Refinishing the wood floors

The wooden floors in the Crofton house were not cosmetically attractive, but much of this was caused by a layer of glue that had been used to fasten down a foam backed carpet. I remember a similar approach to laying carpet in the house I grew up in in the 1970's, so suspect that during the heyday of wall to wall carpeting, the hallways and living-room had been covered in a tasteful orange, yellow, or green covering. The good thing about this is that there was little damage to the maple floors. 

Living room walls have been repaired and gas fireplace vent installed in the wall. Ready for floor refinishing 

Living floor detail showing stains and glue, plus old varnish

The bedrooms are floored in Douglas fir and these had not been carpeted as far as I could tell. There were some scratches from beds and deeper grooves from a door that was a bit too close to the floor.

Bedroom floor in the middle of wallpaper removal. The old floors had a nice red patina but were water stained and scraped up

After much research on YouTube and in various blogs, I decided to use an old fashioned drum sander to take off the old finish and get the wood flattened and ready to varnish. The main alternative would have been a large multi-pad random orbital sander, but I had read that these were very slow and frustrating to use on floors that had a lot of marks or old varnish. I also rented an orbital edger.

Drum sander waiting for its first use in the hallway. 

 

Orbital edger - a quick and powerful way to sand the edges in the hands of a professional

On one excellent set of videos by Ben from HowToSandAFloor (e.g, his demo on drum sanding) I learned that the orbital edger is the most dangerous sander as far as doing instant damage to a floor - even worse than the big drum sanders, which can put a big groove in a floor in a second of inattentiveness! Ben is absolutely right and I quickly decided that the edger was not going to be a tool I would use on this job. In addition to being hard to control and cutting unevenly on the relatively hard maple floors in my amateur hands, the sanding disks clogged up extremely quickly with old melted varnish. Not being able to use the edger safely meant that I spent many hours hand scraping and using my small Bosch random orbital sander with the most aggressive paper I could find (40 grit) to finish the bits I could not do with the big drum sander,

N95 respirator helped with the dust, although the drum sander did a pretty good job of transferring the dust to its bag

The trick with the drum sander is to always keep it moving and to NEVER stop or change direction with the drum in contact with the floor. You start walking forward or backwards with the sander and gently tilt it down to make contact, like and airplane taking off or landing. It took a couple of days to get comfortable with this and by the end of a three day weekend I was feeling relatively confident. 

Drum sanding the living room maple floor after one pass - the dark areas on the edges will be finished later

I sanded first with 36 grit, then moved to 60 and finished with 100 grit. To run each grit over the living room took well over an hour, because you go both up and back on one pass and then move over about 4 inches at a time to overlap the last 8 inch pass. It took me at least twice as long to do each room as I had expected. You also need to unload the dust bag quite frequently and I filled two garbage bags full of sanding dust. 

Hallway after 60 grit sanding. Note the new drum sander sheet ready to fit

First pass in the master bedroom. All that lovely red colour has been removed but will come back over the years as the UV light ages the wood.

Bedroom floor - I am emptying the dust bag on the sander and cleaning up between changes of sandpaper

I was extremely concerned that the drum sander would be too vigorous a machine for the softer Douglas fir floors, but I was wrong. Maybe because I had practiced on the maple floors first, I did not have an issue using the coarse 36 grit drum on the softwood floors. I did make sure I kept moving smoothly and quickly with the sander. Note that the coarse grit paper is mandatory if you have a varnish on the floor because the finer papers will simply gum up and become useless almost immediately if this varnish is not removed first.

The random orbital sander at work on the edges in the bedroom. I also used a hand scraper and had to keep this very sharp using a file in order to remove the old varnish quickly. 

 Finishing the edges took another couple of days of scraping and sanding before I was ready to apply a varnish.

Living room floor ready to varnish. Note a few stains to the top right of this picture. These may have been caused by a dog. I tried to bleach them out with oxalic acid and while this did lighten the stains it also lightened the surrounding wood. I should perhaps have bleached the entire floor...

I chose water based varnish from Varathane that I had used in our own house with good results. It is not as hard as an oil based varnish but dries clear, does not yellow, goes on easily by brush or roller (although this can cause bubbles). It is also better for your brain in that it does not produce too evil an odour.

Living room floor varnished with gas fireplace ready to install

Hallway with first coat of satin varnish

Second bedroom ready for its final coat of varnish

I was very happy with the final results in the bedrooms.

Once the varnish was on I could see all the imperfections of my sanding - mostly small drum marks from starting and ending each pass but also lighter drum marks in the middle of the floors. If I was to do this again, I would rent one of the American Sander 3 pad random orbital sanders and make a pass with this at maybe 80 grit over the entire floor. This would also make finishing the edges quicker than with the small handheld random orbital.

The project was not all that expensive except in terms of labour, which as I mentioned above I grossly underestimated. The time spent could have been reduced by at least a day, though, if I had rented the big random orbital sander as well as the drum sander. I used a bit over 3 gallons of varnish at about $70 (Canadian) per gallon and the sander rentals and sand paper came to about $150.