Lap marks in finish

Q: I recently installed and finished a hickory floor myself. The install was tough, but it came out great. Sanding went well, but finishing left streaks and blotches (did an oil modified sealer then water based urethane).

I wasn’t happy, so I resanded the floor back down, and this time did a water-based sealer and then water-based urethane. No streaks, but I do have the occasional lap mark where I needed to turn the t-bar around when dragging the puddle of finish. Any ideas on how to get rid of these?

I have 1 coat of sealer and 2 coats of urethane. I am thinking of screening\sanding them down with very fine (300-400 grit) paper once the floor is cured for a few weeks. Any advice? And yes – I just found your Q&A, and you are right: leave the finish to the pros – it took me three tries to get the floor to where it is now!

A: The streaking and mop stops is probably related to the flattener in the satin finish. This does cause even seasoned professionals plenty of grief. I have recently switched to an omu finish that doesn’t seem to do this. At least, I have used it in environments where I thought this would be the time it would streak and it didn’t. I would describe it as velvet to apply. Primero from Poloplaz. Best finish I have ever used in over 34 years. Bar none. Not only does it apply beautifully and dry above expectations. It is not just a pretty face. It is as tough as a finish gets. No doubt in my mind at all about this product.

Streaks of urethane from the applicator

Related Q: I recently refinished a red oak floor and put the third coat of urethane down three days ago. There is a section of the floor that shows streaks of urethane from the applicator going across the grain. Because of the way the room is situated I could only apply the polyurethane in that area by standing in the doorway and could this not go with the grain. Is there any way to get these streak marks out?

I was not concerned initially as the first two coats did not show this. The can of oil-based polyurethane says it is self-leveling.

A: I think you will have to buff this down thoroughly and apply another coat. If you can find a finish that rolls on well you should be able to avoid this issue. I use Primero from Poloplaz. This lays down wonderfully with a 3/8 or 1/4 nap roller.

Follow-up Q: Thanks for the response Craig, would you recommend buffing with a pad or using fine grit sandpaper?

A: If you are doing a large area, I buff down the edges with 120 grit sandpaper and use a polisher with whatever grit works, and that would depend on the coating. Generally 180 or 150 grit. If you only have one coat of finish currently I may even go to a 220. Or if you are full of vim and vigor you can rub the entire floor down with sandpaper. Those discs for the polisher are screens, not sandpaper.

Follow-up: Thanks again Craig. I’ve got three coats down, the third one was the one to ripple. I’ll sand it this week with fine grit and give it another coat of poly. Hopefully, this will do the trick. Your suggestions are very much appreciated.

Multiple lap marks in the finish

Q imported from our old site, Face Lift Floors: A contractor just finished installing/finishing hardwood floors and left multiple lap marks (covering the entire width of the floor). The problem first appeared following the 2nd coat of urethane. I mentioned my concern to him and an extra (third) coat of the product was applied. The result was not much better and the satin finish now looks a lot more like semi-gloss or gloss.

When I checked with my contractor, he mentioned that the lap marks should “go away” over time(or after a few washes) and that the “glossy” look of the floor increases with the number of applications of urethane. The plan now is that he will be buffing the floors again to eliminate the lap marks. I am very suspicious of his suggested approach. Is the approach correct or would you suggest another course of actions?

A: One thing is certain. Regardless of how skilled the worker is, sooner or later everyone will have an “event”. Regarding the lap marks, it sounds as if the finish may have dried too fast, and did not have time to flow out. Perhaps it is too dry and warm in the room. There is also a slight possibility there could be a defect in the pail of finish he is using. You did not mention if this is oil modified or water-based urethane. The application method is somewhat different for both. As far as the finish now appearing shiny, when it is supposed to be a satin finish; He has to make sure to stir the finish adequately.

I wouldn’t agree that the more coats applied the more shine there is. The finish has to be buffed to remove the shine before another coat is applied.

If I was facing this, my approach would be like this: Buff the floor fully with a polisher and either a 180 grit of finer screen or a maroon pad, if the finish is still fairly new. Vacuum up thoroughly, and tack rag the floor at least once to remove any dust residue. Shut off any sources of air movement across the floor, such as furnace/A/C. Close windows. Make sure the pail of finish I am using is clean and thoroughly stirred. Apply the finish in sections, rather than applying across the entire floor area, from one end of the room to the other. So, I usually go in approx. 5 or 6 ft. wide section, and do that width from one end to the next. Then I do the next row until I have worked my way over to the door. If this is an oil modified, wait 3-4 hours before allowing any ventilation into the room.

Original / moved link https://faceliftfloors.com/q-and-a/lapmarks.php

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