Contractor Talk - Professional Construction and Remodeling Forum banner
Cancel
Create thread New Forums

Anyone have experience gluing engineered hardwood to gypcrete?

Jump to Latest
1 - 20 of 23 Posts
R

RhodesHardwood

· Registered
Joined
·
1,363 Posts
Discussion starter · #1 ·
We have a large condo project booked that is going to require us to glue 5/8" unfinished engineered to gypcrete in a multi-unit condo building. The plans call for us to seal the gypcrete with a product called Specco S-55. The gypcrete guy and contractor claim that this helps the gypcrete not suck all the moisture out of the glue and that this helps it glue to it better.. I have reached out to Bostik and Taylor to see what they have to say about this but I haven't got much help.. The contractor is on me about getting a contract to him but I want to be sure that this sealer isn't going to create issues. This is a great job so I hate to pass on it, but I also don't want major issues coming up because of it.

If anyone has any experience please help. Thanks!!
 
#2 ·
We did a job with a pre-finished Shaw plank. The job was about 4000sq ft. The Gypcrete was Maxxon with the Maxxon sealer applied. Then verify moisture content was good. I spent many hours getting the shaw rep to commit to being able to put it over the gypcrete. It specifically said in the instructions not to. We have had no issues with the floor.

I would make sure and use the gypcrete's sealer so as not to void their warranty.
 
Discussion starter · #3 ·
Thanks for the reply. Ya unfortunately they want us to seal the gypcrete with the sealer I mentioned.. I did just find that Taylor (the adhesive manufacturer I planned to use) actually makes a gypcrete sealer and it is also acrylic latex based like the other product they mentioned. So think I might see if they are open to using it.. I did specify the psi strength of the gypcrete to that will not be an issue.. My only dilemma is making sure that I'm not going to run into issues with bonding.. Either way I appreciate the reply, and it's good to know that someone has had some success with this.
 
Discussion starter · #5 ·
Thanks for the reply. Yes I've been in discussion about this job for about 30-40 days. I have spoke with the architect, gypcrete guy, the contractor etc.. They are all insisting that we use this. I've done a fair amount of research tonight and it seems that it's at least somewhat common to seal the gypcrete.. From what I am gathering it seems that not sealing it will cause the gypcrete to suck too much moisture from the adhesive and that can potentially cause issues..
 
#6 ·
Ive laid approximatley 8000 feet of solid bamboo over gypcrete with ms plus. No primer. No call back. Floor needs to be flat and thats about it. Ive been doing these installs for the last 30 months. The gypcrete is 20 years old so its perfectly dry; a newly poured slab will require much more caution.
 
#7 ·
Anyone Have Experience Gluing Engineered Hardwood To Gypcrete?

I haven't looked up the specco product nor any hardwood on gypcrete.
But we installed LVP to Gypcrete. We used Ardex primer 81 or 51 can't remember # but the effect it seemed to have was not a "sealer", it seemed to strengthen by penetrating down creating vertical 3 dimensional bond.
You know weakness is right below the product(primer) applied, so when it soaks in it creates a better bond than on a flat plane
 
Discussion starter · #8 ·
Metro M & L said:
Ive laid approximatley 8000 feet of solid bamboo over gypcrete with ms plus. No primer. No call back. Floor needs to be flat and thats about it. Ive been doing these installs for the last 30 months. The gypcrete is 20 years old so its perfectly dry; a newly poured slab will require much more caution.
Click to expand...
Thanks for the reply. The gypcrete guy says it takes 7 days to cure, we will have 3-4 weeks between it being done and the floors. I plan to start monitoring the moisture content after the gypcrete has been poured for 2 weeks. I have also specified that we need the gypcrete to be at 3500psi. I'm going to record the moisture content, take pictures, level/grind as needed before applying the primer/sealer.. Just worried about the bond.. I guess the word sealer just scares me..
 
Discussion starter · #9 ·
MIKE ANTONETTI said:
I haven't looked up the specco product nor any hardwood on gypcrete.
But we installed LVP to Gypcrete. We used Ardex primer 81 or 51 can't remember # but the effect it seemed to have was not a "sealer", it seemed to strengthen by penetrating down creating vertical 3 dimensional bond.
You know weakness is right below the product(primer) applied, so when it soaks in it creates a better bond than on a flat plane
Click to expand...

Thanks for the reply. Ya I've read a lot about Ardex and it seems to be a preferred product for this. Also, in doing more research it seems that you are absolutely right about it actually creating a better bond. Like I mentioned in my reply to Metro, I think the word sealer just had me worried because in most other cases for glue downs sealer is a bad thing..
 
#10 ·
Metro M & L said:
Ive laid approximatley 8000 feet of solid bamboo over gypcrete with ms plus. No primer. No call back. Floor needs to be flat and thats about it. Ive been doing these installs for the last 30 months. The gypcrete is 20 years old so its perfectly dry; a newly poured slab will require much more caution.
Click to expand...
You're braver than I. That crap won't stick to broom finished 30 year old above grade concrete worth a damn. I'd never trust it over gypcrete. I hate that glue.
 
Save
Reply Quote Like Like
#12 ·
We sanded the gypcrete the next day with a floor sander to flatten in out.

So I think your sealer that you are going to use looks reputable, just make sure the glue company is good with their product going over the sealer.

Is there heat in the floor?
 
Discussion starter · #13 ·
elementbldrs said:
Have a fall back plan if the gyp doesn't dry in the time frame you need. Dehumidifiers and heaters as a t&m clause. Bit me for $18,000 on a job, couldn't get my moisture numbers down.
Click to expand...
Thanks for the reply. The contractor has large commercial dehumidifiers they plan to use for this and I triple checked that this bill isn't on me. I think we have 2 weeks between the gyp being poured and the start of the install.. In general do you think this is enough time? I know their are many variables ie; temp, humidity, air movement, thickness of gyp etc.. Thanks for the reply!
 
Discussion starter · #14 ·
donerightwyo said:
We sanded the gypcrete the next day with a floor sander to flatten in out.

So I think your sealer that you are going to use looks reputable, just make sure the glue company is good with their product going over the sealer.

Is there heat in the floor?
Click to expand...

Ya I planned to buff the gypcrete with a 60 or 80 hard plate sand paper if needed to level it out.. Contractor tells me we should have little prep, as he uses these gyp guys regularly.. But you know how that goes.. I'm waiting to hear back from the adhesive company on compatibility..
 
#15 ·
One thing that concerns me personally, and I've heard a tech rep confirm is when you sand a surface your actually forcing dust into the slab and leaving on surface. Then he said shotblasting is preferred method in certain situations.
I've been grinding for quite a while now and the residue is annoying, say when I walk from slab to top of hardwood you see footprints. I have a good vac system while grinding and afterward but doesn't ever get film gone. I always wanted something to spray on surface like a densifier to lock dust and slab together and of course compatible with adhesive/s
 
#16 ·
We ran 15 commercial dehumidifiers a floor (8,000 sq ft compartmentalized to 10 condos) for 7-15 days at 2-3 1/2" gyp poured, this was after 2 weeks of drying due to moisture not coming down to acceptable levels.

I really think it depends on the variables as you stated. Just warning that the bill goes up fast.
 
Discussion starter · #17 ·
elementbldrs said:
We ran 15 commercial dehumidifiers a floor (8,000 sq ft compartmentalized to 10 condos) for 7-15 days at 2-3 1/2" gyp poured, this was after 2 weeks of drying due to moisture not coming down to acceptable levels.

I really think it depends on the variables as you stated. Just warning that the bill goes up fast.
Click to expand...

I appreciate the heads up. I emailed the contractor again making triple sure that they plan to handle everything associated with dehumidifiers if needed and he assured me they would provide them, pick them up etc.. Hopefully we don't have this kind of hold up because it would throw off our schedule horribly.. Guess I'll plan for an extra couple of weeks just in case.. Then if it don't hold us up I'll take a couple week break.
 
Discussion starter · #19 ·
MIKE ANTONETTI said:
There's wood adhesives that don't care how much moisture is in slab, the trowel applies a layer of adhesive and the notch and they say this acts as the barrier. Trying to get water out of slab is time consuming.
Click to expand...
Ya I plan to use Taylor adhesive.. I've only used their stuff once before as we don't do many glue downs, but apparently the adhesive acts as a moisture barrier too at the right spread ratio.. So I plan to do the thicker spread to be safe.. I wouldn't be so concerned but its 6,000sf so I want to make sure everything is perfect so nothing can come back on me as it would put a huge financial hurting on me if it did.
 
#20 ·
I agree, we try to get everything with minimum risk, following or close to guidelines makes life less stressful. Wiggle room is good.
Not that I believe all of the claims on products, the one for thinset where it says it will bridge cracks up to 1/8", and some people say the products for the barrier doesn't work, so maybe not if your at the high mark, but say the dehumidifiers remove a lot of water and the barrier may be just enough to avoid a moisture problem, then it's worth the extra effort. Wagner has a good site for info as well for moisture situations. When you have multiple products they tend to blame one another.
 
1 - 20 of 23 Posts
About this Discussion
22 Replies
7 Participants
Last post:
RhodesHardwood
Contractor Talk - Professional Construction and Remodeling Forum
posts
3.6M
members
169K
Since
2003
A forum community dedicated to professional construction and remodeling contractors. Come join the discussion about the industry, trades, safety, projects, finishing, tools, machinery, styles, scales, reviews, accessories, classifieds, and more!
Full Forum Listing
Explore Our Forums
General Discussion Tools & Equipment Business Painting & Finish Work Decks & Fencing