Pizza oven flue

[aidy55]

I have ordered a twin wall flue kit for my brick pizza oven, it must go through a polycarbonate roof. 

 

Flue pipes advised the products i needed but im unsure where the roof support fits, if it goes on top then where does the flashing kit fit and if its underneath then where does the finishing plate fit. 

 

https://www.flue-pipes.com/roof-support-125-10494.html

 

Can anyone help with exact installations ive a competant plumber friend but its actually not his line of work. No one in the area have been much help

 

[ProDave]

I don't think they understand your roof.

 

What they have supplied sounds like what we used.  The flashing goes on the top (in our case for tiles)  In the roof cavity the support bracket and then on the inside (plasterboard in our case) the internal trim.

 

You don't have that inner layer so the support could go between the rafters but it would look ugly.

 

What flashing have they provided for the polycarb roof?

 

[saveasteading]

I wouldn't want it through polycarbonate.  I appreciate it's an outbuilding but it's still odd. Can you contrive a local area of some more solid material?

[aidy55]

I understand exactly what you mean. To be honest i think it will work fine without the support bracket. 

 

Funny enough, they forgot to send the flashing kit. Ive just sent them an email about this, this is the one they advised and pretty sure it's exactly what I need 

 

https://www.flue-pipes.com/roof-flashing-45-red.html

[saveasteading]

I'm not going into the link because it wants cookies.

But a 'red' flashing is correct for a hot flue. Normally this is screwed and sealed to metal.

How to fix it to polycarbonate? That's what bothers me.

otoh if it fails by letting in rain or cracking, does it matter much?

[aidy55]

My fitter actually mentioned this yesterday, he doesn't want to screw it down, he just wants to get a tight fit for the flashing and then silicone it. 

 

Maybe thats the best course of action. 

[saveasteading]

1 hour ago, aidy55 said:

doesn't want to screw it down, he just wants to get a tight fit 

There are screws with expanding rubber tubes that will grip when tightened. Might still stress the sheeting but less likely to break it. 

[aidy55]

Plumber/fitter thinks tec7 would be a good choice for the flashing kit. 

 

This job is not something he has experience with, strugging to find someone in my area

 

But i think it should be ok, we are going to put two bridgers then the roof support bracket inside the close off with the finishing plate. 

 

So only time we will go through the polycarbonate is the 200mm hole for the twin wall flue

[saveasteading]

found it. 

Rawlplug M8 x 50 Rawlnut, Flexi-plug Rawl P/No. 09-533 RNT-M8/50 SCREWS NOT INCLUDED

 

£1 each... go on spend £5

 

Or a big bag at screwfix. Suddenly it doesn't seem so exotic and wise.   Rawlplug Rawlnut Flexiplug Lightweight Fixings 10mm x 40mm 50 Pack (281VC)

 

Either these or put something solid on the underside, steel or ply, for the tek screws to bite.

[aidy55]

No issues spending a few quid on the screws but don't you think tec7 will hold it down and keep it watertight.