Welcome!! Glad you joined our little addiction! My experience has been that wood is never a good substrate for outdoor use, just for the reasons you stated. That said, I'm not sure that the grout will hold something as heavy as cutlery, esp onto a vertical surface...what are you using as the actual adhesive?

Can't wait to see pics of yoyr work! They sound really cool!

Pat

BTW - there's a thread by lyndalu about posting pics that is really helpful!

I'm puzzled as to why you use grout, DAISYME, instead of mortar. BTW - welcome to this side. If you MUST use wooden birdhouses (shhhhh - I mosaic over wood for outside also. It's a cedar pedestal.) I would recommend you use mortar for the adhesive/grout method of which you speak. You can coat the inside w/a thin coat of mortar also. This w/prolong the life of your b.h. Grout is not meant to adhere tesserae to anything. Mortar is cement-based.

Wow, thanks for the welcomes and the great information. A friend that does pieces for sale in art coops showed me how to do the basic houses with sanded grout. I will definately try mortar. Does it come in colors? Great info. The houses are turning out great, (I'm actually using broken plates) I'm just afraid to put them anywhere outside, and they're beginning to take over the house. LOL

Grout has no adhesive properties and shouldn't be used as such. It will be a giant disappointment. It will also suck all the moisture out of the wood if the wood is not sealed properly.