Basement Floor Framing

[arcwick08]

We're planning to convert our poured concrete basement to living space. There is some moisture, though never to the level of having standing water. We'd like to turn the space into finished living space (eventually, walls are a seperate topic)


I've finished a couple basements in the past with sleepers, foam, poly and subfloor - but those have been in much dryer areas.
I had a few ideas of my own and some that I'd read elsewhere and I'd love any input on them...


1. The way I'd do it: PT2x4 sleepers right on the concrete, screwed to the concrete. Rigid XPS foam in the cavities, 6mil poly across the top of the whole thing, then decked with 3/4 TG ply.


2. The way my wife suggested: Same as above, but use the 1x4 PVC lumber instead of pressure treated lumber and thinner xps foam. Never thought of this before, think the pvc would work?


3. Google Suggestion #1: Poly against the concrete, sleepers on top, XPS in the voids, poly on the top, decked with 3/4TG ply. I've never done poly against the concrete - any concerns here?


4. Google Suggestion #2: 1.5" XPS right against the concrete, no wood sleepers at all. Polcy on top of the XPS, 3/4"TG on top of the poly, screws through the ply and foam into the concrete.


5. Google Suggestion #3: XPS right against the concrete. Poly on top of the foam. Untreated 1x4 sleepers on top of the poly, open cavities, decked with 3/4"TG ply.


I'm going to hit the floor and walls with a good coat of a drylock or something similar prior to flooring anything.


How have others done this down here?

 

[Skymaster]

did you put in a french drain for that floor? the "moisture" ( water " HAS to have a place to go otherwise all the wood you plan on putting in will become sponges. Poly on the concrete is correct, PREVENT moisture getting into the structure. Also DO NOT cover that concrete for a few months, give it time to cure and "dry" out. Green concrete will be full of water that has to bleed out into the air and evaporate

 

[arcwick08]

Sorry, poorly worded first line: The basement is long ago finished (30yo) I tend to write too conversationally... corrected above...

 

[JohnnyR]

I'd use Barricade subfloor. http://barricadesubfloor.com/ Formerly know as OVRX subfloor. You'll find a couple threads here from people like me who have used it as shop floors without a finished floor over it. It's easy to lay down, has rigid insulated bottom with water channels if you have that much water. Also provides a little cushioning. You can cover it with just about any type of flooring. And if you so choose, you can take it up again and re-use it when you build that shop you've been dreaming about.

 

[arcwick08]

I hadn't really concidered any of the modular tile style systems.... Anybody used these? http://www.homedepot.com/p/Amdry-2-...nsulated-R7-Subfloor-Panel-AMD0150G/204395337
The Amdry panels are pre-insulated and vapor guarded.

 

[Endless Pursuit]

Better do a quick test first. Take a 2'X2' piece of clear 3 mil poly and duct tape it to the floor. Place the tape around the perimeter of the sheet to seal it. Allow it to sit for 48 hours, if there is visible condensation on the underside of the sheet you have a moisture problem UNDER the slab. Installing any type of floor containing ANY amount of organic material over that slab will create a home for mold growth. Short of constant power ventilation of the space between the top of the concrete and the underside of the new walking surface, there's no floor system you can install that you will be happy with.

If you don't see condensation, a Heavy vapor barrier that you don't/can't perforate then an open space, then a floor should last a while.

 

[arcwick08]

Better do a quick test first. Take a 2'X2' piece of clear 3 mil poly and duct tape it to the floor. Place the tape around the perimeter of the sheet to seal it. Allow it to sit for 48 hours, if there is visible condensation on the underside of the sheet you have a moisture problem UNDER the slab. Installing any type of floor containing ANY amount of organic material over that slab will create a home for mold growth. Short of constant power ventilation of the space between the top of the concrete and the underside of the new walking surface, there's no floor system you can install that you will be happy with.

If you don't see condensation, a Heavy vapor barrier that you don't/can't perforate then an open space, then a floor should last a while.

Thanks DQ! I'll absolutely do the condesation test, good call. Assuming it returns good results, would you put the poly barrier right against the concrete with sleepers and air void on top?

 

[merrill77]

I used Barricade/OVRX ordered thru Home Depot. The Amdry looks like a similar product...a bit more expensive. Very easy to install.

 

[arcwick08]

If I do find moisture coming through the slab, would these 'floating' vented tile type floors be a no go you think??

 

[merrill77]

If I do find moisture coming through the slab, would these 'floating' vented tile type floors be a no go you think??

Those products are specifically designed for floors and walls that are wet - they allow moisture to flow to a drain and keep it from reaching the wood parts on top. However, they aren't vented (if you're referring to Barricade/OVRX and Amdry). There needs to be someplace for the water to go if it builds up - this is what the channels in the bottom are for. If you have a drain and the floor it pitched correctly, then these are a solution.

Chris

 

[arcwick08]

Those products are specifically designed for floors and walls that are wet - they allow moisture to flow to a drain and keep it from reaching the wood parts on top. However, they aren't vented (if you're referring to Barricade/OVRX and Amdry). There needs to be someplace for the water to go if it builds up - this is what the channels in the bottom are for. If you have a drain and the floor it pitched correctly, then these are a solution.

Chris

Makes sense. If there is water forcing up through the slab are there any ways to remediate it internally (besides correcting the water drainage issues that are the root cause on the exterior)? I've always wondered if grinding the surface down to fresh clean concrete then using a heavy-duty epoxy floor coating would keep it out. Or would the hydrostatic pressure just bubble the epoxy?

 

[Jeff]

How have others done this down here?

New to the South? Where are you from?

It's different here because of our high clay soils which hold water like a cup around your cinder block foundation walls. So the slab and walls are permeable to the hydrostatic water pressure.

​

You'll likely lose several battles and the war too. I'd leave it as an unfinished basement space (think root cellar for spuds and carrots).

 

[arcwick08]

Yep, moved down from northern VT a few years back.
If I went whole hog and dug for correct french drains and drainage around the foundation, would that be effective given the soil type? Again, that's how I'd deal with it up north, but I'm quickly learning that the area and soil change the game completely...

 

[Skymaster]

Perimeter drains are ALWAYS the best way to go in any soil conditions. Water should NEVER be allowed to sit against your footings and walls. Water HAS to have a place to run away from the foundation.

 

[merrill77]

You'll likely lose several battles and the war too. I'd leave it as an unfinished basement space (think root cellar for spuds and carrots).

OP - do you have a fully-enclosed basement or a walk-out? I ask because the layout for most basements in this area is a walk-out on a sloped lot. I'm no expert in this area. My lot has a good slope to it which promotes drainage and I've further improved the water run-off on my lot since moving in help keep my basement dry. A fully enclosed basement is this region is basically a clay bowl. Fixing that problem would be much more expensive. As such, that seems to be somewhat uncommon around here.

So which do you have?

 

[arcwick08]

It is a three-sides-in-the-ground walkout. The walkout is the side of the building, running parallel to the slope of the lot (which is significant)

 

[KenOfCary]

+1 on the OVRX solution. You put it down it has water channels for run-off if it becomes necessary, the only thing in contact with the concrete is the foam layer. You then have an OSB top layer to use as the base for whatever flooring you want to install on top of that. Or in the case of my shop nothing at all. I just put 3 coats of Minwax Poly on top of the OSB.

 

[arcwick08]

+1 on the OVRX solution. You put it down it has water channels for run-off if it becomes necessary, the only thing in contact with the concrete is the foam layer. You then have an OSB top layer to use as the base for whatever flooring you want to install on top of that. Or in the case of my shop nothing at all. I just put 3 coats of Minwax Poly on top of the OSB.

This, I guess, is really the crux of the question: Can these run-off channel equipped floating tile solutions (ocrx, amdry) be used in a basement with a small amount of non-pooling water forcing its way through the slab?

 

[petebucy4638]

The first thing that you need to do is to address the reason why you do not have a dry slab in your basement. There can be many reasons for a damp basement floor - some can be addressed with perimeter drains, sometimes you need to install a sump pump or two under the floor to keep the slab dry. In some cases, where the slab was placed on soils that are not easily drained (North Carolina clay, for example), correcting a moisture problem can be very difficult.

I have never been a fan of basement floor or wall systems that do not address the moisture problem at the source, rather than try to use materials and methods that permit the moisture to flow freely below the finish material. I have seen jobs where the basement slab was cut along the perimeter and across the field to install a gravel/drain system that then connected to sump pumps. A few weeks after the concrete cuts had been repaired, the entire slab and adjoining foundation walls were at an optimal moisture content.

Placing finished flooring over a damp slab is just asking for big problems down the road.

Pete

We're planning to convert our poured concrete basement to living space. There is some moisture, though never to the level of having standing water. We'd like to turn the space into finished living space (eventually, walls are a seperate topic)


I've finished a couple basements in the past with sleepers, foam, poly and subfloor - but those have been in much dryer areas.
I had a few ideas of my own and some that I'd read elsewhere and I'd love any input on them...


1. The way I'd do it: PT2x4 sleepers right on the concrete, screwed to the concrete. Rigid XPS foam in the cavities, 6mil poly across the top of the whole thing, then decked with 3/4 TG ply.


2. The way my wife suggested: Same as above, but use the 1x4 PVC lumber instead of pressure treated lumber and thinner xps foam. Never thought of this before, think the pvc would work?


3. Google Suggestion #1: Poly against the concrete, sleepers on top, XPS in the voids, poly on the top, decked with 3/4TG ply. I've never done poly against the concrete - any concerns here?


4. Google Suggestion #2: 1.5" XPS right against the concrete, no wood sleepers at all. Polcy on top of the XPS, 3/4"TG on top of the poly, screws through the ply and foam into the concrete.


5. Google Suggestion #3: XPS right against the concrete. Poly on top of the foam. Untreated 1x4 sleepers on top of the poly, open cavities, decked with 3/4"TG ply.


I'm going to hit the floor and walls with a good coat of a drylock or something similar prior to flooring anything.


How have others done this down here?

 

[KenOfCary]

This, I guess, is really the crux of the question: Can these run-off channel equipped floating tile solutions (ocrx, amdry) be used in a basement with a small amount of non-pooling water forcing its way through the slab?

I'm no expert, but that is exactly what they've been designed to do. If I were having these questions, I would contact them directly and request answers to your specific issues. The product worked great for me and several others here in our area, but you have to evaluate it in your context. I know of at least 4 satisfied shop owners using it personally.

Your Mileage may vary. YMMV.

http://www.ovrx.com/