Chimney and pipe estimate - second opinion needed

[QuarryHouse]

I need to replace the single-wall stove pipe I inherited connecting my BlazeKing Chinook (6" pipe) to the double-wall chimney pipe that runs from the internal ceiling through the roof. The company I called (who has excellent reviews in the area) told me I needed to replace the single-wall pipe but also the entire chimney, saying it is a fire hazard, and quoted me $10,800 for the materials plus labor.

The internal single-wall pipe is 6 feet long, the ceiling to the roof is about 3 feet (the house is a single story ranch) and there's about 7 feet of double-wall chimney above the roof. The estimate seems high to me and I'm not sure why the existing chimney needs to be replaced. It's old - I bought the house in 2016 and the chimney was there then, and was likely installed in 1974 when the house was built.

Even if everything needs to be replaced, based on some searching around online, the materials seem to be on the order of maybe $2,000. What am I missing?

This is the internal setup. Note the area around the stove is all non-flammable Hardie board with a ventilated wall.

And this is the roof view.

 

[Eman85]

I'd price the materials and give it a go myself, looks pretty straight forward. Might need a new support in the ceiling. My setup height wise is similar and I used DW telescoping pipe inside. It's just work as they say depends on how much time you have.

 

[EatenByLimestone]

The roof pitch doesn’t look steep, I think you’d be surprised how easy it would be.

 

[Murray01]

Go to a chimney manufacturer’s website and study their installation instructions paying close attention to their required clearance to combustibles and check those numbers against what you have.

Do you have access to the attic space? If so check clearances there and what products are currently installed vs the manufacturer’s specifications.

Selkirk has an extensive instructions on line. Make sure you’re looking at USA instructions and clearances.