Hi all:
I’m looking to build a gazebo on a concrete slab, and have what is probably a very basic question but I’m getting conflicting answers. Here’s the setup: Gazebo built on a slab. Bottom of post and floor plates will obviously have lot’s of moisture exposure from rain and snow. Can I use cedar for the floor plate or does it have to be pressure treated wood? This assumes a slope in the slab of 1/8″ per foot.
It’ll be in Maryland, not in a desert. Thoughts?
Thanks for any help,
Ken
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Replies
First question is: Why the floor plates?
I built a large gazebo on a slab, and the only thing touching the slab was the post bases. The posts are actually about 3/8" off the slab, so no standing moisture will reach them. I used CCA treated posts, but cedar would work also.
The slab was the floor of the gazebo.
Just curious...
James DuHamel
"The Power Zone" http://www.thepowerzone.org
Yeah, after thinking about it I came to the same conclusion. I had a enclosed design with windows in mind and now I think I'll do the post like you and have a knee wall that starts an inch or so above the slab.
Thanks for the note,
Ken
Ken,
I agree with James. Have the posts grounded on the concrete with the rails/plates held off by a bit.
One other item...since the bases of the posts will be in contact with the concrete, you may want to "wash" the bottoms of the posts with thinned epoxy. The thinned epoxy will wick into the end grain, somewhat sealing the base of the posts from wicking water from the concrete.
Mongo,
Just a quick question. Are you refering to clear penetrating epoxy sealer, and if so, did using it as you've noted affect your finish near the post end or your choice of finish?
I use thinned West System epoxy. I apply it as I'm building...whether it be garden furniture or an arbor, trellis, etc...whatever.
I use a properly mixed epoxy for joining wood members and a thinned version to wash the parts that will come into contact with the ground/patio/concrete pads.
Wood is always teak or mahogany, left to weather to a natural silver-gray finish. I've not noticed any visual difference in the wood after the structure/furniture is completed. I'm not 100% sure that the wash will not affect how the bottom inch or so of the wood will accept a stain finish. I know some of the structures have been stained afterwards, thogh no one has ever mentioned finishing problems at the base of the wood pieces.
Since your posts will be set in place and never moved/dragged across the ground like a chair, I'd venture you could simply seal the bottom of the post with a regular mix. That shouldn't affect how the post will recieve a finish as it will be a topical application only.
If aesthetics is a major concern, you could pre-stain the posts, then wash the post bottoms after staining.