Collyweston Stone Slate

A Guide Collyweston Stone Slate - Introduction

“Limestone can yield a roof covering Lincolnshire, , and North- of incomparable dignity and beauty. west Cambridgeshire. When the building is itself constructed of local limestone, a roof The ready availability and price of of stone slates adds the crowning modern mass-produced roofing touch of harmony, in colour and in materials have consistently been a texture, with the surrounding threat to the long term survival of landscape.” this feature of our historic buildings. The Collyweston stone Sir Alec Clifton-Taylor slate industry has never been large The Pattern of English Building but specialist Collyweston stone 1962 slaters do still maintain the Collyweston stone slate roofs are traditions and the high levels of one of the most distinctive and skills required to keep the existing familiar features of the historic roofs in sound repair and some new towns and villages around the slates are being made by traditional village of Collyweston in methods to replace the stock. which gives its name to the stone from which they The Collyweston Stone Slaters’ are made. Trust was set up in 1982 to work towards sustaining the industry. The extraordinary richness of their Together with local councils and conservation bodies they seek to texture and colour, weathered with retain this valuable asset to the time, is a reminder of our ability to visual and historic environment utilise local materials and by so and to the rural economy of the doing create a strong sense of place area. and relationship between the landscape and the buildings. “I do not believe that any other roofing Collyweston stone slate roofs m ake material can match the visual a unique contribution to the attraction of Collyweston slating, distinctive local character of both when newly dressed and fixed it has a the everyday and the prestigious soft variety of colour. It then matures buildings which lie along the with age. It has an interest of pattern limestone belt which continues and texture that is fascinating.” north from the Cotswolds. The Alan Wilson FRIBA area where they are found includes Hon Sec CSST 1983 , South 2

A Brief History of Collyweston Stone Slate Stone from the Collyweston area riven oak or chestnut. Slates were was used as a roofing material by hung from the battens by oak pegs. the Romans and evidence has been The underside of the roof was found at several archaeological covered with a soft mortar made of sites where slates were found lime and hair called torching which shaped roughly into diamond helped weatherproof the roof. shapes with a single peg hole at the top point. It is thought that earlier The ready availability of mass- buildings would have been too produced roofing materials and flimsy in construction to support blue slate from Wales in the 19th the weight of a stone roof. century inevitably threatened the viability of the industry. A Roman slates were almost certainly significant decline in the rural made from stone which was found population, with migration to the on the surface, known as ‘gifts’, as it towns and the losses from two was probably not until the 16th world wars, meant that the century when the frosting process traditional relationship between for making slates was widely used. the men and the land, the seasonal In 1375 and 1390 it is recorded that jobs, and the unbroken line of 14,000 slates were supplied to traditional skills were seriously Rockingham Castle; so it can be weakened. By the 1970s there was inferred that in the mediaeval a real danger that the craft was period there must have been an dying out; but today conservation organised industry of some kind measures, a buoyant economy, and and a system of production, the continuing commitment of the possibly as a by-product of firms of specialist Collyweston quarrying activity. It is known that slaters are ensuring that the story by 1633 there were both open pits of Collyweston stone slating and mines in the fields around the continues. village of Collyweston. “If any regard is to be had to the For nearly 300 years the use of general beauty of the landscape, the Collyweston slates on local roofs natural material of the special was commonplace and the industry countryside should be used instead of was thriving. Roof structures were imported material.” made of oak with square section William Morris rafters to support the heavy slates On the External Covering of Roofs and the battens which were made of 1890

3 Further Information More information, including a list of Local Authorities who may be local roofing contractors who are approached are: known to carry out Collyweston Cambridgeshire County slating, is available from the 01223 717111 Collyweston Stone Slaters’ Trust www.cambridge.gov.uk website. Cambridge City 01223 457000 Your local Council's Conservation www.cambridge.gov.uk Officer may be able to provide you Huntingdonshire District with names of Architects or 01480 388388 www.huntsdc.gov.uk Building Surveyors who could also give you advice about the extent of City 01733 563141 repairs required. www.peterborough.gov.uk Leicestershire County For any work at all, you are advised 0116 232 3232 to contact your Conservation www.leicestershire.gov.uk Officer to check the legal position Harborough District about consent. You may also 01858 410000 receive advice about the availability www.harborough.gov.uk of grant aid in your particular Lincolnshire County locality. 01522 552222 www.lincolnshire.gov.uk Points of contact: South Kesteven District 01476 406080 English Heritage www.skdc.com 01604 735400 or 01223 582700 www.english-heritage.org.uk Northamptonshire County 01604 236236 Collyweston Stone Slaters’ Trust www.northamptonshire.gov.uk fax 01733 331200 Corby Borough www.collywestonstoneslaterstrust.org.uk 01536 402551 District This leaflet was produced by 01832 742000 the Collyweston Stone Slaters’ Trust, June 2001.www.east-northamptonshire.gov.uk Borough Disclaimer: The information contained in this leaflet 01536 410333 www.kettering.gov.uk is as accurate as present knowledge allows and is given in good faith. Users of this leaflet must Rutland County 01572 722577 consult their own advisors, as the Trust cannot www.rutnet.co.uk accept responsibility.

4 Planning and Historic Building Legislation

Many buildings with Collyweston It is a criminal offence to undertake roofs are ‘Listed’. This means that or to cause unauthorised work to a consent may be needed from the listed building. Local Authority for any alterations which will affect the character or Buildings with Collyweston roofs appearance of the building. For all are very frequently in parts of towns but the most minor repairs, it is and villages which have been prudent to speak to the Local designated as Conservation Areas. Authority to ascertain whether or These roofs make a positive not Listed Building Consent will be contribution to the character of the needed for the work. area. They are frequently protected and owners may require Buildings which lie in the curtilage permission to remove or alter them. of a listed building are also covered If Listed Building Consent or by the legislation. Curtilage Conservation Area Consent is buildings are those which, required, at least eight weeks although not fixed to a listed should be allowed for th is to be building, form part of the property obtained. Time must be and have done so since before 1st programmed into the work July 1948. For example, farm schedule accordingly. Once buildings surrounding a listed authorised, permission is valid for farmhouse are curtilage structures. five years. Grants

It is always worth checking the mentioned above there are no other current situation with the local potential sources of funding Conservation Officer to see if a currently known which would repair project will be eligible for contribute to the costs of re-roofing grant aid. In general the provision a domestic dwelling. For of grant aid by Local Authorities Churches, Grade II*, and Grade I and English Heritage is becoming listed buildings, English Heritage increasingly rare. Where it is should be contacted. available it tends to be tightly focused on particular priority areas. Apart from the two sources

5 Facts

{ Collyweston stone roofing occurs in a small area of the around Stamford. This is one of only ten localised areas of where local stone used as a roof covering can be seen on historic houses.

{ Collyweston stone slate is not a true slate but a limestone from the Jurassic period which splits naturally along its bedding plane to form slate-like shapes ideal for roof coverings.

{ There are calculated to be 1,500 buildings in north Northamptonshire alone with Collyweston stone slate. Over half of these are listed buildings.

{ The pitch of a Collyweston stone slate roof is usually 47º but can be up to 65º. This means that rainwater is shed very quickly and slates are not easily lifted by even the strongest gales.

{ Collyweston slates for 200 sq ft of roofing are known as a ‘heap’ and weigh about one ton. This consists of 840 slates plus 13 large ones.

{ The largest slates, used at the eaves, can be up to 24 ins (60 cms) wide by 36 ins (90 cms) long.

{ Collyweston stone slates are always laid in diminishing courses from eaves to the ridge. The width of slates is random, but every half inch increase in length gives a slate its own special name.

{ Collyweston stone slates last for hundreds of years and are capable of almost continuous reuse. When the roof of an historic building in Pytchley was stripped for repair recently, it was found that more than half the slates, which were laid in the 17th century, were still sound and reusable.

{ Stone slates are the least expensive roof cov ering, if the lifetime cost of the roof is taken into account.

{ Since 1945 Collyweston stone slates have been used for prestigious new buildings including Guildhall in London; Nuffield College, Oxford; and the Masters Lodge at Trinity College, Cambridge.

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The Production of Collyweston Stone Slate

The making of stone slates has been essential that the log should always been a time-consuming, remain damp so that freeze-thaw labour-intensive activity, dependent cycles of frost could initiate on the weather and requiring great splitting. Present day methods skill, patience, experience, and have reverted to opencast knowledge. Even today nearly all quarrying, selecting log as the the work is carried out by hand, overlying roadstone rock is usually by the same man who stripped out. Once above ground, processes the log and fixes the the log is laid out on a bed of finished slates on the roof. The shale to allow freezing air 19th century method of extraction underneath. It is kept wet until was to mine out the Collyweston frost splitting occurs. Formerly, in slate seam. Miners used to lie on mild winters, when the log did not their sides, picking away at the split it had to be pied: that is sand under the stone slate seam, taken back into the mine and using tools known as foxing picks. covered with wet sand to prevent Permanent columns of waste stone its drying out. It was brought back were built to support the ceiling, to the surface again for splitting and temporary ones for the the following winter. Even today undermined seam. The miner slaters rely on frost to split the log. would tap the seam above his head Once the log has received several to check that it was safe. When the frosts, the slater clives, or splits, it seam was about to fall, a series of into its separate layers with a clicks, known as talking, could be cliving hammer. The skill is to heard. Ideally, it would be ready to produce the largest possible fall at the end of a day’s foxing, and slates from an individual log. the miner would retreat pulling the Once split, the slates are dressed temporary supports out as he went. into the various sizes using a The undermined part of the seam dressing hammer which produces would then fall to the floor, the characteristic rough-edged hopefully breaking into easily appearance. A nail hole is made managed pieces known as log. If at the top of the slate, traditionally the seam did not fall, steel wedges with a bill and elves, but now would be driven into it and a bar electrically drilled with a masonry known as a lion’s tail would be bit. The dressed slates are then used to lever the seam down. The stacked in slater’s thousands each log was taken by a barrow, known containing 840 s`lates. as a shim, to the surface. It has always

7 Setting Out A Collyweston Stone Slate Roof

Showing lath sizes and gauges, slate and skirt sizes

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