What to use to fill in concrete joints to reduce weeds?

There is a concrete caulk just for that purpose---very stretchy.

Perhaps a concrete person will give you a favored brand---Mike---

Sika makes a self leveling product in tan and gray. If the spaces are deep, measure the width and buy backer rod to install in there. It should go down about 1/2" or so. Backer rod comes in widths of 3/8" to 3/4", maybe more. The concrete needs to be clean and dry or the material won't adhere to the sides.
It comes in 2 caulking tube sizes. If you have a lot of work, get the large tubes and a large caulking gun.

Ron6519 said:

Sika makes a self leveling product in tan and gray. If the spaces are deep, measure the width and buy backer rod to install in there. It should go down about 1/2" or so. Backer rod comes in widths of 3/8" to 3/4", maybe more. The concrete needs to be clean and dry or the material won't adhere to the sides.
It comes in 2 caulking tube sizes. If you have a lot of work, get the large tubes and a large caulking gun.

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The picture above is the side yard, it's a sort of wide boat parking area that's kind of V angled. Water can collect around that area. How would using a solid sealant affect an area like this? Would using a more porous material be better for drainage? I can see using a liquid sealant for my driveway since it's sloped and water just runs down to the street.

What are those "felt-like" strips that can be tapped into joints? I don't know the construction lingo, so it's difficult to find. All I can find is some Deck-o-foam, but that seems to be just like a backer rod and most likely requires other material to be applied on top.

Roundup.

Bud Cline said:

Roundup.

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Yea, I know I could use a spray. But you have to be on top of it. You miss an application then ya got weeds that will have to be pulled. Even dead weeds are undesired.

You miss an application then ya got weeds that will have to be pulled.

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Why? Next little beggar that pops up...spray him too.

Use vegetation killer instead of Roundup and that will end your problems for a long time.

Anything you do can still harbor enough soil to propagate a weed.

Bud Cline said:

Anything you do can still harbor enough soil to propagate a weed.

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Which is why I'd like to just fill the cracks. Some type of porous material would be nice. Like I mentioned before, some of the "felt" like material, whatever it's called. Don't know the name, but I've seen it stuffed in a transition from the garage cement to the driveway cement.

a mixture of diesel and oil sprayed in there every so often would probably keep anything from growing, ever


but anyway, get a pressure washer and spray the cracks out really good, you can't fill the cracks if they are already full. Get them emptied out, then get some gray concrete caulk, depending on how wide it might take a lot of it

In my experience, repeated applications of Round-Up over time will have longer and longer lasting results - making the occational missed application not a big deal. Anything you do to fill the cracks will have weeds reoccur - mother nature is very persistant.

There's an extended control round-up that they say works for four months. Also you can sprinkle a pre-emergent weed killer in your joints in the early spring so stop things from growing in them.

STL B. said:

There's an extended control round-up that they say works for four months. Also you can sprinkle a pre-emergent weed killer in your joints in the early spring so stop things from growing in them.

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this is how id go about it, with the joints filled, chemicals wont get in there very good when it is time to spray. Also, it may take a TON of sealant. If chemicals were just sprayed in there, nothing is going to want to grow In the future either. Another thought i had, Maybe clean out the cracks really good and fill with sand. Weeds would still be able to grow eventually, but it would make the growing conditions much poorer, especially when sprayed with chemicals

Diesel fuel (or other petroleum products) = not a good idea.