[VIDEO BELOW]
Hardwood floor refinishing is a subject that is fairly misunderstood. The mistake people make is in thinking its an easy straightforward process. “All it comes down to is applying sandpaper to wood and then applying a finish,” goes the thinking, “how hard could it be”. On the contrary sanding and refinishing hardwood floors is a fine art.
There are lots of articles on this website that will give you the technical instructions to enable you to sand and refinish your floors. However, in this article, I want to introduce some key concepts that will help you better understand the floor sanding process. You will learn the one key difference between the average DIY enthusiast and a professional floor refinisher, something you can implement easily.
This will hopefully convince you to use the methods and machines that I recommend. That is, rather than listen to the advice of the guy at the rental shop.
Does sanding really “damage your floor?”
One of the of the most common fears among prospective DIY floor sanders is the possibility of damaging their floors. Often they have no idea how any why it will get damaged, while others learn that “if you use a drum sander (big machine), you will damage your floors because they are too powerful.”
Here is an example of this ‘damage’:
Let me address this right here, right now.
Most of the drum sanders that you can rent to sand your floors are actually lacking in power! As you would see in my video course, in which I use rental machines, it takes me a very long time, going over the same area again and again with the coarsest grit, just to get it flat and clean.
It’s not the power of the floor sander that inevitably causes the damage.
However, if you don’t use the machine correctly, you can create a dent in the surface of the floor.
People that don’t research the subject whatsoever and don’t realise they have a problem, can cover their entire floor in these dents, much to the amusement of floor refinishing professionals across the globe when surveying floors for estimates.
To get a good idea of how to use a belt or drum sander (big machine) click here, but in short, these dents are created by lowering the drum of the big sander on to the floor before you start moving forward as well as stopping the machine before you lift the drum off the floor.
They are created when the abrasive is in contact with the floor, but the machine is not in motion (moving back or forward), it is just stood still.
Well, my friends, there is a simple trick that can help to mitigate this to a huge degree. All you need to do is use a 100 or 120 grit paper while practising your big machine motion.
- Start moving forward
- Lower the drum onto the floor
- Keep moving towards the edge of the floor
- Lift the drum off the floor
- Stop moving
120 grit is so ineffective at sanding through finish or removing a lot of material that even if you make a mistake, it won’t damage your floor. To the extent that it does create an extremely shallow dent, it will disappear with the first proper sanding pass. I have used this technique to teach people to use a big machine in 30 mins. Just teach them the motion, put a fine or even used fine grit sandpaper on the machine and let them thrash it out until they have it sussed.
Grit Sequence.
One of the very frustrating things about refinishing hardwood floors yourself DIY, is finding countless sanding imperfections (scratches) in the wood that weren’t visible until you applied the finish. Now the finish has been applied, they are standing out like a sore thumb.
The best way to mitigate this is to stick to the floor sanding grit sequence guidelines in good faith.
Starting from the top, you want to use a coarse grit sandpaper to remove the old finish, dents, scratches and to level the floor. This is 36 or 40 grit. Occasionally, professionals may use 24 or even 16 grit before 36 or 40, on floors that are very uneven, hard and/or covered in difficult to remove materials like polish or carpet glue.
You should use this coarse grit to get the floor completely flat and clean. Don’t leave finish or dents in the floor, telling yourself you will remove it on the next grit. This will just make the job harder and more frustrating. Keep going until there are no old finish or dents in the floor before moving onto the next grit.
Then we have the medium grits, 50 and 60. These grits are for bridging the gap between the course grits and the fine grits. This is where a lot of mistakes are made. When DIY’ers see their floor clean and flat after sanding it with the rough grits, they think they can skip to the fine grits. “Sure it might take a little longer to get the scratches out with this one finer grit, but it must be quicker than doing two grits,” goes the thinking.
It may even be quicker, but you are almost certainly going to leave scratches in the floor that are going to stand out like a sore thumb when the floor is finished.
Then you can move onto the grits, 80, 100 and 120
Great job on your website and on this top notch Q/A.
I’ve reserved a drum sander for 2 days from now to use on our straight grain fir floors.
Three of the boards are in various stages of splintering and flaking and appear to be of a different species as they have a swirled grain pattern. The voids this has created range from about 1/8″ -1/4″ deep, 1/4″-1/2″ wide and of varying lengths. Ideally the drum sander will take off enough material to take these problem boards down to sound wood, but having never used one, I’m unsure how much of the surface will actually be removed.
Can you tell me how how far down the #24 or #36 (or coarser) grit will go and the likelihood of reaching sound wood on the problem boards? Again, 1/4″ sounds like a lot of material to remove, but if I knew the answer I wouldn’t be posting the question.
I’ve been unable to find this info on any website and I’m hoping to have and answer prior to picking up the machine in the event I need to first replace/flip the board.
Thank you!
My floor have light scratches and no dents. The previous owner had dogs and they scratch the floor. Should I do a “complete sanding” or follow your video of a buff and coat without sanding.
Hi Stephen! It really does depend on the depth of the scratches. It’s unlikely that the scratches will come out completely with just a buff and coat unless they are really fine. If it was my floor, I would live with it for a few years before fully resanding it.
Do you have any suggestions for “preparing the environment” when applying floor finish? My husband and I want to sand,stain, and finish our floors but it’s the winter time in the Midwest. Some tutorials (Bona for professional) say to turn off the HVAC system when applying and ideal temperature is above 65F and I’m concerned we will be unable to keep it above this temp. We also won’t be able to set up box fans at the doors. Is that necessary?
it should be fine, it just might take a little longer to dry. Whereas if HVAC is on while applying it might dry too quickly which is where the issues arise
I had a chance to pull a board up. The “subfloor” looks like pine that’s about 6” wide running the same direction as the oak.
Hey,
Wife and I bought a house built in 1940. Has old oak floors that at the edges seems like it’s been sanded before. But I’m curious how I should approach wood flooring that when I walk on it, it moves slightly. Is this a subfloor repair I need to do? I’m curious for when I may go to use a filler if that just cracks overtime due to the movement…?
The wood floor could be floating, which is doubtful if it is the original floor. Otherwise im not sure why it might be bouncing like that. In anycase the filler will crack immediately. I only recommend filling on totally solid floors.
Finished my first room. Should’ve started with 36 grit but it was sanded before so I started with 60. 36 grit would’ve saved me sooo much time. But for my first time it turned out well and the next rooms will only be better. Thanks for all your help!!!
Hi Ben, thank you for all of your helpful videos, i followed all the sanding steps and my floor now is ready for stain and finishing coats. I just have 2 questions. I have access to both Loba and Bona products here, since Loba is fairly new here in the US, i cant find much reviews about it but i saw in one of your videos, you were wearing a Loba shirt so i would assume you might have tried them 🙂 Between the 2 of them , if you were to refinish your own hard wood floor, which polyurethane finish in satin would you use? I plan to apply 3 coats with light sandind between coats, is it durable enough to last for more than 5 years?
Nickie
have you tried my free eBook where I give away all the products I use?
Hi Ben – when using resin joint wood filler mixed with the sawdust, would you the resand the floor with a fine grit after its fully dried?
Also, can a finish be applied to the floor after being filled with the resin/sawdust filler?
Thanks
Richard
must sand the filler off the surface before finishing
Hi Ben,
Long time reader / video watcher, love your content and specific details compared to the “overview” others give in their content, really helps a lot for DIYer such as myself.
Thanks so much for your posts, pages, and videos, they’re a live saver!
I’m refinishing my hardwood floors and have a couple questions / points of clarification, but first some details about my situation / project:
– U.S. Midcentury home (built 1962)
– Oak (red?) hardwood floors, never refinished, bedrooms where covered with carpet, sub-par condition (few black stains, some board gaps near stains, etc).
– Stain: Darker (near Dark/Special Walnut / Provincial, etc. Would prefer less grain pop if possible (try via finish sanding of 120 grit)
– Finish: Polyurethane (oil, clear, multiple coats?)
– Tools: (Clark/American Sanders) EZ-8 Drum Sander, Super 7″ edger (newer, not B2, rubber pad) (rentals from The Home Depot)
Several questions, sorry to drop them all at once, I’ve been researching for several weeks and have saved them all to post at the same time, hope it’s not too bad of a wall of text:
1. For fine grit, do you always chose ONLY one of either 100 or 120 grit, but NOT both?
I was planning on doing both since I’m doing a darker stain and I read on the site and in comments / replies that the higher grit might be better?
2. Can anything be done to reduce edger’s contact patch without “dressing” the pad / marrying it?
I’m using a rental Clarke / American Sanders Super 7″ edger and I’ve read around finding that the edger’s pad should be “dressed” to marry it to that specific edger, at a given (caster wheel) height (3 USD $0.01 pennies). However, since it’s a rental, I don’t think I can grind down the rubber pad to lessen the contact patch… right now it’s massive, stretching from edge almost all the way to center of the pad.
I’ve tried raising the height of the caster wheels almost to their max to try and reduce the inner contact areas, but not having much success…
If no solution, is there any technique I should try? I’ve tried various clocking (11:30, 12:30, 1, 2) to try and get a better out come, but so far pretty much everywhere I use the edger results in swirls (assuming a result of using such a corse grit).
3. Floors covered in carpet have a lot of finish, so I’m using 24 grit on drum / edger. Obviously getting some heavy swirl cut lines from the edger. Will these come out as I progress through the sequence of grits or do I need to do something to fix them now in the 24 / 36 grit phase? Do I need to hand scrape and sand all the swirls out now before progressing to higher grit or can I do them on the second to / final grit?
Currently just super paranoid as the cuts are pretty deep / obvious.
4. Any technique I should be using in terms of edger direction?
I’m currently following your video and after the “leveling” phase of pushing edger towards wall, I come back with edger so the contact patch is going, more or less, with the grain to try and hide some of the scratches. However, I did have one instance where maybe I wasn’t moving fast enough for the low grit and going with the grain left uneven lengths. This seems to make sense to me as when the contact patch is parallel to the grain, it cuts a much narrower path, so its hard to overlap and make an area uniformly level vs. cutting against grain and pushing towards the wall results in contact patch being perpendicular and covering a much larger area “left to right”, as it were. I was able to get these out mostly with the drum sander.
Any alternatives I should be doing to try and hide the scratch pattern with the grain?
5. Little uncertain on buffing stage. Should I sand with drum/edger to 120, then square buff with 120 screen? Or should I drum/edge sand to 100 then paper sand on square buff with 120 paper?
Should I be using the circular / multi-disk sander instead of the square buff? Any benefit / downside between the two? I see one of your videos using the disk buffer, and wasn’t sure which to use when.
Lastly, please see my project schedule / sequence and let me know if I left anything out or have anything in the wrong sequence (e.g. scraping during wrong grit sequence, square buffing with screen, etc):
— Sanding —
– Drum sand 24 grit (floor in pretty bad shape)
– Edge sand 24 grit
– Scraped corners for previous finish, attempted to level but hard to get as much wood off with scraper as the 24 grit on edger, may not end up totally level?
– Vacuum entire floor
– Drum sand 36 grit (to remove 24 grit scratch pattern, especially edger swirls)
– Edge sand 36 (for continuity / not skipping grit)
– Vacuum entire floor
– Drum sand 60 grit
– Edge sand 60 grit
– Vacuum entire floor
– Drum sand 80 grit
– Edge sand 80 grit
– Vacuum entire floor
– Drum sand 100 grit
– Edge sand 100 grit
– Vacuum entire floor
– Fill caps / imperfections with wood
– Drum sand 120 grit
– Edge sand 120 grit
– Vacuum entire floor
– Revisit corners / edges with scraper (/maybe/ detail sander in corners if can’t get level enough by hand?)
– Hand sand (with paper, NOT machine) at 120 grit
– Square buff screen 120 (should I use paper instead of screen? Assuming no since floor at 120 already)
– Vacuum entire floor
– Vacuum entire floor
– Wipe with tack cloth
– Water pop (distilled water) Let floor sit overnight.
— Staining (next day) —
– Pre-conditioner? I’ve heard good stories about helping prevent blotchiness?
– Stain, rag on / off
– Check if 2nd stain coat is needed (again, don’t want too dark or to pop grain much)
— Finish (using lamb’s wool) —
– Finish coat 1 with Poly, let dry.
– Light square buff screen 120 to rough up poly for next coat?
– Finish coat 2 with Poly, let dry.
– Light square buff screen 120 to rough up poly for next coat?
– Finish coat 3 with Poly, let dry.
Thank you so much in advance for you time, energy, and thoughts regarding my situation, I sincerely appreciate it!
Thank you for taking the time to write this, but I’m a slow reader and slow writer and it would just take too much time for me to respond. Sorry dude, hope you understand!
My floor is not that old. It has dull and scratch to the finish, other than that it is pretty flat. Can I sand with the orbiter sander? also, do I need full trowel filling and at after what grid should I start troweling the filler?
Thanks
Hi Ben. Just done my parquet flooring with good results thanks to your tutorials. I am planning to rent my property out. I varnished it with 3 coats. Satin finish. Would recommended some kind of wax on top for extra durability or is it a waste of time?
definitely not! wax is not durable at all, it would just compromise the finish. There is no benefit and only downfall
Hello Ben, I have a question for which I can not get an answer. Take a oak solid floor in fair condition i.e. flat, not badly damaged and most likely could be buff sanded. It has its factory clear finish. If I sand the floor in grits 36, 60, 80, then 120 and some of the old finish still remain in places whilst in other it stripped back to wood, can I go a head and apply the same finish. I have read of ways to determine the existing finish but I don’t want to get of the point. The reason I ask is because with applying clear on cars in this way e.g. paint/color showing on some parts of the surface and clear on other; but once it received 2/3 coat of clear after 120 grit finish the finish is perfect. Will this work on wood as it would save time in this instance. However, after watching your videos I now realize a belt sand would have been better than a buff. (Going for belt tomorrow and will try on 120 grit)
no, this will look terrible, it needs to be clean with the 36 and 60, if its not clean by the end of the 60 you need to keep going over it until its clean. Then move up and smooth it off
I have some old floors with what looks like a black glue on them from some other glue down flooring that was on it. Will a drum or belt sander remove that?
Yes, we have removed thick carpet glue and even levelling compound + carpet glue. Its not fun but sometimes it’s the only way.
Hello from the states! Ifound your videos on YouTube and you kindly replied to my question about my floors in a 250-year-old home. THANK YOU!!!
What do you advise about how (or whether) to fill in the gaps between planks. My floors have wide gaps between most planks. It looks as though something was there in between them once upon a time, but now it’s just dust/dirt/what IS that stuff?? that gets sucked up in the vac when I run it. Should those gaps be filled? I’ve seen videos that use stained rope stuffed into the cracks for filler, but it looks like the rope is all they use. Other videos show using handmade wood strips which they then plane down and presumably sand (labor intensive plus 100) once flat. Thanks a million! Any advise?
Thank you again 🙂
There is a stretchy black cord type thing that you can buy that is specifically used for this purpose. I’m sorry I cant remember the name of it at the moment, but thats what I would use. Anything more solid would just come out in time
Hey I bought a house with majority of t being hardwood floors. I have been staring at these “dents” since we moved in and just now confirmed what I though they were. The previous owner dented a few things besides the floor before I bought this place. If it’s all
Throughout about 60% of the floor in my first level of my house, Can it be fixed? Or do i need to replace the floor? The first floor is all oak Hardwood. About 60% of the floor has these dents throughout. I am contemplating getting estimates but the first guy that offends me May end up getting tossed out. I don’t know if it’s ficabe and don’t want to find out angrily and would like to avoid throwing someone out of my house if I can. They’re not quite as deep as your picture, but they’re all the exact same size and shape and he did it in a lot of the house. Refinish or replace ? Thank you in advance.
These dents are usually nowhere near as deep as they look, im sure they will come out fine
I have gone throught the grit sequence and everything was great until I applied the first layer of stain, which revealed some mystery footprints that did not belong to anyone involved. It was recommended to me to first go through with a 120 buffer screen to open up the stain. After that, to mop over with a TSP solution. I am reading about TSP and this stuff seems pretty strong. What you recommend in this situation?
I recommend lightly resanding the floor to take the stain off and start again. Any moisture will pop the grain. Recently my employee walked on the floor with sweaty socks before we were about to stain the floor. All of his footprints came in through the stain. invisible beforehand.
I have been resending a hundred year old hard pine. There have been many “fixes” over the years, including all sorts of glue and goop and fillers, etc. They consistently clogged up my sand paper on the drum sander, edge sander, belt sander…I’m sure you get the picture, which rendered them useless. I later used a heat gun and scraper…very tedious work. I burned through tons of paper$, after just minutes of use. How would you recommend tackling old “repaired” floors without wasting all the sand paper?
You may have been using too fine a sanding paper, if the paper is clogging up on a 60 grit, drop to a 40 or 36, even then sometimes we will drop to 24.
I have some old oak wood floors, I feel like they are a case study in pet stains and dirt in the wood. I feel I need to use the drum sander more in some areas more than in others because the traveled areas are far more dirty. When I tried this in another room the floors were left a bit wavy, I understand that part of this in my skill level with the machine. My question is this; can the orbital floor sander help with leveling the floor? Can I switch to the orbital at 36 or 60 grit to help with getting the floor level after focusing on the problem areas with the drum sander? It’s very hard to see the drum marks and waves when the floor has no finish, I probably could have got them out if I could have seen them a bit. I am a beginner and I appreciate any advice, I’ve watched your videos and they are very helpful. Thank you.
Ive just laid a rustic oak floor and it has quite a few knots and marks. Would you recommend a clear epoxy resin to fill the knots?
Thank you for your videos. I just recently finished sanding my floors with drum sander 36 grit, 60 grit, 80 grit and finished with 100 grit all the edging is done too. what should the next step be? Should I rent one of those square orbital sanders and go over the whole floor with 120 grit?
Thanks in advance.
Thank you for all your videos, super helpful! I just moved to the states from Europe into a very old house and want to re-finish the floors. I have a couple questions now since the house and possible the floors are very old: how do I know that the wood is still thick enough to be sanded properly (drum sander + finishing sander)? I assume the wood is stained oak (as far as my amateurish eyes can tell), is there any easy DIY way to find out what specific type of wood this is? Thanks so much!
if youre in the states, you are probably right, but unfortunately no, easier to send it to someone with some knowledge. If it’s a dark colour but the grain is very polarised, like brown and black, its probably stained oak. Difficult to say, maybe google stained oak!
Thinking of refinishing the oak floors before moving into a new house, and have a couple of questions: Would you ever skip the belt/drum sander and go straight for a random orbital sander on a (oak) floor that’s in pretty decent shape, i.e, generally pretty flat and level, with some worn areas but few or no major dents/scrapes? Most of the floors in most of the videos look in much rougher shape than ours.
Second: How do you deal with transitions between different rooms if the floor is continuous with no thresholds, but not all the rooms need refinishing?
You can do but it will be very slow, you need to pick the edge of a board to work up to in the transitions. Just be aware, even if those rooms don’t need going, they will look different
I want to sand the floor myself and I’m renting the tools from Home Depot. I looked at all your videos but I want to make sure I have the correct sequence. Start with 36 or 40 grit paper, then 60 grit. QUESTION: Can I fill the wood then do final sanding with 100 grit? After final sanding, mop, then stain. Then use water based poly, wait 3 hours, apply 2nd coat, braise floor QUESTION: Do you have a video how to do that? Apply last coat of poly. Please correct all steps missed
Hi Ben,
Your videos are very useful. I’m a hobby cabinet maker & still learned a lot from you. Thanks. Your video on applying floor stains was very useful. Have you got one one on how to apply varnish? I’m applying a water based Nano Defense Varathane. Waterbased because my two grandsons (5 month and a 4 year old) often come over & I don’t want them to inhale solvent fumes.
I do, just head to my youtube channel, should be easy to find. I have more in my video course.
I have thin old wood floors and the finish is completely gone in some spots. Would you recommend screening instead?
resand
Really appreciate your professional insite as I am about to refinish the hardwood in my house.
I do have a question about the sanding grits. At what grit do you transition to a buffer machine? I understand a drum sander is used for the 36, 60 and even 80 grit but as you approach the 100 grit would a drum sander be the best option or a buffer?
Additionally what is the advantage of sanding at 120 vs 100? What would be better if I plan to stain the floor?
Final question, would you recommend applying a stain, letting it dry, then applying a lacquer? Or buy the products that are stain and lacquer in one?
Thank you for your time and energy!
I recommend you use a finishing sander, especially if youre staining, I recommend 120grit, I DO NOT recommend getting coloured finishes, stain first, then clear finish
I am thinking of refinishing my floor but it has glue on it. Should i strip the floor with a paint thinner first or start with a 36 grit and sand only? Also, do you always sand at a diagonal or only with the first and second sanding? Great post, I’m extra to try your technique.
Thanks
Beth
Personally, I would just sand the glue off. I don’t always sand at diagonal to the boards. It is for the earlier passes. I would do 36 diagonal on the glue, then 36 straight, then 60 diagonal then 80 straight then 100 or 120. Then start with the finishing sanders 😉