Sanding out stains in wood floor
DesignBuild
| Posted in Construction Techniques on
hi all — the previous home owner installed slate tile directly on top of the hardwood in my house. The slate came up pretty easily and the wood is cleaning up a bit with some drum sanding, but all of the grout joints have left a dark stain – I assume this is from the water in the grout during the initial installation. Any suggestions on removing these stains? I’ve been able to sand out some of them but am starting to lose hope on getting them all out without spending days sanding and removing a good part of the floor thickness. Also, think I should be concerned about those areas not accepting stain evenly?
thanks for you help
Replies
Design Build
I suspect the stain is deeper than you can sand without reaching the spline.
Your choice left is to stain the whole thing darker or replace the flooring..
I would try bleach--oxalic acid is often used on wood--follow the instructions, wear gloves and eye protection, don't breathe the dust or vapors, etc. Even just household bleach may also work. I'd try it diluted maybe half and half to start with and work my way up. I had a leaking bottle of bleach on an oak floor once and it turned the wood pure white--but also ate the wood away, that's why I say to start out with the bleach diluted.
Another thing to try--just dilute acid, like white vinegar. That may react with any residue left from the grout (which is basic--so acid will neutralize it). Do not mix these ideas--that is, do not mix bleach and acid. If it were me, I think I'd start by dropping a little vinegar on a spot where it isn't real visible and leaving it for a few minutes and see what happens. If that didn't do anything, I'd try a little oxalic acid. If that didn't work, I'd rinse those off and try a little household bleach. A wood brightener for decks may also work, but those usually contain some form of sodium hydroxide or other base, and may not do anything on the stains which are also base.
You are screwed. The lime reacted with the tannin ( or vice versa) and I can tell you for certain, them stains run deep and will always show a hint even if you do manage to sand, bleach or my idea* to deal with them.
* my idea is to wipe down the whole thing with ammonia and let it "Fume" the floor almost black..matter of fact dissolve some rusty nails in a few gallons of vinegar for a few days and swab THAT on the floor..make it BLACK as you can get it.
Now the grain is raised, it's nasty ugly black..sand it. It MAY wind up being like the old Blue stain oak color that was sold at one time, but at least the lines won't be QUITE as horrid..but then again..it's a long shot.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
http://www.youtube.com/watch?v=Dj_oEx4-Mc4
Hello, I've refinished/repaired my share of old floors and have delt with similar situations.
I would not agree with Sphere...literally....let's just say your options are..shall we say......rather...limited. But as Danno said you can try bleach. I have had success with it , mostly with smaller areas. Like smaller spots where the older metal tips on furniture had worn thru the old varnish/poly. But you also have to be careful not to make "white" areas in the floor where you have bleached out the old patina or stain. Then you have to re-stain to try to match the old color. With stain of this magnitude I would try to bleach the entire floor and stain dark.. real dark
And if it is the result of water with the oak forming tannin (I sure it is) then it is deep. That's just the nature of tannic acid, the leather workers of old would mix water , oak chip/shavings and sometimes nails to make tannic acid to cure leather.
Anyway, just my two cents. Good Luck (your gonna need it) Quality Wood Chips, Bill D.
nothing quite like hearing "You are screwed". Thanks for the replies and advice. I've been sanding since my original post and it looks like I am making headway so let me ask this -- are you saying that even if i get the floor sanded to the point where there are no visible stains (I think I can do this with the exception of a couple patches) -- the stains will re-appear when I go to apply the finish?I hadn't decided on a color yet but I don't have a problem going on the dark side though probably not as dark as a fumed oak.Bill - bleaching the entire floor I assume means diluting some bleach and mopping it on? Any idea how long it would need to work?Thanks
Sean
Yes, probably 50/50 solution and I would do 4'-6' areas and rinse each area as you go. But..... you say you're making progress with the stain you might try the bleach solution on those areas , maybe in a out of sight corner or if this might be a kitchen where an appliance might be. When you say drum sander do you mean one of the big older commercial floor sanders I take it ? If not ,then I guess you mean you're using a belt sander, if so watch out not to create low spots in the floor. Just a couple more things : have you sanded past the old patina/stain, then you may as well get a large sander and do the entire floor so that when you do stain it will look nice and even ; and be aware that using the bleach solution will raise the grain of the old flooring. OK..OK.... Just one more thing , honest, a lot of the rental shops have a very user friendly orbital sander with four(4) -6" pads , it's almost impossible to create divots in the floor with that machine. They go for anywhere from $70-100.00 (around here) depending on how much paper you use. Bill D.
As far as "being screwed" that's why I said "limited possibilities". When I'm working, I try to maintain the attitude that the "glass is ALWAYS half FULL" And again Good Luck, I like doing floors, because when done well it ready adds to the whole room.
Tell ya what. 20 bucks as a friendly bet, no matter what he does short of replacing the floor, them lines will still be visable after the new finish hits it, provided it isn't paint..LOLSpheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
http://www.youtube.com/watch?v=Dj_oEx4-Mc4
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
Naw...I gave up betting on someone else's bad fortune a loooonnnggggg time ago (when I pasted 50-ish). But I do agree that maybe ...just maybe the lines will be there forever. But that depends on a lot of factors yet unknown. How dense is the oak..is it old or new? How much water /chemicals leached thru and how deep? Did the floor have a good coat of varnish/poly on it when the tile was laid to slow/prevent most of the tannin forming? How long ago was the tile laid... a year ago or 15 years ? Naw....not gonna bet ...but I would do some experimenting in an out of sight area with sanding ,staining, and varnish/poly, before ripping up the whole floor. And how much "ghost" bleed thru is acceptable? I don't know? I have done some where unless you knew where the stain was and got down on hands & knees you really didn't notice. Anywho... I wish him luck and who knows...maybe .....just maybe he can get a beautiful floor without ripping it up. Bill D. Quality Wood chips
I had a cat pee on a filing cab on an oak floor, with a semi bad finish..it stained well enough that it was like a sharpie perm marker..ammonia+steel+tannin= yikes.
You may be right, he possibly could get lucky, but I've seen more basket cases than salvageable, with lime reactions..and he may not mind the ghosting.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
http://www.youtube.com/watch?v=Dj_oEx4-Mc4
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
Sphere, In your post are the key. Hopefully the key to a much better floor for him. It's not cat pee..urea is worse than tannin ( don't know why..) and bad finish which let more cat pee penetrate deeper. And the addition of steel which acts as a cat-a-list (couldn't help the pun) for cat pee, which is mostly urea (and also a catalist for tannin). Which is why the old leather workers added old nails to the water and oak shavings to increases the percent or strength of tannin produced. Hopefully it'll turn out for the best. Bill D. Quality wood Chips
Oak inner bark, I have tanned hides. More better than wood shavings.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
http://www.youtube.com/watch?v=Dj_oEx4-Mc4
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
Sphere ,, in your post is (are ) the answers to hopefully a better floor for DesignBuid. His is not cat pee ,which is mostly urea. Also the fair , maybe bad floor finish which let more cat pee to penetrate deeper. And the addition of steel/iron which acts as a cat-a-list (sorry couldn't resist the pun) for cat pee which would make it stronger. That's why old leather workers added the old nails/iron to increase the % of tannin (tannic acid )produced for curing leather. Anyhow I hope the floor turns out well.
By the way the formula is not ammonia+ steel + tannin = yikes ;
it's ammonia+ steel + oak = tannin = yikes!!!!!
Anyway it's waaay past my beddy-by time,,,so I'll just say nite-nite for now. Bill D. Quality Wood Chips
Sleep on.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
http://www.youtube.com/watch?v=Dj_oEx4-Mc4
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
Sorry ...Duh.. I just noticed the photo. Floor looks a lot better then the first photo you had! And you are using the large floor sander. Keep going it will be beautiful. Bill D. Quality Wood Chips.
Not just any old bleach. You were already told what to try... oxalic acid. This stuff will remove the dark staining on oak from iron stains or in your case, cement. Follow the direction on the can. You can purchase this from any good paint store. It comes as crystals, and you mix what you need.
It's a small section, replace it. Done. 1/2 day of work max.
How many cuts is that? How dark will you be staining these floors?
Maybe mix up a sample of the stain and try it out. From the pic though, it doesnt look too promising.
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