Q1: there are hundreds of nails and tacks in the floor. What is the best way to remove these? I've been using vice grips, which work pretty well, but sometimes create a nice gouge in the floor.
I use big adjustable pliers if there is anything to grasp that can't be removed with a pry bar (finishing nails, headless nails, broken staple legs, etc.) ... grasp the protruding part at the base firmly and rock onto the rounded side of the pliers to pull the nail or tack. Less chance of a gouge in the wood.
http://en.wikipedia.org/wiki/Tongue-and-groove_pliers (BIG ones)

For intact staples, I use a 3-lb mallet and a small pry bar - one with a split foot that is just smaller than the staples.
http://www.amazon.com/Stanley-55-045-7-1-2-Inch-Wonder/dp/B00002X1XS/ref=sr_1_5?ie=UTF8&qid=1368834414&sr=8-5&keywords=pry+bar

Place the not-curved end flat on the floor next to the staple so 1/2 the foot will go under the staple and tap it gently with the mallet so it catches the edge of the staple and lifts it out.

Nails with heads can be grabbed by driving the prybar under them: place the bar aimed slightly down with the nail in the "V" of the flat end and tap it. If you get under it, pry gently and then swap ends and pry with the rounded end.

If it's a finishing nail (small head), use a nail set and drive it into the board and out of your way.

I also use a 12-inch pry bar and up to a 4-foot monster bar if the nails are really huge.

Q2: How much of the tar paper/adhesive reside do I need to remove before I start sanding.
Test this ... too little and the sandpaper gums up in 6 inches of floor. Too much and it's a waste of your time.

Q3: I need to replace some rotted boards. Ideally I would remove long sections of these boards and reuse the salvageable sections as shorter replacement boards. Is there a good way to remove long sections of boards where the adjacent boards to be removed vary in length?

Can you show a picture? There are several ways to do this, and it depends on where the damage is.

It seems that I could probably cut the boards out along the edges (removing the tongue in the process) - would that create much of a problem as far as reinstallation goes?
The saw kerf will cause problems ... the removed boards will be too narrow to use for patching.

Basically, unless you can access the tongue and carefully pry the board out or cut the nails with a multi-tool, consider removed boards to be trashed.

To match old board height with new replacements, use a planer from the TOP side, not the bottom.

Q4: When reinstalling the replacement boards, should I use some sort of adhesive to attach them to the joists, or just nail them in, or both? I'm planning to attach cleats to the joists to give myself a little more support at the ends.

When I was repairing board over joist, I nailed through the tongue AND uses construction adhesive. And sistered the joists to give me a more secure joint....

Lazygarden's got good advice. My two cents:

1. A wonderbar gets out everything except nails without heads. Skim it along the surface and it pulls out staples, even ones with just one "leg" in the wood. Pry out nails with either the end or the hole near the end.

2. Have you tried a wallpaper steamer? How about a heat gun? See my thread linked below about steaming my floors. Your kitchen sounds similar to mine. And my new heat gun is on tomorrow's agenda. I'll post my results.

3. The normal way of removing bad boards is running a circular saw down the center long ways to cut them in half, then carefully prying the bad board out, leaving the neighboring ones intact. Then you take the new board (you can always harvest from a closet or something if you don't have/can't find any to buy), slice off the bottom of the groove end, tuck the tongue into the next board's groove end, set the groove end down in place, and face nail the board. If you didn't follow my run-on sentence, just google "replace hardwood board" and you'll find some tutorials.

4. You don't want to nail the boards to the joists, just to the subfloor.

Here is a link that might be useful: steaming the black stuff off

Sometimes you don't have any subfloor, just T&G flooring over naked joists ... in that case you often need to add a bit of blocking where you are patching so you have something to nail into.

Thank you lazygardens and weedyacres (great names both!). I will pick up a wonderbar for the nails. It sounds like I'll need to scrap most of the boards, but I think I should still have enough from under the cabinets to replace.

As lazygardens notes, there is no subfloor so adding some supports will be a good step.

Weedyacres - your pictures give me hope. Thanks! The leftover adhesive is much thinner on my floor so hopefully it won't be such an ordeal.

Thank you lazygardens and weedyacres (great names both!). I will pick up a wonderbar for the nails. It sounds like I'll need to scrap most of the boards, but I think I should still have enough from under the cabinets to replace.

As lazygardens notes, there is no subfloor so adding some supports will be a good step.

Weedyacres - your pictures give me hope. Thanks! The leftover adhesive is much thinner on my floor so hopefully it won't be such an ordeal.

I've put in a few more hours with a heat gun and scraper, and progressed to this:

It definitely tasks the muscles (including those that grip) more than the steamer and scraper, and it's slow going, but does the trick eventually.

There's still some adhesive residue. I think my plan is to use a steamer to get that off. The heat gun makes it gooey, but the steamer more generally softens it.

I can't count the number of these rip outs I've done in my flooring career. Careful use of a sharp razor scraper after removal of the bulk of the old flooring can slice off much of the paper and adhesive that is left behind.

Hard, hard work...

Are you sure that is not sub-floor?

It was often laid at 45 degrees so the finished floor could go with the long direction of the room independent of joist direction.

While heart pine may be hard enough for flooring, it was also inexpensive enough to be used as sub-flooring.

Yes, the poster did indicate that there is no subflooring with this construction. However, if the tongues and grooves are well-mated, then this can be an attractive and inexpensive flooring choice.

In my case (OP), I'm fairly certain it was the original flooring. That's not to say that weedyacres floor was not originally a subfloor.

Weedyacres - have you tried any solvents? It could be a waste of time, but it may be worth trying. Like I noted in the original post, my cat's stomach acid did quite a number on the tar paper.

I've tried mineral spirits and denatured alcohol. I can't say conclusively what the effect has been because different sections of the floor/adhesive seem to come up more easily than others regardless. I've also ordered some oxalic acid and will see if that has any impact. At this point, it's more a matter of curiosity, as I don't have that much left to scrape.

My floor has been exposed for quite a while now and it seems like the thicker portions are coming up more easily now than during the winter months when I originally exposed the original boards.

My floors have 1x10s on the diagonal for subfloor. What I'm cleaning off is the original pine, extended in from the dining room.

I tried the chemicals today, got a citrus stripper from Lowe's, smeared it in an L shape in front of the cabinets and across the back wall, and a strip along the window wall (got about halfway before the bottle was empty). The label said to let it sit for anywhere between 30 min and 24 hours. After checking every half hour for a couple hours, and finding no change, I left it alone for 8 hours. Here's a before and after:

Parts were still goopy and parts had dried to a wax-like consistency. With some hard scraping with a putty knife, the wax peeled off and took some of the finish with it, but mostly the brown, not the black stuff. When I used a blade scraper and a lot of elbow grease, some of the black stuff came off. But not enough to make it worth using any more of this citrus goop.

I would love suggestions from the pros and the experienced as to how to get at this black stuff. I think it's still too thick to just sand out.

Well its easy for me to say i would just sand it out. Obviously you would need some agressive sandpaper and a lot of it. Not to mention the required skill. But have you tried boiling water? It may not wrok the greatest for the 1x10.

Maybe try a more agressive chemical peel? Or acetone? Granted its some serious chemicals and obviously you want to be safe.

The stuff you used did work good. Took a lot of the junk off. Unfortunately if you dont sand i think its going to be more blood sweat and tears getting it clean. Good luck.

Hot water? I agree...many times the asphalt felt was glued down with organic linoleum paste. Water will dissolve that into solution. You can make careful razor cuts into the felt to allow the water to penetrate to the paste by capillary action.

I've done a little bit of steaming, and it worked great on the adhesive in the bedrooms, but in the kitchen as yet it has softened but not dissolved the tar, so still takes a fair amount of scraping to hack off. I can try some more experimenting with steam, to see if I can find the right formula.

Mr. Weedy also mentioned trying a carefully-applied wire brush on a grinder. And I can see if super-heavy-grit sandpaper will eat into it without too much dust (you know, asbestos risk and all).

BTW, sorry for the hijack, emcloud. :-)

If you sand this off. I can pretty much assume you would need At least p24. Maybe even a p16. I can promise anything you sand with that low of a grit will not sand to a fine dust. It will be think chunky clunky pieces. And chances are it will melt from the friction of sanding and melt to the sand paper. A simple dust mask should you fine. But if youre worried about abestos, test for it!

Also steaming might not be enough heat.
Boiling or extremely hot water poured directly onto an area or what i would do is get a rag soaked with the hot water and lay is over an area for a minute and then scrape away.

How is boiling water hotter than steam? Steam, by definition is slightly higher temperature than boiling water. And a hot rag laid down would immediately begin to cool, as contrasted with a steamer that maintains the heat.

Not trying to argue, just trying to understand why boiling water might be different than steam.

"How is boiling water hotter than steam? "

If you can see it with your eyes it is not steam, but condensation.

It is almost always below 212F at that point.

Aim it at an instant read thermometer stem and see how high you can make it read.

Stem is invisible, and can be way over 212 F since it is a gas and behaves as one.

Most of the equipment for non-industrial use is a source of moisture and condensation, not actual steam.

Actual steam, even with just a little super eat (above 212 F), is dangerous stuff.

Third degree burns are common from the slightest exposure of tissue (it is all but instantly cooked by the steam to full thickness of the skin).

I actually make steam at about 2-3 PSI to bend wood.

A virgin 5 gallon gas can with a radiator hose on the spout to the steam box, sitting on a propane burner, with a known weight and a small square of EPDM membrane as a gasket on the top of the fill opening.

I can make pretzels out of straight grain hardwood 1/2 inch thick after about 20 minutes in the box wearing insulated welders gloves to manipulate things).

Wearing heavy winter clothing and a full face mask for safety in the heat of summer when using steam makes for short work periods.

Boiling water delivers more heat than the condensation you are likely using.

This post was edited by brickeyee on Wed, May 29, 13 at 14:22

I'm happy to say that I seem to have landed on the formula to get the tar off my kitchen floor. It all comes back to the steamer and a putty knife. The difference between this floor and the others I did is that it takes several rounds. So on the first pass, I scrape at the tar, it doesn't seem to come off much, but I work my way down the row, right to left. Then I go back to the right hand side again, and this time a little more comes off. After 3 passes, most is off, but some stubborn patches take a half dozen rounds before I get to the wood.

This wouldn't work if I just left the steamer on a part of floor for a longer time (the equivalent of several passes) because the wood fibers would start to open up and scraping would splinter it.

Now I'm about halfway done. Here's a progress photo.

One thing that puzzles me. You can see the dark brown still on the floor. It kind of looks like paint, as though the original wood was painted brown, then the linoleum was put over top of that, then the second layer of vinyl. Anyway, when I'm scraping, the brown kind of liquefies, to the consistency of paint: gooey and wet. This isn't typically the way paint reacts with steam, so I'm not sure exactly what this stuff is. I'm assuming I can just sand what's left after I get the black tar off. But I'm curious if anyone can tell me what it is.

Organic linoleum paste.

I just returned to this post after quite a while. I'm glad to see it generated some discussion. The tar paper (or whatever it was) covering my floor was not quite as bad as weedyacres' floor, but it was still a pain to remove.

I tried several things to remove it, including hand scraping with a painter's tool, scraping with a garden hoe, and scraping with an oscillating tool. I also applied hot water to try to help with the scraping. In the end I think the hand scraping was the most effective, but the hot water seemed to loosen it some. The oscillating tool worked pretty well and provided some relief. With any of the scraping methods, a few gouges inevitably were made. Also, I took a hiatus from working on the floor for several months, and found that when I came back to it, the paper was more brittle, so it seemed to scrape off more easily.

I just started sanding the floor this week (with a hand belt sander!), and there are still some patches where the paper is fairly thick, but the sander seems to be working through it pretty well with 36 grit paper. It does take some angling of the sander to get all of it off. This method is not for everyone, but I didn't feel like messing with a drum sander (for the first time) to do a single room.

I have been stripping the wallpaper in my kitchen and have found that wherever I spilled the DIF, the paste on the exposed wood (where the linoleum was removed) scraped off easily.
Then I had to clean it off the scraper -- not so easy!

I have been stripping the wallpaper in my kitchen and have found that wherever I spilled the DIF, the paste on the exposed wood (where the linoleum was removed) scraped off easily.
Then I had to clean it off the scraper -- not so easy!

And a final photo once I got the last of the tar off. Whew!

I've been working on the same type of floor with the same type of covering. I've used about 12 different substances including ox acid (in barkeepers friend) Yet to try the steamer method so I'll be doing that next trip.
I'd paste some pics but do not know how.

Anyway thanks to all you guys for the ideas and the pics. Seeing the pics makes me feel pretty good because my pine floors are nowhere near as covered as the pictured floor

I've been working on the same type of floor with the same type of covering. I've used about 12 different substances including ox acid (in barkeepers friend) Yet to try the steamer method so I'll be doing that next trip.
I'd paste some pics but do not know how.

Anyway thanks to all you guys for the ideas and the pics. Seeing the pics makes me feel pretty good because my pine floors are nowhere near as covered as the pictured floor

here are a couple of other pics

another pic

Looks like diagonal subflooring to me. It can be made to look good...I've done 'em. Yours look nice and tight.

Other than Bona, has anyone used Rejuvenate or Minwax to restore their hardwood floors? A while back, someone was kind enough to suggest the Bona product. I would like to compare and see what the best product might be for my particular problem. I have a genuine oak hardwood floor that is about 12 years old. It needs more than just a polish. There are a few scratches and work spots. Thanks

I bought some of this "DE-SOLV-IT" today after reading good comments about it on another web site. It is supposed to take out all types of stuff, on the label it says "works 100% of the time"
we will see how it works on the stuff on my floors and I'll post back.
Looked on amazon and had very good reviews found it at Walmart in the home cleaners isle near the barkeepers and goo gone stuff.

My floors are pretty tight but there are quite a few gaps, nails etc plan on putting putty over them. Tempted to stain or mix dye with the poly as the walls look too similiar

Glenn
when you say you've "done them" can you elaborate

Thanks

Yes. I have sanded and finished subflooring for customers. Really no different from any other flooring finish work, except that you have to consider the fact that it happens to be a single construction floor system and, therefore, you have to take steps to protect what is below the floor when you sand and then apply stains and finishes. Anything you do above to the floor surface can easily find its way down to the space below...dust, stain and finish.

You have to sink any top nails below the surface of the wood before you sand and continue to punch them below when necessary.

You probably can never remove all tar paper lines and staining, but that is OK, as the floor will have a great look all by itself.

I have finished these natural and stained a few. I also colored one green once at a customer's request. That one was unique and beautiful.

Thanks Glenn,

I have 4 rooms to do kitchen, bath, and 2 bedrooms. I'm thinking if the chemicals, sanding and steaming do not do a good enough job I'll go ahead with the painting concept. That green floor sounds interesting.
Here is the worst of the floor

The de-solv-it and some krud Kutter "tough task remover" did an OK job getting 90% of the stain out. They were about the same effectiveness and KK was less expensive.

after using the Krud Kutter and de-solv-it. Still needs some additional effort, that and even afterwards will probably go with a darkish stain....maybe it'll wind up looking like this