Pine floor in workshop

Wayne Watling

Member
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19
Hi,

This is my first time installing a wooden floor, its for the workshop in a double garage and will be contructed of 1.5" x 8" pine T/G boards. After compiling a list of ideas on floor installation from various sources I wanted to run my final plan via some of you with more experience than I before beginning.

The pine floor will be layed over a 20 y/o existing concrete slab in a cold weather climate (ontario, Canada). Firstly I'm putting down a 6mm vapor barrier then a frame around the perimeter of the room using 8" sleepers ripped to level out the slope in the existing concrete floor. Sleepers will then be layed at 16" centres between the frame which will also be ripped to level out the slope of the concrete. I'll place shims every 12" where the sleepers don't quite meet with the concrete and use string line with level to get a level surface as the sleepers are being layed.

Apparently blocking is not necessary but can aid during the construction process so I'll use only if required.

Is it absolutely necessary to tapcon the sleepers to the concrete? There will be some fairly heavy equipment placed on the floor when complete.

Will the shims stay in place by themselves or do they require glueing to the bottom of the sleepers.

Would it be better to leave a small gap between the sleepers and concrete along the entire length of each sleeper for shiming or should I attempt to rip the sleepers to fit as snug as possible to the concrete and resting directly on the concrete as much as possible.

Thanks,
Wayne

p.s I have not decided on insulation as yet, it depends on the final cost.
 
first and formost

i hope you are planning on using treated lumber! if you dont it will rot from the moisture it gets from the concrete.. have done a wood floor over concrete with plywood but not your methode i did anchor the ply with tapcons every 8" just like underlyment.. then put exterior grade interior ply over that. still settin good but did have screw pop and come up from the
1/2in ac ply. used drywall screws to anchor the top layer wont do that again they are to fragil. use real screws next time
 
vapor barrier or moisture barrier? They're different things. The concern with wood on concrete is that the concrete slab will wick moisture from the ground and provide nice damp conditions for rotting out your sleepers. The flooring itself should be ok regardless, as any condensation would form on the slab (should being the word of choice, still better to go with a full barrier IMHO). One important point is to use PT if you can, as Larry points out, but bear in mind that cutting or milling it will remove its protection. Ends should be "re-treated" with green nasty liquid, and if you rip or plane it, you might as well just use regular lumber and treat it yourself (applying the liquid is not considered as good as pressure treating). You could also look into a decay resistent species like the cedars for your sleepers. Can't say as I see much point to gluing them down if you're planning to (a) use a barrier, and (b) shim them; but maybe I mis-understood that part. Fastening the sleepers with tapcons or ramset nails is probably for the best, keeps them from moving on you as you build the floor, and also keeps the shims from working loose over the life of the floor. If you end up not needing to shim, you could probably skip the fasteners, but I'd still do them myself. I tend to like ramsets or redheads, or those multi-part sleeve anchors, never really got tapcons to work for me -- they either break or strip.
 
This may be off the wall--wouldn't be the first time, but I think I would put a layer of tar paper over the plastic going on the concert floor. Walking, lumber, or anything else will tend to penetrate and/or wear holes in the plastic, the tar paper should help slow or stop the process. Even using treated lumber you want to slow/stop moisture infiltration as much as possible.
 
First lets get this clear. I am not expert so I don't really know this. OK? ;)

First thing that struck me was the 16" spacing on your sleepers. It's probably OK, but considering the WW machines I would think about 12" spacing. Less chance of it giving and less chance of an unlevel spot in the floor. Now if you have info from a supplier that 16" is good by all means listen to them.

Second, I think a properly installed vapor barrier will be OK since you have an air space. Interior floors on slabs are done the same way. Tar paper/felt is not a bad idea in addition to the plastic.

Last, I am envious. I would love to have wood floor over my slab! That the only thing I don't like about the Lab.
 
I've been on the concrete floor now for over 3 years and thats enough, really looking forward to the wood not only for my legs and back but also for its ambience.

Thanks for your questions and ideas.
I guess its a moisture barrier not a vapor barrier as the 6 mil polyethelene sheet is layed to stop the moisture moving up into the subfloor. I planned on running it up the sides of the walls a few inches and seal it using red tape.
Hadn't planned to use PT lumber simply because I had a good supply of non-treated 8" x 2" x 12' beams. Wouldn't the 6 mil poly film prevent the moisture from rising up particularly since the slab is above grade and 20 year old? Worse case perhap I could paint the floor with some type of specialised membrane and also paint the beams with the terrible green stuff. I did read somewhere that tar paper can get smelly in summer when the tar gets hot and soft and begins to melt with the heat and then squeezes out due to pressure from the weight on the floor. Is there anything else I could use, Jeff mentioned felt so I'll look into that.

I thought that gluing the shims to the bottom of the sleepers would keep them from working their way out over time, because of the plastic moisture barrier they couldn't be glued to the concrete but the glue on the upper surface would at least keep them in place, perhaps?. Because the sleepers would be 8" in depth for the most part its going to be quite a job to fasten them to the concrete. They would require some predrilling to get the Ramset device in deep enough to get into the concrete so I was hoping to get away without having to fastens them. Perhaps there is another way using those metal brackets that would lay flat and fasten to the concrete and then fasten to the sides of the sleepers but I'm just thinking out loud here.

The floor boards themselves are a true 1 1/2" in thickness, thats twice the normal thinkness of 3/4" boards, they told me I'd have no problems with 16" centres with that thinkness of board, in fact I could go to 24" if required but due to the heavy machinery I'll stick to 16" centres.

I guess one of the biggest questions I have relates to the sleepers and whether is okay to rest them along the majority of their length on shims say every 12", this would make the ripping process a lot easier since I could just cut them approx width and then shim all the way along.

Really appreciate your input..
Wayne
 
You will be better off if the sleepers are in FULL contact with the floor, and only use the shims where there are low spots. To rip them to match the floor and also be level on top, fasten a chalk line at each side of the room on top of the frame you have installed around the perimeter, with the line centered in line with where each sleeper will be, then set the sleeper down on the floor against the chalk line and pop the line to mark the sleeper, then rip the sleeper and it will fit the floor and be level on top.

This old house program did an install like you want to do on one of their projects and they also used some kind of material that had ripples/grooves in the bottom to let any moisture that collects on top of the concrete flow to the low end and outside and it keeps the wood dry. On the subject of tarpaper, it will work to a certain degree, and I have NEVER sseen or heard of the problem you mentioned, because unless the building is on fire, you would not ever generate enough heat to cause a problem. It has been used ever since I can remember, on the underlayment of floors, and is still used today in our area and we are a very hot climate. I have NEVER smelled the tarpaper in any house or building I have ever been in.

You might query the guys at "This Old House" to see what that stuff was they used if it interests you. They fastened their sleepers down with the drive in expqnsion fasteners.

Oh, yes, if your flooring is 1 1/2" thick, the 16" on center for the sleepers will be fine.

Keep us posted on your project, and good luck with it.
 
Last edited:
Norman,

Thanks for the reply, I'll rip them to fit. I'll post back with a few pics as the floor starts to take shape.

Regards,
Wayne
 
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