St Margaret of Antioch

The Parish church of St Margaret of Antioch in Wellington dates back to the 12th Century with alterations
made in the the 14th & 15th Centuries. Major Victorian restorations were carried out in 1883 and 1887.
The Church was given a Grade 1 Listed building status in 1985.

The Heritage Group were asked to comment upon the unusual type of underfloor heating system in the St Margaret's church.  Upon visiting the church the Group was surprised to discover a similar type of underfloor heating system to that found in the St Michael's Church at Ufton Warks. St Margaret's heating system was most likely installed during the church's first Victorian restoration in 1883.

Built into the floor of the various aisles in the Nave are five cast iron floor plates each approx 400mm square with a centre lift out  section. Each floor plate covers a deep pit, with brickwork forming the sides of each pit that is scorched and burnt.

The purpose for these various floor pits was for use as fire pits. The scorching of the brickwork inside the pit is a positive indication of the high temperatures reached and emitted by the fire, and there is also a small amount of ash residue left in the base by the fire.

The use of these floor pits as fire pits was confirmed by an elderly member of St Margaret's congregation who remembers as a youth the fires being lit in the Autumn, then the cast iron covers being replaced and becoming very hot. Never to be stood upon.

She also recalls delivery by horse and cart of coke from Hereford, most likely left as the residue from the manufacture of towns gas at the local gas works.
Her recollection was that the fire pits were in use each year up to the winter of 1940/41 when fuel rationing was introduced which possibly prevented further supplies of coke being available. 

Cast iron floorplate with removable centre section

View showing floorplate set into the floor tiles in side aisle

View looking down into a floor pit showing the burnt brickwork.

View looking along the flue duct leaving the bottom of the fire pit

Location of the five fire pits and the route of the underfloor flue duct noted in three of the fire pits.

With the cast iron floor plate removed the open fire pit would have been filled with hot coke and allowed to become red hot. The cast iron floor plate was then replaced with the small centre section left open. This allowed fresh air to enter the pit chamber to create sufficient draught and induce the flue gases to enter the floor ducts and travel towards the chimney.

The passage of the very hot flue gases from each hot pit would travel through the brickwork ducts and then transfer its heat into the floor slabs and tiles which then transferred heat by conduction and radiation into the occupied space of the Church.

It was only possible to open up three of the five floorplates. In each of the three opened fire pits there was only one flue duct exiting the pit at bottom level in the direction of the chimney.

Unfortunately it was not possible to open the cleaning door in the chimney to establish if there had been fires lit at the chimney base to create an upward draught to draw and induce the hot gases from each fire pit.  


Large view of the cleaning and access door into the chimney

View of the cleaning door and lower smaller clean-out door

From the rearranged layout of the stonework in the external wall
it is possible that the internal flueway was built into the wall from
the outside during the restoration works.

The height of the chimney is level with the ridge line
of the North Transept which would possibly have been
inadequate to create sufficient draught.

April  2016