Pizza Oven Build – Plinth

Hello again.  So now that I have managed to have a level base I need to crack on with the rest of the plinth.  This for me was another first as I have never really done any brick laying or mortar mixing.  Again I will be relying on my nice level base to help compensate for how my brick laying may turn out.  Turns out if you follow the instructions and keep your patience the large blocks aren’t too bad to lay.

I used large blocks for two reasons:

  1. The blocks are big and strong, if they can support my house and roof then a pizza oven will be fine
  2. The blocks are big so less chance of having wonky brick laying…(less brick laying in general)

Plinth Build – Calculations for ordering all the bits

After doing some simple maths and knowing that the Celcon blocks were 440x215x100mm I realised that some plinth walls with 4 layers of blocks would be ~900mm tall and I wanted my plinth (pizza oven base) to be about 1000mm off the ground.  A few more calculations showed me that 2.5 blocks would give me a wall length of 1100mm.

I decided that there was no benefit to doing tricky corners so planned to do three straight strips of bricks.  ( I really wasn’t looking forward to laying bricks)  In order to add some sort of support and back to the pizza oven plinth I also put a tower of four blocks in between the three mini walls.  I would leave gaps to allow air flow and drainage as I plan to put wood in the spaces and don’t want water pooling under the pizza oven plinth.

The main plinth which would be placed on top of the Celcon blocks would be constructed of my favourite Council pavers. Two 600x600mm and two 600x750mm.  The larger ones would give a little over hang on the front of the plinth.

NOTE:– These concrete slabs are known as “Council Pavers” in the UK as they are used by the local authorities to lay their pavements, they are very thick at 50mm and large at 600mmx750m.  ~53kg each.  Please be careful!  Two persons to lift.

Tools Required:

  • Shovel
  • Builders pad (to mix mortar on)
  • Builders level
  • Trowel
  • Large carpenter saw (To cut Celcon Blocks)
  • Rubber mallet

Materials:

  • 40 Celcon Blocks 440x215x100mm (2 Spares)
  • 5 Bags of 25kg pre-mixed dry morter (just add water)
  • 2x 600x600x50mm Council Pavers
  • 2x 750x600x50mm Council Pavers
  • Water (via a hose-pipe)

1st Layer of blocks

The brilliant thing about using Celcon blocks is that you can cut them effortlessly in half with a cheap carpenters saw.  I was quite surprised that within 4 strokes you cut through 215mm of block.  I double checked the compressive strength and the blocks are strong but seemed to easy with my new saw.

So each layer of blocks would be 2.5 blocks long.  I cut the half blocks and would move the half block to different positions depending on the layers so that you get good brick overlap.  Here is the first layer

1st layer done…nice and true

2nd Layer of Blocks

Much to my amazement if you follow the instructions on the mortar bags (add water to suit) are very accurate.  Thankfully if you get it too wet you add a bit more mortar, if it’s too dry keep adding water.  One thing that did catch me out is how little water is needed.  However, you quickly realise what is good or bad.  I found 2/3rds of a bag did a layer of blocks.

So after waiting a day I had a go at layer number two.  As I am creating 3 seperate walls I decided that waiting a day for a layer to “go off” was better for structure and my patience.  The weight of the blocks does squeeze the mortar, so if you try and do two layers you have to be quite consistant.  I was determined to keep my level of the plinth as much as possible.

2nd layer of blocks was laid with the half block shifted relative to the previous layers half block.  Remember to be generous with mortar and then tap down with the trowel to get your level.

2nd layer completed, nice and Level

As you can see I am putting a column of blocks inbetween each pair of walls.  The sideways shots look a bit lik an optical illusion but the three wall are not linked in anyway.

NOTE: At all times I checked each wall was level.  I did check the leves between walls and this remained equal as each layer was always made from the same mortar mix.  Therefore no risk of different mortar thicknesses in a layer

2nd Layer completed, slow and steady

3rd and 4th Layer

The third layer was done in the morning and the 4th layer was done in the afternoon.  I decided to push on a bit with the third and fourth layer due to the success of layers one and two.  Now it was successful but will admit I did try to lay one layer on top of the next and my level started to go.  So I removed the premature 4th level.  I’m sure a pro-bricky would have no problems but all my tapping of the fourth layer push out mortar from the 3rd layer…so I started again.

So 3rd layer was relaid and level checked.  Then 5 hours later I added the fourth layer and it all seemed much more substantial, straight and (you guessed it) level!

TIP: Use brand new bags of pre-mix mortar (or any cement product) as once you open a bag the cement starts to degrade.  Using fresh bags meant I knew that all the strengthening reactions would take place to stick and hold my walls.

4th Layer complete and nice and straight
4th Layer done, brick laying complete

Placing the Plinth on the Blocks

I waited another 24 hours to allow the blocks and mortar to dry and develop some strength before lifting the large concrete pavers into position.

I mixed up a large batch of mortar to place on the top of the blocks and layered it entirely over the blocks.  I did this so that I would tap the concrete pavers into place.  I say tap…but it was pretty aggressive with the rubber mallet if I am honest.

NOTE: Concrete Pavers very heavy, two man lift

Placing the Concrete pavers on the mortar is really quite tricky, you should not attempt this on your own  so that you place it down on the mortar Level.  Once you you get the first paver level, get the second.  I did the rear left corner first and then did the right rear corner.  The second stone I levelled to the first stone.  The 3rd and 4th stones were levelled and levelled to all the other stones.

I know that I have been really keen on the level of the plinth and this is purely due to knowing that the pizza oven dome will be a structure that supports itself.  Therefore having a level base will prevent one side being higher than the other and upsetting the structure.

I wasn’t happy with the front two stones as they dropped too low and therefore I removed them and added additional mortar and replaced the stones.  It took some serious smacking of the rubber mallet to achieve the level but I am very please with the finished plinth.  (and not having to use concrete)

Plinth Done, large stones at front for little bit of extra space
Plinth finished, play snooker on that

So I have a plinth, it is 1200 x1450mm and there is space underneath to store wood.  Did I mention that it was level 🙂  I also have no fear putting 750kg of pizza oven on it.

Next phase is starting to build the oven…

Pizza Oven Build – The Base

So I’ve built a pizza oven, from scratch and thought I would share it with you.  I don’t really know why other than a whim and lifelong desire to eat delicious pizza.  Living in the UK and only occassionally experiencing good pizza I thought I’d sort the problem so that if in doubt I’d just make my own.  This is the first blog of a few showing the build.

If you want hopefully you could construct your own from this.  This is a very substantial build and so far hasn’t blown away….as it weighs nearly 1 metric tonne!

The Pizza Oven Base

To me the key to any build, including a pizza oven, is making sure its all level.  As a pizza oven is basically a pile of bricks resting on one another you want the plinth to be level.  I got a little bit anal about this as I tend to but suffice to say my plinth is possible “too” level but my theory is “whatever you begin with affects what you end up with”.

NOTE:– This took a 3 hours as you have to take up the stone, put it back down and level and level.  It’s a pain but it means the rest of the build doesn’t have to compensate for lack of a level base!

I chose to use 600mmx600mmx50mm pavers to make it the simplest way to a level base without having to pour concrete.  You could do this, but I thought this was simpler and less messy and you can control the level.  It’s also quite cheap and far easier than levelling lots of smaller stones.  Also these stones will take more weight than a pizza oven so no worries there.

NOTE:– These concrete slabs are known as “Council Pavers” in the UK as they are used by the local authorities to lay their pavements, they are very thick at 50mm and large at 600mmx600m.  ~42kg each.  Please be careful!  Two persons to lift.

Tools Required:

  • Spade
  • Builders Level
  • Rubber Mallet (I wore it out just doing this)

Dig a hole

First you must dig your hole and in theory this needs to be as big as the base you need.  I was going for a 1.2m x 1.2m square plinth, based on wanting an oven with an 80-90cm diameter.

Digging the hole for the Base and leveling…sort of

Try to get as level as possible with the soil stamp it down hard.  Then I used a thick layer of sand to give OK drainage and also allow a bit more levelling.  I used two bags of sand which is 50kg of sharp sand.  (see next pic)

Laying first stone – (Stones are 600mm x 600mm Concrete pavers 50mm thickness)

 

Two stones done…looks so easy in the pictures

Compact the sand as much as possible and throw the first stone down in the top left corner.  Get this stone perfectly level using a masons level as your guide.  I lifted the stone many times and moved the sand a little.  Then when it was close to level I used very deliberate hits of a rubber hammer to get the bubble absolutely perfect between the black lines on the level.

2nd stone needs to set down at exactly the same height as the first stone and then lots of rubber mallet hammering to level   This one is a bit trickier as the stone has to be level and it also has to be level to the previous stone.

3rd and 4th Stones

4 hours work…its more level than a billiard table

So in keeping with the theme, the leveling of the 3rd and 4th stones involves placing it down, checking it’s height relative to the first and second stones and then shifting sand and lots of hammering of rubber mallet to get level.

Repeat again for the fourth stone…!  Don’t be surprised if you have to pick up the stones and move sand around.

Tip:- If it looks like its going to be down in a corner, don’t try to keep hitting mallet, face facts and lift stone and redistribute the sand.

Level Base

I know you’re thinking it might seem excessive to get it this level and it probably is but I never had to worry about anything being level after this.  As you are stacking bricks later, level is good!

Level Base
Checked a few days later after heavy rain and still level

Ok so Plinth is done.  Have a break, have a beer and I’ll build the plinth in the next post