gas stove chimny for rocket stove mass heater

First of sorry if it has been esked before, I'm new to the forum and jumping a bit in the deep end.

I have an excisting urban home in a row, the floor is a concreet foundation slab directly on suporting sand ground with no crawl space and the chimney is made for a gas heater, it has no internal pipes just a brick chimney with 2 open pipes at the roof and one pipe in the living room.

because the concrete slab is also supporting the walls between the houses and outside walls I'm fairly sure it can support a termal mass but what i am not sure about it if the chimney can be used without modification.

Greets Andre

hey Andre
what is the ID of the chimney?

if it is 4 inch you will need some help and may need to modify the pipe. the OD on some 4 inch is 6 inch so you can convert the chimney easy.

but if it is 6 inch or larger you will be fine.
yes the cement foundation will do fine for support you will want to probably lift the burn unit off the floor a bit unless you are going to heat next door as well. the cement will conduct heat so unless there is a thermal break you will be inadvertently heating both houses.

Good questions that i dont think have been asked before. thank you and welcome to permies.
you can use the search function to find info in this forum and i would encourage you to search so folks can answer those questions that are not covered already.

thank you ernie,

the id of the feedpipe is 6 inch but inside the brick chimney itself there is no pipe at all, just bricks so there is a lot more cross section there.
offcourse with it being brick there is a higher risk of chimney fires.

Didn't think of the termal conduction to the next house trough the floor, just the wall.

still have some researching to do but with the huge amount of info on youtube and here I'm sure to figure things out.

greets André

The stove produces steam and CO2; almost no soot and no creosote. when you build it well and to plan you should be getting about 2 min of smoke. the exhaust is CO2 and steam so there is no real chance of fire in the chimney. 6 inch ID would let you build a 6 inch system pretty easy. how big is your house? a 6 inch will heat about 900 sq feet depending on the configuration. an 8 inch can heat around 2000 sq feet depending on configuration. there are different ways to make the heater more effective.

let folks here know what all your house configuration is so you can get the help you need.

size would be usefull true, living room is roughly 55 sqm with another 30 sqm for the hallway and kitchen, the seccond floor has the bedrooms and bathroom, the attick is mostly unheated and unisolated.

I plan to only heat the living room with the RMH and keep the rest heated by the central heater, it would just be a matter of moving my thermostat to the master bedroom and closing the living room radiators.

so that would be no problem for a 6 inch system I guess.