Faced with a similar situation I sprayed Round-up over the entire yard, waited 10 days and then did it again. After I was sure everything was D-E-A-D I waited for the right amount of rain and hired a laborer off Craigslist to go over the yard with a roto-tiller and definitely more than one-time over. (Again, ground too dry tillers wouldn't have gone deep enough, to wet well, you can't till mud.) After that I spread grass seed (but NOT TOO MUCH!) and Milorganite and as soon as weeds started appearing I relied w(with success I might add) on the different Ortho Weed-B-Gone mixtures to keep the weeds at bay. Oh yeah, Milorganite every month for the first couple months and then several to four times a year after that. Rains did their part to level everything out and where ant mounds started to appear I relied on a product called "CrossCheck" I got from my local SiteOne (used to be John Deere landscape supply houses). If I couldn't find the crosscheck I'd order "Taurus SC" from DoMyOwnPestControl.com

Once the lawn is established you can use Lesco Pre-M 0-0-7 ($22/bag from Home Depot) each Jan-Feb and then May-June and then again September to prevent any weeds from even appearing!!!!

Biggest challenge on a budget will be irrigating the seed and keeping soil moist until the grass can get established. You don't mention where you're at so, once you some others here may be able to recommend the type / variety / source for the grass seed you want to use. (Where I was a blend of tall fescue and fine fescue I got from Rural King did just great!)

Congratulations on home ownership and Best o' Success!

oh yeah, don't ever mow below 3-1/2 inches or before 3pm during heat months and don't mow wet grass and wait til Fall to fertilizer after lawn established (fertilize after March and, depending upon where you're at, nitrogen will just set you up for fungal diseases (to be avoided!)

Wow! Lots of great information. I am in the southeast corner of BC. Weather's been pretty extreme and unpredictable for the last few years. Need to plant hardy varieties of everything.

Yes, we did something similar. Sprayed roundup (bought the commercial 5 gallon bucket for cheap), waited for the grass to die, then waited even longer for the roots to loosen up. Weeds seemed to take longer to kill than grass, possibly two treatments. But the main thing it that the grass is dead. Then you should be able to use a regular rear time tiller to till up the soil. Ours was front time but I think a counter tine may have broken up the soil better, bought it for 200 off Craigslist. Or you can rent the heavy duty super tiller from somewhere like home depot, this one you wont even need to use the glycophosate first, wbich is nice becuase you have less hard dead grass clumps to rake out later. We bought the tiller since we knew we would have to till several times. After that we let the soil sit and waited for weeds to sprout (good if you have rain or can water), and retilled, and then tilled several more times, possibly six times total over serveral months. The tilling kills the weeds and breaks up the organic matter so you dont have to take everything to the dump and buy new soil. You can then level with a leveling rake and pull out any remains clumps. I had 10 wheelbarrow full of dead grass clumps for 9000 sq feet. We then got a neighbor's riding lawn mower and towed a pallet behind it over the soil, which worked great, and picked out clumps that had surfaced. You could probably leave the clumps but I thought it would be best to remove them.

Ha-ha, pulling an old wooden pallet behind a rider --- I LOVE IT! And, I swear, I woulda never thought of that (gonna "steal" the idea in the future, I am sure, though)! :-)

What you might need is called a "pasture drag" or a "drag harrow" ... something heavy pulled behind a tractor or ATC that will knock down the bumps.

They can be as simple as a chain link fence gate with concrete blocks tied to it or something built especially for that. Often you can hire someone to do it.

Thanks lazy_gardens. Finally something practical. DO NOT ROTOTILL. If you do that you will have the same thing you have not in 3 years. Rototilling fluffs up the soil unevenly. After it gets fluffy, it settles, and it settles to the profile of the underlying untilled soil. It it is uneven (and it is) then the future settled surface will be uneven.

I would ignore the ants entirely. They will go away once you get the soil working. Flatten it out with the drag, scatter some turf type lawn seed, water it in, mow when it gets up to 5 inches tall, and worry about ants next year. Chances are real good they will go away by then. Oh and use organic fertilizer to feed the soil microbes. They will help with the ant control, too.

Also pouring borax on the soil can effectively sterilize it. So again, leave the ants along and they will go away by themselves. Focus on making the soil perfect (leveling and organic fertilizer), then seed, and water. No -icides until mid spring.