We had just lifted our carpet to find out that the original 1950’s pine wooden floorboards were in reasonable nick. I decided to test the water whether we should get somebody in to do the work or learn how to sand wooden floorboards ourselves. A few quotes later (about €800-1,000 for someone to sand and varnish 40sqm of my floors in a day) we decided to try it ourselves and if it didn’t work out sure we could always slap down some laminate.
In hindsight, I didn’t realise what a commitment it was going to be… or indeed how rewarding it is to walk barefoot on an original floor that you have sanded and varnished yourself. The floorboards are over 60 years old so it will never look as perfect as laminate flooring, but that’s part of the charm!
I’ve split this post into two parts where this is part one where I’ll detail how to sand wooden floorboards. You can read how to stain the floor and varnish the wooden floorboards in the next post.
Just a bit of advance warning – when you decide sand wooden floorboards yourself, realise that this is the dustiest job you can possibly do in your home! It’s incredible how much of the stuff is kicked up by the sanders, so it’s best to prepare for it. Totally empty the rooms that you are going to sand (certainly remove all fabric furniture). Ideally also tape some sheets over any doors where you want to limit the dust entering (you’ll never avoid it all!).
This mantelpiece shows how much dust was gathered in the room after the first hour of sanding! Open all possible windows and vents.
Preparing the floor
When we lifted the carpet the floorboards were in pretty good shape. There were small gaps between all of them, some larger cracks between a few of them and some radiator hole cutouts from various upgrades over the years. These would have to be fixed before the sanding work could begin.
- The holes and large cracks (>10mm) were fixed by cutting offcuts of a similar wood and using wood glue to push them into place
- The small gaps (<10mm) were filled using Rustins Floor Filler (plastic wood) which was the same colour as our wood. This was mixed with some Evo-stick wood adhesive. This mixture was painstakingly filled into the gaps along the floor using a filling knife.
I have a confession – I didn’t do the preparation by myself. We still had a few builders around finishing off the insulation work that we did on the house, so I got a joiner to spend a day on the above items, where it would have taken me 2-3 days.
You should also make sure that any nails and screws are below the surface of the wood. I didn’t get all of these and the occasional sparks that flew out from the sanders scared the crap out of me! They could also rip the sandpaper so worth burying them as much as possible.
Now you’re ready to sand wooden floorboards!
How to sand wooden floorboards: the equipment
There are three electric sanders that you need to sand wooden floorboards:
- A drum sander
- An edging sander
- A handheld corner sander
Fortunately, I own a Black & Decker handheld corner sander already which I’ve used to sand the banister, so I only needed to rent the first two. I popped into Sam Hire in Chadwicks in Sallynoggin, Co. Dublin and was sorted in no time. It cost about €70 a day (inc. VAT) to rent them and about another €60 for sandpaper. They’ll sell you more paper than you need, and then you return what you don’t use. Way better than running out half way! For the 40 sq meter floor, it worked out at about €3.25 per sq meter for the sanding, and then probably another €7 per sq meter to stain and varnish it.
The drum sander is a big beast of a thing, weighing in at nearly 40kg with a vacuum cleaner and sanding belt all in one, and looks like a lawnmower for floorboards. This does the bulk of the work. The edging sander has a circular sanding disc which makes it ideal for everywhere that the drum sander can’t get into… apart from corners. That’s where the final one – the corner sander – comes in.
You will also need a dust mask, ear plugs and knee pads. Trust me on all three of these! I wear glasses so I didn’t use goggles, but they are recommended. Also, have some eye drops ready – your poor pupils will be like the Sahara afterwards.
Using the drum sander
This is really a combination of a belt sander and a lawnmower! It’s very heavy and when you have it set up correctly you will slowly walk it around your room taking off layer upon layer of varnish and crap from the floor.
Turning the body upside down, you will see a rubber coated cylinder with a metal bar held on with screws – this is what holds on the sandpaper. Undo the screws and remove the bar. Feed the sandpaper around the drum – my tip here is to use some masking tape to help feed the sandpaper around the back of the cylinder.
Make sure this is on really tight. If you don’t, the sandpaper will tear and cause a really loud bang when the drum is going full speed and will scare the absolute shite out of you!
Now you’re ready to go. If your floorboards are all different heights, you should start like I did by going diagonally across the boards, turn around and go back across the same line the other direction. This will smooth the edges and make them all the same height – really important for smoothness under foot. Once you have covered the whole floor once diagonally, then slowly go up and down each board with the wood grain until you have covered the room.
You will need to repeat the process with multiple grades of sandpaper going from coarse (around 40 grit), through to medium (around 60 grit) to fine (around 120 grit). Do not skip any of these – if you leave out the last grade, the floor won’t be as pleasant to walk on barefoot. I used about 8 sheets of the 40 grit, 4 sheets of the 60 grit and 2 sheets of the 120 in the end. Some houses in Dublin painted a thick black paint around the edges of wooden floors in years gone by – something resembling bitumen – if you have that you might want to add a super coarse paper like a 24 grit, to begin with.
Top tips to remember:
- Keep the drum moving at all times when it’s on the surface of the floor
- Always tilt the sander backwards when you get to a wall otherwise the drum will carve a groove out of your floor if it stays in the same place for too long
- The drum will naturally pull the sander forwards – make sure you control it, and not let it control you. You should be walking slowly one foot in front of the other.
Using the edging sander
Once you have gone around the room with a drum sander, you’ll realise you haven’t got very close to the edge of the room. This is where the edging sander comes in handy. Using the same sandpaper grades as with the drum sander, walk around the room on your knees (this is where the knee pads are useful!) and get the edges as smooth as the rest of room. Replacing the sandpaper is easier on this than with the drum – there will be a special device like a socket wrench for tightening the screw in the middle.
DO NOT TOUCH RADIATOR PIPES WITH THIS SANDER. I had to put that in capital letters because it’s exactly what I did. The circular sander is incredibly sharp and acts as a saw – I nicked one of the radiator pipes and the water squirted across the hall. I needed to get a plumber out to lift floorboards and replace the pipe which was a real pain, so I would strongly advise you learn from my mistake on that one.
Using the corner sander
Your edging sander will get almost everything, but not the very corners. Use a handheld electric sander to get these areas and any other areas of roughness that you might have missed or which need touch ups. This is the easiest of the sanders to use. I was lazy and only used 80 grit sandpaper on this one – I figured that I wouldn’t be in the very corners of the room in my bare feet so I wouldn’t need the really fine stuff.
Before you use the sander for the last time with the highest grade of sandpaper (i.e. largest “grit” number), sweep the floor and fill any cracks with plastic wood like Rustins Floor Filler because the sanding will dislodge some of the preparation work. This will give a lovely finish when it is completed.
Top tip – don’t use as much plastic wood as I did below. Use only enough to cover the crack rather than spill out onto the clean wood. It will make for a cleaner finish.
Voilà – the sanded floor
Once you have given it a clean, here is what the floorboards look like after sanding compared to how they looked before.
One last thing – tell your neighbours that you’re planning on doing the work if you’re in a terraced or a semi-detached house. It’s bloody noisy!
For the next step, read how to varnish a wooden floor.