Tips and advice for installing a chimney cap

How high is your chimney?

We're looking at installing a wood burner and had someone round to quote. We discussed the options and they were adamant that they would need scaffolding erecting to reach the top of the chimney. They said that manoeuvring the liner up the outside of the house would be nearly impossible without it.

Now our's is a three storey house so that's a lot of scaffolding and I expect that to be a major part of the cost. So the quote could well include that which you might not have accounted for.

This would make it, for me, something I'd be happy to pay someone to do. We fitted a lightweight pipe in another chimney where we had access to the top from inside the house and that was very easy, but a heavy weight liner for a fire/furnace would be a different matter altogether.

In your case - for a single storey house the cost of scaffolding (if any) will be a lot less.

What you should do is to ask for a quote that's broken down into parts. So you want to know (as a minimum):

• the cost of materials (not just the pipe)
• the cost of labour
• the cost of scaffolding (if any)
• the cost of removing waste - in the UK this can be significant

Given that the cost of the pipe you found was less than $1,000, $2,000 for the whole job doesn't seem too outrageous when you consider the other factors. As a rule of thumb I look at the cost of the parts and then double it to account for the labour charges.

I would really suggest that you should hire a local expert to come out to your place to give you advice on the chimney condition, design and safety. I am quite sure that there was good reason to cap off and close up the chimney and fireplace in the past and it is highly unlikely that you will come to an understanding of the reasons without some seasoned advice.

Some things to consider:

1. There was a time when many chimneys were built by laying in the bricks with damp sand that was mixed with lime and horse hair instead of regular cement bearing mortar. Aging by wind and rain could wash out this material in the upper part above the roof line leaving the bricks with open spaces from inside to outside.

2. Many old chimneys were built simply as a stack of bricks without any specialized flue liner at all. A good quality modern chimney would have a decent flue liner that was mortared in with a high temperature silica material that does not degrade with heat.

3. It is an art to design and build a chimney installation that will function well with a fire place. It is really impossible for anyone to evaluate your installation without being there first hand to attest to the the quality and design.

Advice on whether to use some type of natural gas fireplace insert with using the existing chimney as a holder for a vent stack will depend on several factors that cannot be ascertained without direct evaluation. Structural safety of the chimney would be one issue that I can think of. Another would be whether the chimney opening can accept the insertion of a vent stack of sufficient size (diameter). Yet another is the uncertainty of maintaining the joint integrity of the vent stack as it is assembled piece by piece, up to 40 feet total, and lowered down into the chimney from above.