How should I flatten my uneven back yard in Toronto?

Question

I need to regrade my backyard. Currently I have a good green layer of grass and other small unwanted :-) plants covering my backyard. The previous owner dug a patio and I suspect that they spread the soil around the house. The soil under the grass is not level and the grading of the lot was ruined.
I intend to fix the above by removing the sod, leveling the soil, grading the backyard and putting the sod back.
My question is: do I need to do anything special when I use a sod cutter on this unevenly leveled soil? All the above are going to be during the same day (a weekend probably).
Also a related question: is the beginning of June a good time for this? Here in Toronto we had a quite cold and dry May, and it rained quite a lot 6 days ago.

Edit: I think that I have two options: a) remove the sod, grade the soil and put the sod back AND b) use a rototiller (rent it from HomeDepot) and turn the old sod over

I would like to go with b) because: -the existing sod is poor quality -there is less work involved to remove and put back -I understand that using a rototiller will also help me to aerate the soil, make it easier to be graded

To get my lawn back I can either buy sod or seed and wait for the grass to grow back. This should be easy with the wet summer that we are in for here in To.

Any pros and cons ?

Edit2: here is a picture, the two sheds are not there anymore, that spot has no sod now

Answer 1

As you stated you have several options. First, I'll answer a few questions:

do I need to do anything special when I use a sod cutter on this unevenly leveled soil?

No, specialised sod cutters cut through sod at a certain depth, which can be set low enough for most applications. If it doesn't get everything (very unusual) you can re-cut the area or use a sharp spade.

is the beginning of June a good time for this?

In Toronto, yes. Just make sure the new lawn is kept well watered until established.

To get my lawn back I can either buy sod or seed and wait for the grass to grow back. This should be easy with the wet summer that we are in for here in To.

Any pros and cons ?

Both should be equally successful if done well, with the sod being faster, at a cost. Both can be a great lawn, and in a year or so of good growth, differentiating between them isn't often possible.

About your two options: cutting the sod, regrading, and replacing the old sod, and your other option of rototilling and reseeding/sodding, Here are some pros and cons for each:

Method 1, cutting the sod:

• That doesn't look like the greatest sod; I wouldn't reuse it, but you could if you want. Just mow it off rather short beforehand.
• If you want to add new sod, this is the best option. It also makes it easiest to regrade.
• If you want to seed, this is a good option also, although you will have a pile of composting sod sitting by, and the lawn level will be lowered.

Method 2, rototilling:

• Green grass decomposing in the soil has allelopathic qualities which inhibit/retard the growth of new grass, especially seeded.
• This method keeps all the topsoil in place
• You will likely need to regrade after complete decomposition, because of shrinkage and settling.

Other options:

• Kill the lawn by herbicide or tarping, then regrade and replant
• Use new soil to fill in the uneven areas of the lawn, and then overseed

In any case, you won't go wrong by adding compost to the soil. It would also be a great time to do some testing and find whether your lawn could use lime, etc.