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:

466979

Finished flooring:

466980

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.

[Frank Pratt]

I hate to be a downer, but I have read many threads on milling your own flooring in various forums over the years and everyone that's done it swears they'd never do it again.

[Robert London]

Hi Albert,

As a few others have mentioned, it’s very risky to glue down solid wood flooring on concrete. Most flooring professionals would never do it as the risk of cracking, warping and splitting can be high. You need to glue down multi ply engineered wood to concrete. Solid wood flooring is meant to be nailed or stapled to a plywood subfloor.

[Mark Bolton]

I hate to be a downer, but I have read many threads on milling your own flooring in various forums over the years and everyone that's done it swears they'd never do it again.

No downer there. Its a nightmare amount of work no matter how you slice it.

[Mark Bolton]

Hi Albert,

As a few others have mentioned, it’s very risky to glue down solid wood flooring on concrete. Most flooring professionals would never do it as the risk of cracking, warping and splitting can be high. You need to glue down multi ply engineered wood to concrete. Solid wood flooring is meant to be nailed or stapled to a plywood subfloor.

I think the reason most flooring pro's dislike glue down over concrete, or any glue down/glued to itself floating, whatever, is that its slow, its messy, and they have to bill it at a rate that is extremely high and even then they dont feel like they make as much money. Typically when you do these you have to setup straight start points, glue down a section, let it dry, so you have a rigid start point the following day or nail down starter strips that then have to be removed and filled in. You have to use strap clamps to pull sections together, weight the floor, tape, constantly keep rags/solvent handy for cleanup, scraping or very cleanly planning for overnight stop points so you dont wind up having to scrape up yesterdays glue today, and so on.

Its a slow/pita process for flooring installers who are accustomed to coming in and slam bamming nail-down floors even at the higher rate.

Combination products from Bostik now are adhesive, 15lb vapor barrier, leveler, right out of the pail. Expensive adhesive, expensive labor, but its perfectly fine and people are gluing down full 3/4" prefinished material regularly even though its likely not recommended by hardwood manufacturers.

[Jim Becker]

Actually, you bring up a good point here, Mark. Floating the floor is a real option and removes the glue to concrete challenge/risk, although it exchanges that for other "fun". I actually like floating floors, myself.

[Frank Pratt]

I simply cannot imagine a worse, slower, more labor intensive way to put down a floor than gluing hardwood to concrete. Please reconsider.

[Dave VanDewerker]

My entire house is a concrete slab and wood floors, none are glued down. If you are using a vapor barrier you would need to glue both down to have have the floor glued down. All of my floors float on a vapor barrier/pad and IMHO it make the floors feel a bit softer, ie not like you are walking on concrete.

[Mark Bolton]

Actually, you bring up a good point here, Mark. Floating the floor is a real option and removes the glue to concrete challenge/risk, although it exchanges that for other "fun". I actually like floating floors, myself.

We did several glue-to-itself floaters (glue each tongue/groove, tape, ratchet strap clamps) 3/4" thick, and its a royal pain especially weighting them and even then you can still have hollow areas where there is either a slight hump/dip in the floor or a bit of over-clamping creates a hump.

Ive never been a fan of the feel under foot of a floating floor especially the snap together types over a pad but everyone says they get use to it and they like how cheap they are. They just dont feel good to me but Im old school.

Given the concrete slab doesnt have a major moisture issue I dont see an issue at all with gluing down over concrete. Everyones issues with wood movement and hardwoods is overblown in my opinion especially in modern homes but it is what it is. There are enough tiny gaps in even a tight floor to allow for a lot of fudge. Modern adhesives that help with moisture, stay rubbery, allow movement. The OP is not in the US so I can only imagine, like numerous other places around the planet (outside the US) they are doing things smarter than we are here lol.

[Mark Bolton]

I simply cannot imagine a worse, slower, more labor intensive way to put down a floor than gluing hardwood to concrete. Please reconsider.

What would you reconsider? The cost and effort of installing an inch and a half of sleepers and subfloor, plastic, concrete nails, cant glue the sleepers to the concrete because of the vapor barrier so fasteners will allow creeks/crunchy grit under foot, expense of installation, raising up every door opening by 2 1/4"? Dealing with and installing some steep transitions/thresholds?

Its about as broad as it is long. If I had to rework every opening in the space, baseboard, thresholds, cost of sleepers and subfloor,.. uh...

[Alan Lightstone]

I had to have a number of engineered boards taken up and replaced due to a window leak. They were glued down. I could only find one installer who would even consider doing the work, and it was a nightmare. This was on the second floor, but over a concrete slab.

If I had it to do over again, I'd never glue down the floor. My $0.02

[Mark Bolton]

I had to have a number of engineered boards taken up and replaced due to a window leak. They were glued down. I could only find one installer who would even consider doing the work, and it was a nightmare. This was on the second floor, but over a concrete slab.

If I had it to do over again, I'd never glue down the floor. My $0.02



Sounds like youd be better off blaming whaever caused the water leak as opposed to remidiation difficulties. Building anything with anticipation of replacement due to some other failure is a backwards way to build anything.

[Albert Lee]

thank you all for your input... I have been doing a bit of homework myself, it seems hardwood on concrete is quite normal here, our general practice is that vapour barrier x 2, moisture test and then adhesive, its an expensive exercise, got quoted for the recommended vapour barrier product itself is $150 USD per 200ft2, thats 1 coat. the adhesive is the same price. so effectively thats $450 per 200ft2 just to purchase the adhesive and vapour barrier.

would love to install over plywood or float but I dont have the height in my floor, the height difference between the concrete and existing tiled area (kitchen) is only 13-14mm. I will need transition strip.

Not too fussed about the laborious work involved with the moulder (I invested in a relatively expensive shaper recently, should take off the pressure a bit).

The area is not that big, its only 355ft2.

[Greg Quenneville]

As you have by now discovered, concrete floor waterproofing primer isn’t cheap. I think 10 litres of Mapei primer is around $170 US here in Australia. We are using both Mapei and Soudal brand adhesives for our flooring. Good luck with your project Albert. I don’t envy you the work involved. I have to make about 150’ of oak stair nosing and 50’ of handrail and find even that puny project tiring to contemplate.

[Frank Pratt]

Sounds like youd be better off blaming whaever caused the water leak as opposed to remidiation difficulties. Building anything with anticipation of replacement due to some other failure is a backwards way to build anything.

That's just silly thinking. Anticipating repairs should always be considered when building. Stuff happens. I've never had a house that didn't need unforeseen repairs.

[Rich Engelhardt]

Sounds like youd be better off blaming whaever caused the water leak as opposed to remidiation difficulties. Building anything with anticipation of replacement due to some other failure is a backwards way to build anything.
Why is that backwards?

I'm always glad when I find a "trap door" that allows access to the plumbing so I don't have to tear apart a ceramic tile wall just to get at the mixing valve.

I just wish the idiot that built our house had done that. :(

[Albert Lee]

As you have by now discovered, concrete floor waterproofing primer isn’t cheap. I think 10 litres of Mapei primer is around $170 US here in Australia. We are using both Mapei and Soudal brand adhesives for our flooring. Good luck with your project Albert. I don’t envy you the work involved. I have to make about 150’ of oak stair nosing and 50’ of handrail and find even that puny project tiring to contemplate.

Thanks Greg, I started ripping the Tulip oak yesterday... realised I need new blade straight away as smoke were coming out...

I have made some weather board recently for a builder using my moulder and thought the floor board will be similar... will wait and see.

[Mark Bolton]

Why is that backwards?

I'm always glad when I find a "trap door" that allows access to the plumbing so I don't have to tear apart a ceramic tile wall just to get at the mixing valve.

I just wish the idiot that built our house had done that. :(

Again. Dont wish for the idiot to have supplied you resoutions to the shortcomings of materials, construction practices,.. instead avoid the idiot and build in sound practice that avoids chiseling uo glued down hardwood due to a water leak. Accitents happen. Natural disasters happen. Its not the reaponsibility of glued doen hardwood to be "easily replacable" in such situations. If its installed in a sound and responsible manner it ahould never have to come out. My last house was 50 years old, thoughtfully constructed for the time, and zero issue. Our current disposable society should have no bearing.

[Albert Lee]

well the flooring timber is almost done, I clocked myself;

1 hour cross cutting to cut it from 4m into 2m pieces,
4 hours ripping (not easy to rip a piece of 190 x 45 into 6 pieces of 92 x 13, bandsaw blade is 1mm thick. 45-13x3-2 = 4mm, I only have 4 mm of allowance for error shared between 3 pieces.
2 hours thicknessing/planing
3 hours to carry out the tongue and groove profile (profile already saved as one of the program so no need to muck around)
1 hour of handling and sorting

I began with 16 pieces of 190mm x 45mm. I endup with 188 pieces of usable 92mm x 13mm. 4 pieces waste (ripped too deep)

now I am thinking if I should hire a professional installer or install it myself.

the concrete RH is 8% in the middle of the room and 9% around the wall, its wet season now.

[Jim Becker]

Did you do the moisture test with the plastic to see if any real moisture comes to the surface?

[Mark Bolton]

well the flooring timber is almost done, I clocked myself;

1 hour cross cutting to cut it from 4m into 2m pieces,
4 hours ripping (not easy to rip a piece of 190 x 45 into 6 pieces of 92 x 13, bandsaw blade is 1mm thick. 45-13x3-2 = 4mm, I only have 4 mm of allowance for error shared between 3 pieces.
2 hours thicknessing/planing
3 hours to carry out the tongue and groove profile (profile already saved as one of the program so no need to muck around)
1 hour of handling and sorting

I began with 16 pieces of 190mm x 45mm. I endup with 188 pieces of usable 92mm x 13mm. 4 pieces waste (ripped too deep)

now I am thinking if I should hire a professional installer or install it myself.

the concrete RH is 8% in the middle of the room and 9% around the wall, its wet season now.


Sounds like youve got it licked Albert. Good for you. Im sure you'll crush it regardless of hiring out the install or not. My guess is youve come this far, you'll smack it down yourself. Thanks for the update.