Flooring in Basement for workshop - material question

[Kurt Redlitz]

I am following Building Science for finishing my basement (16' X 40', 3 outside walls). For my walls, I am using 2" XPS and 2x4 Stud walls with mineral wool insulation, and then drywall.

For the floor, I am putting 1" XPS on the concrete, and Advantech 3/4" T&G OSB subfloor. Not decided about finished floor, but leaning inexpensive laminate.

Two questions on the flooring:

- The laminate says to put a 6mil vapor barrier under it, but the approach for building science is to dry to the inside, so no vapor barrier. What to do there?

- With the 1" XPS directly on the concrete floor, if there is any moisture, there is no where for it to go. Looking at dricore design, they have
the 'normal' product (a membrane panel under osb), it leaves airflow to allow release of the moisture... and the R+ product (with XPS under the osb), but the XPS is 'slotted' on the bottom, I suppose also similarly for airflow.
Should I also cut slots in the bottom of my 1" XPS, both directions as they did, to allow for breathing?

dricore-project-panels-fg10003-64_400.jpg

[Jim Becker]

Any vapor barrier on the floor would go toward the cold side of your entire assembly, IMHO.

As to your "finish" floor...whatever you choose, be sure it's not something that's going to be slippery if it gets sawdust, etc., on it. Many laminates are not good for that. Some of the new vinyls may work, depending on their surfaces. You could also just paint the Advantek and be done with it.

[Kurt Redlitz]

Any vapor barrier on the floor would go toward the cold side of your entire assembly, IMHO.

As to your "finish" floor...whatever you choose, be sure it's not something that's going to be slippery if it gets sawdust, etc., on it. Many laminates are not good for that. Some of the new vinyls may work, depending on their surfaces. You could also just paint the Advantek and be done with it.

So are you recommending putting the vapor barrier on the concrete?

Thanks, I've read a lot of commentary about the laminate, some people saying slippery, some saying that it was just fine, so that's why I'm not 100% sure yet.
Thought about painting the Advantek, though not sure about if it will still be hard to sweep/clean up, or if the paint will fix that. And if it will look ridiculous.

[Jim Becker]

Yes, I was suggesting the vapor barrier go on the concrete before you put anything down. That's not an uncommon thing to do when you're going to float a floor over it.

Some laminate is slippery and some not so much. What you choose is the bottom line, given the safety aspect for woodworking. I agree that painted Advantek isn't "ideal", but it's a valid option.

[Terry Wawro]

Yes, lay poly over the concrete to keep the moisture level down. It will go a long way towards keeping rust away. Advantek or any plywood will be much better on your feet than raw concrete. If you do put down laminate (I did in my shop) be careful like Jim said above. Some of the non-textured stuff gets as slippery as ice with a little sawdust on it.