Where is MO are you?

What type of Zoysiagrass do you have?

I think burning off your lawn will result in a lot of dead patches and lots of weeds coming up.
I tried this once and those were my result.

If you are using a propane torch, the ones used for torch downs (roofing) then you will heat the soil up too much and kill lots of the rhizomes. There are lots of types of weeds that wait for fire to sprout. You will be overrun with these.

I would scalp it short in the early spring.

Not for sure which zoysia it is, has a failry broad leaf, I will try and post a pic tonight. As I said earlier, I have had it for 15+ years, and it was well established when I got the place.

It is Meyers aka Z-52 the most common Zoysia on the market and about the only variety available variety 15 years ago.

Burning is not going to touch thatch. Thatch is dense and firmly packed against the soil. A fire is not going to get hot enough to burn it out. Get a Power Rake to remove it.

My son complains that my Zoysia is just too thick and hard to even push his mower through. The thash is quite heavy I know. He wants to burn it but that just doesn't make any since to me. Isn't burning actually Killing it? I have seen where people have extensive burned spots in their lawns in late autumn but I just can't see or understand how that's beneficial.I can see Liquid Thatch Remover mentioned in another posting but after reading about that and what it does I still fail to understand how that'd help his mowing any.

Isn't burning actually Killing it?

No not at all, burning dormant Bermuda and Zoysia can do quite a bit of good, mostly fertilize it.

Zoysia and Bemuda reproduce by rhizomes (underground) and stolons (above ground) runners. Grass fires are no where near hot enough to burn it. All it does is clear out the dead dormant grass, let the sun shine in, and the ashes renew the soil with rich nutrients.

Look along any highway in the south where there has been a grass fire about a week or two after. It will be bright green and lush assuming some rain and warm weather...

But to the question at hand of burning Zoysia to get rid of heavy thatch buildup it will not work because the fire is not hot enough to burn the thatch off. I twill just pass right over it as it acts like a fire wet blanket on top of the ground.

Now you could lift and loosen it up and would burn if left to dry out. But at that point you just as well rake it up and avoid the risk of burning.

You maybe overfertizing it. chemical fertilizers can do that. I would just stop fertilizing and top dress it with some compost/top soil early spring. That would help the thatch to slowly breakdown.

If too much thatch is a problem, see the May 8, 2012 post in the following thread called "Too much dead grass."

I know here in the ATL area, it's illegal to burn your lawn.

Ahh... good memories of setting grass on fire...

Lesson learned... Always keep a hose ready to put fire out.

Burning Zoysia grass DOES in fact remove thatch. I've done it myself many times with great results. Faster, clean greenup. Kills bugs too. Anybody saying it doesn't work has never done it. If they have, they likely attempted a burn when grass was damp.