Some time ago we wrote a post on chimney stacks, highlighting some of the common defects that we find when carrying out Building Surveys and Homebuyer Reports.
We thought it was about time we dealt with the other end of the operation and talked about the fireplaces, flues and chimney breasts inside the building and how these are connected to the chimney stack above roof level.
Before we go into too much technical detail we’ll start with a very quick history of fireplaces and chimneys. Open fires of some description have always been a fundamental element of buildings in the relatively cold climes of Northern Europe, and the way in which fireplaces and flues have developed over the years has had a significant influence over the way in which we live and the design of our houses.
In the early medieval period most buildings were heated by an open fire in the middle of the floor with the smoke (or at least some of it) escaping through holes or louvres in the roof. The ‘fireplace’ could be beaten earth or stone slabs. This obviously wasn’t going to be very satisfactory as buildings developed, particularly if you wanted to have more than one room and preferred it not to be full of smoke.
A means had to be found of containing the fire and conducting the smoke out of the building. Over the years this developed into what we would now consider the traditional arrangement of fireplace, chimney breast and flue. Fireplaces were initially quite large and inefficient and were designed to burn mostly wood. In historical terms it is only quite recently that small, fairly efficient, coal burning grates and fireplaces were developed, and it is this type of fireplace that we will generally find in the Georgian, Victorian and Edwardian houses of London.
Much of the development of this ‘modern’ fireplace can be attributed to Benjamin Thompson (later Count Rumford) who was born in pre-revolutionary North America in 1753. Rumford was essentially an enthusiastic amateur scientist and inventor. When he arrived in England in the late part of the 18th Century he was appalled by the inefficiency of the open fires that he found, prompting him to write as follows:-
“The enormous waste of fuel in London may be estimated by the vast, dark cloud which continually hangs over this great metropolis and frequently overshadows the whole country, far and wide. For this dense cloud is certainly composed almost entirely of unconsumed coal, —. I never view from a distance as I come into town this black cloud which hangs over London without wishing to be able to compute the enormous number of cauldrons of coal of which it is composed. For, could this be ascertained, I am persuaded, so striking a fact would awaken the curiosity and excite the astonishment of all ranks of the inhabitants and perhaps turn their minds to an object of economy to which they have hitherto paid little attention”
As a result, he developed by 1796 a ‘modern’ and efficient fireplace and grate which came to be known colloquially as a ‘Rumford’. Essentially he achieved this by reducing the size of the fireplace, introducing angled rather than square sides to reflect more heat back into the room and restricting the size of the flue immediately above the fireback to increase the speed of the airflow and thus improve the efficiency or ‘draw’ of the flue. One of the advantages of Rumford’s design was that his new, improved fireplace could be built inside the large and inefficient fireplace openings that already existed in the majority of London houses of the late 18th Century.
Fireplaces continued in use well into the 20th Century and it was not really until the 1960’s that open fires were largely replaced by central heating in the majority of houses. At this time many fireplaces were bricked up or removed and modern houses and flats began to be built without fireplaces and flues at all.
In more recent times there has been something of a renaissance in open fires and most new houses are now built with at least one working fireplace. When we carry out Building Surveys and Homebuyer Reports these days