Fireplaces, Flues and Chimneys
by Neil Quinn
Fireplaces are often the focus of reception rooms and bedrooms within period country houses, so make sure you get yours in good working order.
However, over the last 500 years the designs of fireplaces have changed radically. In fact some very old houses may originally not have had fireplaces at all, just a hearth and a hole in the roof, which isn’t quite as cosy. Some houses had fireplaces added later, which may mean that they don’t work properly and those pretty chimney pots on top of houses from the Georgian era onwards may be hiding a dark and smoky secret.
The key to having a fireplace that looks good, burns well and doesn’t smoke is knowledge and research. If you’re buying or adapting an old or listed building and want to ensure the fireplace works properly, look for telltale signs that might indicate the contrary.
Are there smoke stains and streaks around the fireplace? Has the hearth or grate been raised on bricks or blocks? Has the previous owner put in a glass panel or hood to try and make the fire draw better? These could indicate that the fire isn’t working properly.
Before buying a house, instruct your surveyor specifically to inspect the chimney flashings and condition of the stonework around them. Bird guards help because jackdaws love chimney pots, but they should be conical or triangular so that nests can’t be built on top of them. Commission a smoke test to identify gaps where smoke could enter the house. I’ll also often use CCTV to examine the flues in detail. Make sure the whole chimney system works properly from top to bottom – and that includes bedroom fireplaces whether or not you plan to use them.
If a fireplace has been out of use for years, the flue will have degraded and floor or roof timbers built into the chimneys could have become exposed inside, adding to the risk of a chimney fire, and before lighting the first fire make sure the chimneys are swept of soot and debris stuck to the side of the flue.
The traditional and proper way to repair a fireplace is by plastering the inside of the flue with lime plaster, a process called parging.
This can be a big job, often taking two or three layers of plaster, and sections of masonry may need to be taken out to gain access but if you are having major building works done it’s worth it to give the smoothest surface and the best draw for the fireplace, and it helps to protect against chimney fires. A reparged chimney could last 100 years. The alternative is leaving the flue as it is and installing a stainless steel liner which may only last for 25 years. A word of warning: Don’t reline a chimney with clay liners. Clay is fired to a much lower temperature than a chimney fire and could cause the clay to expand and possibly explode.
Good ventilation is important. This was seldom an issue in old houses where the building was draughty, but as we’ve draught stripped our rooms and installed double-glazing; extra ventilation may be required. Install it as close to the fireplace as possible and at high level, because four fifths of the air required for fireplace ventilation comes from the top six inches of the fireplace and lower level vents further away will just create a cold draught across the room.
If you have a fireplace that is blocked off and not in use, make sure you install a vent in the fireplace opening and it is ventilated at chimney level, this will reduce the risk of damp problems later.
A large fireplace with a straight flue should have a damper – a steel plate with a flap operated from the fireplace which can open or shut the flue to stop the rain coming straight down the chimney, the damper can be opened before a fire is lit.
Where a room doesn’t get daily use, such as a dining room, but you still want the comfort and atmosphere that a real fire offers, log burners are an excellent alternative. They are efficient and the speed of burn can be controlled, but if you want a real fire on a grate or andirons then it needs to be done properly.
Chimneys and open fires are a wonderful feature of a house. Get the fires working well and the design right, perhaps using fire bricks or stone with render that is allowed to burn and deteriorate to blend in with the age of the house, and your home will be warm and welcoming for many years.