Purchased 5/16" Bruce Natural Reflections Solid Red Oak 2-1/2" wide planks for glue-down over cement. Installer laid up to 1/2" Mapei Planipatch mixed with water over entire 350 sq ft area to level it. I got concerned because it cleans up so easily with water days after application off of baseboards - seems to melt right off. It is also easily smoothed and dug into with screw driver. I even cleaned up piles of it dumped in my driveway and bushes by the installer with a power washer. Mapei tech support says 'Novaplan 2' with 'Primer L' should have been used and Bruce says cementitious material mixed with latex additive should have been used. They say the Planipatch should be removed and start over. I cancelled the gluing of the wood till I can find out more.

Do I have what I see you calling 'soft concrete' or gypcrete on some of your replies to other people? Is it safe to glue the wood upon or will it crack up or cause the glue to come loose over time? Will Ardex GS-4 or other product fix the Planipatch underlayment and turn it hard enough? Should I have it removed and how? Can I just mix water with it and turn it back to mud to remove it? Sure don't want a mess but don't want to problems after the install either.

Here's what Mapei says.
http://www.mapei.com/MapeiAmericas/cana ... _WR_EA.pdf
http://www.mapei.it/referenze/Multimedi ... _TD_EA.pdf

It seems Mapei does not recommend Planipatch for "large surfaces" but don't define what they mean by that. They do say you can build up to 1/2" if mixed with water and it is a portland cement product. I do not know if the floor guy mixed it right or not. Mapei does say it cleans up easily. It is not gypecrete and it should not breack down over time. Mapei warranties it. There isn't anything you can apply over it to make it "harder". You could skim coat it with Ardex feather finish I suppose but I fail to see any benefit. You need to decide whether to risk it and install over it or break it out and use something else. I'd question Mapei on exactly WHY it would not work, given that they say it is warranteed, and can be used up to 1/2" for leveling. Isn't this what you said your installer did? Then why would Planipatch NOT work? This is what I'd ask Mapei again before proceeding.

1/2 in of planipatch would not bother me one bit. As far as scratching it goes, that is not an effective barometer for how it performs under a floor.

Where are you laying this floor on grade or above?

I am laying it on grade>

A guy at Lowe's says they have done 100's of floors with just a mix of Planipatch and water so it seems quite standard. I asked them for a warranty of 10 years and they said they might be able to give me a 3-yr warranty instead of just 1 year. I think I'll go ahead and have the wood laid if I can get the 3-yr warranty on the install. Lowe's also said the Planipatch will cure in about 1 month and will be harder.

All I use now is PlaniPatch. It hasn't failed yet. PlaniPatch has latex in the powder mix. None should be added to it.

Your reply is helpful. Do you use it to prepare concrete for glue-down installations of solid wood? I sure hope the shrinking/swelling of the wood planks will not cause the glue to pull away from the Planipatch.

I prep all concrete substrates with it. no matter if it is a solid or engineered.

I hope your applying a moisture blocker before installing that solid over the concrete!!!!!!!!!!!!!!!! Bostiks, MVP4