The Base - Part I

I used concrete bessa blocks to build the base for my brick oven to sit on. Be warned: BESSA BLOCKS ARE HEAVY! If I were to do it all again, I would opt for Hebel Brick, or some other kind of aerated masonry unit. Any difference in cost will easily be offset by the money you save in chiropractor bills.

It took me a while to find enough second-hand bessa blocks for the job – but patience pays. I eventually found all I needed on ebay for $1 each. I was lucky enough to have a friend with a flatbed truck so I could collect them all in one hit. Otherwise it would have taken half a dozen trips with the trailer.

The bessa blocks sat stacked against a wall for months, while I contemplated the task ahead (no sense rushing these things). 

Eventually I tried setting out a few blocks on the foundation, as a kind of dry run, to make sure the pattern I had in mind would work as planned. It looked like it might!

Once I’d psyched myself up, I roped in my father-in-law to help with sticking the blocks together. We proceeded slowly and carefully, laying the blocks with a basic mortar mix of 1 part cement to 4 parts brick sand (and water, of course). 

The consistency of the mortar should be a bit like thick cream. We soon discovered that, because bessa blocks are so heavy, if the mortar is too wet it all gets squished out the sides. Live and learn!

We applied the mortar with trowels, in the traditional manner, tapping them down here and there with a rubber mallet to keep them level and in line.


After laying each course, we stopped to check our progress with a spirit level, to ensure things were working out true – which they were!

To form the alcove for wood storage, I had to run the final course of bessa blocks over the top of the alcove (plus a second course of half blocks, laid flat behind the outermost blocks – you’ll see what I mean in the backfilling pics). This meant devising some support system to hold it all up.

I bought some 3mm right-angle steel section from my local scrap yard (a spare change purchase), scrubbed them clean and gave them a coat of paint. Here they are:

I simply ran the steel rails across the opening, overlapping by 200mm at each end, and mortared the blocks in place over the top – no drama. And here they are in place, performing admirably:

Having built the main base structure, the next step was to back-fill and seal the whole thing with an insulated top-layer, which you can read about in Part II…