What I did and what I'd do if I was doing it all over. Long-winded, but I don't know another way. Just telling what I learned. I'm no expert. Nothing exotic here.
FLOORS/BASE/DOOR CASING/PLANNING Floors are oak, cicra 1959. 2 1/4" t&g They had darkened varnish, dog piss stains, scratches, etc. Ugly as hell. We covered them with various rugs. The dog piss stains were mostly where there's always a carpet under the dining room table. One of our girl dogs did that sometimes, and a couple times left a stain before we found it. We went through a few good rugs there.
Never found which one was the culprit, but I suspect the big one. She's the one that scratched off the old varnish too. Anyway we waited until she took off for dog heaven to do the floors.
Besides dogs and the usual suspects, watch out for carpet installers if you want to preserve a good hardwood floor. Two years in we removed the cheap new carpet that was in there when we bought our house empty. Grab strips nailed in the floor with cheap nails, and I probably pulled 100 staples from the floor as far as 2 feet from the wall. Any staple or nail that rusts will leave a black marks in the floor. I've got some from the grab strip nails, and the sanding guy told me there's no help for it. They don't detract unless you take to staring at them, but could have been avoided. Can't even see where the staples were - smaller holes and they didn't rust.
Think about the base/shoe/door casings before the you call the floor-sanders in. In our case we weren't even thinking about replacing the painted base/shoe, even less the door casings. But the floors came out much better than we thought they would. Even the piss stains gone. Really nice, so they deserved new oak base/shoe to match. Floor turned out golden oak with no stain, 3 coats of matte poly. Connected living room/dining room/hallway. Base/shoe butts the door casings. so there you go. I'll mention here we've done some paint stripping, and unless it's very special wood that's hard to replace, forget it. We would have spent more on stripper than we paid for the oak, it would have been much more work, and wouldn't look as good.
When I pulled the shoe/base there was a ridge of old blackened varnish at the edge. The sanders would have removed that if I had pulled the shoe before they came in. BTW, there was no significant ridge from the sanding itself, maybe
1/16" max. If more wood is removed from the floor, which I've heard of, removing the base/shoe first is even more important. To fix the varnish ridge I had a couple choices. Knock it off with a chisel or resand and revarnish. I used a chisel. Easy. Bought standard cut same size new oak base and shoe from Menards. Shoe was identical, but the base was maybe 1/8 thinner than the old stuff, so a black line showed where the ridge was, Flipping the shoe so wide side is down covered the line. Looks good and it works, but if I had removed the base before the sanding I wouldn't have to think about it. There's a black line at the door casing bottoms, as the new casings were also a bit thinner than the old. Hardly noticeable, but there. Think about paint ridges when replacing woodwork too, and whether you should hold off painting until you remove the wood and take care of the ridges and any filling you might have to do. We were lucky. Wife had already painted, but we used the same height baseboard and same width door casings, and the paint ridging was minor. - came off easily with a putty knife and needed no filling. I lifted the baseboard a bit and moved the casing out a bit to cover the old lines.GRAIN Didn't stain any of the oak, just put 3 coats of poly matte on it. If I had to do it over again I would do more sanding between coats. Grain gets raised with the first coat. Good hog hair, or foam brush, doesn't matter. My wife was pushing and she did about half the varnishing. Not that it's real rough, but hey, new varnished wood should be smooth as a baby's ass. It ain't. Big thing I want to say about grain is matching butts at the store. Lay it out and get it right as you can. Mark it there so you have to redo it. We didn't do that. We picked pretty close matching grain. Base/shoe were 12's and 16's, crown 14's. Grains at corners don't matter, but they really show up where you butt the long runs. Doesn't matter that the butt cut is perfect. Might just be me, but I don't want to notice joints. Everybody else seems to love it - but they could be lying.
SAWS/SAWING/SANDING.
There's saws and there's saws. I gave up my table and radial arm saws long ago, and just wanted a cheap saw for this job, and that could be useful later as 2x4 cuttoff. Used this
Corners came out good because my walls/ceilings are close to square. Used golden oak filler in just a few places that were about 1/16" off and sanded off a few sharp outside edges with an orbital. None of itt noticeable unless you look hard. BTW, I make a lot of dust. I always start cutting oversize, then rework it by a blade width or less, refitting. A pro would laugh, but it works for me. Had very little scrap. But lots of saw noise and dust (-:
Where the oak shoe meets the different sized painted shoe in the kitchen doorways I belt sanded to get them flush. Mitered the shoes 45 where they butted casings, then touched up with varnish. If I did it all over I would have sanded them round. Same with the 6 thresholds I put in. That's another case where I followed my wife's rushing cue. She was helping me, and pushing to get done. Even complained about me sanding off outside miter burn marks on the shoe because it was slowing us down. Didn't listen to her about that. She's happy with it all, so I can't complain about her. Without her pushing it would never get done.
Besides the butt grain mismatches, I've got one bad spot on a crown butt because of an otherwise unnoticeable wall defect causing about a
1/8" bump at the butt, and the same vertical offset. Only way to make it fit would have meant mucho sanding along the length of the crown back side, or sanding it down now. First time my daughter - the rude one - saw the new stuff, she said, "Wow, nice. Eeeew, what's that?" I have to sand that down and revarnish it.Something related to this I'll mention. Most know this, but so what. When you're pulling woodwork and pulling nails give plenty of thought to how you're doing it, and never rush it. It's easy to dent wood and hole drywall. I knew that, but forgot it until I holed drywall and dented wood. And I came prepared with different wrecking bars, a good hammer claw and my usual wood shim wedges, which I slide behind tool fulcrum points. But at the beginning I was rushing and not thinking hard. Patching the hole in the drywall was a kick in the ass. The wedge backing didn't help. You just don't want to fulcrum against drywall. And wood dents easy too, even when you think it won't, so you always want a backing behind your bar or hammer claw to take the dent.
Other things - using a hard drive magnet to find studs, and a nail gun. I used a cheap one, and it lasted the job. Well worth it. Only oak thresholds I saw had holes drilled in for screws or nails. Since I cut them to a hammer tap fit and just gunned a few brads through to fix them, had to putty the factory holes. Doors didn't have thresholds, but a gap under. Those room floors weren't sanded and are in good shape but dark. The thresholds make a good transition and seal the doors better. A couple doors rubbed the new thresholds so I belt sanded the back of those to get clearance. Kept the contour, but made a lot of dust. If I ever have a door rubbing a threshold I'll pull the door stops and threshold to reduce that before I go sawing on a door bottom.
Anyway, that's my story. Maybe it will help somebody, maybe not. Maybe somebody will teach me something. Just know what I'd do different if I ever did it again. But only if I remember.
--Vic