Canvas deck covering

AuntyRinum

AuntyRinum

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Can anyone advise on the use of canvas as a deck covering over ply?
I plan to stick canvas onto a ply covered coach roof which is currently covered with deck paint, and then paint again.
Does anyone have experience of this? Type of canvas, type of adhesive? Any advice would be gratefully received.
 
ArthurJStoatfondler said:
Can anyone advise on the use of canvas as a deck covering over ply?
I plan to stick canvas onto a ply covered coach roof which is currently covered with deck paint, and then paint again.
Does anyone have experience of this? Type of canvas, type of adhesive? Any advice would be gratefully received.
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Painted canvas works, but my impression is that nowadays you'd normally replace it with fibreglass woven matting stuck with epoxy, which will last a decade or two longer. That is what I have for my cabin tops. It's not so terribly hard to do. Important thing is to get enough epoxy to completely saturate the matting but not enough to pool on top. Rollers and squeegees.
 
If the ply is sound, would not use canvas. The usual use for canvas is when the deck is tongue and grooved boards and is likely to move. Canvas is usually bedded in lots of conventional paint which acts as an seal, but is actually held down with tacks.

As suggested epoxy glass is the ultimate in covering, but if the ply is sound a conventional primer/undercoat, followed by non slip deck paint is usually OK. Some people soak in a couple of coats of epoxy first as extra protection.
 
Canvas or epoxy ( canvas will be fine) Make sure the original paint is sanded to clean and key. Plenty of good adhesives as the canvas can breath.
You will know that masonary paint works well ( tried and tested by many on this forum) on epoxy but less sure of on canvas.
 
as a young lad, I lived on Ham Hough Island near Shepperton. I remember my Aunt's mobo having its canvas decks replaced.

Plain canvas ex-RN, seasoned by being wetted and dried a few times. It was stretched between clamps to the gunwhales, then pitch (tar) poured over the wooden deck planks and then the canvas laid very quickly and carefully on top.
 
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I did the canvas route on my ply roofed boat and for a year eighteen months it was fine, but eventually the canvas rotted despite using 2.5 litres of oil paint. I do believe that modern paints are not suitable for canvassing. My roofs are now glassed and dry.
 
Tranona said:
If the ply is sound, would not use canvas. The usual use for canvas is when the deck is tongue and grooved boards and is likely to move. Canvas is usually bedded in lots of conventional paint which acts as an seal, but is actually held down with tacks.

As suggested epoxy glass is the ultimate in covering, but if the ply is sound a conventional primer/undercoat, followed by non slip deck paint is usually OK. Some people soak in a couple of coats of epoxy first as extra protection.
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The area is too large for a single sheet of ply so has ply sheets which are jointed, the joints are leaking, hence the need for a covering. This is a fifty year old vessel so I don't want to use fibreglass.
 
ArthurJStoatfondler said:
The area is too large for a single sheet of ply so has ply sheets which are jointed, the joints are leaking, hence the need for a covering. This is a fifty year old vessel so I don't want to use fibreglass.
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Then seal the joints. I have exactly the same problem and have sealed all the joints with epoxy before painting. In some cases where there was some rot at the joints I remade with either veneers or glass set in epoxy. Really cannot see any advantage in using canvas. To get it to fit properly you have to tack it down onto the wood thus introducing new points for damp to get in. BTW my boat is also 50 years old and I have no hesitation in using modern materials where appropriate. Plywood is a manufactured product and epoxy is commonly used to strengthen and protect it.
 
Canvas covered wooden decks were very effective when the procedure was carried out properly. After removing old canvas, decks were scraped and sanded then a coat of Smudge was applied, basically this was a very thick paint recovered from the bottom of the paint manufacturers mixing tanks and the consistency of treacle.
Boatyards would "manufacture " their own from the dregs of traditional oil based paint cans ( I have seen traditional red lead used) and mixed with a small amount of linseed oil putty until the mix was suitably gooey and able to be spread onto the deck ,then roughly shaped canvas would be laid onto the mixture and rolled, ideally the Smudge should be applied at a thickness so as it only just penetrates the canvas, the material would then be stretched in situ, re rolled and copper tacked and trimmed to size, followed by timber beading at the likes of cabin sides and rubbing strakes at the deck edge.
this was to hide the edge and tacked finish, with white lead paste being used as the bedding compound, laterly sikaflex, then deck canvas would be painted with undercoat until canvas could absorb no more paint then a non slip coating would be applied.
 
I can appreciate your wanting the boat to maintain its appearance - and that includes the methods of finishing. However, I would be inclined to go for belt and braces... fix the leaks and encapsulate the ply with epoxy/cloth, then for cosmetic reasons, apply the canvas and paint. Only thing is, don't tack through the epoxy! May as well have the advantages of new technology and traditional appearance, hopefully with far lower maintenance needs thereafter.

Rob.
 
rob2 said:
I can appreciate your wanting the boat to maintain its appearance - and that includes the methods of finishing. However, I would be inclined to go for belt and braces... fix the leaks and encapsulate the ply with epoxy/cloth, then for cosmetic reasons, apply the canvas and paint. Only thing is, don't tack through the epoxy! May as well have the advantages of new technology and traditional appearance, hopefully with far lower maintenance needs thereafter.

Rob.
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I'm inclined to be pragmatic about these things. Having seen Grajan's description of the traditional method I'm happy to use the epoxy and glass method.
 
mogy said:
hillyards used glass cloth with I assume polyester resin over their ply deck,looked ok.
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Yes, was common in the days before epoxy, but not a good idea as polyester does not stick well to ply. If water does get underneath the glass will lift. Effectively what you have is a thin GRP moulding loosely attached to the ply. Epoxy (and glass cloth rather than matting) bonds much better.
 
Tranona said:
Yes, was common in the days before epoxy, but not a good idea as polyester does not stick well to ply. If water does get underneath the glass will lift. Effectively what you have is a thin GRP moulding loosely attached to the ply. Epoxy (and glass cloth rather than matting) bonds much better.
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Yes I agree.Although I worked at Hillyards for a while I never saw them apply the covering.I guess in the late 1960 maybe the problem had not arisen by then.I imagine in its day it seemed the answer to decking.A few years later I re covered a nic 36 and a little 2.5 ton hillyard using a scrim cloth and resin which was used as protection against wood borers,I wonder why Hillard s didnt use that material(mermory defeats me cannot recall nameof material)
 
ArthurJStoatfondler said:
The area is too large for a single sheet of ply so has ply sheets which are jointed, the joints are leaking, hence the need for a covering. This is a fifty year old vessel so I don't want to use fibreglass.
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My boat is 50 years old too. The woven glass mat, epoxy sealed and painted looks like canvas and doesn't detract from the traditional look in my opinion. The boat was professionally restored, and it was the method recommended by the boatyard and the surveyor.

Vent1 by Graham Cameron Himself, on Flickr

Vent2 by Graham Cameron Himself, on Flickr
 
mogy said:
Yes I agree.Although I worked at Hillyards for a while I never saw them apply the covering.I guess in the late 1960 maybe the problem had not arisen by then.I imagine in its day it seemed the answer to decking.A few years later I re covered a nic 36 and a little 2.5 ton hillyard using a scrim cloth and resin which was used as protection against wood borers,I wonder why Hillard s didnt use that material(mermory defeats me cannot recall nameof material)
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cascover!
 
Tranona said:
Cascover is a different animal altogether. It is nylon cloth set in Resorcinal adhesive and then an optional vinyl coating. Superb if done properly - as on my boat.
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Gosh - I'd forgotten about it. Amulet had it between canvas and glass/epoxy. Very good stuff.
 
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