Thanks Pete! I appreciate the detailed information you've provided. I hope you won't mind some followup questions...
Pete A. wrote:
With pre-finished wood it will be more practical to just cut out the old, defective board and replace with a new one.
While I may have become fairly proficient at installing HW for a DIYer, I've never attempted to remove a single board from the middle of the floor and until very recently felt somewhat intimidated by the thought of having to do so. And while the HW retailer, who sold me the wood 10 or 15 years ago but had nothing to do with installing the floor, has offered to come out and replace the board at no charge, I'm not so sure I really want to "take advantage" of their generosity and willingness to help. So I'm really considering doing the repair myself and may try the repair option first and see how it turns out before replacing the defective board. Do you really see no chance of winding up with a good looking and long lasting repair by filling the void?
Pete A. wrote:
The worst case scenario that produced the cavity is a beetle tunnel. You could shoot an entire 2 part injection kit of epoxy that 3M makes and it may not fill the gap.
Is a beetle dug tunnel something that could have occurred since the floor was installed? Or is it more likely that the beetle did the dirty work during storage in a warehouse or even while the tree was still alive and the void was just not discovered during the manufacturing process?
And, is the 3M injectable epoxy you mentioned specifically designed for hardwood flooring repairs or simply a general purpose epoxy product? Can you, perhaps, provide the name of the specific product you had in mind?
Pete A. wrote:
After removing the plank by drilling a hole at each end, use a circular saw to cut out a strip the width of the drill diameter, ¾ inch, and after chiseling out the strip the board will be easier to remove. One side will be loose so take that out first. Be careful not to damage adjacent boards. The replacement board end with the tongue will need to be trimmed off and bottom of the groove removed to fit. A block plane to undercut the groove will help it to fit.
After watching a few YouTube videos I must admit that the prospect of removing and replacing the defective board doesn't seem so intimidating anymore. I especially liked your suggestion of drilling a hole at each end of the board which should result in a lot less chiseling, cracking and splintering than I've seen in some of the videos. If it does come to replacing the bad board, how close to the ends of the board should I be drilling these starting and ending holes?
Pete A. wrote:
If you are using a flexible glue, like latex sub-floor adhesive there will be no loss of integrity in the T&G, but you could glue only the bottom edge of the groove to the tongue after adding nails to the adjacent board where the tongue will fit to help the row next to what you are replacing more secure, since you will have removed some nails by taking the defective board out. Flat power-cleats work well to "back-nail" through the bottom part of the previous board, just don't set it through.
Do you recommend using a flexible latex sub-floor adhesive as opposed to a polyurethane construction adhesive?
And do you recommend, as I've seen in some videos, cutting out the felt paper in the empty space and glueing the new board directly to the wood subfloor? Or should I leave the felt paper in place and apply the glue only to the underside of the two remaining upper flanges of the grooved edge and end of the new board?
How about the tongue side of the new board, should I apply any glue to that joint? Or leave the tongue dry to allow for some expansion and contraction?
I do understand the beveling of the edge of the remaining upper flange of the new board's edge groove to allow the new board to easily rotate down into place but I'm not sure I understand the back-nailing part. The adjacent board with its tongue facing the empty space should still be nailed securely in place; so I assume the back-nailing all takes place on the adjacent board with its groove facing the empty space. Are you suggesting that I back-nail into the lower crotch of that adjacent board's edge groove?
As for the power cleat nails... I have only a Bostitch MIIIFS which, I believe, only shoots staples. I do however, have a pair of Senco 15g (1-1/4 to 2-1/2) and 18g (5/8 to 1-1/4) finish nailers. Are either of these finish nailers suitable for shooting the power cleat nails? If not can the power cleat nails be driven by hand or should I just pre drill and then back-nail with regular finish nails? Or perhaps, ring shank siding nails?
And finally what size and length do you recommend for the back-nails? My floor is 3/4 and the subfloor is two layers of plywood with 5/8 laid on top of 1/2.
I look forward to your reply Pete!
I really can't thank all of you, here on this forum, enough. If it wasn't for the help I received from all you guys in past years, i would never have been able to successfully install my wood floors in the first place. Now here I am again for more help with this repair job and I'd be lost without your help once again.
Thank you! Thank you! Thank you! ZT