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Refinishing Hardwood Floors--Use trow...

Jim_Hartman's picture

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I'm about to refinish some oak hardwood strip flooring that have gaps that have opened up between the flooring strips. In many articles I've read, no one seems to mention using a troweled on wood filler to fill these gaps. So, my questions are 1. should I use a filler, or just sand and polyurethane and leave the gaps as-is? (The concern I have with filling is about what will happen when any expansion occurs in the summer. The room for expansion is now filled with filler.) If it's recommended that I use the filler, two other questions... 1. At what point is the ideal time to apply the filler (i.e. after initial passes with sander, apply filler, resand/screen floor with 120 grit, then poly?) 2. Any recommendations on products to use/not to use? Thanks!

(post #157817, reply #1 of 16)

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Jim, not knowing where you are, and what the Relative Humidity is, both ambient and wood moisture content,
it's not easy making a recommendation.

IF the gaps are under 1/8th inch average. Leave them.
They'll push together come July/August.

If you're talking B-I-G gaps, then you've two choices:

1) Fill with a solvent or varnished based wood filler, color matched to the original floor, after the initial sand and vaccume.
Resand, and finish.

2) Lift and re-set the floor, closing the large gaps.
Adding new material to compensate.
The is very unusual, and we've had to do it once, on a
200 year old Softwood floor.

Hope this helped. You can search the archives here
for more extensive replies.

(post #157817, reply #2 of 16)

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Thanks George. The gaps are for the most part less than an 1/8", and this is in a house without a humidifier in SE Michigan. The floor is original to the house, circa 1940. I wish I could tell you more about the ambient humidity as well as moisture content, but they're both unknowns.

Since the gaps aren't really major, I figured that I'm probably better to leave them, but I decided I'd ask for some opinions or "rules of thumb" from anyone who does a lot of floor refinishing. Thanks for the input.

(post #157817, reply #3 of 16)

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Jim:
I have been experimenting with wood fillers for years.
I used famo wood thinned down for a long time with good results.
I also used wood dust from the first cut (2nd cut on refinish) mixed with sanding sealer, but that tended to darken the filler too much.
I now use wood dust from the first cut (2nd cut on a refinish) mixed with waterbased polyuerathane and trowel the whole floor. This raises the grain and fiils all the voids. I sand the excess and knock the grain down on the next cut. Final cut is done with 80 or 100 grit depending on the species of floor.
I do this on new floors as well. I have inspected my floors in the spring and have never experienced any squeeze out with this method.
I vac and tack very well after the final cut and run an air cleaner overnight before I apply the first coat of finish.
We always buff, vac and tack between each coat.

(post #157817, reply #4 of 16)

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Rich,

Do you use the wood dust & water based polyurethane filler if you use an oil based polyurethane for the floor finish?

Ken

(post #157817, reply #5 of 16)

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Thanks Rich. Actually I've heard of other people doing exactly as you suggested... initial sand, mix dust with the poly, and trowel the whole floor. Your process sounds exactly what I was planning on doing.

The reason I posed this question was based on a (simply stated) comment made a few years back to me about sand, apply filler, resand, apply polyurethane. Back then I didn't think to ask the question "What about if the wood expands, what happens when that 'expansion joint' is filled?" Most of the articles and information I've come across don't address filling the voids between the strips, which I thought might have been purposely left out because of expansion. Another question I walked away with was that I wasn't sure about whether the fillers may be more flexible than the polyurethane approach. Essentially the filler could compress (in summer) where the polyurethane would want to crack.

It's always helpful to have experience dictate how you do something... I've seen enough bad floor jobs (typically sanding gouges from hell), I don't feel like turning mine into one. Thanks for your insight!

Actually, one more question for anyone experienced with floor refinishing... any recommended polyurethanes? I've heard good things about Basic Coatings products and Bonaseal Traffic. Anyone know how those compare to Flecto Varathane (which was Consumer Reports "Best Buy" for floor finish)? CR didn't test any professional grade finishes, just your basic Minwax, Flecto, Pro brand finishes you get from a big box store.

(post #157817, reply #6 of 16)

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Ken, Jim,
I use waterbased poly mixed with sanding dust with water based finishes. Oil based sanding sealer mixed with sanding dust for use with oil based finishes. I prefer to use an oil based top coat. However with time constraints on refinish jobs sometimes water based is the way to go. I also use water based topcoats with maple when my customers are trying to achieve a 'white' floor. Some detail species like purple heart require a water based top coat as some of the exotics tend to 'bleed' with oil.
I always use bona products.
I was initially concerned with squeeze out caused by floor expansion when I started trowling my floors and went back a few months later to inspect them. Here in N.W Pa. we suffer some incredible humidity in the summer but during the worst of it customers have the A.C. running and the humid season is short lived. I have never found any squeeze out that was noticeable using this technique.
Another note: Just purchased a random orbit floor sander that is nearly completely dustless and sands flat as a pancake with no chatter. The last floor we did looked like furniture.
Rich

(post #157817, reply #7 of 16)

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Thanks again Rich. I'm thinking of using the BonaTech Traffic (water-based). It's not cheap at $91/gallon here in MI, but I've heard it provides a nice lasting finish. I've been tempted to use a cheaper finish (Flecto for instance is half the price), but you get what you pay for.

What type of RO sander are you using? Do you use this just for new floors or also for refinishing? I've heard it suggested that unless you use a belt or drum sander, you'll spend all day getting the old finish off/floor even. Unfortunately I'll be renting the equipment (floors aren't typically my thing, but I wanted to give this one a shot), so I'll have to look around to see what's available... and make the equipment isn't broken...

(post #157817, reply #8 of 16)

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Jim,
'Pacific strong' in 'silkmat' by bona is also a good product and may be less in cost. Although it is a two part product.
I'm using the 220 contractor ro floor sander by Cherry Hill called the 'u-sand'. Go to their web site and see if any rental stores are carrying the smaller version. www.u-sand.com
On a refinish I start with #24 grit paper and keep the machine moving. The paper loads up fast with old shellac or varnish, faster if you let it get warm, so you can't let the machine sit. I use a crepe block to clean the discs and that adds a little life to the paper. After the #24 I go to #36 then #60 then # 80. You've got to vac well between grits or the machine rides on and drives the larger grit into the floor.
I say nearly completely dustless because although there is dust on the floor, it isn't thrown into the atmosphere. The first time I used it I kept lookinq up into the lighting overhead and never saw any dust in the air.
Good luck,
Rich

(post #157817, reply #9 of 16)

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< Obsolete Link > This is a thread with some pics of trowel filling, before and after. It was done in the summer, but i don't see any appreciable shrinkage this winter, though the house hasn't been heated. Fill was oil-base poly and dust from the drum sander. We used Parkes oil-based poly from Home Depot--reasonable and it looks great, as the photos will hopefully show. I used the Parkes Poly bec i'd had good results with their lacquer on my woodwork. Good products and very reasonable.

(post #157817, reply #10 of 16)

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:-)

brian

(post #157817, reply #11 of 16)

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Thanks again for all the information. I'm going to check on the U-sand... looks like an interesting sander.

Nice thread guys! we will try (post #157817, reply #15 of 16)

Nice thread guys! we will try to throw this a reference in our hardwod refinishing information centre, Moreover i like you post.

 

[url]http://www.woodsmithhardwood.ca/information-centre/[/url]

(post #157817, reply #12 of 16)

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I'm about to refinish some oak hardwood strip flooring that have gaps that have opened up between the flooring strips. In many articles I've read, no one seems to mention using a troweled on wood filler to fill these gaps. So, my questions are 1. should I use a filler, or just sand and polyurethane and leave the gaps as-is? (The concern I have with filling is about what will happen when any expansion occurs in the summer. The room for expansion is now filled with filler.) If it's recommended that I use the filler, two other questions... 1. At what point is the ideal time to apply the filler (i.e. after initial passes with sander, apply filler, resand/screen floor with 120 grit, then poly?) 2. Any recommendations on products to use/not to use? Thanks!

I need to get my old wooden (post #157817, reply #13 of 16)

I need to get my old wooden flooring refurnished but don't have much budget and I find some Hardwood Refinishing Services online who provides the advantage of financing but is it advisable.[url] http://www.woodsmithhardwood.ca/hardwood-refinishing-services/[/url]

Unless you must have the (post #157817, reply #14 of 16)

Unless you must have the floors finished NOW for some good reason, you're generally better off waiting until you can save up the money.

The only exception would be that currently some outfits may be offering free/cheap financing to generate "traffic", since most building/remodeling activity is "depressed".  But even in those cases you should be able to negotiate a lower price in place of taking the "free" financing.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Hardwood Flooring Toronto (post #157817, reply #16 of 16)

 

At Top Toronto Flooring we deliver long lasting, high quality hardwood floor Toronto and hardwood flooring products as Engineered Flooring, Laminate Flooring, Bamboo & Cork Flooring in Toronto.