Waxed concrete floor bubbling

5 replies [Last post]
Juliette Harris

Dear professionals,

I need your advise regarding my brand new waxed concrete floor.

1 yr 1/2 ago I had my whole first floor done by a professional contractor specialized in decorative concrete. At that time they demolished my wood floor to apply what you guys call a polished stained concrete floor. After a while, we noticed multiple problems (tiny needle size holes, lighter "ghost" stains where the carpets were, irregularity of the color making the floor looks like stained etc.). The contractor came back to fix the problem. After multiple problems, due (in my non professional opinion) to rushing the different steps (they had to redo the entire floor 3 times before to obtain the one I have now), we followed the contractor's advice and decided to do a waxed non stained floor. I am still not happy with this new floor. It is covered with thousands and thousands of tiny little holes... I asked the contractor about it and he said that it was a normal/common decorative concrete reaction.


My first question is: is it really a normal reaction, or is it due to something not done properly during the process?

Second question: if it is normal, what can I do to fix it?

Third and last question: if he did (again) something wrong, what can I do to prove it, can I call an inspector or a professionnal to check my floor?


I have been more than patient, I moved all of the furnitures, appliances 3 times now and damaged some in the process, I don't want to do it all over again. I really need your advices.


Thanks in advance

GandCFloor's picture
Can you please post what the

Can you please post what the process was in the floor removal and install. You have mentioned you had a timber floor? was there existing concrete underneath this timber? did the contractot install a overlay topping on this concrete??

we then can advise you a bit furhter. i do think i can see what is going on but i would like to know the entire process before i comment. Im sure this is frustrating for you...


Juliette Harris
First of all, thank you for

First of all, thank you for your answer.

The floor has been redone so many times that I don't remember everything he did.

Before the demo it was woodfloor on top of tiles. They removed both to find the slab, and then worked on it. As of the detail of what they did exactly, I don't know. They ground the slab, patched the cracks and holes, they polished and cleaned before to apply a primer and pour the concrete overlay on this slab. Then they applied a sealer (solvent based) and layers of wax.


Thank you


Dr J's picture
Dr J
Good info we can help... The pinholes in your concrete is caused by out gassing from the slab underneath. It can be fixed. Will need to be sealed and then resurfaced. Your contractor missed a step when installing the overlay. Before installing an overlay the surface needed to be primed to prevent this out gassing. It is fixable though.

Juliette Harris
Thank you so much for your

Thank you so much for your answer.

I do think he applied a primer, here is one of the email he sent me before to redo the floor the last time (round number 4):


I spoke with Jamie and recommended doing a hard trowel concrete finish which will look great, be in your color tones, really smooth and very shiny.  This is a very strong and durable finish and would be completely locked off.  This will also eliminate the issues you had with the rugs.  That line from the rug still showed up today when we were priming the floor even after how many times we ground the floor now.  This is another reason we are concerned with doing the polished overlay again.  I'm afraid your rugs may cause ghosting again which none of us want. 


Thank you :)

GandCFloor's picture
It is outgassing of some

It is outgassing of some sort. Are you saying that you have had 4 seperate overlays done? and these holes have been on all layers?,if so then you have a problem in your slab of some sort that could have been overcome with an adequate primer. In this case it looks like you should have had a waterbased epoxy hydrostatic moisture barrier to stop this issue. This 2 pak is then broadcasted with fine sand for the overlay to adhere to. This would hae stoped it IMO. Ive learnt the hard way on this matter. My hat goes of to him comming back to try again 4 times. Some concrete is just plain difficult to deal wit because of so many differant variables. if i was you i would get the fllor prepared by removing the current sealer and abrading you overlay again. Install the Epoxy moisture barrier and re install your floor. it should fix the problem.

Hope that helps you a bit. others in this forum have plenty of experiance on these matters and might recommend other solutions also, but that is the way i would go...

Good luck