All the stuff I find at HD/Lowes for patching concrete
cracks at intended for a maximum size of, at most, 1/4" wide
cracks. I have some very wide cracks/openings to patch, and
I'm looking for product suggestions. (I asked this earlier
with a different title, and attracted no responses. That
surprised me, and I still wonder why.)
Anyway, her is my situation: 27 years ago my concrete patio
was poured. 2" x 4"s were used to divide it into four large
areas. Patio has served me well. 2" x 4"s are beginning to
rot, and slots are
developing in the patio where the 2" x 4"s are. I'm
considering just pulling up the remaining 2" x 4"s and
filling the cracks with some sort of "gunk" I could purchase
at HD or Lowe's. My expectation is that the "gunk" would
generally match the color of concrete, be smoothed to be
level with the rest of the patio, and that it would harden
in a few hours/days. Question, what is the best
type/style/brand of "gunk"?
Any other ideas?
Former slayer of dragons; practice now limited to sacred
What do you mean "slots are developing" ?
(Probably got no reply cause there's no easy answer. I'd replace the
wood with wood, the only other thing i can think of is that asphalt-in-
a-bag they sell at HD. Nothing I can think of wouldn't just crack and
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
(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
I doubt if I could force new boards into the openings. In
some places plant roots are growing, horizontally in the
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.
* The old wood has to come out, no matter what, before you repair.
* So do the roots.
* So does anything else that's in the slots.
* You definitely DO need expansion joints. Concrete changes sizes with
temperature forever. That's why buildings, bridges, and roadways have
expansion joints. A 30' slab will expand by ~1/4" for your temperature
Some recommendations, in order of my personal preference:
* Replace the old wood with new wood. The boards can be trimmed down to
fit, no matter the dimensions of the slots. I did this for a client last
summer, and it looks great. Use cedar or redwood. They'll last 10-20
* Put in pavers, as recommended by another poster. It will look nice.
You can make them narrower than the slot, then fill the gap with sand,
to make room for expansion. This requires a brick-cutting saw.
* Put in soil and plant steppable plants, as recommended by another
poster. You might have trouble finding something that likes to grow
* Partially fill with sand to 1/4", cover with waterproof membrane, and
put self-leveling concrete crack filler on the top. This is the stuff
you see in parking lots that looks like rubber. It's easy to do a
parking lot-quality job, but hard to make it pretty enough for a patio.
You'll also have to replace it every few years.
A Trex 2x4 is 3.5 x 1.5" on the side. Can the OP live with this size?
I would not waste time with real wood. It is a maintenance headache
because it sits on dirt. Trex is not everyone's cup of tea because of
the mold problem, but at least it does not rot.
As the OP, the size doesn't sound like a problem, but I have
no idea what "Trex" means in this case. Is that a brand of
formed plastic? Something I could inspect at a HD or
Lowe's? More info please. Thanks.
If you pour concrete you would have to put expansion joints between the old
and new. If the joints are 1/2" wide you would end up with little 2 1/2"
slivers. Which would crack up in a few years.
The only thing I can think of is to put in some sand and find or cut some
pavers to fit the slots and make it an accent.
You may want to remove the old 2x4's and replace them
with new 2x4's. This would keep your expansion joints
as they were intended. Just don't pour in any concrete,
cement, epoxy, or any other substance that hardens and
will cause cracks.
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