Most concrete patios are 4" thick. And most likely, the concrete used to pour your patio slab was 2000-3000 psi. That would be an 8000-12000psi rating for a 3000lb wood-fired oven. We aren’t going to say yes or no… but it’s your call.
But if you do go ahead an build on an existing concrete patio…
Verify the actual thickness of the slab by digging down along the side of the slab. It needs to be close to 4" or more.
Drill a 3/4" hole into the existing concrete where the CENTER of each CORNER CINDERBLOCK will be when placed into position.
Drive an 18" or 24" piece of rebar or metal spike / metal stake through the holes and into the ground so just 2"-3" is sticking out of the TOP of the first layer of cinderblock.
Attach a 4" or 5" piece of rebar to the top of the spike.
Fill the cores or each corner cinderblock as you work upwards / adding cinderblock rows.
Existing Paver Patio -
As former contractors, we’ve seen well-built patios that could hold an elephant… and we’ve seen paver patios that would warp after the first rain. It really depends on the quality of the installation of the paver patio and how the sub-base was prepared.
Additionally, pavers are generally 2 1/2"H - Not the 4" concrete minimum we ask for.
Personally, having installed numerous paver projects, I WOULD NOT RECOMMEND building your oven on top of an existing paver patio. No sir!
Simply remove the pavers where you want your oven located, pour a proper 5.5" concrete base slab with rebar and then cover the base slab with the pavers you removed after you’ve built your oven base (if you chose to go that route).
Is the minimum thickness of an existing concrete patio any different for the Brickwood Box than for the Pizza Ovens? My existing concrete patio is 4 1/2" thick and I would like to use it as the base for the Brickwood Box, but I do want to make sure that the support at the base is sufficient without pushing any limits.
I have a 5 inch base and will be building my barrel oven (of course with a block foundation) on top of it. I see no issue with this. I live in Ohio, the weather is starting to break enough to where I can finally start. I am not worried about weight being an issue. I am more worried about the insulating mass then anything. I have a couple on masons that have never constructed one before so that is my concern. My contractor is leaving it up to me and the masons. My concern is getting it right the first time. Hopefully I can start soon. I have a very good general idea. I feel the weight will be more then adequate distributed to support the oven.
I checked in on this before I built my oven. A regular concrete patio typically 4 to 5 inches thick can support 8000 pounds. Plenty of support for you oven. But here is the thing. Everything moves and settles. Especially in climates that have all four seasons. Building on top of an existing patio risks future structural damage. Do you want to make that kind of investment and have it fall apart.
Follow brickwood instructions with also local code guidelines. It’s fool proof and yes literally indestructible.
I tore up my existing patio. Put in four 10 inch pilings 52 inches deep(10 inches below frost line) with a 6 inch pad. Rebar is connected from the pilings to the top insulated pad the oven sits on. Over kill yes but I know my investment is soild and will last way past me.