The Base

This is the finished block base ready to add the slab.

My dad just happened to have a lintel lying in his garden next to where I got the blocks from.

There have been no additional costs so far.

I found the cementing to be quite tricky but it was enjoyable. The most difficult part of doing it is getting the quantity of water right for the cement. If it's too liquid the weight of the block pushes it out, if it's too hard it doesn't bed the block properly. There seems to be a very fine point where the water is just right but if you keep mixing it will get more liquid.  It's much trickier than you think to judge this right and if you end up adding more sand or cement to try and balance things out the mix can go off. If it's been raining and the sand is wet you hardly need any water at all. It's surprising how little is needed.  I used a 3 sand to 1 cement mix. only a few inches of water in the bucket was needed. I'd give it a few minutes in the mixer then toss some out onto a flat aqua panel board I had lying around. Then scoop it up with the trowel.  See how it worked...

I keyed in the joints after. Not any need to I just wanted to try. I intend to cover the outside so nobody will see it anyhow.

My levels are not perfect. This was due to the different consistencies in my cement which meant some blocks sank further than others and squeezed out a lot of mortar.
It seems to be really solid and if I cast the slab on top in place the levels will not be so important I think.... time will tell!