can you use different bricks in a dome oven?

[Bandit]

I am a newbie to the forum and I'm about to start building a small 34inch dome wood fired oven.
I've built the base for the oven (railway sleepers and concrete blocks)

I have managed to get 141 firebricks with 40% alumina content from ebay
Unfortunately the bricks are thinner than the bricks everyone else seems to use (25 mm 230x114 mm) and I only have 141 bricks - not enough to build the dome and base. I was thinking of buying cheaper non refractory bricks to save on costs and to mix these with the higher quality firebricks.
is this a bad idea ?

Would appreciate advice on
1) can I use ordinary bricks with refractory bricks for the dome- or will they expand differently in heat and lead to problems?
2) if I do this - should I use the firebricks on bottom rows of the dome or at the top of the dome?
3) any advice of which type ordinary brick would be better e.g are the harder engineering ones better?
4) is 25mm firebrick (set in concrete/sand/refractory mortar) thick enough for floor of oven?

Thank you for help and advice and all this amazing content on this forum.

[UtahBeehiver]

Q 1,2,3 - Are you in the US since the brick dimensions you mentioned were in mm. The thickness are what are called splits (1" thick) so in reality you only have 70 standard size bricks. It is not advisable to mix non refractory and refractory bricks in the floor or the dome. I have seen a couple builds where the used non refractory bricks in the vent chamber but never heard any feedback and they can be used in the outer arch.

Q 4 The splits can be used in the floor one of two ways, Double up the layers giving you a min 2" thick floor or lay on side giving you 4" thick floor. 2" is min.

[Bandit]

I'm in the UK
Thank you for the advice
I think I will use the firebricks for the floor and outside arch and use engineering bricks for the rest of the dome.

I couldn't see any long term feedback on domes built with standard bricks - any thought on longevity ?
Do I need a bigger insulation layer if I use standard bricks vs refractive ?

[Toomulla]

I believe that almost any clay brick usd in an oven will outlast the builder, maybe a bit of spalling but an oven is not a house and the implications of a failure after years of service would have little impact other then letting you build another

[UtahBeehiver]

Bookemdaniel built an oven with common solid red bricks prevalent in the UK. He has not been active on the forum for quite some time but you can look at his thread. You mentioned "engineered" bricks for the dome, I recall that these type of bricks are for strength and low water porosity and are a fire clay brick but it does not mean an engineered brick is a refractory brick able to withstand thermal cycles of a WFO.

K values (thermal conductivity) of different type of bricks are as follows:

Dense brick 1.31, Refractory Brick 0.47, Insulating brick 0.15. These numbers show that refractory brick is 2,8 times better at NOT letting BTUs move through the brick than dense brick, FYI. Take it for what it is worth.