rust Why proper insulation is important.

[neilforsythmac]

Hello boaters, 

 

Recently bought a 1930 admiralty ammunition barge, the stench of mould and damp were there. Had a hull survey done but not an interior survey. Not to worried about the interior as it was destined to be stripped out. 

 

When converted 20 years ago and clearly done by a bodger on a budget. When stripping out the interior every wood board, every wood support, every sheet of celotex and all if the loft insulation jammed into every corner......was damp and mouldy

 

Pictures attached hopefully show the extent of the hull damage caused by the rot to the interior. I only post these in the hope that it helps the inexperienced make better decisions when it comes to insulating their boats.

 

The steel has been sweating behind the celotex, dripping water into the bilge constantly, most of the paint has separated and peeled off as the steel was not prepped properly and the paint was cheap and not fit for purpose. Although all of the damage to the steel is on the surface and can be repaired/welded etc the rest of the interior has to be stripped and replaced..........After the hull gets blasted/painted and most importantly SPRAYFOAM INSULATED.

 

So my advice is don't be cheap, do it properly.

 

 

Edited November 23, 2024 by neilforsythmac
Spelling

[BEngo]

The essential of all insulation is to ensure that there is a vapour barrier, either separately as needed with polystyrene, or included, as with sprayfoam

 Celotex usually includes a vapour barrier on each osheet, but you still need to fill gaps with canned foam and  put aluminium tape over all the joints to make the barrier continuous.

 

Rockwool or fibreglass rolll appears OK when new, and a separate vapour-barrier is fitted, but it soon slumps ahd becomes pretty useless.

 

N

 

 

[truckcab79]

Probably several factors going on there I suspect not least the poor prep and paint that you mention and the use of loft insulation.  I know people use it but I can’t think of anything worse. Might as well fill

it with sponges to make sure it stays wet. 
 

As a contrast to yours our near 50 year old Springer was stripped back to find steel that looked like it was painted yesterday, a hull much the same (bearing in mind 50 years of water being designed to drain through it), as-new battens and a ply floor that was rotting in just a couple of corners.  Our only steel rot was the stub of a leaking welded in skin-fitting.  The only insulation was about 10mm of loose polystyrene sheet. The fact that it wasn’t fixed to anything possibly helping with some level of air-circulation behind the cladding. Remarkable really. 
 

Any idea how pristine it was before the conversion out of interest? Would be interesting to know whether it was in good nick or whether they just bunged it on over an  existing issue.  
 

We’ve insulated with Celotex but all glued into place on a bed of foam adhesive. Spray foam would be even better but wouldn’t really have suited the pace and method of our build. 
 

Interestingly in the car world any mention of filling anything with spray foam would have you criticised for its propensity to hold water and destroy any steel within a 100 mile radius.  
 

Start a build thread.  Would be good to see more of it.  
 

Good luck.  
 

 

[GUMPY]

41 minutes ago, truckcab79 said:

Interestingly in the car world any mention of filling anything with spray foam would have you criticised for its propensity to hold water and destroy any steel within a 100 mile radius.  

Depends on whether it's closed cell or open cell foam. I've been doing some research into underfloor insulation and the differences are stark. Some companies are now refusing to insure/mortgage houses with spray foam in the roof due to possible damage from rot.

 

[David Mack]

54 minutes ago, truckcab79 said:

We’ve insulated with Celotex but all glued into place on a bed of foam adhesive.

I'm going to be doing this soon in a back cabin. What adhesive did you use and how did it work out?

Edited November 28, 2024 by David Mack

[Tonka]

11 minutes ago, GUMPY said:

Depends on whether it's closed cell or open cell foam. I've been doing some research into underfloor insulation and the differences are stark. Some companies are now refusing to insure/mortgage houses with spray foam in the roof due to possible damage from rot.

 

Just need the banks to outlaw damp proof companies now

[truckcab79]

54 minutes ago, GUMPY said:

Depends on whether it's closed cell or open cell foam. I've been doing some research into underfloor insulation and the differences are stark. Some companies are now refusing to insure/mortgage houses with spray foam in the roof due to possible damage from rot.

 

The conversation is normally about your bog standard ‘squirty foam’ in a can which as I understand it is classed as closed cell, though both are available.  
 

The roof insulation spray foam industry I think has pretty much disappeared due to so many cowboys and so many horror stories about long term damage and the ability to work on any roof that has had it done.  Unsurprisingly there is quite a business in removing it. (Probably the same people who sprayed it  few years back 😂)

49 minutes ago, David Mack said:

I'm going to be doing this soon in a back cabin. What adhesive did you use and how did it work out?

Went in well. I put in as much depth insulation as would physically fit so 25mm on roof and upper walls and 50mm from gunnels down. 
 

I like the Screwfix own-brand No Nonsense stuff.  Don’t mess around with the little cans.  Use the gun grade and at the risk of stating the obvious it’s the adhesive foam you want, and not the regular expanding foam.  I’m sure either would work but the adhesive one goes off far quicker and most importantly expands far less so doesn’t try and push your sheets out. Any curved or shaped areas score along the back following the shape and snap the foam. Even possible on compound shapes if you score in both directions.   So long as you keep the foil intact on one side it’ll stay together and then when you’re gluing it in place slather the open bits with extra foam and and it’ll expand to fill bits where the foam has opened up.
 

Curvy bits need propping into place with a piece of timber while they go off or if you’re going to have use for them again, then adjustable plasterboard props are a godsend.   
 

Any gaps you then just fill with more foam (non adhesive as it’s cheaper but doesn’t really matter), and trim when dry. 
 

Only issue we had was in the summer the roof was so hot any excess glue just dripped out. Didn’t affect the sheets gluing though. 
 

Best foam guns I’ve had are ToughMaster on Amazon. About half the price of the rubbish ones that screwfix sell.