This is not technically a "tile" question, but still a product question. I recently had to tear out a section of finished wood floor and the slab underneath to repair the main sewer line that had been run over and pushed out of place during construction. When I replaced the concrete, not all of it was level and I have already replaced the wood floor. Now there are three or four spots where the wood doesn't make contact with the concrete. It's obvious when you step on it. Previously, when I've had similar problems, I used DriTac (wood floor glue) that I injected with a syringe through a tiny hole drilled in at the joints, then set a heavy weight of some sort on it until the glue dried. I'm out of DriTac, though, and a four gallon bucket is $80 or more. Does anybody know of anything else I can buy that is thin enough to be injected through a large bore needle that will eventually set up and become solid to fill in the void? I don't really want to use glue, since I'm trying to actually fill in the void as opposed to adhering the wood to the concrete. Glue that is thin enough to inject probably wouldn't dry for a very long time, if ever, since there won't be any air getting to it.