I checked out the archive and got some good info : but I’d like some direct advice on my plans for a wide plank floor. Ive got 1/4 sawn red oak 3/4″ thick / 5-8″ wide I want to put down for flooring. A builder friend says I’m nuts : it will cup/crack/gap me senseless.
I figure if it’s on a good 3/4″ ply subfloor, isolated with flooring paper/end biscuited / and nailed every 12″ I’ll be ok. I will make sure that the subfloor and the oak are moisture matched wich means around 9-10 % here (checked with a meter). It will be installed perpendicular to joists 16″ O.C.
Do I also need to screw and plug it to be safe? (and if so at what schedule ? )
I’ve yet to see a firm answer on the “need for underside mill/stress relief slots” on the flooring / I was planning on tongue and grooving with my shaper but have no means to cut the grooves you see on a lot of commercial flooring. Any Ideas?
Replies
Okay, no one else is touching this for some reason, so here's my two cents worth and my apology to all in advance for this long post.
I haven't read all the posts on the thread I seem to recall preceding this post so if I'm covering old ground here, forgive me.
It seems your builder friend's concern for the use of wider flooring boards revolves around cupping, gapping, and splitting and rightly so, but here's some info that may help you get an acceptable result.
A board that is at EMC and flat-milled (except those from stress wood) will remain flat if both sides are exposed equally to the environment/moisture.
Normal change in dimensional width of wood is attributable to changes in moisture content via absorbed/dissipated moisture within the board. The board will remain flat as long as the exposure/moisture exchange is equal on both sides but…… it's total width will vary with shifts in moisture content. This is probably the main reason why narrower quarter-sawn stock has become the desired norm for flooring boards……..smaller cracks between the each of the boards from dimensional change.
Cupping of a milled board is due to exposing the board's two faces to different moisture values/content causing the two sides of the board to absorb or dissipate moisture at different rates. This potential is realized in solid wood flooring because the up/face side has more/faster access to atmospheric moisture than the bottom side. This is also a reason why the use of quarter-sawn narrower stock has become the desired norm for flooring boards………less potential cupping per unit as the annular rings are vertical and much of the dimensional change is therefore in the board's thickness rather than in its width.
Bear in mind though that quarter-sawn wood can still be made to cup if exposed to uneven amounts of moisture on its two sides and the resulting cupping in each individual wider board will be greater and potentially more problematic than cupping in narrower boards.
In that the bottom of the board when used as flooring is theoretically exposed to less air flow and therefore less water vapor/moisture than the top, it's essential (but virtually impossible) to match that exposure on the face side of the board by choosing and applying a finish that will minimize moisture absorption if you want to minimize any potential seasonal cupping. In plain words, I wouldn't recommend any penetrating "oil" finishes, such as Watco or linseed oil type finishes on this particular floor as they don't offer much in the way of resistance of water vapor exchange.. You need a quality film type finish and in that regard, I'm still a fan of oil-based poly for floors because of its excellent vapor resistance, durability, relative ease of initial application and recoating if this ever becomes necessary (FYI, Helmsman poly is not an appropriate product for a floor from what I've heard). I know many pros frequently favor some of the new catalyzed finishes because they set up fast leaving them both dust free and ready for recoat in shorter periods of time. I usually lay three coats of oil-based poly, but four wouldn't hurt. If you choose a water-borne product or catalyzed finish, you'll be limited to fewer mils of coat thickness and remember that water-borne finishes aren't as resistant to the passage of water vapor per mil of thickness. Follow the manufacturer's recommendations as regards maximum final build of finish.
As for the gapping of these somewhat wider than normal boards ....it's a subjective judgment/issue. The issue is moot so long as you're willing to live with fewer, wider gaps in place of more frequent, but narrower gaps and only you know the answer to that. The eventual cumulative seasonal gapping is identical for any given total width of quarter-sawn red oak flooring in the room. Illustration: if you were to edge-glue all those boards together, nail the floor down only on one edge (parallel to the grain) along one side of the room…….you'd have one big gap develop on the other edge of the room. If the potential look of those wider gaps from the use of individual wider boards doesn't bother you, it shouldn't bother anyone else. If it does, it's their problem, not yours. Some folks love rustic log cabins and some don't. Same deal.
If you're planning on milling those T&Gs with standard bits, you won't get the underside relief for the joint when traversing hills or humps in the floor so you may end up with small gaps that refuse to close from the get-go. If that's a problem to you, you should consider buying a set of " regulation" flooring cutters.
IMO, screwing the floor down wouldn't be necessary, but won't hurt anything so long as you oversize the shank hole a bit for the screws allowing them to tilt in the hole when needed. Dimensional changes will take place and if the board can't move, it'll relieve the internal forces any way that's necessary, i.e., split. This screwed-down approach would mean that you wouldn't want to let your plugs sit down tight on top of the screw heads or they could be dislodged when the screw tips in the hole and force the plugs to protrude. Use a tapered plug cutter that allows a firm fit prior to touching down on the screw heads or insert straight-sided plugs such that they don't touch down.
I've laid solid wood flooring and seen alot of solid wood flooring laid without the stress relief grooves and don't know of any problems resulting from the lack of them on those jobs. It would perhaps seem more necessary to me on plain sawn stock than on quarter-sawn stock.
If you're running a humidifier in the heating season and AC in the summer, the occurrence of potential problems should be minimized.
Remember to leave a 1/2" gap minimum at least on the room sides parallel to the grain of the floor.
Right or wrong…….there's what I have to offer you. Good luck whatever you decide to do.
Thanks for the post : obviously an informed answer based on experience : let me do some more brain 'pickin if I may:
To equalize MC shift on both sides of the board what do you recommend UNDER the board ? Ive heard of builders felt, waxed underlay : what do you think?
And thanks for pointing out the fact that TOTAL floor movement is the SAME for wide or short boards / the way most explain it you'd think skinny boards don't shrink !
The floor is going into a cottage with no A/C or heat . Here in Ontario we get humid summers and COLD winters. Should I worry about the adhesive effect that poly will have on the floor and it's tendency to try and adhere the boards together on their edge (thereby preventing free movement) ?
Thanks :)
I really don't know what to suggest you put under the boards for your cottage. I normally lay solid wood flooring over felt. But in special circumstances, it would depend upon what lies under the floor. If it's a dry basement, I wouldn't treat it in any special way, but if it were to be laid in an ACed room over a non-ACed humid garage, for example, I might then consider applying an equal amount of finish to the bottom side of the wood (not the edges) as well in hopes of evening out the moisture exchange in an attempt to prevent cupping. But again, these attempts are only ever that, as virtually nothing you can reasonably do with a solid wood floor under normal human living conditions will guarantee the total absence of cup or movement in the wood (unless of course, you're up for laying some Pergo or the like). It's always an attempt toward a best result under a given set of circumstances and should never be confused with "the way" to a perfect result. If there were an established scientific route to the perfect wood floor, there would no longer be debates about the right and wrong things to do, finishes to apply, etc.
As for your question…if I'm getting it right….. concerning the potential negatives of the panelizing effect of poly on a floor …………I haven't ever had a floor exhibit this problem nor have I seen one that did, but then none of the poly-ed floors I'm familiar with have been subjected to the types of extended extreme cold that you're suggesting in an unheated cottage. All I've ever experienced is the poly separating nicely at the edges of the boards upon the "call" for shrinkage with no evidence of finish adhesion failure. My guess is that this panelization effect may be a more prevalent problem with water-borne poly as it's a more brittle finish, but I can't say for sure as I haven't encountered it.
If you're concerned about the poly effectively gluing the boards together causing the wood to split when it needs to shrink……………never saw that and don't think I've ever heard of it either. Then again, I suppose if someone were to get really carried away and apply it to the edges of the boards prior to laying them…………it could happen. Don't do that.
A piece of advice…..even though some may disagree with me on this…….if you choose the oil-based poly…make sure you apply it at a time when you can be assured of temps not falling below 50°F for six weeks prior to subjecting it to freezing temps if this is at all possible. I'd prefer 65°F. Better safe than sorry.
If you choose a different finish………follow the manufacturer's recommendations/knowledge concerning proper preparation, application, and curing time.
Knowledge is power, but only if applied in a timely fashion.
You the man, Goldhiller. Nice responses.
Brinkmann for president in '04
Thanks, Jim.
I give what I've got to offer, but I always leave here with more than I gave.
My thanks to all for that. That means you, too.
Knowledge is power, but only if applied in a timely fashion.
Ever hear of putting down wide plank flooring in a full bed of Bostik's? That's in addition to nailing. That was one fo the flooring guru's methods...one of the Greg's...Warren? Brown?
Sounded totallt unconventional at first, but he backed it up with either manufacturer or hardwood association info. Says it works well.
What is "Bostik's"? Is it that glue that comes in a tub that you trowel on, like you would for tile?
Brinkmann for president in '04
jb,
"Bostik's Best" is a urethane adhesive, most commonly used for glueing down floors. Very good stuff.
It doesn't crystallize and become brittle as easily as others, which is very important with RFH glue-downs. It holds tenaciously, and is moisture resistant as well. I'd think that it's probably the top recommendation of most flooring manufacturer's when gluing over slab.
It runs about $175 for a 5-gallon bucket.
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Mongo,
I've heard this sort of thing proposed more than a few times, but I've never tried it nor recommended it because as of yet the idea just doesn't equate in my brain with what I know and understand about wood. I'm a skeptic.
Perhaps this is the result of a lack understanding concerning the physics of such an approach on my part, but until my teenie brain can make sense of the notion, I'd sure hate to stick the liability of my wallet, my reputation, and the customer's satisfaction on the line.
If someone can direct me to an article on the technique, I'm always ready and willingly to learn/give consideration about new materials and ways of doing things, but they've gotta to be proven over a period of time before I'd foist them on my clients.
There I said it again…..I'm a skeptic.
Knowledge is power, but only if applied in a timely fashion.
Okay, Mongo……I'll bite.
On the notion of applying a full bed of adhesive on the subfloor in an attempt to avoid cupping on wide plank floors ………………….and the point would be ???
Even if one should succeed in avoiding the knockout punch in his struggle with the forces of physics, i.e., having the flooring split itself in many places …………..doesn't this strike you as somewhat analogous to welding the wheels on your car ??
Talk about making a commitment.
Now when the time arrives because of wear, severe damage, or change of aesthetic desire on the part of a homeowner (present or future), they'd be faced with either building up the flooring levels thicker or tearing back all the way to joists. I can see the pleasure in their faces now when they hear how much $$$ for the tear out. I think they might be prone to saying something on the order of …….. "Why the hell would somebody do something like glue this all together?" Or at least I can assure you that folks here in middle America corn-country sure would. Perhaps we're all too practical-minded and less prone to figuring out ways to enforce our aesthetic wills of the moment, based upon what's currently desired/fashionable, at any cost.
I've been accused/ribbed about worrying about the next guy too much when I build something, but perhaps that comes from finding myself in the position of being that next guy too many times, confronting things done in a manner that made things unnecessarily difficult for me. Usually, I feel this stems from lack of foresight, which stems from lack of concern. But as I try to remind myself and those that work with me when attempts are made to dismiss such concerns and issues……………..don't forget, we may be that "next guy". Ya never know.
I guess my attitude about such things can best be summed up as follows……………
Just because you CAN do something.......... it doesn't mean you should.
(Alright, alright………..steps down from soapbox…………. again……to the jeers of the crowd.)
Edited 11/13/2002 1:25:47 PM ET by GOLDHILLER
Knowledge is power, but only if applied in a timely fashion.
Edited 11/13/2002 1:55:45 PM ET by GOLDHILLER
You're debating the wrong person.
I brought forth the same areguments that you did, but the person who posted it tossed out a few manufacturer's sites that defended, and encourages, the idea.
Normally I can make the SEARCH function click into place and spit out what I'm looking for, but since they changed over it seems to clunk more than click. I couldn't find the threads, which were...I'd guess...two years ago?
I'll dig more, but I doubt if I'll bring anymore info to light.
Ooops.........sorry about that............. but then I didn't for sure get the notion that you were promoting it anyway, so I wasn't so much debating as trying to expand thinking concerning the things we do.
Smack on hand cheerfully accepted. Knowledge is power, but only if applied in a timely fashion.
what a Pandora's box I've opened ! my thinking pretty much aligns with Goldhiller on this and I appreciate the experienced viewpoint. This "glue it down" deal comes way out of left field for me .....I'm definitely skeptical as I've always been taught that you have to "let 'er move" as wood always does / if things get in the way they give or the wood splits : what is the thinking on wood movement with this adhesive? How does it accomplish what no other technique has?
Cutter,
No need to be concerned about opening Pandora's box here as this subject is hotly debated all the time.
Having not used the adhesive bed technique on a solid wood floor, I'm only guessing here so keep that in mind.
I think that the notion behind the "safe" usage of Bostik urethane adhesive or any similar substances is that it remains elastic enough under there to allow adequate movement and thereby doesn't endanger the structural integrity of the wood.. This may very well be true if it's at all similar to the urethane caulks that I'm familiar with. A "hardening/setting" glue/adhesive of any kind would surely spell disaster for a solid wood floor if the flooring was applied to a composition or plywood subfloor, or perpendicular (as is the norm)to a solid wood board subfloor; that is unless the environment was subsequently held in a sort of suspended state where humidity levels weren't allowed to change.
I'm sure it's just the ticket for laying composition floors on concrete, for example, but
I have a hard time understanding the advantage of using the stuff for laying solid wood floors……….particularly wide board floors……..beyond the squeak suppression that might result from its presence. What perplexes me in terms of any additional benefit is that unless this is one very high-tech "smart" elastic adhesive, it wouldn't know which way to allow the wood to move (laterally) and which way to restrain it (if it could) in order to prevent the cupping phenomenon.
Maybe Ditch or someone else will jump in here and enlighten me.
Knowledge is power, but only if applied in a timely fashion.
I soent another ten minutes trying to dredge up the old threads with no luck.
Guys, I'm in with you. It does go against common sense and traditional methods.
I have used pallets of Bostik's ver the years, and it is great stuff. Still, the idea of a full bed on wide plank flooring does make me wag my head.
I'm nearly positive it was a "Greg" that posted the idea. His work was impeccable. But like you, I'd need more info to even contemplate the idea.
Here's a bite to chew on:
http://www.edelweissflooring.com/sika/
I have never seen this method used, but someone was trumpeting it a while ago. It's a gluedown/floating floor hybrid. Again, I'm not advocating this for your floor...just tossing it out fer betta lernin'.
Thanks for that link, Mongo. Interesting materials and methods.
After reading the company line I do feel vindicated concerning my views on this as I read their own precautions/warnings about using the full bed glue down with solid wood flooring on the main installation page. I for one, wouldn't be inclined to try it. They're talkin' about the same tight control on relative humidity that I imagined would be necessary to avoid disaster.
I never joined the Tyvek or OSB club, either. Took alot of ribbin' about that for years on end as I was considered antiquated and "behind the times". Fact of the matter is that the company line on a product shouldn't be considered as the gospel truth. A few simple self-done tests with most any construction material will reveal much.
Knowledge is power, but only if applied in a timely fashion.
I'm a ply and tar paper man myself. I do have to admit, though, that I use TJIs.
I do wish I could find those old links regarding the full bed adhesive. Greg had some interesting things so say about it, but still...it is unconventional, and with a mighty big downside if things went wrong.
Living in Sydney, Australia, this may be of only limited value. I live in a 110 year old house and think the flooring is the same age. The ground floor is 4-6 in wide timber boards nailed directly to the floor joists. This floor has no cupping - I presume the reason is that any cupping was removed when the floor was sanded about 20 years ago. From what I've seen in other houses that are more than 40 years old, cupping may occur but it only needs to be sanded out once. A house up the road is about 160 years old with floor boards up to 10in wide - there is little evidence of cupping in its floors. Of course, we don't get the low temperatures you do but the annual humidity range can be severe: from less than 8% a few days ago with over 90% expected in February and March.
Ian,
It doesn't make any difference where you live, the same principles apply and will prove themselves time and time again. Sydney is a perfect example and I'm sure glad you checked in with your post.
I think you said it all when you stated that the boards are nailed directly to the floor joists.
The lack of a subfloor allows a more even exposure of both sides of those floorboards to the relative atmospheric humidity and the result should be (and evidently is) a board that will remain flat/flatter throughout the seasonal humidity shifts and cycles.
This is exactly the point I try to convey to folks concerning what makes a board prone to cupping or not.
For those of us who live in homes where the finish flooring is applied over a subfloor, the attempts to prevent cupping become more problematic……..and frustrating. We're fighting with the forces of physics when we do this and the best we can expect is to avoid a knockout.
Knowledge is power, but only if applied in a timely fashion.
Edited 11/13/2002 10:36:14 AM ET by GOLDHILLER