Suggestions needed to feed a rigid tube liner above the roof with a flat concrete top.

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yonny33

Member
Feb 9, 2021
120
Uruguay
Made good progress last 2 days. Hole cut in the top. Metal cross bars that were 1.8m from the top cut with my extension on the grinder. Just needs another sweep and we're ready for the liner etc.
 

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begreen

Mooderator
Staff member
Nov 18, 2005
90,646
South Puget Sound, WA
The liner will not be insulated. They don't have those here. Not even flexible liners unfortunately.
You absolutely want insulation on that liner. There is no clay liner in there. Insulation kits can be ordered online if not available locally. I would flash twice like bholler suggested. Use a flat plate with a liner clamp and storm collar on the actual chimney top. The insulation would stop right below it. Then a regular flashing or another top plate on the cement top would suffice.
 
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yonny33

Member
Feb 9, 2021
120
Uruguay
You absolutely want insulation on that liner. There is no clay liner in there. Insulation kits can be ordered online if not available locally. I would flash twice like bholler suggested. Use a flat plate with a liner clamp and storm collar on the actual chimney top. The insulation would stop right below it. Then a regular flashing or another top plate on the cement top would suffice.
Why would the liner need insulation inside the sealed chimney? They only insulate the liner that is exposed to the elements here. So would be the part protruding from the upper part below the concrete top and above.
Planning to put a plate below and above the concrete top.
Insulated liners as standard are not available here.
The installers would fit a sleeve on the exposed pipe fill with Lana roca followed by a reducer then the cowl.
 

yonny33

Member
Feb 9, 2021
120
Uruguay
btw - the flue is on the inside in the middle of the house sandwiched between the neighbors. The walls are not exterior walls.



Just to add unfortunately we have to make do with what we have available here in Uruguay. not a great deal of options are available to us due to the imports.

Coming from the UK I do get frustrated on occasions when parts you get easily are taken for granted then here it's impossible to find as they just don't import them.

Just importing items is a challenge. We can only import items up to 200 USD ONLY 3 times a year. Anything more than you are hit with huge taxes and fees. (60-100% plus a load of admin/custom fees).

Cars cannot be imported unless they are 25+ years old and labelled as historically important. That saddens me greatly as I am a car fanatic. Miss my Jag very much.
 
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GENECOP

Minister of Fire
Jan 31, 2014
734
Ny
What kind of cowl is used inside to prevent water ingress there?

We live on the coast and when the subtropical storms come in the torrential rain is often sideways. I can imagine if I had such large openings I'd have a cascade of water flowing in.

The stainless pipe actually rises up and ends about 6” from the underside of the concrete cap. I also installed SS mesh around all sides, I don’t really get much water ingress , but I’m not dealing with the kind of weather patterns that you are..
 
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yonny33

Member
Feb 9, 2021
120
Uruguay
The stainless pipe actually rises up and ends about 6” from the underside of the concrete cap. I also installed SS mesh around all sides, I don’t really get much water ingress , but I’m not dealing with the kind of weather patterns that you are..

I see. This was my first plan just to do what you've done but then reconsidered as the neighbors chimney exit is right next to ours (20cm) so to avoid any further cross-flow of smoke I've decided to extend it through the concrete top so they are at different heights.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
90,646
South Puget Sound, WA
Why would the liner need insulation inside the sealed chimney? They only insulate the liner that is exposed to the elements here. So would be the part protruding from the upper part below the concrete top and above.
Planning to put a plate below and above the concrete top.
Insulated liners as standard are not available here.
The installers would fit a sleeve on the exposed pipe fill with Lana roca followed by a reducer then the cowl.
Multiple reasons. The first is it is code here unless the chimney has a 1" gap from the house structure. The second reason is that without any clay liner there are less layers of protection between the very hot flue liner and the combustibles of the house. The third reason is that insulation will keep the flue gases hotter. This last reason really helps improve draft and by keeping the flue gases hotter it can really help keep creosote buildup down as long as dry wood is being burned.

In the kit you posted the link for, they are using lana roca (rockwool) for insulation which is not as good as insulating the liner itself.
I'm not sure what you would find in Uruguay. This may be the preferred method there.
 
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yonny33

Member
Feb 9, 2021
120
Uruguay
Multiple reasons. The first is it is code here unless the chimney has a 1" gap from the house structure. The second reason is that without any clay liner there are less layers of protection between the very hot flue liner and the combustibles of the house. The third reason is that insulation will keep the flue gases hotter. This last reason really helps improve draft and by keeping the flue gases hotter it can really help keep creosote buildup down as long as dry wood is being burned.

In the kit you posted the link for, they are using lana roca (rockwool) for insulation which is not as good as insulating the liner itself.
This is more like what we use.
Fully understand.
Ideally I'd like a flexible liner with insulation but just not possible.
It will have to be a single liner up to the top with the exposed 1 metre with the insulation.
It's not a code here and never heard the technicians talk about this.
Just a different way of doing things due to what's available.

Off topic but they don't even use torque wrenches at garages. I always retorque my wheel nuts after they have been removed as they always use an impact wrench.

Regards
 
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yonny33

Member
Feb 9, 2021
120
Uruguay
Multiple reasons. The first is it is code here unless the chimney has a 1" gap from the house structure. The second reason is that without any clay liner there are less layers of protection between the very hot flue liner and the combustibles of the house. The third reason is that insulation will keep the flue gases hotter. This last reason really helps improve draft and by keeping the flue gases hotter it can really help keep creosote buildup down as long as dry wood is being burned.

In the kit you posted the link for, they are using lana roca (rockwool) for insulation which is not as good as insulating the liner itself.
I'm not sure what you would find in Uruguay. This may be the preferred method there.


Interesting read about liners with or without insulation:

 

yonny33

Member
Feb 9, 2021
120
Uruguay
Made good progress today. Hours of work installing the lower flashing and upper sleeve and cowl. Lots of cement work.
Will seal the joins tomorrow.
Then wait for the next heavy rains to test its water tightness before installing the liner, fireplace hearth etc and stove.
 

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begreen

Mooderator
Staff member
Nov 18, 2005
90,646
South Puget Sound, WA
No storm collars?

strom collar.jpg
 

begreen

Mooderator
Staff member
Nov 18, 2005
90,646
South Puget Sound, WA
No such thing here.

I'll be adding some membrane lining around the join.
It would be easy for a metal shop to fabricate this. The part is not complicated. It will improve weather sealing. The problem with the current method is that the pipe will move as it expands and contracts with heating and cooling. That will break the seal around the pipe. The storm collar is attached to the pipe with silicone so it moves with the pipe.
 

yonny33

Member
Feb 9, 2021
120
Uruguay
It would be easy for a metal shop to fabricate this. The part is not complicated. It will improve weather sealing. The problem with the current method is that the pipe will move as it expands and contracts with heating and cooling. That will break the seal around the pipe. The storm collar is attached to the pipe with silicone so it moves with the pipe.

Once I have finished installing the inner liner to the stove I'll be lining the outer join (where it meets the concrete) with a bitumen auto adhesive tape we commonly use here for roofing. Flexible, thick and lasts about 10 years at least. This is the outer liner so won't be exposed to high temperatures (only the sun).

Currently, now it has a flexible liquid membrane applied by brush (easy to remove if I need to adjust the wide sleeve). This stuff fills in gaps and waterproofs them also being flexible will not crack.
 

yonny33

Member
Feb 9, 2021
120
Uruguay
Taking all the advice kindly I think I will try and wrap the single tubes and pull them up from below.

What kind of insulation should I wrap them with?

Thanks
 

yonny33

Member
Feb 9, 2021
120
Uruguay
Also, should I be drilling and joining these rigid tubes with a couple of screws on each section? I can't imagine pushing up 6 metres of the wobbly liner without them being somehow joined properly rather than just push fitted together. I've read somewhere that no holes should be made but then I've seen videos of installers drilling them and dropping them from above down. I am confused.

Regarding the insulation, we have rock wool and fibre glass insulation available here.
I hear rock wool is more suitable. Wrap and tie with steel wire on each section before fitting?

Thanks
 

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gthomas785

Minister of Fire
Feb 8, 2020
530
Central MA
Rock wool. It is fireproof and suitable for the high temperatures of the liner. Fiberglass would catch fire and burn your house down.
 

yonny33

Member
Feb 9, 2021
120
Uruguay
Rock wool. It is fireproof and suitable for the high temperatures of the liner. Fiberglass would catch fire and burn your house down.
Thanks a lot!
Thought so, fiber glass has a much lower temp rating I read.

Now just to the liner installing dilemma. I imagine screwing each join together will make a more secure structure.
Please let me know if perforating the joins with small screws is a bad idea.
 

gthomas785

Minister of Fire
Feb 8, 2020
530
Central MA
If you use stainless screws made for sheet metal I don't think it would be a problem. Usually around here, rigid liner sections are held together with pop rivets. However the connector pipe is commonly held together with short screws and it doesn't cause any issues
 
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yonny33

Member
Feb 9, 2021
120
Uruguay
If you use stainless screws made for sheet metal I don't think it would be a problem. Usually around here, rigid liner sections are held together with pop rivets. However the connector pipe is commonly held together with short screws and it doesn't cause any issues
Great that's what I wanted to hear thanks.

Thought about using screws over rivets just to save having to buy a rivet gun but could be an option I might consider. You can never have enough tools! :)

Rivets I imagine will leave a cleaner flusher finish on the inside for sweeping.
 

gthomas785

Minister of Fire
Feb 8, 2020
530
Central MA
Yes, in my opinion that is the main downside to using screws. If you go that route, try to find some screws that are just long enough to hold the pieces together and don't protrude too far into the pipe.
 
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yonny33

Member
Feb 9, 2021
120
Uruguay
Yes, in my opinion that is the main downside to using screws. If you go that route, try to find some screws that are just long enough to hold the pieces together and don't protrude too far into the pipe.

These rivet guns are cheap.

Would this one be suitable? Sorry it's in Spanish

 

gthomas785

Minister of Fire
Feb 8, 2020
530
Central MA
That looks like the right tool. Make sure you get stainless rivets. aluminum ones will melt and leave you with a real mess.
 
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