Dark stains on paneling in new boat, advice please

[Derek R.]

It may be superfluous to add to this thread, as much valuable information has already been given. But with the exception of one person, mention of a vapour barrier has been left out completely, and is of prime importance.

 

Let alone the fact that living afloat is in close proximity to water, air born water, in the form of vapour, is present all around us at all times, measured as a percentage of humidity, and is given off from the human body in quantity. With the addition of more heat from heating appliances - some of which will give off direct vapour - there are the acts of cooking and washing. Even with the minimal amount of vapour contributing elements, any vapour will be permeating every crack and crevice in panelling until it finds a surface cold enough to condense upon. Once condensed, the droplets become heavy and gravity does the rest - it runs and drips.

 

A steel shell is in itself a vapour barrier keeping water out - rain and the canal. But within that shell is required another kind, and it's position in relation to the internal panelling and the cold steel is vitally important. Hugh mentioned polythene, it is light, flexible, does the job, but must be fitted with all possible joins and gaps made up and taped together to prevent the warm moisture laden air within the boat to reach cold steel. This vapour barrier needs to be immediately behind any panelling and between the insulation and the panelling. This is especially so with the use of glass fibre based materials, Rockwool, and any kind of insulation that itself is permeable. If no vapour barrier is fitted when used with these insulating mediums, vapour will flow through the insulation until it condenses on the steel, then soak back into the insulation material until it begins to sag and fall down under its own weight in the panelling to steel gap. The condensation will continue to build up until it soaks the panelling from behind and show itself in the angle of the 'gunnel' or around window frames staining the wood black in the process. This is indicative of poorly applied insulation, or a lack of the most essential elements of knowledge about insulative techniques.

 

Spray foam insulation, if of the correct grade and applied by conciencious professionals, is superb at what it does. But it must be applied in adequate thickness and to every part of the steel - no single fraction of a square inch must be missed. Even an eighth on an inch hole exposing steel will begin to 'bleed' moisture just as if you had pricked your finger as water vapour finds it and gathers to form a droplet. In itself, spray foam once set is a vapor barrier, it is in effect waterproof by virtue of the tiny cells of foam which are sealed from one another and cannot therefore transmit moisture laden air, or moisture itself as a sponge would. As this is the case, then no extra vapour barrier such as ploythene should be needed. However, if the spray foam is applied incorrectly; in insufficient thickness, and/or not covering all the steel, condensation may and probably will occur. To suggest that a can of DIY expanding foam will cure the inadequacies of a few or many areas, or that stuffing Rockwool into certain gaps will be sufficient, is a sign that someone is wriggling off a hook, for in such circumstances that have been described by Waitey, the job would appear to have been spoiled for possibly speed of finish and reduced cost of materials. Moreover, the cans of aftermarket expanding filler will neither have the same content of flame retardent, nor R value of the original spray foam.

 

As to how thick is enough, four inches is the industry standard in construction for effective insulation using Cellotex, and I would chance my arm at saying absolutely nothing less than one inch of quality spray foam, and if the case is still the same today with cost of application being worked on the square foot as it was in '86 when we had our boat previous sprayed, then go for as much as you can get in the available space - only 'cowboys' will sell you short. It should also be remembered, that any air space between panelling and insulation, or insulation and steelwork, will allow currents of air to convect. Convected air is a transmitter of temperature exchanging cold for hot, it needs to be stopped by filling - not to a packed capacity, for that encourages conduction of heat - but through simply trapping air in tiny pockets and keeping it immobile with a lightly 'fluffed' filling.

 

I've mentioned Cellotex, which is available in sheet form in varying thicknesses from 10cms up and comes with a foil face which is a vapour barrier and a heat reflective surface in one. It isn't cheap, quality does not come cheap. 3m have also launched into the boat market with their Thinsulate, a comparatively easy to apply material in varying thicknesses. That suggested for boats is one inch thick, and is its own vapour barrier. I am using it behind the panelling on Tycho, and although not having been yet tested in the heat of battle, I'm impressed with the vapour barrier qualities, ease of fitting and sound deadening. Not cheap!

 

Something I have not touched on is what is happening to the steel behind all this. Paint can and does crack and flake over periods of time. Waxoyl and the like cannot be 'stuck' to. Spray foam is not invulnerable to parting company from the steel, though in all honesty, little rust or corrosion is going to take place that would have any detrimental effect structurally. It also will be necessary to know how the various insulative products and the methods of applying them, behave when plating has to be welded from the outside. Will it catch light? Is any adhesive used flammable over time? Will the insulation properties be eroded? I have witnessed quality spray-on foam self extinguish, though leaving behind a shrunken hole. Rockwool may glow when direct heat is applied, but extinguish when withdrawn. Polystyrene slab on the other hand, I have seen burn quite merrily, giving off noxious fumes into the bargain. And of course we all know wood burns, as will the spirit medium that carries Waxoyl, though as time passes this usually evaporates away and is only a great risk when freshly applied (though I would stand corrected on that).

 

None of the above is any real advice on Waiteys predicament, but in the hope that more knowledge means more power, then I hope the above - which has all been gleaned from first hand experience over many years of 'doing it my way' (and not always the right way) - is of some guidance. It looks like Waitey has a battle on his hands to win compensation, or fulfilment of a better quality of workmanship from the builder, and that may be down to what guarantees and agreements have been entered into.

[Nick R]

We live on a 60x10 widebeam manufactured by Aqualine. It is 2 years old and we have experienced major problems with condensation and damp. It is so bad the boat is returning to the factory( in Poland!!) to be sorted after a fairly damning report . Is there any body out there who has had the same problems on an Aqualine widebeam as we thing it could be a major design fault or is it just our boat? Let me know

[blackrose]

We live on a 60x10 widebeam manufactured by Aqualine. It is 2 years old and we have experienced major problems with condensation and damp. It is so bad the boat is returning to the factory( in Poland!!) to be sorted after a fairly damning report . Is there any body out there who has had the same problems on an Aqualine widebeam as we thing it could be a major design fault or is it just our boat? Let me know

That is surprising. Aqualines are fairly expensive boats.

[johnjo]

That is surprising. Aqualines are fairly expensive boats.

 

Dosen't follow that it's well built, anything is only as good as the person/s who put it together!

Edited January 31, 2009 by johnjo

[alan_fincher]

I'm not suggesting those posting here don't have serious problems, but it is always difficult for a third party observer to be clear on whether a boat has a serious problem with the insulation or not.

 

I say this because much of it has to do with how the boat is used, heated, and ventilated.

 

You could give identical boats to two different owners. One of these shuts all the windows, leaves kettles and pans boiling, and has hot steamy baths. The other keeps a lot of permanent ventilation, but does far less moisture producing activities. There is a very good chance that the first would suffer damp, staining and mildew, but that the second would not.

 

I can recall complaints about a boat from a particular fitter, but that someone else who had had a boat fitted there in a similar time-frame had no problems. (Not conclusive I know, as one may have had skimped insulation, and the other not).

 

That said spray-foam is always touted as the best insulation, but one hears so many tales about trying to aerosol in extra, that I actually have serious doubts that many installations may be thin or patchy.

[bag 'o' bones]

I seem to recall a thread here recently which was asking why anyone would possibly want to do their own fit out, when the professionals do it so much better...........

 

 

 

......... I rest my glass.

 

Rick

 

It all depends on what you class as 'better'.............

[Derek R.]

It all depends on what you class as 'better'.............

 

I think it means more 'noughts' on the end of the bill.