Flue inside lean-to with a difference

[DJK53]

I know this has been asked, and answered, a few times but this is slightly different.

We want to install a lean-to at the side of the house, which is where the boiler flue (an Ideal Logic Heat H24) exits.

I know that there is a flue kit than can be fitted to raise the external outlet, however is it safe to pass this through the polycarbonate roof, so the boiler vents to the open air.

The reason is that the lean-to will go close to the fence along its long side and there are 6ft gates at either end. Although there will be an air gap on all three sides they will not really be fully open to the air (see photographs).

I was planning to have a weather collar fitted where the flue passes through the roof. The question is will the flue be too hot at this point and if so can I replace a short section of the polycarbonate with Fireboard for the flue, still using a weather collar.

Am I over thinking this?

 

[denso13]

To be honest you'd be better getting the views of a local Gas Safe person, they'll need to do the flue alterations if required.

The manufacturer's instruction should show the clearances required.