[fclauson]

Any thoughts on which is best

• Air in via underground duct to back of stove
• Air down "double" chimney stack using proprietory system

Given the choice which would people choose

You advice and thoughts please (need to decied in about 2 weeks)

[BryanF]

underground duct imo

but pm the details of the other option, the only system I've seen using the chimney stack seemed overkill

[Do-more]

+1 on the underground duct.

I'm running the duct under the insulation and then coming up immediately behind the proposed stove location which is near the centre of the slab where heat losses to the ground should be at a minimum so minimising the cold bridge.

I'm only putting it in as an insurance policy for the future as at this stage I don't intend to fit a stove. I will fill it as best I can with loose bead insulation and cap both ends.

[sas]

Originally Posted by fclauson

Any thoughts on which is best

• Air in via underground duct to back of stove
• Air down "double" chimney stack using proprietory system

Given the choice which would people choose

You advice and thoughts please (need to decied in about 2 weeks)

Whichever option you go for, it would be good to pick your stove now because the sizing of the air supply duct does vary somewhat stove to stove.

Granted, a standard 4 inch sewer pipe is what most use. It's what I used.

The specific stove may rule out the system chimney.

[BarneyMc]

If going with the underground duct then is it just a standard chimney to use?

[Do-more]

Originally Posted by Do-more

I'm running the duct under the insulation and then coming up immediately behind the proposed stove location which is near the centre of the slab where heat losses to the ground should be at a minimum so minimising the cold bridge.

Just to correct that, the duct is not completely under the insulation as that would pose a condensation risk. I have 3x100mm of insulation under the slab and the duct will run in the middle layer of the insulation.

[fclauson]

Originally Posted by Do-more

Just to correct that, the duct is not completely under the insulation as that would pose a condensation risk. I have 3x100mm of insulation under the slab and the duct will run in the middle layer of the insulation.

You raise an interest point there on all ducts

How do you make the above work at the rising wall

Where does your radon barrier fit in relation to your duct & insulation

Currently all my ducts are coming at the base of the rising walls into the build and up through the radon

[Do-more]

Originally Posted by fclauson

You raise an interest point there on all ducts

How do you make the above work at the rising wall

Where does your radon barrier fit in relation to your duct & insulation

Currently all my ducts are coming at the base of the rising walls into the build and up through the radon

I don't know how this works at the ring beam, I will quiz the ground workers on site later. I know the duct will end with a vent cover on the vertical face of the insulated slab, I will put a fine mesh on it to stop ants.

They did mention that they use a special sealant around all pipes and ducts coming up through the insulated slab for radon protection.