Flue through the roof ridge

[twobecks]

Hi all,

I am at a critical stage of my build where I need some assistance.

The oven dome has been bricked in, and a ridged roof constructed. The 5" single wall flue from the dome will be extended out through the ridge of the roof (see attachment), but I am struggling to find a decent solution which will provide a water tight seal around the flue and also provide thermal stability. The roof will be tiled, and ridge tiles fitted, so I don't want any mortar getting blown due to thermal expansion.

I'm sure it can be done using something like this:
www.obrienleadfab.co.uk/lead-ridge-slates.php

But I don't want to use a cheap looking rubber boot for a seal, there must be a more elegant way of doing this.

I've even considered twin wall flues, but the joining piece between the existing single walled flue and the double walled flue connects to the outer wall, which will conduct heat and render this solution useless.

www.directflues.co.uk/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=390&category_id=31&option=com_virtuemart&Itemid=7

Any ideas - I'm pulling my hair out?!?!??!

Cheers,

Steve

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[800degreedan]

Aug 22, 2012 12:52:44 GMT twobecks said:

Hi all,

I am at a critical stage of my build where I need some assistance.

The oven dome has been bricked in, and a ridged roof constructed. The 5" single wall flue from the dome will be extended out through the ridge of the roof (see attachment), but I am struggling to find a decent solution which will provide a water tight seal around the flue and also provide thermal stability. The roof will be tiled, and ridge tiles fitted, so I don't want any mortar getting blown due to thermal expansion.

I'm sure it can be done using something like this:
www.obrienleadfab.co.uk/lead-ridge-slates.php

But I don't want to use a cheap looking rubber boot for a seal, there must be a more elegant way of doing this.

I've even considered twin wall flues, but the joining piece between the existing single walled flue and the double walled flue connects to the outer wall, which will conduct heat and render this solution useless.

www.directflues.co.uk/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=390&category_id=31&option=com_virtuemart&Itemid=7

Any ideas - I'm pulling my hair out?!?!??!

Cheers,

Steve

Hi steve - we both have a similar problem, mine is pushing a flue through a wooden roof making sure it wont catch fire and leak.
( see my posts ) thres a lot of good help here so im sure youll find the right solution. I can tell you lead might not be the best idea as it dosnet have a high temperture rating. twin wall selkirk would work but you clearly have a connection issue. as far as a heatproof and watertigh solution, try high temerature sisicon flashings, a google will reveal a few suppliers.
personally im probably going for this solution, or similar, dependent upon the amount of heat leaving my chinmey flue top, which might work in varation for you
www.stovesonline.co.uk/wood_burning_stoves/Dektite-high-temperature-flashing.html
good luck
dan

[turkey]

if you just want to seal the lead you can get high heat silicone that is suitable for flue usage as far as I am aware, I am not an expert on any flue systems but I am sure I have seen reference to high heat silicone in use at the base of the flue right by the fire so I am sure it would work at the colder end

[cannyfradock]

Steve

I'm a bit ashamed to say that all my builds have been on a bit of a shoestring. I have adapted second hand double walled insulated stainless steel flue's .....with the help of an angle grinder....and a hammer to make them work.

The principle of a double walled flue is that the inside tube takes all the heat and the outside skin of the flue is not in direct contact with the heat of the oven. When bought new a flange is fitted to the vent outlet and the chimney sits on top of this, thus creating a barrier between between inner and out walls of the chimney.

Hope this is help to you.

Terry

[twobecks]

Hi guys,

Thanks for the responses. I think I'm going to use a bit of advice from each of you (Cheers Dan, Turkey & Terry!)

I'm going for some twin wall Selkirk, adapted to fit my single walled flue. This will protrude out through the ridge of the roof, and be finished with a fitted lead ridge slate:

www.obrienleadfab.co.uk/lead-ridge-slates.php

High temperate silicon can be used to join the outer wall of the Selkirk flue with the inner edge of the lead slate, thus creating a watertight seal. Any thermal expansion should be minimal, as Terry explained the outer wall of the flue "shouldn't" get too hot. I could finish the seal between the Selkirk and the lead with a storm collar or high temperature silicon collar to guarantee waterproofing.

Really appreciate the help!

Cheers,

Steve

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[turkey]

don't forget ebay, its great for random flue parts that are left over from people wood stove installs. Especially if you are flexible on brand and length to a point etc..

[conic]

why dont you build a brick chimney, and lead flash the roofline to this,

check out my wfo chimney, also recycled parts, its more fun getting the parts to fit together and save the landfill sites. I also got my firbricks free from an old foundry furnace which were dumped in a landfill site.

The chimney is solid and will never fail in a hundred years .

Conic

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[turkey]

lucky man, my firebricks where from an old demolished gas furnace but had to pay for mine as the lads there where smart enough to take them all home and sell them in batches.