I'm thinking of putting a canopy over our back door, and possibly building a covered walkway between the house and our garage, the walls of which run parallel and about 3 feet apart. However there's a problem in so far that the central heating boiler chimney exits alongside the back door, and this would end up with the chimney venting into the canopy/walkway. Obviously I'm not going to do that!
There's also an extractor hood vent the far side of the back door, but I'm more comfortable with extending that if I need to.
Here's a couple of pictures of our back door with the chimney clearly seen to the left:
The CH boiler is a Potterton PrimaF if that makes any difference.
Advice would be welcome. Does this require a gas fitter to do the job to ensure it is done right, or is it in the realms of general DIY?
PoP