Tuesday, 28 August 2007

Two thirds of walls done

That's about two thirds of the walls done now - notice I've built a little brick 'box' into the top at the front to hold the thermometer I plan to install. I probably won't build the walls any higher than the top of these bricks - by my judgement this should place the hearth at about hip height.

The slab is there to help judge the height - the oven front will be inside the summer house, which will have a pebble mosaic floor, so the floor will be about 2-3" higher than the slab. I'm stopping for a rest now - hopefully I'll get some more done next weekend.

Monday, 27 August 2007

Third of walls done

Probably finished about a third of the walls now. It's taking a long time - the rockery stone on the front is like a very heavy jigsaw puzzle... I'm trying to stagger as many joints as I can, and make sure that any stones that don't span the whole wall are capped with ones that do.

You can see I've added a triangle of concrete blocks in the middle for support. I plan to fill the gaps in these (and the triangular gap in the middle) with poured concrete, and insert bent rebar into them to tie these columns into the hearth slab. This should provide all the support the slab needs - leaving my outer walls only supporting a small fraction of the weight. The hearth slab will be reinforced as well - I feel sorry for anyone who tries to demolish this future...

Saturday, 25 August 2007

Started the (recycled) base

Made a start on the base today. I'm building it out of some waste concrete from the garden (a demolished concrete wall made of breeze blocks, plus some concrete steps) and some rockery stones that I got from freecycle. Total cost = £0 (so long as you forget about the mortar and cement...). I'm using a 2:2:1 sharp sand:builders sand:cement for mortar, as I want a stiffer mortar that will be strong. The rockery stone will only go around the front, since only the front will be visible when it's finished. I'm planning to have some concrete blocks in the middle of the circle to support the oven hearth slab - the walls I'm bodging together here won't be very strong, and I don't want to have to rely on them for structural integrity. I'll start adding these tomorrow.
This is slow work, and it's fiddly trying to get stones to fit in gaps. I'll probably fill the spare space in the base with rubble and subsoil from elsewhere in the garden. I'm saving doubly here - to get rid of all this concrete and subsoil I'd need to hire a skip, and the cheapest you can get a decent sized one for round here is £130!

Friday, 24 August 2007

The foundations

The slab was poured using 5:1 ballast:cement in a 6"x1" wood frame, and was originally sized to take a arched style brick oven as detailed in Alan Scott's book (see the links). Then I realised how much the firebricks would cost me - they seem really expensive in the UK compared with US prices. So plans changed... I'm now planning on building a round, domed oven and haven't decided on whether I'll build a firebrick or a earth/clay dome (adobe/cob). This will probably depend on whether I can get any cheap firebricks before I need to start building the dome.
Here's the slab, all marked out ready to go. I'm only building within the big circle, so my maximum diameter will be 1550 mm. Hope that's enough space - we'll see.

Thursday, 23 August 2007

In the beginning...

So here's where it starts. We'd already decided to have a covered area at the back corner of our garden. Summer round here usually only means that the rain is a little warmer than normal, and I'm sick of having barbeques rained off. I want to be able to cook under cover, and the idea of a wood fired oven was born.
The picture here shows the site, taken in May 2005. My plan is to have half the oven enclosed in the summer house, which will be set at a 45 degree angle in this corner. The bit behind the fence has my polytunnel and veggie garden - must remember to get a decent spark arrester for the chimney to save melting holes in the plastic... The plants up the fence are siberian kiwis - they've already started to cover that ugly fence pretty quickly.