Flue repair - quick/decent fixes for terracotta brick

[RickInNJ]

Hiya,

[I'm new to the forums but have been lurking for quite awhile.]

I'm about to buy a FPX Large Hybrid Fyre and am hopefully getting a new flex liner kit from Rockford Chimney Supply this weekend to get everything ready beforehand.

The last clay (teracota) section of the flue that sticks out of the chimney top is not looking great. The house was built nearly 60 years ago and it's original. [Please see pics.]

Questions:
1) Since I'm putting in a liner anyway now, can I just firm up the clay with some refractory cement (or something else)?
2) If no on 1), can I replace just the top piece of the clay flue with a section of a new section (from the cement chimney crest on up), and use refractory cement to bind it in?

The clay section measures 8" x 12" and I think I'm seeing where the big box stores (HD, Lowe's) sell them in 2 foot sections. I probably need the top 8-10 inch section replaced.

Many thanks in advance for any advice you can offer.

Rick

 

[Lake Girl]

There are some members that are certified sweeps but you may have to be patient ... otherwise, check here with your zip code to find a local sweep that can take a first hand look. http://www.csia.org/ Sweeps need to be NFPA certified.

It would be small money well spent if you do it right the first time

Welcome to the forum ...

 

[begreen]

Looks like it needs a replacement top tile liner and perhaps new crown. A mason or good sweep with mason skills should be able to fix it up.

 

[RickInNJ]

Thanks a lot for the reply, Lake Girl.

I'm really hoping to do this myself if possible, and am not sure that repairing the (fireplace only) clay flue is really needed given that it'll soon have a liner in it anyway.

The goal is to do something reasonable and/or cosmetic unless there's a good reason to do more.

 

[RickInNJ]

Begreen, can't I do that by myself?

I'm sure a mason would do a better job, but as long as it's sealed well (with refractory cement), esp. around the crown, it's hard to understand what I could do wrong.

I'm happy to add a chase too, if that'll help. Water seeping into the brick via the crown seems like the biggest risk here, from my current understanding.

 

[bholler]

I would just cut that liner down flush and install the stainless liner. But it looks like you need a new crown. Plants growing out of the top of the chimney are never a good sign

 

[Lake Girl]

Rick, bholler is one of those sweeps I referred to (see his signature line). Would do well to heed his advice. Ask questions...

 

[RickInNJ]

[Thanks Lake Girl!]

I would just cut that liner down flush and install the stainless liner. But it looks like you need a new crown. Plants growing out of the top of the chimney are never a good sign

bholler, thanks a bunch for the reply. Making it flush sounds good if meets code. The furnace flue clay is right next to the fireplace one and in better shape. I could make both clay flues flush or just one, but don't know what I'd attach the rain cap to if it's flush. I guess I could rework the cement and add a rain drip overhang, and then put a chase over it all, and attach the rain caps to the chase. Your recommendations would be most welcome.

My bad on the plant. "Fixed" the crown ~7 years ago with a combo of regular cement and bonding cement (when I ran out). Either I didn't go right up to the clay with the cement, or the cement pulled away when it cured. Is there something I can use to seal between the cement and the clay?

Two more issues if you could be so kind:
1) When I install the insert (in the current fireplace pit), I may have a space issue with a GreenStart add-on. Is it ok to take out an existing firebrick, cut it in half, and then re-mortar/tuck-point around it using refractory cement?
2) For tuck-pointing on the outside of the chimney, do you use a mix of Type N cement and sand or something else? [If so, what mix?]

 

[EG GREV NED MIN ELD]

I'm in the process of tuckpointing a crack 3 courses down on the outside of my chimney. I'm using type "s" mortar

My furnace flue terra cotta looks just like yours. Only the top tile though. I was thinking about cutting it out, cleaning it up and dropping a new one in to replace.
I would say give it a shot, worst case you have to hire someone to come fix your repair.
I'm no professional though, so you might not want to listen to me.

 

[chemical_man]

I would just cut that liner down flush and install the stainless liner. But it looks like you need a new crown. Plants growing out of the top of the chimney are never a good sign

My top clay is showing the same type of wear. The chimney is part of my oil-fired boiler system. How difficult is it to remove that top clay and replace it with another? The crown looks good, no cracks last time I was up there, so it is possible to replace without breaking it? How much would this service cost (say no full crown work) from a pro (I realize I'm in Canada, I can reasonably assume double it here...)?

 

[bholler]

I would say to any of you if your furnace liner looks like that you need a liner there also. The moisture from the furnace exhaust will tear the chimney apart if you don't take care of it.

 

[RickInNJ]

Hi BHoller,

The furnace clay liner looks fine in my case. Only the fireplace chimney liner looks like heck.

This weekend, I took some refractory cement, mixed in some terracotta color mix, and tried to patch it up. I'm not fully sure that it'll bind, but this is what it looks like. I'll never be confused with a real mason, but it seems pretty functional.

Next weekend, before I put the liner down the chimney, I'll put some refractory cement around the base of each clay liner where it connects to the white+gray cement chimney cap, to try to prevent growth of weeds, etc. I'll also put a light layer of new cement on the chimney cap so that it looks uniform.

Thanks for all your help. If you have any comments on the above, please let me know.

 

[kennyp2339]

I think that should work out, the liner will be taking the abuse, just get a nice cap for the top and you should be good to go.

 

[RickInNJ]

Many thanks to all for your help.

 

[jotul?]

I would just cut that liner down flush and install the stainless liner. But it looks like you need a new crown. Plants growing out of the top of the chimney are never a good sign

I'm not a sweep but I am a bricklayer. The repairs you are suggesting are temporary, and the repair you've already done with refractory cement is extremely temporary considering that refractory cement is not to be exposed to moisture. Get a proper cap repair and a new top liner put in and be done for 20 or 30 years.

 

[bholler]

The repairs you are suggesting are temporary

What repairs i am suggesting are temporary? I it needs a crown and then take the clay down flush and install the stainless with a top plate. that is easily a 30 year fix. It also may need some relaying or at least some re-pointing but cant see that from the pics. I agree what was done is not going to hold up for long but that was not what i suggested at all.

 

[jotul?]

100% my typo. The first sentence of my post should have read; Listen to bholler... my suggestion for repair was to the OP.

 

[bholler]

100% my typo. The first sentence of my post should have read; Listen to bholler... my suggestion for repair was to the OP.

ok good your post didn't make sense to me now it does

 

[Smoked]

Your liner install should include a top plate and rain cap. https://www.firesidechimneysupply.com/flexible-liner-components/top-kit.html
The top plate seals and supports the top of the liner and can be sealed to the top of the clay liner using hi-temp caulk so it does not need to be repaired above the crown. Dito on "listen to bholler", cut it flush after the crown is repaired. If the furnace flue is close, you may need to trim the top plate so it does not interfere with that, but the top plate should resolve your worries about that top clay liner segment once the crown is solid.

I need to work on my crown next time I get on the roof...

 

[RickInNJ]

Thanks again guys.

Code says that the chimney must be 3' above the junction with the roolf. I just need to measure that height a bit more precisely to make sure that I don't need the ~6 inches of terracotta tile to make it to 3'.

I've noticed some bad mortar on the roof side of the chimney when I was up there last weekend. Is there a strap or mini-scaffolding that I can use when working on my roof to attach myself to the chimney so that I don't have an accident?

Also, the (6") flex liner plus insulation is a bit over 7 inches, and I'm getting stuck when I am going down my 13" x 8" terracotta flue. It's ok to elongate the tube to make it fit better, yes?