What should be done before using a fireplace that has not been used in decades?

Question

We are moving into a house with a fire-place. The current tenants (friends of ours), have been living there just short of 2 decades, and have never used it once.
The house is about 90 years old, so it certainly saw a lot of use once upon a time.

I myself rather enjoy a fire. Though I've not lived in a house with one, since I was a kid. Not really planning on using it for heating, but for a couple of times in the winter it would nice to be able to use it just for the enjoyment of the thing.

Is there anything I should do before using it?
Should I be worried about the chimney being blocked?
How would I go about inspecting for that?

Answer 1

You hire a chimney sweep to inspect (and clean) it. In some cases it may need to be completely rebuilt - in others, it may simply need cleaned and inspected, or it may need something in the middle.

At that age, you may well find that you'll face relining to make use of it under modern conceptions of what's safe - it will have deteriorated with age and probably was not built to standards that are considered safe these days in the first place.

There are ways to solve that problem, but which way is applicable will vary with the state of the chimney, and any work that might have been done to it in the 70 years before it was disused for 20 years, as well as what's been going on inside it for 20 years.

Answer 2

Another thing to consider with a chimney that old is the distinct possibility that the bricks were laid up with a mixture of sand, horse hair and a bit of lime mixed in. It is not uncommon for a chimney like that to have the external weather at the roof line and above erode away some of or all of the sand leaving the bricks literally free stacked with spaces between them. Use of a chimney in that condition can set your house on fire if sparks sneak out through the cracks and smolder in your roofing material and rafters.

Another thing with old old chimneys is that they used to think that it was right OK to use the interior surface of the bricks as the heat exposed surface of the stack. Now days the chimneys are built with a much different construction with some type of liner that isolates the brick/blocks of the chimney from the heat in the stack. The liner could be a high tech triple wall stainless steel stack ($$$) or a more contemporary liner that is a fired clay affair with an inside glazed finish. Such liners are specially mortared with a refractory cement which is a special high temperature silicate material.

One of the reasons that liners are used is that it gives the interior wall of the chimney a smooth surface so that there is much less chance of tar, pitch and gum build up in the chimney as opposed to what happens on the inside of a plain brick chimney with rough bricks and mortar joints. Chimney fires that resulted from these deposits catching fire when an especially hot fire was in progress in the fire place were rather common place often leading to a good part of a house or all of it burning down. As a matter of fact in my young years in a farming community in the 50's and 60's there were at least four such fires that I recall left the families without a home.

Answer 3

If someone offers to modernise your chimney by putting some sort of metal tube or liner inside, make sure the chimney is cleaned first and all soot is removed. If this is not done properly, you risk having a fire in the space between the tube and the chimney, which you (or the fire brigade) won't be able to reach to put out.

Answer 4

Consider installing a wood-burning stove with a glass door in the same fireplace, along with a suitable new liner in the chimney. You get the look of the flames combined with modern technology to keep the heat in the house and not burn it down.

You might even get a grant from your local authority.

Answer 5

If you want this to be a working fireplace you will need to first have it inspected and swept by a chimney sweep. The chimney sweep can do a smoke test to check for issues such as leakage and blockages. This involves setting off a small smoke pellet and looking to see if smoke comes out the chimney at the top, and anywhere else it shouldn't be.

At his point you may find that the inside of the chimney has issues such as being blocked up, or even be at risk of internal collapse. If the pointing is in poor shape this could let gasses through into rooms which are passed by the chimney. The inside may have become rough which will reduce the flow of air up the chimney due to friction. The usual solution to these issues is to fit a flue liner which will offer some support. These can be flexible and fitted by shoving (to use the technical term) them down the chimney from the top.

Be warned though that this can be easier said than done. In my circa 1830 house the flue has bends and a few holes (small, about 500mm square) had to knocked in walls to get access and clear blockages.

If you do require a flue, in the UK it must be fitted by a HETAS registered installer. An incorrectly fitted flue and fireplace can lead to carbon monoxide poisoning.