Flue Clearance from roof

[willt1984]

Hi All.

So I'm currently planning where to place a new combi-boiler. I want to make sure the location is ok before getting the gas man out.
I'm planning on putting it in the kitchen (moving it out of the small bedroom).
I'm reading the Worcester installation manual, and wondered if anyone could clarify something for me.
It states that the flue should not be closer than 300mm from the roof of an adjoining extension.
Where I wish to place the boiler, there is a small outside building with a toilet and store in it. This joins to the house with lead flashing. Where is the 300mm take from, is it the top of the extensions' tiles, or the start of the flashing?
I ask this as I'm a bit cramped for room, and the tiles start about 50mm below the start of the flashing.
If anyone could help it would be massively helpful, I can add a picture tonight if it would clarify anything.
(Dont worry, I'm not going to do the gas work)

Thanks
Will

[Edit]

I went home last night and took some pictures of the work to explain further.

So, the horizontal line at the top represents the internal ceiling height.
The vertical line next to the tape measure represents 300mm from the door opening.
The top angled line represents 300mm from the end of the 'rendered' wall.
The lower angled line represents 300mm from the top of the tiles on the adjoining building.

So my basic question could be summed up as: where should I take the 300mm from the adjoining buildings roof?

I can squeeze it between the top lines, however, I would like to pass a couple of pipes above it, and I don't want to put it too close to the door.

Any help will be really appreciated.

 

[muggles]

You're going to need to provide some pictures here...and you can do much better than a Woofter

 

[willt1984]

Ok, I'll get some pictures up when I get back from work.
[EDIT] - Done, see earlier post

 

[RTFB]

Bear in mind that an 'opening' means the opening part of a window or door, not fixed glass. Take advice from your Installer, who must know these things.

 

[denso13]

Measure from the tiles.

 

[Agile]

Bear in mind that an 'opening' means the opening part of a window or door, not fixed glass. Take advice from your Installer, who must know these things.

I was taught that it is from the brickwork reveal "because Anglian Windows may replace with different openers".

 

[gasmanstu72]

if that window doesn't open then you only need to be 150mm away from it, if it does then you need to be 300mm away, as mentioned above you take the measurement from where the opening actually is not the end of the brick work, so you might be able to squeeze in an extra 50mm or so.
you can fit a plume management kit which then allows you to go as close as 150mm to the opening (same criteria as above) but the terminal of the plume kit must be 300mm away, if you do that you might find it then comes close to some other obstruction (eaves, down pipe etc.) then you have to consider that too, from memory the minimum distance a worcester plume kit can be cut to is 550mm and the max is 3m.

you need 300mm from the tiles to the bottom of the flue (this is to stop snow building up on the roof and blocking the flue) and that would be the same for any boiler.

most regulations on flue terminals are standard when it comes to openings and surfaces below the flue, they will differ from different manufactures when it comes to internal / external corners and down pipes etc.
you'll have to bear in mind the clearances above the flue inside too, i think 150mm is whats needed above the flue turret for a 100mm flue.

have a look online for the manufactures instructions on terminal positions, but ultimately get your installer to check it out

 

[gasmanstu72]

you could also extend the flue internally too,
for example a 90 bend on top of the boiler pointing left or right, then a short extension, then another 90 pointing out through the wall, doesn't look pretty but it might help