G'day renovators. I am about to attempt to fill in spaces in old jarrah floor boards. I have been told that there are gaps in the flooring as when it was laid (60's) the boards were green and were not meant for a finished visible surface. I am going to fill the gaps inbetween the joists with black sikaflex 290 which I have read is a good flexible sealant. Is it best to seal all gaps first and cure then sand or sand first, then seal? I know that the product is sandable just worried it may clog the sanding sheets.
Any info or recomendations would be greatly apppreciated.