shop floor question..

[Don Palese]

I live in Southern Oregon where Winter isn't terrible but it does get your attention. My shop (25 * 30) is insulated and I do keep the air temp around 60 deg. during the cold months. My problem is the concrete floor. Once my old feet get cold it seems to signal the end of the day in my shop. I've been planning on a wood floor by putting down treated 2/4 sleepers and then 2 layers (alternating) of 1/2" osb. Since I don't have a moisture problem with the floor, my question of the hour is: What should I use under the sleepers .. roofing tar paper or 10mill plastic sheet ?? What comes first, the moisture barrier and then the sleepers or the sleepers directly on the floor and then the moisture barrier directly under the osb layers ??

Thanks. Don in Medford

[David G Baker]

I don't know the recommended method but what I would do is lay down the 10 mil plastic then the sleepers and in between the sleepers as much blue foam board as will fit between the slab and the OSB (probably 1 1/2 inch). I have had roofing tar paper stain surfaces. I would use pressure treated lumber for the sleepers.
My pole barn does not sweat and my smaller barn doesn't sweat but my 2 1/2 car garage will have puddles of moisture on the slab when it is humid or raining.
If I spend a lot of time in one spot in my shops I stand on the thick rubber mats and this keeps the old tootsies warm.

[David Hostetler]

Instead of all that effort, and gobbling up height with the additions, you might try DriCore Air Gap flooring tiles. Yeah the 2x4 sleeper arrangement works, I would just be concerned with loosing upwards of 4" to 6" of overall height in the shop...

Either way, you are MILES ahead in comfort with heat / cold and fatigue by using some sort of wooden floor compared to straight concrete...

[Jerome Hanby]

You could turn that height loss into an advantage and run some dust collection pipes and/or power lines inside the floor.

[Jason Beam]

I did exactly what you're thinking of, Don. Only - i didn't use pressure treated.

I laid 2x4 sleepers down onto a 6mil plastic moisture barrier. I ran the plastic up the walls about a foot, but i don't know if that's really needed. The way I figure, the plastic keeps the moisture from wicking through the concrete into the sleepers so i wasn't worried enough to go with PT. If i live to regret that, I'll let ya know.

I don't see any reason to stand them vertically, though. I laid mine down flat - 16" on center. I laid T&G osb suflooring down and for now just painted that with garage floor paint.

My goal was inexpensive and adequate - 3/4" T&G osb is having no problem holding up things like my 400lb+ bandsaw or jointer. My lumber cart probably wieghs 1000lbs fully loaded and the floor doesn't mind that, either.

Not a hint of cold floor in the winter, and the wood floor is softer anyway which lets me keep going even longer

[David Hostetler]

Okay I had to rethunk the math here...

2x4 laid down width wise, is 1.5" tall, OP is talking about adding 1" of OSB on top of that, for a total thickness of 2.5". Not that bad of a loss...

I would say that is a good bet. Lay down a moisture barrier, set your sleepers, fill the void in the sleepers with styrofoam insulation, Lay down your first layer of OSB, then do your alternating layer, paint it up, let it dry and move in... Cheap, fast and easy. The hard part is getting the shop stuff out for a while so you can actually do the work...

[Jason Beam]

The hard part is getting the shop stuff out for a while so you can actually do the work...

Man you ain't kiddin!

I did it with 80% of my stuff in there. 4x8 at a time, dangit.

It got done, but I really hated moving everything 4-5 times. I almost .. almost .. rented a POD just so i wouldn't have to. Cheap won.

[michael osadchuk]

I live in southern Ontario and the rule that was used when I built my basement workshop/house extension was :
:vapour barrier on the warm side of the insulation
so I would put vapour barrier just under the OSB and on top of both the sleepers and foam insulation
(this location probably isn't super critical in your situation 'cause presumeably the existing concrete floor has some insulation value)

as Jason said 6 mil polyethelene sheeting is plenty strong

- I used this in my situation which was:
undisturbed earth
gravel
2" foam slab
6 mil vapour barrier
poured concrete floor

when I did this construction I learnt that there was a type of white beaded foam slab that was fine for this situation and did not go with the much pricer "blue, SM? foam" .... no sag in the flooring, virtually no vapour leakage; I can lay a fresh saw plank on the concrete floor overnight and there is no wood movement from moisture.....

good luck

michael

[Charles Murray Ohio]

http://
Don,

I just recently completed my shop. I put down 6 mill plastic, over top of that I place 1 ½” wide strips of PTL that I ripped from 1 x 6. These were just layed down, 14½” wide ¾ thick pieces of foam were laid down in between to insulate AND act as a spacer. T&G plywood ¾” thick was laid on top and screwed to the ¾” sleepers using 1 ¼” deck screws. The whole floor floats. Doing it this way allows the space to be converted back to a garage, if needed with no damage to the concrete. I also ran some wiring under this.

[Jamie Buxton]

Instead of insulating the entire floor, put insulation just where you need it: on your feet. People work all day outside in the snow, and their feet don't get cold. They wear insulated boots and thermal socks. You can do the same in the shop. It will cost you a lot less.

I used to get cold in the shop in the winter until I realized that I can look like a snowmobiler dressed for freezing weather. Strangers may think I look a little weird, but comfort and safety trump their opinions.

[Steven Ley]

According to code in southern Ontario:

1) firstly, any time you are putting wood to concrete there must be a barrier of 6 mil under the 2x4

2) then you would put you 2x4 down

3) if you chose to insulate than yes there should be a vapour barrier placed on the warm side (6 mil)

4) then your OSB sheeting goes down.


personal opinion is that dri-core is a great product and definately takes up less room.

[Don Bullock]

You might want to look into some kind of radiant floor heating system if you're going to install a wood floor in your shop. There are some electric systems that could go between the concrete and the wood.

[Thom Sturgill]

Since you are already planning on two layers of plywood, you can sandwich extra insulation between them. This will give a complete thermal block. Make sure that you stagger all joints and use construction adhesive. Works like a SIP. I believe that you either need a barrier on the concrete or use PT sleepers. I would agree with having the floor float. Leave a small gap at the walls and use canned spray foam (low expansion 'Good Stuff' for example - the type used for around windows and doors ) there for expansion & insulation.