wrote :

What do you mean "slots are developing" ?

The boards (2" x 4"s) that were used to divide the patio
slabs (other posters have called these expansion joints)
have begun to rot. They seems to rot, un-uniformly, from
the top down in several places, so the space previously
filled with wood becomes open to the air. Those spaces I
call slots; they are not cracks, but I don't know a better
term.

(Here is a graphic representation, that may get
all screwed up by different computer formatting rules.)

_______________ ____________
| |
patio concrete | previously | patio concrete
| wood |
|~~~~~~~~~~~~ |
| remaining |
| wood |
______________| ______________|_____________

sand sand sand

earth earth
earth




I doubt if I could force new boards into the openings. In
some places plant roots are growing, horizontally in the
slots.

I wonder if, after 27 years of curing and drying, there
still needs to be provision for expansion. This is in
Southern California, with an annual temp range of,
at most, 35 to 100 degrees.

Other thoughts?

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