Hollow sound in glued-down wood floor

[ievans]

After applying a sealant, our installer glued down an engineered wood floor to a concrete base (which he first leveled by sanding it down). A few weeks later, several (but not all) boards began to end-lift. In other parts, tapping on the floor produces a hollow sound. He "injected" more glue to deal with the hollow sound, but more hollow spots seem to be appearing elsewhere. He proposes to deal with the end-lift problem by replacing the problem boards (and will re-apply sealant). He used the best Bostik glue and sealant. I am very anxious that the entire job has gone wrong? Will his solutions work? What is the best way to deal with both problems? Should I be worried??[/b]

 

[WoodYouLike]

Could be several things:

A) concrete base to 'wet' when glueing the floor
B) wood to wet
C) not enough glue used.

Dud your fitter check any moist-levels in concrete and wood?

 

[ievans]

The concrete base was not wet or moist at all: it is an old concrete foundation and a moisture check (conducted in my presence) revealed little to no moisture throughout. The wood (Anderson, Hickory, 5 inches wide) rested for a 7 days in our house before it was installed. He did not specifically check the wood for moisture before installing it, however. If (A) and (B) are not the problem, does this suggest that he did not use enough glue??

Assuming that there may be more hollow spots, long does it take for hollow-sounding spots to appear?

Many thanks for replying.

 

[big-all]

other possible causes for not sticking contamination dust oil grease on either surface

 

[WoodYouLike]

The concrete base was not wet or moist at all: it is an old concrete foundation and a moisture check (conducted in my presence) revealed little to no moisture throughout.

What is little to no moisture? 5 ,4 3, 2 % ?
It shouldn't have been more than 2.1%

If (A) and (B) are not the problem, does this suggest that he did not use enough glue??

Could be, but also what big-all says could have happened.
I haven't heard of Bostik and neither have ever seen an ad of their products for wooden flooring in trade magazines for wooden flooring.