Rockwool for welding?

[Polishicebreaker]

Hi folks, I'm about to insulate my boat. Kingspan taped and sealed etc but someone recommended also using a thin layer of Rockwool direct to the steel in case of future welding to hull. It may need welding at some point but not for a while. Too much foresight or a good idea?

[Kae]

It's true that rockwool won't burst into flames, but neither will it insulate the kingspan enough to stop that from potentially burning up either, so can't see any advantage for that reason.

 

If you think it might need welding sooner rather than later, then either get it done before the fit out, or, make the panels around where the welding will be needed removable.

[Timleech]

It's true that rockwool won't burst into flames, but neither will it insulate the kingspan enough to stop that from potentially burning up either, so can't see any advantage for that reason.

 

If you think it might need welding sooner rather than later, then either get it done before the fit out, or, make the panels around where the welding will be needed removable.

I'm not convinced that the Rockwool wouldn't serve, of course that would be very much dependent upon thickness, but I do agree that providing removable panels would be a good plan.

 

One thing to bear in mind with rockwool and glass fibre is that there seems to be some sort of resin used in the maufacturing process, and that can burn even though the actual fibres don't. The amount is small, probably not enough to ignite anything else in normal circumstances, but sometimes you can see a brief 'fire' travelling along the fibres.

 

Tim

[Kae]

I'm not convinced that the Rockwool wouldn't serve, of course that would be very much dependent upon thickness, but I do agree that providing removable panels would be a good plan.

 

 

 

I suppose ultimately it's a case of "would you bet your boat on it?".

 

Thinking further on it though, the alternative is to only insulate with rockwool on the lower part of the boat and leave the kingspan for the upper surfaces?

 

(NB I'm not disagreeing with Tim, he's much more experienced than I, just my "thoughts")

[bag 'o' bones]

Assuming your fitting out the boat yourself instead of worrying whether or not rock wool is fire proof, line your boat in such away that it can be dismantled. There are those who will say that if it is built properly in the first place it will never require dismantling. However, despite how well you plan your boat there will always be an afterthought requiring access behind the panelling - installing extra wiring being the most common I imagine. I reckon there are more than few boaters out there who wish they could take the panelling apart without wrecking it in the process!

[smileypete]

I would say if it can't be dismantled easily enough it wasn't built that well in the first place!

 

cheers, Pete.

~smpt~

[onionbargee]

rockwool is not as good insulation as kingspan, i think it's around 1.5 times less.

[blackrose]

The only problem with the advice to make the panelling dismantlable (if indeed that is a word), is that kingspan or cellotex should be bonded to the steel, in which case it will be difficult to remove anyway, even if you have access to it.

 

I wouldn't even worry about it. How many of us have sprayfoamed boats without easy access behind the panelling? How many of us have had welding done on our hulls?

Hi folks, I'm about to insulate my boat. Kingspan taped and sealed etc but someone recommended also using a thin layer of Rockwool direct to the steel in case of future welding to hull. It may need welding at some point but not for a while. Too much foresight or a good idea?

 

To make kingspan as good as sprayfoam you really need to bond it to the steel with something like this.

 

http://www.marinemastics.com/marine-flex/marine-flex-onetube.html

 

or this

 

http://www.toolstation.com/shop/Adhesives+Sealants/Grab+Adhesive/Stixall+Adhesive+Sealant+290ml+Clear/d180/sd3199/p77137

 

There's not much point taping & sealing "loose" kingspan that's just leaning up against some rockwool. To create a proper vapour barrier the kingspan should be bonded.

Edited December 7, 2013 by blackrose

[blackrose]

I would say if it can't be dismantled easily enough it wasn't built that well in the first place!

 

cheers, Pete.

~smpt~

 

Since the linings of most narrowboats aren't easily dismantled then I guess that means most weren't that well-built. Anyway, as I said, if it was properly insulated you can dismantle all you want, but there's not much point unless you're going to cut out and scrape the insulation off.

[smileypete]

 

Since the linings of most narrowboats aren't easily dismantled then I guess that means most weren't that well-built. Anyway, as I said, if it was properly insulated you can dismantle all you want, but there's not much point unless you're going to cut out and scrape the insulation off.

 

How is the panelling on your boat fixed down?

 

If it's panel pins and screws it shouldn't be too hard to remove, though it might need running around some edges with a multi saw.

 

Seems quite common for people to want to get behind the panelling to make changes to the electrics and plumbing, if the linings are stuck to the battens with no-nails goo it'll be hard to remove them without them getting trashed.

 

cheers, Pete.

~smpt~

[Polishicebreaker]

Thanks for your responses, the discussion has perhaps highlighted something more important with my boat build which is the Vapour barrier issue. I've not heard of sticking the Kingspan straight onto the hull. I was thinking to wedge them in and tape them but maybe this isn't enough? After living on a boat for 4 years thats poorly insulated with no vapor barrier I know how much condensation you can get. what about sticking the rockwool to the hull or probably wont hold?

[Ex- Member]

Thanks for your responses, the discussion has perhaps highlighted something more important with my boat build which is the Vapour barrier issue. I've not heard of sticking the Kingspan straight onto the hull. I was thinking to wedge them in and tape them but maybe this isn't enough? After living on a boat for 4 years thats poorly insulated with no vapor barrier I know how much condensation you can get. what about sticking the rockwool to the hull or probably wont hold?

 

Hi there

 

We insulated with Rockwool, we didn't adhere it to the hull, but we did fit it in such a way it would stay tight to the hull sides when the panelling was fitted. We used 50mm high density Rockwool batts but we also used Cellotex on top of the Rockwool at 10mm thick and foiled either side. You won't be able to buy Cellotex at 10mm thick though. But insulation suppliers will usually have some as the manufacturers use the insulation Block off cuts and use them on the top and bottom of pallet loads for protection when delivering to the suppliers.

 

I think we paid a fiver a sheet.

 

 

 

Basically the battening was made using plywood strip and set at 58mm so when all the Rockwool & Cellotex was scribed in and completely sealed over with Aluminium tape, the application of the panelling pressed the Cellotex/Rockwool tight to the hull. I must have worked as 9 years on we have no damp or condensation problems, not even a drip in any of the bilges.

 

If doing this again though, I would actually use Kingspan or cellotex or the like @ 50mm thick adhered to the hull and additionally fill tubing and any gaps with hand held spray foam used with a gun. Screwfix used to do starter packs, six cans of foam free gun and cleaner.

 

A wee tip, fill all the tubed ribbing with tinned spray foam, it will prevent condensation forming in the tube. A fiddly job as you need to drill 10mm holes every 12 to 18 inches to ensure filling. If tubing is nicely welded with no air gaps at the welds, just spray foam the ends of tubing where they've been cut away for windows portholes mush vents etc, better to completely fill though IMO.

[blackrose]

 

How is the panelling on your boat fixed down?

 

If it's panel pins and screws it shouldn't be too hard to remove, though it might need running around some edges with a multi saw.

 

Seems quite common for people to want to get behind the panelling to make changes to the electrics and plumbing, if the linings are stuck to the battens with no-nails goo it'll be hard to remove them without them getting trashed.

 

cheers, Pete.

~smpt~

 

It's pinned, but I wouldn't need to get behind the panelling to access the majority of my electrics and plumbing. Contrary to what you say I think it's the boats where you need to take the panelling off to get to pipes and cables that aren't very well designed.

 

You won't be able to buy Cellotex at 10mm thick though.

 

I think the thinnest you can buy is 12mm thick.

 

http://www.insulationgiant.co.uk/p/celotex-insulation-board-tb4012-12-x-2400-x-1200mm/778033

Edited December 10, 2013 by blackrose