Vinyl Plank Flooring on concrete slab - Recommended assembly for 3/4" to 1" Build Up

[Charles S White]

Hello,
New to Vinyl Plank Flooring and having trouble finding consensus on what the best assembly would be for the concrete slab I have in a new building we have.
Looking for the total thickness of the build up floor to be between 3/4" and 1" (exterior door thresholds are about 1 1/4" over the slab).

I'm seeing advice for moisture barriers, then OSB, then Vinyl Plank, then advice against it.

It's a fairly fresh slab on grade, so good chance for moisture.

I've seen the Dricore option, but wondering if there's something more economical yet dependable.

Any help/advice would be great.

The Vinyl Plank flooring I'm planning on using is 6.5mm thick.

Thanks!

 

[Floorist]

Concrete needs to dry for about 4 months before floor covering is installed.

 

[Charles S White]

Slab was poured in November, though the building was dried in at the tail end of December.
March would be ideal to start doing flooring. That would get us to about 3 months, almost 4.

After a few YouTube videos and articles/posts, it seems like one option would be:
- DMX or Delta underlayment
-1/2 OSB (The thicker T&G OSB would be better but then I'm over on overall thickness
- 6.5mm Vinyl Plank

That or just the 3/4" dricore and the 6.5mm Vinyl Plank.

Again, appreciate everyone's help.

 

[highup]

I read that properly poured cement dries at about 1 inch pet month. Curing is not related to drying, so that 28 day thing does not apply
I also read from Latacrete that actual drying of concrete does not start until all the doors and windows are installed AND that the heating system is running......
That means, if the home was totally enclosed a year ago and the heating system was installed yesterday...... The concrete will start to 'dry' the date the heating was turned on, not from the date it was actually poured.
Think of this as 'lived in' conditions.

Ok...I re read your initial post.... Vinyl planks? Why add OSB?
If you suspect a moisture issue, install/apply a moisture retarder.
OSB just makes moisture issues worse.

 

[Jon]

Further to highups comment about doors and windows installed
Here we look at the building being water tight so that any rain which could leave "lakes" on the concrete slab will slow the drying time

 

[Charles S White]

I read that properly poured cement dries at about 1 inch pet month. Curing is not related to drying, so that 28 day thing does not apply
I also read from Latacrete that actual drying of concrete does not start until all the doors and windows are installed AND that the heating system is running......
That means, if the home was totally enclosed a year ago and the heating system was installed yesterday...... The concrete will start to 'dry' the date the heating was turned on, not from the date it was actually poured.
Think of this as 'lived in' conditions.

Ok...I re read your initial post.... Vinyl planks? Why add OSB?
If you suspect a moisture issue, install/apply a moisture retarder.
OSB just makes moisture issues worse.

Due to some constraints, heat won't be on for a while.
Can't let the building just sit for 3-4 months heated and unused.

I don't have particular concerns beyond the fact it's a new slab.

It seems given my time constraints, I want to install a system that allows moisture to escape, whether it be Dricore or some other system.

Saw some people online using the mix of DMX and OSB as a cheaper option to Dricore, which I think is also OSB. The DMX raises everything up to allow air circulation.

If I was going to go the moisture retarder route, any recommendations? Is this a pretty sure thing to prevent issues?

Thanks for the help

 

[Charles S White]

Further to highups comment about doors and windows installed
Here we look at the building being water tight so that any rain which could leave "lakes" on the concrete slab will slow the drying time

Building has been sealed up for about a month now.
Unfortunately won't be heat for a while though.

 

[Charles S White]

Concrete needs to dry for about 4 months before floor covering is installed.

Looking for any solutions to cut down that time. Unable to wait four months, especially if that clock only starts once heat is in the space per the comment below.
What's the best plan for that?

 

[Floorist]

OSB falls apart if it gets damp. You can take a chance and hope it works. I turned down a big job because the concrete was only 30 days old. Guy who took the job replaced it out of his own pocket after it failed.

 

[Jon]

Get someone with a good, not a cheapy moisture meter to take some readings of the concrete slab to check how the drying process is going then you could work out the next stage
It might be dry already?

 

[Floorist]

Get someone with a good, not a cheapy moisture meter to take some readings of the concrete slab to check how the drying process is going then you could work out the next stage
It might be dry already?

Seattle is a really humid area.

 

[DarisMulkin]

Drying and cured are 2 different animals I believe. Cured to me is when it is the hardest. Concrete never really dries or it would turn to powder, there is alway moisture moving through it, just how much the moisture tests and insitue tests tell you. Also then you have to deal with the pH levels as well. Moisture pushes pH.

 

[Jon]

Another way for a guide is grab a sheet of heavy duty plastic say 4 foot square then tape all the edges to the slab
Remove after 24 hours then if the concrete is a different shade under the plastic your floors still wet

 

[highup]

Like Jon said, get the slab tested for mosture content. I would consider that as mandatory.
I once was asked to install vinyl in a kitchen. The slab had cracked over the years, so it was jackhammered out and repoured. A month after it was poured is when I was asked to install the new floor.
I told the lady there's no way the slab was dry this soon. I went to the house to take a look. The heat was on and the floor felt warm and it was dusty...... It looked dry as a bone. I did a moisture test and the slab was about 19 lbs per thousand, way too much emissions to lay the floor.
I took over a dehumidifier, emptied it almost daily for a month and a half and the slab was about 70 degrees.
I retested the moisture emissions and it had dropped to a bit over 10 or 11 lbs per thousand, still almost 3 times too much moisture emissions two and a half months after it was poured.
Have a moisture test done.

 

[Floorist]

Drying and cured are 2 different animals I believe. Cured to me is when it is the hardest. Concrete never really dries or it would turn to powder, there is alway moisture moving through it, just how much the moisture tests and insitue tests tell you. Also then you have to deal with the pH levels as well. Moisture pushes pH.

Yep. My dad was a concrete guy. He said it takes at least 50 years to dry and then begins to crumble.

 

[highup]

He's not going to wait 50 years. (Smiley face)