Patching Wide Cracks?

[CWLee]

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?

[roger61611]

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 come apart.)

[Cliff Hartle]

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.

[Lou]

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. Lou

[CWLee]

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?

==========================

[Nancy Young]

"CWLee" wrote

There are tiny plants that do well in that type of situation and would look cool. Google for steppable plants to see what types are good for your application if that would interest you.

nancy

[Steve]

"CWLee" wrote on 11 Nov 2007 in group alt.home.repair:

Some thoughts: * 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 range.

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 years. * 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 there. * 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.

[Abe M.]

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.

[CWLee]

this size?

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.

[Nate Nagel]

yes, it is a brand name of plastic boards intended for decking.

nate