Front walk repair - do you have a better idea how to do this?

[tomtheelder2020]

The front walk at my MIL's house had decorative 2x4 strips at shrinkage control joints (see photos). Several need to be replaced. These were only about 1! thick set down into the concrete (i.e. concrete continuous beneath them) and held in place by nails extending from the boards into the concrete. The boards are long gone. Measuring the gaps, there is little consistency in width or depth of the boards. That is ok; cutting them to unique sizes will take some time but won't be difficult. to fit them in I will have to use my oscillating tool to cut off the old nails.

The issue is - how to hold the new wood pieces in place? My guess (and it is only that) is construction adhesive would not hold them very long. Holding them in place with screws set into concrete anchors seems like overkill. The best idea I can come up with is to: 1) cut the wood to about half the original thickness; 2) set several screws along the length of the bottom, extending about 1/4 inch below the bottom; and 3) set the board down into a thin (about 1/4 to 1/2 inch) layer of mortar in the bottom of each gap. When the mortar sets the screw heads should hold down the boards. That is a pretty skimpy layer of mortar but I can't think of anything that would pull up on the boards. I live in the Sacramento Valley so freezing is not an issue.

What do you think? Anyone have another idea? Thanks.

 

[Snoonyb]

Forget all that milling,I'd use SIKABOND.

 

[Steve123]

+1 on don't use wood. It will rot away.

Use a grey polyurethane masonry caulk. Put down painters tape on the top of the adjacent slabs to minimize possibility of getting caulk on top of the sidewalk slabs.