Thread: Flexible floor gap filler

Hi, short time lurker, first time poster

Just sanded floors in my new federation place (previously carpet), ready to apply polyeurethane. Happy except for a section of hallway where boards have 3-4 mm gaps. Tongues are covering so not drafty, but it is a bit uncomfortable to walk on in bare feet. As there is some flex in the boards, you feel the edge of each board under your feet as you walk.

I didn't putty these gaps because I thought the putty would split out. long stripes of it look a bit silly anyway.

Anyone know of a flexible and preferrably clear filler that can be covered with polyeurethane that I could use here?

P.S. Just rang HB Fuller regarding Caulk in colours product and they reckon it's unsuitable.