Almost all upstairs floors are traditionally made of wooden floor boards. But not quite all. Some are made of lime ash. This is a mysterious substance about which few people know much. There's very little in the literature and we don't really know much about how the material was prepared and used. Looking at first glance much like a 2 inch thick layer of concrete, it has little to do with Ordinary Portland Cement, which was invented long after most lime ash floors were laid. The material, dug out from the bottom of a lime kiln, is a mixture of lime and wood ash, clinker if it was a coal fired kiln. Often, it seems, gypsum was added as well. In 17th century Derbyshire there was a tradition of burning alabaster to produce gypsum for floors. In some area the floors contain so much gypsum they are better described as gypsum floors. The mixture had pozzolanic properties, setting hard after being laid as a wet slurry a couple of inches thick supported on reeds or laths fixed across the timber joists. It formed a floor strong enough to walk on and even support considerable loads, but flexible enough to survive on a timber beamed floor where OPC screed would just crack. There are quite a few buildings with lime-ash floors on the ground floor, particularly in dairies and pantries, but it is the upstairs floors that are really rather a rarity. They occur in houses from medieval to well into the 19th century and scattered across the country though there seem to be more in the English Midlands. Proximity to a lime kiln may have been a significant factor in the distribution. They are found in a variety of buildings, from humble country cottages and farm buildings to grand town houses.
A search for lime ash in the Images of England website showed that the 36 buildings with lime ash floors upstairs mentioned in their listing descriptions were distributed thus:
Of course, there are probably many other listed buildings with lime ash floors but the listing description, which are often quite cursory, do not include them. And there are a literally uncounted number in unlisted properties. Nevertheless, they remain a very rare feature of our building heritage.
Lime ash floors are more commonly, but not exclusively, found in attics and outhouses rather than in the principal rooms. In twenty of these listed buildings the lime ash floor is restricted to the attic, and with a few granaries, maltings, cheese rooms and other stores, only a small handful of the lime ash floors seem to be in rooms used for normal domestic occupation. It seems they were considered more appropriate for storage areas than everyday living but the there are some fine exceptions such as Newton's house at Woolsthorpe, which has lime ash floors throughout, and one bedroom in Gainsborough Old Hall, both in Lincolnshire. Hardwick Hall in Derbyshire, one of the finest late 16th century houses, has extensive lime ash floors. Where lime ash floors were used in principal rooms the surface was sometimes polished with an egg white, casein or isinglass finnish. The use of lime ash in several granaries and a couple of 17th century maltings suggest that the hard smooth surface was a practical alternative to boards and perhaps offered some protection from rodents. The potential strength of the floors is attested to by such uses. Lime ash was even used in the roof of a Doric Temple at Wollerton Park in Nottingham in about 1800.
Part of the historic importance of lime ash floors lies in the near impossibility of recreating it today. The material was essentially a waste product of an industrial process long gone. Without the small lime kilns that formerly dotted the landscape, producing quicklime for building mortars and farm fertiliser, in their dirty, poorly controlled way, there can be no real lime ash.
Some floors are made exclusively from gypsum, with virtually no lime content at all. Such a 'plaster floor' as it would be better described, in a house in Tuxford, Nottinghamshire was analysed and shown to be 75% gypsum and 25% sand. The gypsum content comprised aggregate with a binder of fine casting plaster. The plaster is laid on reed n the upper floors but on the ground floor a c.2 inch thick layer of plaster is laid on a foot thick layer of cobbles. These appear to have provided a sufficiently damp-proof surface for the long term survival of the gypsum. It seems likely that gypsum plaster floors are more prevalent in the East Midlands where local supplies were available. The Newark area seems particularly rich in plaster floors, their abundance being much greater than is suggested by descriptions of the listed buildings.
The supporting reed base of lime ash floors was usually plastered underneath or hidden from below by a lath and plaster ceiling, but the are instances where the reed is exposed. The SPAB leaflet has a picture of the exposed underside of a reed based lime ash floor over an external passageway between two buildings. The reeds probably add little to the ultimate strength of a lime ash floor but supported the mixture while still wet.
Lime ash floors are inherently flexible and the lack of fixed connection between a reed based floor and the supporting joists allows the floor to cope with movement in the building. Where lime ash floors are laid on oak laths or thin boards rather than reed the supporting medium is often over-strewn with straw, enhancing the disconnection between floor and building structure.
A fundamental characteristic of lime-ash floors is their undulation – this is considered an important natural feature of such floors.
Nigel and Mary Kerr, in an article in Lincolnshire Life, November 1987, report that, "A traditional mix used in Nottinghamshire, Northamptonshire and south Lincolnshire was: 'One third lime, one third well sifted coal ashes and one third loamy clay and horse dung from grasses'". They also say that ox blood and horse hair were sometimes included.
A particular curiosity is a Tracing Floor. Only two are known to exist, at York Minster in the Masons' Loft and at Wells Cathedral in the Chapter House. Here is a description of the York Minster example. The floor is constructed from gypsum with a fine plaster of Paris surface. The outlines of window tracery and other large architectural details were scratched into the surface to form patterns at full scale from which the stonework could be modelled.
Modern materials used for repair or recreation of lime ash floors use various mixtures of hydrated limes and pozzolans, hydraulic limes and ash, sometimes including vermiculite or light expanded clay aggregate (LECA) as a light weight aggregate. The 'Welsh White Lime Putty', available through Rose of Jericho may be a good starting material for the recreation of lime ash. It is a hydrated lime putty from a coal fired kiln that contains a small amount of coal ash and burnt clay.
R.W.Brunskill, in Traditional Buildings of Cumbria 2002, says:
The plaster floor is a noteworthy feature. A conventional system of beams and floor joists might be covered not with floorboards but with a thin concrete-like layer of gypsum plaster carried on a permanent shuttering of straw or thin boards. Plaster floors usually occur immediately under the roof at first floor level or higher. They may have been laid to provide a smooth, rot-proof surface for storing grain or fruit; alternatively it has been suggested that they provided a fire-resistant layer under thatch. Two of these are recorded at Maulds Meaburn, Westmoreland, (IoE #74058) in the hall of 16th-century date and the rebuilt dairy or 1739-40. An example at Edenhall, Cumberland, probably 16th-century has also been noted.
Buildings with Lime Ash Floors mentioned in their list descriptions:
Moreton Old Hall, Congleton Road, Odd Rode, Congleton, Cheshire IoE number: 56552
Newbiggin Hall Farmhouse, St Cuthbert Without, Carlisle, Cumbria, IoE Number: 473924
Church Farmhouse, 5 Church Street Derby, Derby, Derbyshire IoE Number: 401322
North Esworthy Farmhouse Oakford, Mid Devon, Devon IoE number: 96785
Stone House, Wide Street. Hathern, Charnwood, Leicestershire IoE number: 189462
Old Hall, Rectory Lane, Medbourne, Harborough, Leicestershire IoE number: 480385
Stables And Granary At Pelhams Lands Farm, Holland Fen, Holland Fen With Brothertoft, Boston, Lincolnshire IoE number: 192031
Woolsthorpe Manor House, Newton Way Colsterworth, South Kesteven, Lincolnshire IoE Number: 193262
51-55 Barrowby Road,Grantham, South Kesteven, Lincolnshire IoE number: 192907
Paradise Cottage West And Paradise Cottage East, Church Folly, Caistor, West Lindsey, Lincolnshire IoE number: 196593
Prospect House, Washdyke Lane, Glentham, West Lindsey, Lincolnshire IoE number: 196780
White House Farm House, High Street, Newton On Trent, West Lindsey, Lincolnshire IoE Number: 197007
32 Coney Street, York, York, North Yorkshire IoE number: 463250
10, 12 and 14 Lendal, York, North Yorkshire IoE Number: 463811
6 Patrick Pool, York, York, North Yorkshire IoE number: 464357
20 Shambles, York, York, North Yorkshire IoE Number: 464666
24 Moorgate East Retford, Bassetlaw, Nottinghamshire IoE number: 240973
Doric Temple, Wollaton Park, Nottingham, Nottinghamshire IoE number: 459097
Low Grange, Basildon Road Dearne, Barnsley, South Yorkshire IoE number: 333657
31 Manor Road, Hatfield, Doncaster, South Yorkshire IoE number: 334625
Hawthorne House, Manor Road, Hatfield, Doncaster, South Yorkshire IoE number: 334616
Manor House, Doncaster Road, High Melton, Doncaster, South Yorkshire IoE number: 334509
Falcon House, Main Street, Hooton Pagnell, Doncaster, South Yorkshire IoE number: 334549
Home Farmhouse, Village Street, Hooton Pagnell, Doncaster, South Yorkshire IoE Number: 334535
Sandhill Farmhouse, High Levels Bank, Thorne, Doncaster, South Yorkshire IoE number: 334678
Stable at The Yews, Maltby, Rotherham, South Yorkshire IoE number: 335951
Queens Arms Hotel, Ashbourne Road, Rocester, East Staffordshire, Staffordshire IoE number: 449461
Manor Farmhouse, Kings Bromley Road, Alrewas, Lichfield, Staffordshire IoE number: 428496
Charlecote Park, Charlecote Park, Charlecote, Stratford On Avon, Warwickshire IoE number: 482163
Home Farm Building, Number 9 Brighouse, Calderdale, West Yorkshire IoE number: 338873
Hall Croft, Main Street, Yeadon and Guiseley, Leeds, West Yorkshire IoE number: 433671
Kirkbank, Main Street, Badsworth, Wakefield, West Yorkshire IoE number: 342636
Malt House, Blacker Hall Farmhouse, Branch Road, Chevet, Wakefield, West Yorkshire IoE number: 342311
Granary at Heath Hall Farm, Kirkthorpe Lane, Warmfield Cum Heath, Wakefield, West Yorkshire IoE number: 342412
Deer-shed in Park at Heath Hall, Kirkthorpe Lane, Warmfield Cum Heath, Wakefield, West Yorkshire IoE number: 342409
Pear Tree Farmhouse, Wintersett Lane, Wintersett, Wakefield, West Yorkshire IoE number: 342414
The following buildings do not have their lime ash floors mentioned in their list description.
Hardwick Hall, Derbyshire IoE Number 79178
Lilly's Cottage, 54 Hall Gate, Long Whatton, North West Leicestershire, Leicestershire IoE number: 358230
Maulds Meaburn Hall, Westmoreland, IoE number 74058
The Old Hall, Gainsborough, Lincolnshire. IoE number 196291
Barlborough Old Hall, Park Street, Barlborough, Bolsover, Derbyshire IoE number: 79211
Old Farmhouse at Lodge Farm, Back Lane Edlaston And Wyaston, Derbyshire Dales, Derbyshire IoE number: 81395
The Old Blue Bell, Devonshire Square, Sutton In Ashfield, Ashfield, Nottinghamshire IoE number: 410956
Market Place, Tuxford, Nottinghamshire, IoE number 420406
Lodge Farm, Hollington, Derbyshire IoE Number 81395
Hall Farm, South Duffield, Selby, Yorks IoE Number 326269
Old Cheese Factory, Windley Hall, Windley, Derbyshire.
Brizlincote Hall, Bretby, Derbyshire, IoE Number 82807
Juniper Cottage, 25, The Leas, Cottesmore, Rutland.
23-25 Market Street, Leicester.
The Gatehouse of Torre Abey, Torquay.
The Wig and Mitre, Steep Hill, Lincoln is a 14th century timber framed building with a lime ash floor.
The George Inn, Norton St. Phillip
Great Hall, Hele Bay, Devon
Ye Olde Globe Inn, Berrynarbor, Devon
From The Truth About Cottages, John Woodforde
1979 ...the cottage builders who bothered to be deliberately picturesque
were a minority; most stuck to basic practicalities. In the matter of floors,
for example, smart pattern books might call for certain types of stone or tile,
but one could always follow John Mordant, author of 'The Compleat Steward'
(1761) who said that earth floors were perfectly all right. Such floors were
made of one third lime, one third coal ashes well sifted and one third loamy
clay and horse dung made from grass, these last two in equal proportions.
Another sort could be made of loamy clay with one=third new soft horse dung with
a small quantity of coal ashes. the material was tempered, rested for ten days,
again tempered and rested for three days, then laid upon the ground. Making
floors like this was a well-established practice; they were known as lime ash
From the Building Limes Forum:
Lime Ash Floor
Q I am interested in learning about installing a lime ash floor on the upper story of my strawbale house in Vermont, USA. would the lime ash be durable with in-floor heat (hot water with oxygen barrier pex tubing)? E
A It is very important to have the right mixture and consistency for the lime-ash and in particular to allow it to harden and dry out naturally before any heat is applied. This should be left for at least one month and ideally longer. Some would say that 'lime-ash' is often a misnomer for old floors, which were often made of gypsum not lime. Hydraulic lime would be safest for the binder, otherwise you need to be very sure of the pozzolanic qualities of any ash, brickdust etc used, as carbonation will only take place in the outer surfaces of the slab. RJS
A I have successfully carried out repairs to a lime ash floor using NHL 3.5 with brick dust, sharp sand and crushed charcoal added to replicate the appearance, but not the mix, of the original. Do you intend it to be left uncovered? If so, you can create a very attractive finish with the traditional mix (including quartz). We have treated ours with hard oil and wax which really brings out the colour and material variation. If you are happy with materials which are currently more easily available, you may want to use LECA (light expanded clay aggregate) in a layer under the heating pipes. This is very light (which will help with any weight issues) and also has good insulation qualities, so will direct heat upwards. We laid the mix onto reed, but straw may be more appropriate for you as you are using straw bales. RJS
And from PPUK Agony Uncle page:
SUBJECT: Lime ash floors should be as reliable as modern flooring materials
FROM: Richard Porter (Leicestershire)
I'm in the process of buying a cottage in Leicester. I am not sure of the age of the property but most in the area have thatched roofs. My main concerned relates to the material used for the upstairs flooring which appears to a mixture of plaster and hair. Would this be the original floor? I am concerned about its strength because it's damaged - could I replace it with a more modern flooring?
What you describe may be a lime ash floor. These are relatively uncommon and an important feature. They are quite strong and if looked after can serve very well for many years. The SPAB have produced a leaflet on the repair of lime ash floors and there is an increasing body of knowledge relating to such floor structures.
You do not say whether the building is listed, but if it is then you will not be able to replace the floor without consent, which I doubt would be given. I suggest you look into methods of repairing the floor. There is no reason to suspect that a properly repaired lime ash floor should be any less reliable etc than a more conventional floor.
Hartley,Phillip (1996) Introduction to the Repair of Lime-Ash and Plaster Floors, S.P.A.B. Information Sheet 12
Harvey, J. H. (1968) 'The Tracing Floor in York Minster' in The Friends of York Minster Annual Report 40, p.9-13.
Please let me know if you know anything else about lime ash floors.
Tithe Farm Bed & Breakfast
©Biff Vernon 2006, 2007