Hi again,
A couple of questions related to the alternatives of gluing down hardwood versus using a ply base.

Firstly, as far as glue down is concerned I'm a little concerned about how good a bonding surface we might have. As mentioned in another post, we had a local contractor 'correct' our floor in anticipation of a glue down operation, only to have him royally screw it up. I'm about to start fixing it all up tomorrow via the use of a grinder and some self-leveling compound, but I'm a little concerned about what I'll be left with. Firstly, the contractor used Sandmix to do the job, and after reading what the sister site here had to say I was a little concerned over whether it might be an appropriate enough surface to bond well with the glues. Secondly, with all the corrective work using SLC, is the mix and match of an SLC and Sandmix surface going to be alright for gluing?

As far as going the alternate route of using ply, can anyone explain to me why the shift to layered floating floors, when the sister site stated that ply screwed down into the concrete was the preferred method for quite some time? I'm guessing that moisture must have something to do with it, but if there aren't any problems on that score, why not just screw that sucker down with Tek screws, and maybe even put some decent Urethane glue underneath to both help the bonding and dampen the base?

Also, I noted on the sister site a job that got ruined because the installers laid the flooring down on ply that had sat in a humid garage. Does this mean that if I buy ply from one of the big box stores to use as a base, I should leave it in the room for a week or two prior to use?

Thanks in advance

Gary are we dealing with 3/4 inch floor or engineered product ? as for the plywood I beliive it is the best way to go screw or shoot it 15 mil plastic never havd problem with that process . as long as plywood not sitting in rain you should be just fine . wentzwood arizona

Okay, I've been called many things in my life, some of them not very nice - but Gary?

Sorry, i should have mentioned the flooring - it's 3/8 x 3" solid tigerwood and comes in lengths from 18" out to 4'. It's more or less made for gluing on concrete, but I guess it will work just as well being either glued or nailed to a ply base?

Timbo:

Though I am not familiar with Sandmix, it does appear to be a standard type mortar and not designed for floor leveling. The reference below highlights it's use outdoors, but I didn't dig into the specs. If in doubt remove. Lottsa problems there but hard to pinpoint the exact way to go about it without seeing it. Going over with ply would be the safest approach in my opinion, providing it doesn't crack when the ply is fastened. I can already hear a crunchy subfloor.

http://www.sakrete.com/products/detail. ... s/Sand-Mix



Good question. I would be safe to say it's the optimum subfloor for a nailing base with the best moisture protection being the primary benefit. I'm quite sure the older method still outnumbers the new.

Buying ply from big box stores. I really never thought twice about it as most of it's stored indoors. I would think twice if buying from a place that had lumber stored under roof but open to the elements.

Thanks Ken on both counts. Certainly helped to clarify matters.

Spent a few hours grinding down the new high spots on Friday - what a pain! The vac unit I attached to the rented grinding didn't do a good job at all of filtering out the dust - it erupted out of the top of the unit like a volcano, and even though I tried to fix it, checked the filter, etc and opened up windows, it wasn't very effective. Discovered later that the dust had not only got all over the walls, but also the ceilings - had to brush down everything. Then to top it off having the windows open all day (and the room cooler as result) affected all the new crown molding I put up, contracting the wood and opening up cracks where the joins are - first time it's ever happened to me.

I'll either use patcher to try and fix up the areas I've ground down and the low spots, or some SLC. Then I'll take the ply route for the floor just to be safe, even though it will mean having to build up the steps directly affected. The Sandmix does seem to be solid enough - it didn't break up while I was grinding into it.

Thanks again