Restoring my roof collar

[jetzi]

I have paid a stove guy to overhaul my Morso Squirrel ahead of the winter (replacing all the ropes between the panels, rope seals, glass, fire bricks, baffle plate, new collar on top of the stove, repaint).

There was a bit of a water leak into the cabin from the top of the flue which I am sorting out at the same time.

 

When removing the stove it became apparent that the flue has rusted through and also needs to be replaced. The top of the flue has broken off into my roof collar.

I removed the roof collar and chipped away the rusted flue which had kind of bonded to the inside of the collar through the rope. The inside looks like a bit of a disaster at this point now, though. It's very uneven and is full of hardened tar, old rope and rust that is all bonded to make a rather rough inner surface. I used a wire brush on an angle grinder and a hammer and old chisel to make enough space for the old flue to pass right through it.

 

My question is - is this collar salvagable or should I just replace it?

 

If it is salvagable, can I just wrap ropes around the new flue and jam it in, and then use sillicone to make a seal? I feel like that might be a great place for rainwater to get trapped and rust the flue again. If it is salvagable, can I repaint the outside with ordinary boat paint (primer/undercoat/topcoat) or should I use something special, perhaps heat resistant?

 

Here are some photos:

 

[Guest]

@matty40s is your man to advise.

 

I will simply say you did well to get the thing off the roof!

[Richard10002]

I had exactly the same issue a few years ago, (as predicted in the survey when I bought the boat in 2011).

 

I cant remember if the inside of my collar was anything like yours but, when fitting the new flue, I just wrapped some thick rope around it, and I think I filled the space with Plumba sealant. I cant remember, but I hope I made the sealant level with the top of the collar, so as not to create a water trap. I'm no expert, but cant see any logical reason for you not to do the same/similar - somebody may know better than me  

 

As far as I can tell, the corrosion at the top of the flue is not due to water getting in, it's to do with the products of combustion, possibly acidic to some degree, and which corrode the flue from the inside, aver a 14 year period in my case, (assuming the flue was the original).

 

 

[BEngo]

Roof collar looks reusable to me, provided the roof face is flat enough to be sealed down.  Give it plenty of Fertan then an ordinary paint scheme.  Black is traditional but no reason you can't paint it to match the boat!  Heat resistant paint on the collar is wasted.

Once the collar is on the roof fit the flue pipe with some  rope under it at the stove end collar, then use more rope to centralise the flue in the roof collar.  You will probably need some thicker rope at the top.  Caulk it up pretty tight with a blunt chisel or old screwdriver.   Then  Envirograf sealant round the stove collar and both the inside (bottom) and outside (top) of the roof collar.  That keeps the upper rope dry and stops the flue rusting from inside and out at the same time.

N

[Tracy D'arth]

15 minutes ago, BEngo said:

Roof collar looks reusable to me, provided the roof face is flat enough to be sealed down.  Give it plenty of Fertan then an ordinary paint scheme.  Black is traditional but no reason you can't paint it to match the boat!  Heat resistant paint on the collar is wasted.

Once the collar is on the roof fit the flue pipe with some  rope under it at the stove end collar, then use more rope to centralise the flue in the roof collar.  You will probably need some thicker rope at the top.  Caulk it up pretty tight with a blunt chisel or old screwdriver.   Then  Envirograf sealant round the stove collar and both the inside (bottom) and outside (top) of the roof collar.  That keeps the upper rope dry and stops the flue rusting from inside and out at the same time.

N

A point, its fireproof rope , glass fibre rope.

[Machpoint005]

I have the same problem, but we're getting the stove replaced next week so it will go away. It's a personal thing, but I don't fancy dealing with carbon monoxide risks when I can pay an expert to do it properly.

[jetzi]

Thanks all. Its what I had in mind so good to have confirmation. There is actually very little to no rust on the outside, so I'm going to clean it up well and then paint it.

 

I'm more concerned about the inside than the outside, but I think as long as the flue sits well inside there is no point in having the inside of a flue spotless!

 

2 hours ago, Machpoint005 said:

I have the same problem, but we're getting the stove replaced next week so it will go away. It's a personal thing, but I don't fancy dealing with carbon monoxide risks when I can pay an expert to do it properly.

I agree wholeheartedly which is why I am paying an arm and a leg to have it refurbished professionally. It is just the final install of the flue that I'll have to do myself.

[BEngo]

11 hours ago, ivan&alice said:

I'm more concerned about the inside than the outside, but I think as long as the flue sits well inside there is no point in having the inside of a flue spotless!

You will need to get the inside of the collar clean where the fire rope and sealant are going to be, otherwise the sealant will not stick to the collar.  Then you will get 'orrible dribbly bits running down the flue.

Similarly, get the outside of the flue nice and clean in way of the fire rope and sealant. That should be easy on a new flue.

 

N

 

 

[GUMPY]

Sand blasting is a quick and simple method of cleaning up metal, gets rid of everything and leaves a clean paintable surface. There should be someone local that can do it. Time to look at yellow pages

 

[BWM]

I'd junk it, the chances of getting a good seal will be much reduced due to the roughness and the remaining corrosion may shorten the life of your new flue. It is good practice to have the flue pipe level with the top of the collar for a liner to work properly and by the look of this you would end up with a sump like area at the top which can only collect chimney gunk and moisture, again leading to early faliure and leaks.