A friend of mine living near the coast in Massachusetts is refinishing her oak floors. She has sanded them to 100 grit. She then cleaned up the sawdust by mopping, which, of course, raised the grain (she wasn't expecting this).

I suggested that she sand to 180 grit before finishing. But here are my questions:

1) What grit is a floor usually sanded to?
2) Is it worth wetting to raise the grain and then sanding again?
3) What's the best way to get sawdust up off the floor?
4) How long should she wait after the last sanding before putting on finish?
5) Does she need to use a sealer of any sort?
6) Is the Home Depot floor polyurethane a good product for finishing?
7) Will two coats be enough?
8) Are there some questions I didn't ask, but should have?

Thanks in advance for your help!

Peter

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I don't have as many Festools as Fred. Or Marcou's, or Brese's, or Lie-Nielsen's, or Lee Valley's, or Blue Spruce's, or Harold and Saxon's, or...

I have no idea, I hired a floor guy. The floor guy said that Swedish finish last the longest so that is what we got.

Peter,
Sorry, I'm not going to be much help. I was pretty cavalier about my shop floor. I rented a floor sander at Home Depot, with whatever they recommended for the sanding belt. I did use a product from Home Depot that the paint guy recommended and put on two coats. But mine is not a finish like I would want for my house. It's great in the shop, but I'd certainly pay more attention for my home. I don't believe the finish was a HD brand. Oh, and I just vacuumed prior to applying the finish.

When I refinished the floors (yellow pine) in a rental building I own, we used a rental floor sander and I think it only went to 150 grit, which still left a raggy surface. We put on two coats of polyurethane and it held up well for the beauty shop that occupied the space.

After they left, I used the building as a shop for a year and we sanded the floors with an ETS 150/5 to 100 and put on two more coats of poly to get it ready to rent. A Veterinarian now occupies the space and the floor is doing well, but those claws are leaving marks.

In both cases, I swept the floors and then vacuumed with a CT33 with the floor attachment.

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Thanks for the thoughts and advice! I'll pass this along.

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I don't have as many Festools as Fred. Or Marcou's, or Brese's, or Lie-Nielsen's, or Lee Valley's, or Blue Spruce's, or Harold and Saxon's, or...

we sanded the floors with an ETS 150/5 to 100

Holy Cr*p how are your knees????

Sorry I missed this thread-
'Grit sanded to' is based partly on what species the wood flooring is and how dark of a stain would you like the wood to be able to take. The higher you sand it, the less able the pores are to take a really deep amount of pigment. Generally speaking, 150 for a stain job floor is usually about it, with many people stopping at 120 grit.
I don't raise the grain on a floor, but I have heard of people doing it.
I vacuum, and vacuum the floor, before applying sanding sealer or stain.
If I'm using an Oil based stain but a Water based clear finish on top, I'm prone to using Dewaxed Shellac as a stain sealer over that stain once the stain has fully dried- Humid conditions WILL slow down the stain drying process, so beware of that. You can also use dye or water based stains, but the problem I've run into with water based stains is the grain raising issue all over again, and you have to be SUPER careful not to sand through the stain while getting the wood flat again and free of 'whiskers', so I don't use it and stick to Oil Based Gel Stains or Regular Pigment stains.
I've used several lower priced clear film/polys out of Home Depot, the only I don't like for several reasons is one from Mini-Wax, Water based but a Hybrid of sorts- I can post the name of it later on- Weak Film strength, and isn't holding up to either Dog Claws or General Wear and Tear nearly as well as other products we've used in the past.
3-4 coats for me with Water Based Polys, esp. if the floor sees animal traffic. Water Based is fast drying and you can in the right conditions put 2 coats down in a day, with light 400-600 grit screening in between the coats[ And Vacuuming again..] I know many pro floor people don't sand between coats, I believe they call it Hot Coating.
Traditional Oil Based Polys , I'm putting down 1 coat and seeing if I can level it out the next day with the same grit- 400-600 again, and Vacuuming...always Vacuuming esp. if there is floating animal hair in the house....

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