Fitting a cast iron fireplace

We do not fit fireplaces or gas fires but we do have a list of recommended fireplace fitters and CORGI registered gas fitters.

You can fit a fireplace yourself and this guide will show you how but it does require a level of building competence.

If you are unsure about fitting a fireplace then please phone us to use one of our recommended fitters.

If you have any doubts about the installation of your fireplace or about local building regulations then competent builders, chimney sweeps or chimney lining specialists can generally be taken as a good source of Information and advice.

You must ensure that any gas pipe work and gas fire connection is carried out by a plumber or gas fire fitter who is CORGI-registered.

How to fit a cast iron fireplace

This guide is based on our experience of fitting our fireplaces. It is my opinion and should not be taken as law. If these fireplace fitting instructions seem long winded it is because making a mistake when installing a fireplace can have disastrous results.

If you have any doubts about the installation of your fireplace or about local building regulations then competent builders, chimney sweeps or chimney lining specialists can generally be taken as a good source of Information and advice.

The Flue or Chimney

First ensure that your flue is safe with a smoke test. It must not leak since.any leakage could be life threatening. If the smoke is going anywhere other than up the chimney associated with it then you must have it checked by an expert.

Smoke Tests

The usual method for testing a flue is the smoke test. Although you can do this yourself, I would always advise that an experienced person carry this out. Fireplace fitters, builders and especially chimney sweeps may be your best bet. A local chimney sweep from your yellow pages will clean your chimney, which should always be done when fitting a new fire, and should also be able to do a smoke test to check the flue for soundness.

Smoke tests are very simple. A smoke pellet is burned in the fire opening. Smoke should emerge from the correct terminal only (usually one chimney pot). This is a good indication that your flue is sound. However, since many houses have had their flues messed around with at some stage I feel that there is no substitute for seeing the bristles of a chimney-sweeps brush emerging from the top of your chimney pot!

While the smoke pellets (which are deliberately strong smelling) are burning, you should check all of the rooms that the flue passes through, including the loft space. There should be no leakage into any of the rooms above or below where the fire is to be fitted.

Roughly speaking, houses built before the first World War (1914) are likely to have leaky flues and must always be thoroughly checked. In my experience, solid fuel fires will damage the flue much more than a gas fire. Many houses built after the second World War tended to have gas fires fitted and so the flue will probably still be sound. However, since house builders were a mixed bag of variously qualified people, all flues should be checked prior to the installation of any fireplace

If there is any leakage, chimney sweeps can be very helpful. Good builders should also know how to repair the damage and there are also specialist flue fitting firms who do nothing else but fix leaky flues.

If you find yourself confronted by a solid brick wall where you think the fireplace used to be, remove the vent or knock a hole in the wall to enable a smoke check to be done on the flue.

Capped Flues

If the smoke stubbornly refuses to rise up the flue it may be because it is capped off at the top. Capped flues must be uncapped to do a flue smoke flow test. However, it may just be that the flue is filled with moist, cold air. This air will be heavier than that in the room and prevent the smoke from rising. Warming the flue with a blowtorch or burning some sheets of newspaper inside it will often do the trick of getting the smoke moving up the chimney, enabling it to be checked

Chimney Liners

An existing metal liner within a brick flue may indicate previous problems which have necessitated the flue being lined. A single wall 5 inch diameter liner will work with class II gas fires only. A single wall 7 inch liner is for class I or class II gas fires. An 8 inch twin walled stainless steel liner are tested for solid fuel appliances and will also accommodate gas fires. The liners must be adequately sealed within the flue at both the bottom of the chimney terminal and should generally be in one single length.

Constructional Hearths

You must have a fireproof area in front of your fireplace. The constructional hearth is the patch of fireproof material (either a concrete, stone or tiled surface) in every wooden floored house that should finish flush with the floorboards in front of where the fire is to be fitted. If this has been removed for some reason and you are fitting a fireplace to burn solid fuel (coal or logs) it must be adequately replaced before starting to fit the fireplace. The constructional hearth is there to stop the joists of the floor extending beneath the fireplace. If they did, then they would dry like tinder and any small ember finding its way down to them from the fireplace would cause a much larger fire than you ever intended. A constructional hearth will usually consist of fireproof material at least 6 inches deep, around 48 inches wide and extending out approximately 18 inches .

A good start when fitting any fireplace is to check whether the chimney breast is plumb and if the floor in front of it is level using a spirit level. In many older houses this may not be the case. Fitting a fireplace level and plumb on a chimney breast that is not looks dreadful. It is easy to notice a difference in level of only 1/4 a bubble on a spirit level, so I would suggest that you fit the fireplace exactly as crookedly as the existing chimney breast. Ground floor fireplaces are almost always fitted central to the chimney breast. Bedroom fireplaces may be fitted off centre as several different flues may rise up inside the same chimney breast. Ensuring that every fireplace could be fitted centrally was not always a priority for house builders. Mark the centre of the chimney breast on the wall.

To fit a Cast Iron Fireplace Insert and a Wooden Mantel

Wooden mantels must be fitted on dry plaster.

Our guide to fitting a cast insert with a wooden_mantel is on our vicfires website