In my opinion nothing mosaiced on wood will hold up outside.it may make a couple of years but not much more.I have used marine grade plywood before I realized even that doesn't hold up forever. Others may feel different but thats the luck I have had.I am in hot humid south texas a lot like florida.

Glad you posted this question Lisa, I was just about to ask pretty much the same thing. I've got that box of birdhouses to work on and I'm not sure what to seal them with. Hopefully someone will have a good idea for something that worked for them. I sure hope your project can be saved!

Cindy

Here's a photo of what happened to the mosaic I did on a wood table that was outdoors in the rain for less than a month. I sealed the table thoroughly with marine spar varnish and then sealed and double-sealed the mosaic with grout sealer. Luckily the mosaic came off in large chunks and I was able to salvage it and re-mosaic onto a table top cut from hardibacker.

Here is a link that might be useful:

Thanks Silvamae, for posting that photo again. People just don't believe that wood is like a sponge outdoors.

Guess i'm one of the lucky ones with the wood outside. I have made 3 tables on wood. One has been on the deck for 5 years. It is still fine. Just got done doing 2 others just need to seal the grout and put on the metal stands.

Lisa: You say you want to use the table outdoors. Does that mean sitting out where it's exposed to the elements? Or will it be sitting on a covered patio, etc. I would think that if it's protected by a roof, it should be ok. I'm working on a wooden planter stand that I plan to put on my front porch. It has a roof and will be protected by tall plantings and the weather comes from the opposite direction so I'm thinking it will be fine.

This table will be sitting on a covered porch, but that area can get hit with rain as it is toward the edge of the roof area.

I have to put my two cents in here. From your other thread I think I see that you didn't use mortar for the adhesive. I've had a cedar pedestal outside for almost two years that shows not one bit of change. I used mortar for the adhesive and grout. I'm also wondering if the varnish Silvamae used was oil-based. Some water-based adhesives w/not adhere to oil-based sealers.