considered insulation on a building. Its not until you get in the 150- 200 mm region that it you get diminishing returns on cost over insulation factor. 

 

( my boat is 60 mm up to the gunwales and 40mm on the cabin sides and under the floor. )

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Whilst the insulation knowledge is to the fore, and since there's read across for the OP, I'm replacing a 75mm radius cornered MDF window trim which has succumbed to damp from condensation behind it. I've discovered that my sprayfoam insulation ends aT the battens about an inch from the window frame.  This leaves cold steel with the inevitable results. I'd like to insulate this void when the new trim goes in, so I'm thinking it'll need to be with something compressible that won't end up as a wet sponge. Has anyone fixed a similar issue or does anyone have a recommendation of how to fill such tight awkward spaces?

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20 minutes ago, Sea Dog said:

Whilst the insulation knowledge is to the fore, and since there's read across for the OP, I'm replacing a 75mm radius cornered MDF window trim which has succumbed to damp from condensation behind it. I've discovered that my sprayfoam insulation ends aT the battens about an inch from the window frame.  This leaves cold steel with the inevitable results. I'd like to insulate this void when the new trim goes in, so I'm thinking it'll need to be with something compressible that won't end up as a wet sponge. Has anyone fixed a similar issue or does anyone have a recommendation of how to fill such tight awkward spaces?

Closed cell polyethylene foam springs to mind. You can get it with self-adhesive backing. Search ebay for 'closed cell foam' and there'll be lots to choose from in various thicknesses and sizes. 

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43 minutes ago, Sea Dog said:

Whilst the insulation knowledge is to the fore, and since there's read across for the OP, I'm replacing a 75mm radius cornered MDF window trim which has succumbed to damp from condensation behind it. I've discovered that my sprayfoam insulation ends aT the battens about an inch from the window frame.  This leaves cold steel with the inevitable results. I'd like to insulate this void when the new trim goes in, so I'm thinking it'll need to be with something compressible that won't end up as a wet sponge. Has anyone fixed a similar issue or does anyone have a recommendation of how to fill such tight awkward spaces?

Builder's spray foam and cut back?

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