I think/guess :) regular streched canvas (of the size you're talking)would mildew and warp something awful, even on a covered porch. Maybe? buy a cheapo painting at a tagsale just to see how it holds up?

What about panels made of greenrock- you know? the stuff like drywall they use behind tiles in bathrooms? I've not used any sealers like polyurethane(sp?) so can't comment on that but perhaps the folks on the Garden Junk forum might be able to offers more ideas.

take pictures when you're finished! :)
Julie

he called it 'Wonderboard'(or? dur-rock?)
anyway, it's a 1/2 inch thick sheet of cement,sold as 3x5 foot panels, very smooth on one side, rather easily cut and drilled. I told him about the outdoor painting idea and he thinks it could work!

also, maybe ask around at an sign, awning, tent, boat cushion shop, they might have durable canvas ideas

Julie

I am a professional artist, and last year I did a painting that was installed outside, on the exterior wall of a sauna.

The painting was done on 1/4" gessoed masonite. It was done in artist's acrylics, which, you probably know, are water proof, plastic actually, once dry. The board was screwed to the sauna wall with brass, counter-sunk flat-head screws, the holes then filled and painted over. The edges were caulked all around, sealing the board to the building. Because the painting's installed against a solid structure and caulked, it's not in danger of warping. I didn't clear-coat it at the time, but I think if I were doing the project now I would do so.

If I were doing a free-standing piece, I would look into MDF board, which can be primed and sanded to a very smooth finish, then completely sealed once painted. Masonite would be too flimsy for such a project and would certainly warp. I would be very interested to hear any other ideas, too. This kind of project can transform a garden into something really spectacular!

~kate

Kate

Sue