I have an expansion joint in my drive that needs to be filled. The garage side of the joint is about a 1/2" higher than the driveway side.

What products and procedures do y'all recommend? I've seen a lot of DIY online with mixed reviews.

What's the width?

A tick under 5/8".

Does the 1/2" lip bother you? If not, just use self leveling sealant. If it does, you could either chamfer that edge with a grinder or use a standard caulk and tool the joint.

This is my next project also. I want to replace all the expansion joints on my part of the sidewalk and on my driveway. I was just going to clean it out and use wood. What kind of wood do i use for this? Is a caulking better to use? Does it entail anything other than cleaning the joint out and putting the wood in it?

Also is it better to do this in the winter when the concrete is cool or in the summer when it is hot?

Try to get the joint sealed before Winter sets in so you keep moisture out. Try to seal the joint in the morning and you should be fine. if you try to seal in the winter, it will take a very long time to cure. If the joint is level, look for a product called Masterseal SL-1 by BASF. It is a great sealant, just be certain you don't get it on anything you don't want it on. It will stick to your clothes and not wash out.

The 1/2" doesn't bother me at all. I've seen the self leveling products. Do I fill to the lower side or just below (does it expand any)?

Fill the joint as full as you are comfortable. If you overfill, it will run out of the low side. SL-1 will NOT expand at all. Make certain that the joint is defined and clean before you get started.

Who sells masterseal SL-1? I'm having trouble finding it.

Home Depot sells a good self levelling sealant. I think it is a yellow tube with red letters on the masonry aisle by the quickrete.

It is gray and matches concrete well.

It is expensive and will cost you several hundred dollars to do a driveway.

You can put sand in the bottom of the joint to partially fill it so you use less sealant.

I just used the stuff crossbow is talking about. Not really expensive, 15 bucks a tube, my driveway and sidewalks took about 6 tubes to do completely. I did it because the wood had all rotted out, and it's was mostly dirt and I'd get HOA letters about weeds.

I used the Home Depot stuff as well. But I quickly found they sell large tubes online. Three times the size and only like $15 compared to $10 at HD IIRC.

You have to get the larger caulk gun. It took me about 10 big tubes for a 30' long double wide drive.

This was several years ago so some of my number could be off.

You can get the SL-1 at CMC construction Services. (Disclaimer: I work there).

You can get the sealant in 10 oz tubes, however, the higher cost of packaging will be higher than the cost of a quart tube caulk gun.

When sealing a joint, you want to have the least amount of interruptions (tube changes) for the best looking joint.

Sikaflex is the mfr of the product at HD. Just as good as SL-1. And yes, buy the 29 oz. tubes and the cheapest large gun. I probably used 7 tubes when I did my driveway and sidewalks. They have gray and tan, so pay attention when buying. Use sand or backer rod to fill any large joints before caulking.

Oh, btw I did mean that I bought the extra large tubes and the large specialized caluk gun

I would recommend using a Styrofoam or wood rather than sand as a backer rod. You will want to make the sealant depth the same as the width. This is primarily to avoid using too much sealant, but it also helps maintain the bond upon contraction/expansion. Also make sure the sides of the concrete are clean. If they are not clean, then it won't maintain a bond. I would recommend at a minimum use a power washer before installing g the backer rod. Either Sika flex or the base products are good.

Sealant depth is half the width of the joint for a proper joint profile. This allows the joint to expand and contract properly, otherwise it will tear loose.

Blow out debris with compressed air, if deep install backer rod and fill with sl-1. Be carefully if joints runs down a slope because sl-1 is truly self leveling and will puddle at bottom of slope. In this case consider NP-1. Buy the backer rod and SL-1 at CMC.

Sikaflex or Masterseal are both good products. Use a foam backer rod so that your sealant is no more than half the widthbof the joint deep, or 1/2", whichever is less.

You can get foam backer rod in varying widths at HD. Sika is the manufacturer, they will be next to the sealant in the concrete isle.

If I want to use wood instead, what is the best kind of wood to use? Seems like it can be very expensive to use the caulking.

Check this out...I used it on my pool deck and driveway/ front porch areas...easy to install and looks great!
http://www.slabgasket.com

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If I want to use wood instead, what is the best kind of wood to use? Seems like it can be very expensive to use the caulking.

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Redwood. You can use treated pine, but it wont las as long.

Do not put sand or other dirt in the joint to cut down on the amount of sealant you're using. If you do that, you might as well not clean it out to begin with. The wood was used because it does provide some "give" when the concrete expands and contracts with temperature. Sand will pack down and not provide any room for the concrete to move. Remember, concrete is mostly sand by volume anyway.

Additionally, keep in mind that as you remove the deteriorating wood there are rebar dowels that go from one side to the other. Frequently they're tied to the rebar on one side and have a plastic sheath to allow movement on the other. If you cut a board to go in there it will have to be notched around those dowels.

I'd use 5/8" backer rod and Dow Corning 790. It will last longer than NP-1 and SL-1 (both are polyurethane) and will bridge the exp joint better.

If there was old caulk there before, be sure to grind and clean the surface so the silicone adheres better.

Assuming the OP hasn't already finished this project, 5/8" backer in a 5/8" gap doesn't work too well. He would need 3/4" so there's some resistance to keep the backer rod from floating to the surface in the sealant.

I've had to go back and nail down some backer that wasn't stuffed tightly enough into a joint and floated to the surface ~10 minutes later.

HD has a pretty crappy selection of backer rod, but if you need something wider you can always twist two strands together.

Oops, I thought he said it was 1/2" gap.