[spooky in CO]

Updating my graveyard fence columns – the ones I made from wood deteriorated horribly due to moisture. Priorities in order: realistic look, weight, weather resistance.
I plan on using 2x2 framing and 7/16 osb sheathing. I'm making my own stones and using perlite or crushed lava rock or styrofoam as aggregate for weight saving with the stones.
What's the best way to attach the stones for this application? For normal construction I'd use mortar and wire lathe and heavier/stronger stones. However I'm thinking a simple mastic would work for my purposes. I plan on using a mortar grout in between the stones and having a concrete (same concrete recipe) cap on the columns so the only water issues I should face are snow or rain coming in from the sides or from the interior wood sitting on the ground.
Any issues using mastic or grout for between the stones directly on osb? Any other issues I should be looking for? Also, any ideas for weight saving are welcome.
Thanks for your time

 

[Sinister Sid]

I would consider possibly using liquid nails to attach the stones. It might save on the weight (not sure how heavy the mastic is?). But I know that stuff is strong and sticks to just about anything. If you end up using just perlite, I would use a foam adhesive (it comes in caulk tubes) but I don't remember the brand name? I also seem to remember Terra doing a tutorial about comparing foam adhesive a while back. If I remember correctly, I think Drylock was the best product that she tested. What ever path you decide on, keep in mind that you do want a little bit of weight to your columns. I made mine extremely light weight and I am considering re-doing them to make them heavier. I made mine out of 1 x 2's and styrofoam. I really have to anchor them down and I still have problems on windy days. Don't forget to post pics of your progress. I might want to steal some of your ideas. Hehehe....

 

[Scottv42]

Wow that sounds like some serious engineering of a column

Just out of curiosity how did you treat your previous ones? I have wood columns that i have used for the last 3 years now and other than repairing a few little cracks here and there they have stood up fine in all kinds of weather including hurricane remnants.

For weight savings I would suggest skipping the sheathing. Make your frame and put your foam on it and then carve the stones into the foam. It will make it a lot lighter and obviously the foam should not have any water issues.

 

[spooky in CO]

Thanks. Mastic for tile and liquid nails are roughly the same weight.... I think.
The columns will be heavy enough, the perlite will be a substitute for the rocks in regular concrete mix, but I'll still be using concrete mortar and sand so they'll still be plenty heavy when I have 50 or so stones per column.

 

[Sinister Sid]

It was Glidden Gripper that was the best in Terras tutorial not Drylock

 

[spooky in CO]

ScottV42 - Hindsight being 20/20.... I did a poor job. I wanted to make the columns as realistic as possible so I stippled them with drywall mud to hide the texture of the osb. I should have painted the osb and THEN applied the drywall mud to simulate the look of concrete.
Either way, after I did this I painted with "Make it Stone" by Kryon (which I HIGHLY recommend for a realistic texture) and then covered with a sealant... which didn't work. I feel if I painted the osb first and then applied the texture, they would have turned out fine. But, since I am having to redo the whole thing from scratch anyway... I figured I might as well try something new. Always pushing the envelope