Flooring

I’m putting a one-piece vinyl sheet in my basement, and it crosses one of the control joints the contractor cut in the original floor. The floor is five years old. The joint runs about 5 feet through the middle of the hall floor where the vinyl is going down, and the joint itself is about 1/2 inch wide at its widest point.

The official guidance from manufacturers (Armstrong / Dupont) say not to use a thinset to fill expansion joints, but to use an "expansion joint cover". However I read somewhere (can’t find it now) to put a foam backer rod in the joint, and then cover that with thinset. Has anyone done this type of install and can recommend the right way to do it?

I can’t seem to find any "expansion joint covers online, except for technical specs that seem more like they are used in commercial applications.

I suppose a slightly more expensive but less rigid option would be foam rod in the joint, with an elastic caulk on top instead of the thinset. OR using that "filler" fiber-stuff that is used for exterior expansion joints?? (the control cut is less than one inch deep though!).

All help is appreciated!

Use a rubberized caulk, something like BIG STRETCH. Stretches 1 to 12. Scrape any excess flush with razor scraper. Contractor.

Flooring

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