Refinishing tongue and groove wood floors in bathroom

masraum · 10-15-2021, 09:43 AM

There have been several other threads on our new (old) house.

I've got 2 questions for this thread.

1 Can I reasonably use a regular belt sander (instead of a drum floor sander) to refinish a 9x9' floor?
2 Thoughts or recommendations on fixing holes in the floor.

more detailed info.

But we are gutting the bathroom to the studs which includes taking out a couple of small walls.

There are spots in the bathroom that have probably never been finished, and then other parts that have. I don't think it would be possible for me (I'm sure Greg or Zeke could do it) to match the existing finish and therefore just spot finish where needed.

So, would you agree that I need to refinish the whole thing? This is 3/4" TnG. I think it's had some refinishing done before, but not a lot. My thought is, sand it all, stain and seal with polyurethane or whatever the recommended is (this is a bathroom, so something that's good in a potentially wet environment).

Here's most of the floor. We'll be taking out the toilet and shower too. It's not quite 100% demoed yet since this is the only full bath that we have. Whoever installed the shower, did not install shutoff valves in the supply lines.

The bathroom is 9'x9'. Does it seem reasonable to use a regular belt sander (like a 24x4" Makita) to do this

vs renting a

THere is a HD that supposedly has a drum floor sander about 40 miles away. It's $70 for a day. The Makita above is ~$270 to purchase (plus, I assume, several belts?).

What say you? Buy and own something that is relatively small or rent something big and quick? I've never done this and don't know how long 9x9' is likely to take with either option.

We'll also have several spots where we'll have to fix holes that are in the floor from old plumbing. Fortunately, I can come up with boards from other parts of the house. Although I'm not sure how I'll get a board in between 2 other boards. I assume in some cases, if the holes are small, I might be able to fashion a plug? In other cases, I may want to replace a board or part of a board, but I assume I'll need to brace from underneath to make sure the floor feels as solid as it does now (it feels very solid).

Thanks for all thoughts and suggestions.

1990C4S · 10:05 AM

I have done a lot of floors.

Yes, a belt sander will work, even a 4" is hard work and takes some practice, don't use a 3". I have done large bedrooms with oak floors. A pine bathroom is doable, but be careful. You can leave marks very easily.

A drum sander is pretty good and easier, but you can still ruin a floor if you're too aggressive or pause in one spot too long. The drum sander does not get very close in corners, so in a small bathroom you still have a lot of hand work remaining.

Vibratory square machines work to final sand an unfinished floor, I would not use that to strip, although on pine it might work.

The best are the three rotating head units, they are very heavy and hard to find.

If you're nervous about it, don't use anything too coarse to start.

masraum · 10-15-2021, 10:05 AM

Thanks.

Maybe I should find one of these!

Nah!

1990C4S · 10-15-2021, 10:06 AM

A lot of people use scrapers. For your size room it's doable.

https://www.leevalley.com/en-ca/shop/tools/hand-tools/scrapers/45784-veritas-ball-joint-scrapers

masraum · 10-15-2021, 10:18 AM

I think that would be a nightmare. These boards are cupped and have plenty of texture. I suspect I'll end up taking 1/8" off. Doing that with a scraper sounds like a nightmare.

911 Rod · 911 Rod's Garage

We're talking 100 square feet. I'd replace it and not "dust" up the house.

908/930 · 908/930's Garage

The big floor belt is likely the way to go, you will also need something smaller to do the perimeter. Another option if you have the time is something like a 6" dual mode random orbit, I picked up a Bosch GET75-6 and it works well for removing surface material quick, I think better then a small belt sander. Need an assortment of abrasives no matter what you use.

One problem with the large square vibratory is that they wont keep the floor flat, they will remove more where the wood is soft, the big belt or drum will keep it flat.

masraum · 10-15-2021, 10:40 AM

Quote:

Originally Posted by 911 Rod

We're talking 100 square feet. I'd replace it and not "dust" up the house.

This is a 100 year old house and it's the 100 year old floor. It's not wood laid on top of a subfloor. It is THE floor. If I take it up, I'm looking at floor joists, plumbing and mud.

mattdavis11 · 10-15-2021, 10:53 AM

I'd number them, pull, put down a vapor barrier, then ply wood while you make them look pretty for re-install.

masraum · 10-15-2021, 10:57 AM

Quote:

Originally Posted by mattdavis11

I'd number them, pull, put down a vapor barrier, then ply wood while you make them look pretty for re-install.

That would give nice (probably the best) results. I don't think the missus would like this one room being at a different level from the rest of the house.

908/930 · 908/930's Garage

Looking at that again, just buy or rent a dual mode random orbit, tie the outlet to a shop vac placed outdoors. Should be able to bring that down flat in a couple of hrs. A 6' straight edge will be useful to check your work and keep it flat. I used mine to remove two layers of varithane I had on my subfloor and level it, about 2000 sq feet of it. 40 grit works well.

911 Rod · 911 Rod's Garage

Crazy idea, but can you pull it up and flip the boards over?

drcoastline · 11:35 AM

Quote:

Originally Posted by masraum

I think that would be a nightmare. These boards are cupped and have plenty of texture. I suspect I'll end up taking 1/8" off. Doing that with a scraper sounds like a nightmare.

I have done my fair share of floors as well. 1990C4S has pretty well answered your question. I will just reirerate it is imperative to to keep the sander moving so you do not dig in. I would also say if you haven't done ths before don't be to agressive with the grit. Start with 80 max and see what happens and get used to the sander.

This statement has me worried based on the cup in those boards. Removing an 1/8" is going to leave you really thin on the top edge of the groove. You are going to run the risk of splitting the top of the groove off. Where the finished floor meets they grey floor that was under the tile is there a lip? The finished floor should be lower from wear and refinishing. Can you gauge how much wood has been removed?

Don't hesitate to buy a used belt sander off FB.

MikeSid · 10-15-2021, 11:41 AM

Quote:

Originally Posted by masraum

This is a 100 year old house and it's the 100 year old floor. It's not wood laid on top of a subfloor. It is THE floor. If I take it up, I'm looking at floor joists, plumbing and mud.

Are you sure about that?? My house was built in 1913 and has hardwood floors throughout. Both oak and fir. There is diagonal shiplap subfloor under every floor in my house.

masraum · 10-15-2021, 11:52 AM

Quote:

Originally Posted by 908/930

Looking at that again, just buy or rent a dual mode random orbit, tie the outlet to a shop vac placed outdoors. Should be able to bring that down flat in a couple of hrs. A 6' straight edge will be useful to check your work and keep it flat. I used mine to remove two layers of varithane I had on my subfloor and level it, about 2000 sq feet of it. 40 grit works well.

Like the bosch that you suggested farther up? Why would you consider that better than a belt (just out of curiosity)?

masraum · 10-15-2021, 11:53 AM

Quote:

Originally Posted by 911 Rod

Crazy idea, but can you pull it up and flip the boards over?

That would be even worse. Those are the bottom of the house and have spray foam on them that I'd have to remove.

masraum · 10-15-2021, 12:37 PM

Quote:

Originally Posted by MikeSid

Are you sure about that?? My house was built in 1913 and has hardwood floors throughout. Both oak and fir. There is diagonal shiplap subfloor under every floor in my house.

I was expecting something like that myself, but when I pulled up the sink in the bathroom I was able to confirm that there's only one layer of wood in the bathroom.

This is a photo of one of the perforations through the floor for plumbing that was under a sink. There's only one 3/4" layer of wood.

The TnG runs East-West when looking at the floor inside the house. The floor joists run North-South, and then the primary support beams (4x6) under the joists run East West. When I look up at the bottom of the house from under the house, I can see the bottom of the 4" TnG going East-West. Our floor is only a single layer of wood. And it's surprisingly solid.

908/930 · 908/930's Garage

Yes, the GET 75-6 is a dual mode random, they work really well at rough sanding and also well at finishing. The discs for a 6" will be way cheaper than belts when they clog up. I was going to pick up a Belt sander when I found this one, no regrets.

I have 4 other random orbits and they are like a toy in comparison.

masraum · 10-15-2021, 01:11 PM

Quote:

Originally Posted by drcoastline

I have done my fair share of floors as well. 1990C4S has pretty well answered your question. I will just reirerate it is imperative to to keep the sander moving so you do not dig in. I would also say if you haven't done ths before don't be to agressive with the grit. Start with 80 max and see what happens and get used to the sander.

This statement has me worried based on the cup in those boards. Removing an 1/8" is going to leave you really thin on the top edge of the groove. You are going to run the risk of splitting the top of the groove off. Where the finished floor meets they grey floor that was under the tile is there a lip? The finished floor should be lower from wear and refinishing. Can you gauge how much wood has been removed?

Don't hesitate to buy a used belt sander off FB.

Good call. There is no lip where I've already pulled up the walls, and there's a TON of grain showing on the wood, that I suspect is 100 years old. When I had a closer look, I see that someone hit the floor with a belt sander, but only took off peaks, and maybe let the thing sit so there are a few troughs. Using a straight edge and feeler gauges, I found that most of the troughs are less than 0.010". I found one (the one in the red box) that is .025", so less than 1/32". Who knows, maybe I won't have to take off 1/8". In places that I was able to measure, most of the flooring seems to be closer to .85" than .75"

masraum · 10-15-2021, 01:12 PM

Quote:

Originally Posted by 908/930

Yes, the GET 75-6 is a dual mode random, they work really well at rough sanding and also well at finishing. The discs for a 6" will be way cheaper than belts when they clog up. I was going to pick up a Belt sander when I found this one, no regrets.

I have 4 other random orbits and they are like a toy in comparison.

Thanks.