Patio slab too small-how can I make it bigger by myself?

Find someone who can lay down 12" patio blocks around the perimeter to enlarge it.

The easiest way would be to dig out a border section around the slab, spread and compress a good layer of sand and then add paver stones. It would be an attractive edging, while expanding your area. And the pavers you select can be chosen based upon the size you can manage handling.

Hire your self some help, at 70, you are supposed to enjoy life ,not be in pain from doing to much hard work ,which patio slab work is.

How about a perimeter of pavers or flagstones? A bit time consuming, but each piece is fairly light. Choose a different color than your slab and it could look really amazing. Almost like a quilt.

The paver or block suggestion is great, You can find pavers that are not too heavy(under 20 pounds) for about a dollar not on sale. We did this, and took our time to make a long narrow seating area between our sidewalk and the house last year. We did it in sections due to budget and other project we had going. Just don't work for long in the hot weather, it is too easy to dehydrate and get sick. This is the type project you can do over time and will have the same end result, putting in an addition to what you have. You can do this to expand even more in the future if you want even more space.

Add pavers to extend slab. You can do it over a bit of time or hire some neighborhood high school kids for a few hours.

thanks that a good idea abouy the neighborhood kids.