Bamboo is a really tricky material to work with, from the challenges of cutting and milling it into a floor, then acclimating and installing it, and finally the sand and finish. I will walk you through the basic steps of a refinish we did on a solid prefinished bamboo floor; the floor was a local public organization, so it was in a bad condition, as you can see here:
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Bamboo is a really tricky material to work with, from the challenges of cutting and milling it into a floor, then acclimating and installing it, and finally the sand and finish. I will walk you through the basic steps of a refinish we did on a solid prefinished bamboo floor; the floor was a local public organization, so it was in a bad condition, as you can see here:
I hope this helps those of you who have never sanded a bamboo and those who have but had trouble with it.
- The first cut should be at a higher grit than your usual 36 or 50. That is because of two reasons: it is bamboo and it is a factory-finished product. Bamboo scratches really easily, so we don't want to put scratches in it more than necessary. Prefinished floors tend to sand better starting at a higher grit. So the first cut was 60. In this case, the scratches were so deep and the wear-and-tear was so pronounced that 60 was our choice. We would have started with 80 if the condition of the floor were better. Here's the floor while we were sanding with the big machine:
- If we had to cut this floor at a 7 degree angle, we would have used 80. When you cut a floor, the big machine is creating a more aggressive scratch pattern on the wood fibers. Any scratch you will put in at an angle will be very hard to take out. Keep that in mind.
- Make sure you vacuum thoroughly between every step of sanding. Keeping the floor clean will give you more control over the consistency of your scratch pattern.
- The big machine finished with 100 grit. The edger had the same sanding sequence as the big machine. Your edger technique should be perfect. I would not put your new guy on the edger on any floor, yet alone on a bamboo floor.
- The floor was hard-plated with a 100-grit backed with a maroon pad. The pad helps reduce the aggressiveness of the cut. Then final buff with 120 grit, again backed with a maroon pad. A note on hard-plating: if the floor is not clean and your technique is poor, don't hard-plate. You will have a lot of scratches on the floor you will not be able to get out.
- Much like any floor, get down on your hands and knees and check the floor at the beginning of each step. I like my eyes about 10 inches from the floor. For example, hard -plate 10 square feet, stop and check the scratch pattern. That way you know if you need to tweak your technique a little.
- Finishing: I use water-base on my floors but I had seen others use oil modified. Whatever works for you. I have very few things in the finishing category that I call "annoying," and applying sealer and finish to bamboo is one of them (a distant second is wiping on stain). Bamboo will shadow very quickly. Shadowing is when you leave a wet edge on the floor without moving it for one minute too long, then you have a line in the floor. You had seen it with oak before, but the difference is that in bamboo the line will stay there. So …
- Work fast, move the finish around and don't let it stand in one spot for too long. When you turn your T-bar next to the wall, don't squeeze the finish out on the bare wood. You will leave a mark. Squeeze it out on an already wet/sealed floor area.
- Go with the direction of the grain. No, no exceptions. It is not like the "go with the grain" on oil pigmented stains when you know you can go in circles and eights.
- The final finish coats and abrasion between coats are the same as any other floor. Pay attention to your first finish coat over the sealer. It may still be a little challenging if your seal coat was not great. Here's our final result:
