My wife wants hardwood floors to replace the old vinyl in our kitchen. So we’re doing hardwood floors. But the hardwood in the rest of the house expands and contracts with the seasons producing small cracks at various times, and I’m concerned that in the kitchen, the small cracks that might open between boards in the dry winter will make the floor hard to keep clean, and vulnerable to wet spills.
Beyond the normal techniques of letting the wood acclimate in the house for several weeks before installation, and finishing with 3-4 coats of high-quality polyurethane, I’m thinking that it might make sense to backprime the wood with poly before installation. Just one coat, to seal it, and presumably prevent the under surface from picking up seasonal humidity. Obviously, I wouldn’t prime the tongue-and-groove edges; the floor would still be laid and finished the normal way.
The kitchen is over a full-height unfinished-but-heated basement.
I’ve asked a number of friends and contractors, and nobody has ever heard of this being done. Realizing that it will cost extra labor time to do it, I’m still inclined to backprime the boards as “insurance.” But does anyone know of a reason why this might be a bad idea? Has anyone ever done this?
Thanks!
Replies
I don't think backpriming is enough to seal the wood 100%. It will retard the frequent swings in air moisture from affecting the wood (the 24 hr cycles), but over the course of several weeks & across seasons, moisture will get in & out and the wood will move. So you won't solve the problem of the "cracks". That and considering how expensive it is to do it (labor) may be the answer why it's not commonly done.
OTOH, I was considering using one of the sekkins (sp?) products recently on an existing porch floor and discovered that the mfg'r specifies that the wood be coated on all 6 sides before installation. They were pretty adamant about it when I called them, so I used a different product. Different application but not totally unheard of.
As always, YMMV...
I have never heard of backpriming hardwood floors. We have hardwood in our kitchen. No kids but 2 big, active & lovable dogs. Floor is holding up OK, but after 8 years it is due for a recoat. BTW - we have oil polyurethane.
Your best bet to minimize movement is to use quarter-sawn flooring. Quarter sawn lumber is much more stable than flat sawn. It's also more expensive.
The other choice is to use Pergo, or one of the other laminate floorings.
There's no finish that will eliminate the wood's absorption of humidity. Backpriming the flooring will help, but won't completely eliminate the problem.
Sharpblade, Matt, and Shep -- Thanks for your responses. We looked at Pergo, and similar products, but none of them had the "look" that my wife wanted, so they are out. Although it's more labor, I'll probably end up doing the backpriming myself prior to the contractor arriving to install the floors, so I think I'm going to go ahead and try it. Worst case seems to be that it will do no good. I was principally concerned that there might be some negative effect that I wasn't thinking of, but nobody I've talked to, nor anyone on this forum, seems to see anything like that.
By the way, Sharpblade, I had Sikkens deck stuff put on my decks about 10 years ago. The decks on the 2nd floor were done top and bottom, and they still look good today. The decks on the ground level didn't get a coat underneath, and were peeling, some, within about 5 years. So Sikkens' advice is accurate, at least as far as I can tell.
Thanks again everyone.
BTW, in this application you're backsealing :-)
Yes it can't hurt, and since you decided to do it, you may consider thinning the poly 10% to get deeper absorption into the wood & better sealing.
Another BTW, any chance you intended your handle (name) to be woodnut but mispelled?
Yes, I guess backsealing is a better word than backpriming.
Good idea on thinning the poly; I'll do that.
As far as the handle: I wanted "woodu" (as in "I'd do this, but would u?") but it was taken. So I tried "wouldn't you"... which is what it is supposed to be. In retrospect, if I'd taken more than 30 seconds to think about it, I might have tried harder! But now you know. :-)
"Worst case seems to be that it will do no good. "That is right, it can't hurt a thing, unless you gob sealer on so thinck it prevents T&G from fitting together. It may do you some good in slowing the moisture and movement of the wood.If this is an air conditioned controled environment house, then it is less likely to do any good.
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I don't intend to get any on the tongue-and-groove sides (or at least intend to minimize that) as I don't want to screw up the fit, and with those sides pulled tight together and the top and bottom sealed, I'm thinking there won't be much surface that can absorb moisture.
The house does have an a/c, but we don't run it a lot, and the internal humidity of the house does vary widely across the year. (See an earlier reply I wrote about seeing a lot of movement in the bedroom floor.)
Thanks.
"I don't intend to get any on the tongue-and-groove sides "It will end up there unless you plan to spend three times as much time doing this to neatly cut in on the edge. It's easy to just brush it out smooth so it is not left dripping. You want that edge sealed at least as much as you want the back sealed anyways.
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Piffin, your several posts make many good points, and I appreciate your suggestions. With the help of you and the several other folks who have responded to my query, I'm feeling that I will be able to find an "ideal" way of flooring my kitchen with hardwood... I'm now looking into some of those engineered products, and also will weigh them against treating "ordinary" red oak flooring.
Thanks, to you Piffin, and thanks, to all of you who have contributed to answering my questions.
You can use ENGINEERED wood flooring.Some stiles of it are floating. With a floating floor you don't get any gaps between planks or boards. It is all at the outside edges. And an engineered floor does not move as much as solid wood floor.There is also at least one brand of floating solid wood flooring. The one brand that I know of uses metal clips to hold the boards together..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I've seen one house, that I know of, that had backprimed flooring. 4" quarter sawn oak, with mahogany, and brass inlays. A bunch of different patterns. House was heated, wood acclimated in loose, stickered stacks for 3 weeks (I know, because we had to work around it). It still moved.It didn't move much by my apparently low standards, but it botherd the clients to the point about half was ripped out and replaced. Shrank again...they shoulda got formica<G> "But to be honest some folks here have been pushing the envelope quite a bit with their unnecessary use if swear words. They just put a character in to replace a letter. But everyone knows what they're saying." Sancho
Wow, that floor sounds scary! Brass inlays?! And it moved even though it was backsealed! Your point in jest about using formica isn't so far off... Our present vinyl floor, though ugly, has never opened cracks!
I'm not naive enough to think that it won't move at all, and will remain perfectly sealed. I just want to make those movements as small as possible.
Thanks.
Well, we looked at a bunch of floating engineered products (like Pergo, and many others), but the bottom line was that my wife didn't see any that she liked the look of. However, I don't think we saw any engineered full-depth floating systems, such as the one you are referencing. Can you suggest the name or manufacturer, or where you might have heard of it. I'd certainly like to investigate it.
Thanks.
Pergo is not an engineered wood floor. It is a laminate flooring. Pictures of wood (or stone) under a melimena wear surface. It is related to high pressure laminate (counter tops).Engineered wood floors are like plywood with multiple wood wear layers. In some the wear layer is 1/4" thick and can be refinished many times.Here is one higher end brand.http://www.br111.com/productlines.htmlKahrs is another.http://www.hardwoodinstaller.com/hardwoodinstaller/kahrs-wood-floors.htmWhat you want to look for is a square edge product.In general engineer wood floors can be floating (glued togethere, but a few are click lock), nailed down , or glued down. But not all products are speced for all types of installation so you need to check that also.This is the solid floating wood floor. IIRC they impregnate the wood to make it more stable.http://www.junckershardwood.com/index.html.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill, your links are tremendously helpful. Thanks so much for your pointers!
Don't mean to hijack this thread, but does engineered flooring need to be acclimated to a house prior to installation? What about pre-finished hardwood?Thanks.
I'm not a professional, but I have done about 5000 sq ft of hardwood flooring. I'd forget the back priming if I were you. The wood will not pick-up/loose much if any moisture from the bottom unless you have special issues like over a concrete slab or wet or high humidity crawl-space.
Under normal or good conditions, you shouldn't have so much wood movement that problematic cracks open up. If you do, then you probably have other moisture problems with the materials or house in general.
If you can't stand cracks at all, then use tile or something else.
Also, if I had to do any more hardwood flooring, I'd definately go with the pre-finished. They come in more durable baked on finishes (up to 50 yr warrantee). Once it is nailed down, it's done. No sanding mess, no finishing fumes, done.
MrSQL,
Thanks. I'm basing my concerns on the fact that a hardwood (oak) floor laid in the master bedroom in the house (which is on the second floor) shows substantial cracks at certain times of the year, and seems tight at other times. I don't know if my house has unusual humidity swings, but generally-speaking, here in New England, there are times of the year when all the air is quite dry, and times when it is quite humid, so I'm thinking that unless I protect the underside of the wood, it will do what wood does.
I'd love to use pre-finished, but all of the prefinished stuff I've looked at seems to have "micro-chamfers" on the edges (probably to hide minor imperfections in the fit), and those turn into "micro-grooves" when fitted together, which seems like a bad idea for a kitchen floor. Again, I'm concerned about being able to clean up spills, and the general nature of "stuff that falls on a kitchen floor." But your suggestion will make me look harder to see if I can find some pre-finished product that will install as a perfectly flush floor.
I do this often with wider width pine and birch flooring - usually use Shellac because it dries fast - and the buzz from the vapors is fun...
;)
it hel[ps - not a perfect cure, but wood is wood
you say hardwood - what kind and size? Narrower has less move4ment per piece and some species are more stable than others.
You do plan to get rid of the vinyl floor first, right?
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Shellac sounds like fun (!) but I'm not sure how to decide between thinned polyurethane and shellac. Probably, either will dry in a day, which is good enough for me. Is the high off of shellac better than off of poly??? ;-)
Floor will be just "normal" red oak. Yes, the old vinyl is going away, and the subfloor made sound, before the new floor will be installed.
Thanks.
Red oak wicks water something terrible. If I recall, this is a kitchen floor? Don't ever spill anything and let it set.red oak makes a good case for seqaling the backs. I would be more likely to use water based poly for that. It is more heavy bodied to seal the pores than shellac is.Water based poly will dry in about an hur, for this purpose, and need no thinning. Shellac dries almost immediately. When using shellac to back-seal, on long lengths , I'd have a helper, a pair of benches, and spread several boards backside up. He would use the roller to apply, and I would brush it in and smooth the edges, then we would take those several pieces, stack them on stickers in the dry pile, then ready several more pieces again. Those are dry by time we place stickers for next level up on the pile.
If you get moving well, two guys can do 300 feet a day in long wide lengths like that.
You will probably be alone working short narrow lengths so it'll probably take every bit of a day to do a room's worth.
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woodntu,
backpriming won't help! wood shrinks and expands depending on moisture.. that's the nature of wood.
frenchy, I don't understand the logic of your response... Wood moves because of moisture changing in the wood, so if I seal all the exposed surfaces, shouldn't that limit the changes in moisture in the wood?
thanks for your interest in my problem.
It doesn't limit the changes - the water vapor will get in and out. What it does do is slow them down; if all sides are sealed it slows them down a lot. As to what timeframe "a lot" is, that's a question for someone who knows more than I.
woodntu
No I'm sorry. wood absorbs moisture. it's easy to see with wide planks. When Carlise puts wide plank flooring down they leave expansion gaps, otherwise they'd get buckling when the wood swells in high humidity days..
Actaully you asked about shellac,versis Polyurethanes.. Shellac dries inside of 15 minutes, poly never really dries completely but you can handle it in 4 to 8 hours..
Shellac is one of the wonder floor finishes that everybody over looked..
It's been around for 5000 years and is pretty wonderful stuff. Depth and class without the plasticy look of polurethanes. Antique fine furniture was all done in shellac!
Its harder than most other floor finishes. My 150 pound puppy doesn't scratch it inspite of him never clipping his toe nails. I talk and I talk but he never listens!!!
Anyway if he ever did scratch it I'd have to teach him to get out a rag and dampen it with denatured alcohol and rub the scratch for a few moments.. scratch-be-gone! In fact one of the great things about shellac is just how easy it is to fix problems..
It takes me less than two hours to shellac a floor and get the furniture back on it.. if I open windows the fumes are almost completely gone by the time company arrives and if they do smell anything it's this slightly sweet smell that's not offencive. It's gone by morning..
Every pill you take is coated with shellac by the drug companies so it must be pretty safe..
It's designed for the sloppiest do-it-yourselfer.500 sq ft. will cost you less than $50.00 to do and that includes the paint brush!
You can brush, mop, wipe, spray, or put it on with a brick in a windstorm (well the latter might cause a little extra sanding)
There are two tricks to doing fabulous jobs with shellac..
First way over thin it.. Buy the gallon at Home depot (My last cost me $22.00 a gallon, Zinzzlers clear) buy three gallons of denatured alcohol Please listen to me (or I'll flick boogers on your computer screen) denatured alcohol not thinner or anything else! denatured alcohol..
Second don't go slow!
carefull won't cut it.. flood it on , mop it on, just do it fast!
If you are the cautious type get your kids to do it, make it a game..
If you miss a spot so what! the next coat will melt right into the first coat
Just to review
Put a fast coat of overly thinned shellac on, wait 15 minutes for it to dry then sand it,, give it a real lick and a promise. 10 minutes with a palm sander with 220 sand paper is about right. cover a sq.ft in a second, second and 1/2 max.. Slop the second coat on quickly, let it dry a 1/2 an hour, same kind of sanding. put the final coat on.. you might use a tiny bit more time to do it to make really sure everything is coated.. but don't go slow!
A dry edge is problems! Speed but full coverage is your goal..
Now
If you are insane and want to kill yourself with work you could color sand.. that's where you start with 400 grit make the whole floor satin,, go to 600 then 800 and stop at 4000 grit.. You should be insanely happy but if you are absolutely certain that you want an over the top finish worthy of the finest furniture, you can now french polish everything.. On 500 sq.ft I'll talk to you next year.. I'd like to see how you plan on having everybody elevate themselves over the floor but maybe you're wealthy enough to have your staff do such things for you..
OH and suppose you wear thru the finish in a decade or two or six.. just dampen that same rag with denatured alcohol and it wipes off easily right down to bare wood.. when you slop some new stuff on it melts right into the old stuff and you have a seamless repair.
Shellac was a popular finish that reqires periodic waxing. Basically, the wax is the wear surface. I think some old house fanatic types still use it but it's use has pretty much been abondened for low maint more durable finishes like poly. Also I believe that shellac water spots therefor using it in a kitchen would definately not be a good idea. If someone doesn't like the high sheen of regular poly then use satin.
I'm not a contractor but have installed hardwood myself also click together laminate floors and from my experience I would recomend putting down 6mm poly as a vaper barrier if you have a crawl space this would cut down on moisture and this is rcmended by alot of manufacturer.