Oak Flooring Over Cement Subfloor

Nick H

Do any of you guys know the best way to install 5" oak flooring over a cement subfloor. The oak is 3/4" and random lengths from 3' to 5'.
I would prefer to fix the flooring down rather than float it so would presumably use a suitable adhesive, what would you recommend?
I've installed this stuff onto joists before and found it necessary to clamp the boards together to straighten some of them before nailing down, how do you do this if your not nailing ?
Any help will be great.

Nick

Zero Punch

Only 3/4 in hardwood I've ever glued down on concrete was parquet blocks with cold stick tar on a small dance floor. I don't think there is an approved installation for what you want to do. I assume height is a consideration. Engineered is the way to go if glue down is your only option. If height does not matter consider 3/4 plywood subfloor glued and screwed or shot down then install even then not the best better two layers of 3/4 ply, second diagonial to the first which can be loose layed but on rubber screeds. I did do a track and clip system once years ago don't know if that is still available but that too will add 3/4 to the installation.

John

drunkrussian

I wouldn't glue it down, its messy, slow, messy, and did i say slow? I had a young couple who bought some armstrong flooring (cheep, tavern grade crap) and wanted it glued down. Slab was in ok condition, told them i'd install it for $4000, or I'll show you how to do it for $300. They got the picture, but didn't want to pay the 4000, so I made 300 for about an hour of work.

Anyways, Lowes, HD, larger hardware stores should have a product there to glue a floor. I forgot the name of, but it all the same, messy and stickey.

Floorwizard

If you glue down 3/4 solid hardwood down on concrete, you are asking for trouble.
HD uses Bostik's best but only for a thinner 5/8 solid floor.

3/4 solid moves around too much. the only way to properly secure it is to install a plywood substrate over the concrete first, and then nail it.

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PrecisionFloors

Actually there are some adhesives on the market now that will warranty a solid glue-down. I believe Bosticks Best, and Staufs will. I wouldn't want to do it though, and I'm pretty darn quick with glue down.

adams,b

The only solid 3/4 wood we glue down are "shorts", because you can keep the floor straight. You could chop the long boards up into short ones but it will be more work and you lose the tounge and groove on the ends but it will work.

Nick H

Thanks guys, I'll try to talk him into leting me install a ply base, the only consideration really is the hieght difference against the other floors (tiles/carpet).
Whats the best way to fix the ply down? the cement is in good condition and i'm thinking plenty of construction adhesive maybe.

Thanks

Nick

TimNJ

I wouldn't put any wood down on concrete without doing a moisture test. My plumber of all people got me a customer who had hardwood glued down on a slab on grade townhouse. The floor started buckling in the powder room and the floor guy told the homeowner there was a plumbing leak causing it. Make a long story short, moisture was migrating up through the slab. We ripped out all the hardwood. Did the moisture test (plastic sheet sealed to slab) to show the condensation on the plastic after 24 hr. Homeowner said use ceramic instead. What a dirty job that was, but worth it$$

Floorwizard

Oh yea, good point.

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"in 20 years you will regret more what you did not do than what you did"

kenvest

i've also seen wood over concrete buckle due to moisture creeping. it was glued straight to the slab but i can't help but think that even if it were nailed to a plywood sub-floor it would still have been a challenge. wonder what the best way to seal the slab would be if they're dead set on wood instead of tile?

thanks!

ccoffer

Just use MVP and Bostiks best. As long as you are not below grade you can do whatever you want. They have no vapor limits for their warranty. It is an incredible system.

Nick H

Thanks for the info guys. It gets a little confusing as I'm in the UK and we have different products, what exactly is MVP and what type of adhesive is Bostick best ?

Thanks again

Nick

PrecisionFloors

I can't post a link yet but Google Bostickfindley and you'll find everything you need. MVP is:

MVP4® Moisture Vapor Protection is a one-part, trowel applied, elastomeric, moisture cure urethane membrane designed to 1) reduce moisture vapor transmission from the subfloor; 2) create a noise reduction barrier over the substrate; 3) establish an anti-fracture membrane that can bridge cracks that can occur in the substrate prior to or after installation (up to 1/8"); prior to the installation of engineered and solid hardwood flooring with Bostik’s Best®, BST®, EFA®, Ultra-Set® Hardwood or Fast Tack® adhesives. MVP4 may be used over all substrates common to hardwood flooring installations including: concrete, plywood, particle or chip board (underlayment grade), well bonded vinyl, ceramic tile, cement backer board, cement patch/underlayments, radiant heat flooring, and terrazzo. 4) MVP4 contains Bostik BLOCKADE™ antimicrobial protection which inhibits the growth of bacteria, mold or mildew on the surface of the dried membrane; the dried membrane resists stains caused by mold.

ccoffer

Being over there and all, you might consider opting for Stauf 960.(Made in Germany) It is very cool stuff. You just dump it out of the bucket and take care of emissions and adhesion in one swipe with no need to prime the floor.

I have played with it and have found it to be an awesome product. Stauf has been around for 200 yrs.

Leo G

I've used a product called Dri-Core. It is an OSB substrate on top of a plastic formed into 1/4" tall circular cups. The plastic goes towards the concrete and keeps the OSB off the crete while leaving a 1/4" space for air flow. The plastic also forms a vapor barrier. The pieces are about 22 1/4" square and are tongue and grove. You assemble them together and they form a floating subfloor. I think the product is 7/8" thick. You can now use a standard floor nailing/stapling machine to apply the oak flooring. I don't know if they have anything comparable in the UK for you though. I got this stuff at HD.

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Nick H

ccoffer and precisionfloors, are you saying you would go with a direct glue down using MVP/Best ? Would this be Ok with solid 3/4 boards up to 5' long? Or would I be better to MVP the cement, glue down 3/4 ply and then nail the boards down ?
Thanks for your input everyone.

Nick

Nick H

Just had a read of the Stauf website and they seem to have the products for a glued down floor. The main problem I can forsee is straightening out any bent boards. when i've nailed a floor I have been able to clamp/lever/whack boards straight and then nail them, how so with glue ?

Thanks Nick

go dart

looks like he really wants to NAIL the floor. if you can stand another 3/4" go ahead install vapor barrier then ramset 3/4" cdx ply, 15 lb felt, then install as you always have. we've done a couple of these in finished basments and worked for both familys a few years later. no problems. good luck

Nick H

Its not so much that I want to nail it as there is an issue with the extra 3/4 thickness, its just that I can see myself having problems getting longer boards with any kind of bow to sit up tight without nails to hold them. Have any of you guys done it OK, if so how?
Its a pretty big floor and I cant afford to get it wrong !!

thanks
Nick

justin savage

We have done a couple floors with a layer of plastic then 2 layers of 1/2 plywood staggered and run different dirrections then nailed or screwed together then run your flooring like usual.Works great as long as you have room for the extra height.Went to the advanced installation school at the national wood flooring association's new headquarters a few years ago and we installed there floors like this, have done a few since very clean no glue.