Solid wood flooring

[Albert Lee]

I am about to install solid wood flooring for my living and dining room, it is on concrete, the slab is 20 years old.
I have bought some 8 x 2 oak and will rip them into 100mm x 13mm (roughly 4 x 1/2), each board will be about 2000mm long
I have the moulder, cutter and feeder to do this work.

I have a few questions about this job

1. Do I need the grooves at the back of the floor board? searched the web and I cant find a solid answer, some suggest its there because floor is not flat, a grove in the board will help to bridge over the inconsistency, some say its relieve the stress, and even weight saving was suggested.

2. There is damp proof membrane between the concrete and the soil, It will be beneficial to install moisture membrane?

3. Do I need micro bevel on the face of the board?

4. Since I am moulding my own floor board, would it be better to have them in the same orientation so the face of the board was always the side of the board facing the centre of the tree? or would it better to alternate just like panel glue ups?

5. any other tips you can share?

[Ron Selzer]

I am about to install solid wood flooring for my living and dining room, it is on concrete, the slab is 20 years old.
I have bought some 8 x 2 oak and will rip them into 100mm x 13mm (roughly 4 x 1/2), each board will be about 2000mm long
I have the moulder, cutter and feeder to do this work.

I have a few questions about this job

1. Do I need the grooves at the back of the floor board? searched the web and I cant find a solid answer, some suggest its there because floor is not flat, a grove in the board will help to bridge over the inconsistency, some say its relieve the stress, and even weight saving was suggested.

Yes, more for inconsistencies

2. There is damp proof membrane between the concrete and the soil, It will be beneficial to install moisture membrane?

Yes, check first, tape down plastic sheets 4'x4' , various places on the floor check after a week to see if any moisture trapped under plastic

3. Do I need micro bevel on the face of the board?

No, better to sand and finish the floor after install. micro bevels are for prefinished boards to hide the mismatch

4. Since I am moulding my own floor board, would it be better to have them in the same orientation so the face of the board was always the side of the board facing the centre of the tree? or would it better to alternate just like panel glue ups?

5. any other tips you can share?

How do you plan on fasting this floor down? answers above in quoted section, not certain how to undo this

Good luck
Ron

[Scott T Smith]

A good moisture barrier under the flooring is important.

Narrower strips will show less movement. I would not worry about growth ring orientation but select the best face.

Moulder profile cutters for flooring are designed so that there is a slight gap between the boards below the tongue and groove. This is to accommodate for the presence of any small derbies that get caught in-between the flooring strips when they are being installed. The strips only touch above the tongue and groove, not below it.

[Tom M King]

To answer question 3: Prefinished flooring has the bevel because it's almost impossible to put down wood flooring, and have the face plane exactly flush with every board. The bevel just hides that, and is the only purpose.

If the floor is going to be sanded, there is no reason to have any edge bevel. That's one of the main advantages to sanding flooring after being installed.

[Richard Coers]

The place to worry about dampness in the concrete is around outside walls. Your barrier protects from underneath, but not in from the side. The fastening question is excellent. Personally I wouldn't install solid wood directly on concrete.

[Albert Lee]

How do you plan on fasting this floor down? answers above in quoted section, not certain how to undo this

Good luck
Ron

I will be glueing it down.

[Jack Frederick]

Yes, you need to relieve the back of the boards. It is done to assist in preventing cupping. I would also use sleepers for this. !/2” is pretty thin for a floor. Okay if you were planning on just placing it on the concrete, but thin for any span. Close up the sleeper centers and/or increase the thickness of the flooring. I would not chamfer the edges. To me the smooth sanded edge to edge board floor is one of its best features.

[Albert Lee]

Thanks. The cutter set I have seems to be designed for this there is a 0.4mm gap between the tongue and grove itself (ceiling height so to speak) and 1mm for the bottom gap and internal gap of the tongue and grove - so it’s not tight fit, but the face is tight fit.

[Rich Engelhardt]

I would also use sleepers for this. !/2” is pretty thin for a floor. Okay if you were planning on just placing it on the concrete, but thin for any span. Close up the sleeper centers and/or increase the thickness of the flooring.

Sleepers were my first thought also - but - with the way hardwood flooring is installed, positioning the sleepers so they fall under the ends where two sections meet would be next to impossible and/or, you would have so many sleepers you might as well just lay down a solid underlayment.

I'd use DrIcore as a base for this type of project.
It's a vapor barrier (provided you tape the seams) & in the event of an actual water leak, the base allows the water an avenue of escape.
It will also provide somewhat of a level base for your flooring with the use of DRIcore shims.

[John K Jordan]

I will be glueing it down.

Don't know if it was said here (I just scanned a few of the messages last night) but if putting wood flooring on a concrete slab I'd be concerned about the possibility of moisture coming through the slab. I'd want the ground sloped away from the slab all the way around and add drainage ditches and/or good french drains if needed.

I have zero experience with putting wood flooring over concrete. If considering such a floor I'd first consult an expert. If in a jurisdiction that required permits/inspections I'd ask the authority before planning the floor.

Without research my first thought is even with a good moisture barrier under the slab I'd probably put down one or two layers of continuous vapor/water barrier (heavy poly) on top the slab and turn it up against all outside wall studs before covering the walls. I might put down PT sleepers if necessary covered with a layer of moisture-resistant sheets of sub-flooring, then fasten the hardwood flooring boards to that. But that's just me. I might do it differently after some research.

I have no experience or opinions for you about milling flooring. I assume it will all be tongue&groove. Our house is a timber frame and all flooring is T&G heart pine, no bevels on the face of the boards, no bevels or grooving that I can see from inspecting the ends of boards in an unfinished closet. Subflooring (the underside of which is also ceiling for ground floor) is T&G 2x6 SYP. Built in the 80s, all flooring is in excellent shape with no bounce, squeeks, shrinkage, buckling, etc. (No concrete slab at the house except in the garage.)

JKJ

[Eric Anderson]

Solid wood flooring is NOT designed for direct glue-down to concrete. Solid wood must move and if glued it can't move so it will crack and split. That is why only engineered flooring is approved for glue down to concrete. If you don't want to put down sleepers, a plywood sub-floor or something else to allow the wood to move you are putting yourself in for a huge long-term disaster.

[Warren Lake]

helped a friend do this years back with his instructions from his supplier. Plastic dimpleboard like on outside of homes clipped into itself on edges where they meet, and or Gaffers tape over that. 3/4 ply tongue and groove held in place with tapcons then some sort of slippery stuff not tar paper but something over that then solid pre made floor tongue and groove red oak using my large senco which has a big kick to it but not with the hammer knocker thing. I held at 45. The quality of the floor was so good only one or two boards were not straight so a good fit was easy. Let the wood get used to the room and Id likely pay attention to time of year as well or at last see how the place is run. HIs basment was nigher level than mine and we are in a wet area here so his a better concrete basement to work with. LIkely there are newer ways to do this as stuff usually improves. First thing that comes to mind with me is if there is or can be air ciculation under the dimpleboard when used. Maybe not needed but I wonder about it.

[Dave Cav]

A neighbor and I ran several rooms of ash flooring a few years ago. He is an arborist and had a few logs from trees he felled milled into rough lumber, unfortunately mostly in the 2 to 3 foot range, and random widths. We milled it into 2, 3 and 4 inch flooring using standard shop tools, my Powermatic 180 planer, a 12" table saw, 12" jointer (with power feeder) a Delta shaper (spindle moulder) with a power feeder and a Woodmaster moulder for the back reliefs. It was an ENORMOUS amount of work and I would not do it again.

After sorting the lumber by rough width and marking the good faces, everything was run over the jointer to flatten one face, then through the thickness planer for final thickness. Then, since I don't have a straight line rip saw, we had to joint one edge of each board, then rip to width. After ripping to width we ran each piece through the moulder to cut the back reliefs, then ran one edge (the groove edge, I believe) on the shaper first, then ran the tongue edge. Everything on the shaper was fed with the power feeder, and since I don't do a lot of power feed work on the shaper, it took several hours to get everything set up to make consistent cuts. One challenge was to keep everything a consistent width coming off the shaper. As I said, it was a tremendous amount of work; there is a reason that four sided planer/moulders were developed over a hundred years ago. As I recall, it took nearly two weeks to run all the flooring, working three to five hours each day.

About half of the raw material:

Befpre.jpg

Finished flooring:

finished flooring.jpg

He hired a professional to install, sand and finish the floors, and they turned out very well.

I agree that you'll probably need back reliefs to help the wood lay flat, and that gluing the flooring to the concrete is a very bad idea. I think some sort of additional moisture barrier on top of the concrete is probably a good idea, and you need either a subfloor or sleepers to fasten the flooring to. It needs to be able to move.

[Jim Becker]

I'm with the others...yes to relief cuts on the back due to the nature of the product. And I'd also be looking at using something like DriCore over the concrete unless I knew for a hard fact that the slab was already engineered from the ground up (pardon the expression) for a moisture free glue situation. It can be done as Matt Risinger has shown on the 'Tube, but it's a careful dance.

[Mark Bolton]

Gluing solid hardwood to concrete is done all the time but manufacturers will typically only spec' glue down for thin material (usually 7/16" thick or less) so your 1/2" is close. Relieving the back would be wise in a glue down in my opinion so you will be less apt to have boards that only hit on the centers or edges.

We did a job a long time ago where a commercial flooring supplier (hundreds of thousands of square feet under their belts) glued down full 3/4 prefinished material without question but this was 20 years ago and there was never a complaint other than they didnt do a very good job keeping glue off the surface or cleaning it up.

Your knife profile is less critical in that you'll only benefit from the gap'd back and a rounded tounge for installation. Nail grove, etc, not critical. You'd still be wise to do a moisture test just to be sure even though you have vapor barrier under the slab.