Property: The craftsman: Caught Knapping: Cutting, or knapping, flints is a Stone Age skill, an expert tells Caroline McGhie

MUCH of Bernard Bartrum's craft is neolithic. He learnt it from the former custodian of Grimes Graves, the ancient flint mines on the borders of Suffolk and Norfolk. Bernard is a flint knapper: he cuts, or knaps, the stones as they come off the field or out of the quarry. He is also a skilled maker of flint axeheads, of the kind used by prehistoric hunters and farmers to fell trees and skin deer.

Some of his tools, too, are more often seen in museums. For certain types of flint knapping and for fine finishing, Bernard uses pieces of deer antler, which jostle with old coal-breaking hammers in his plastic bucket. His wheelbarrow is full of 16th-century lime mortar, which he has been crushing so that he can re- use it on the walls he restores.

'Lovely stuff,' he says. 'Modern cement mortar is terrible. It has no suction with the flint at all. I have just been to see a flint building at St Albans which is ruined because the flints don't like cement mortar. You don't use a steel hammer for neolithic reproduction work. It takes off a different sort of flake. The steel makes a very deep shave.'

To demonstrate, he turns the mottled blue-white knob of a flint over in his hand and cracks it with a steel hammer. A sliver of flint splits away revealing the almost black core, slightly swollen like the shape of a mussel shell. 'That is called the bulb of percussion, and you get that with a steel hammer,' he says. 'With deer antler you get a flat cut.'

The discarded slivers might be used as 'gallets', little stoppers in a wall between larger knapped flints, designed to give the darkness of the wall greater density. He is making safe the ruins of a church at Roudham in Norfolk, so that villagers can continue to hold occasional services among the roosting pigeons.

The church walls are random flush work, which means that each cut flint is placed haphazardly with its flat black core facing outwards. There are chips and dimples in the flints, showing where the hammer has worked. Were this 'fine' flush work, each one would be smooth as marble.

The skill of flint knapping lies partly in being able to 'read' a flint. You or I might hit a flint for hours and never achieve a break. The core inside the white, crusty outer cortex is made of silica, which has no grain at all and is only slightly softer than diamond.

The experienced knapper will first look for the angles before he cuts it with a single strike. 'I look for a certain kind of platform,' Bernard says. 'It is no good striking a flat surface. It can get very technical explaining how different angles respond, but basically it's the angles you go for.

'Some people say you can turn the flint round in your hand, tapping it all the way, and you get a clean break, but it doesn't work. That way you just send shock waves through it.'

Flint that has been freshly dug has a slight moisture content and is easier to work than flint that has been exposed for many years. Those that have frost damage simply disintegrate when they are cut. You can tell a damaged flint by tapping it: a good one rings like a bell; a bad one sounds muffled. 'Most flints have fossils inside them because they were originally formed round fossils, usually sponge fossils,' Bernard explains.

The finest square flints will take at least 20 minutes each to cut and prepare, while a rough-cut flint will take around five minutes - 'But some houses actually have very few flints. Some of those along the coast that I've worked on have only around 20 flints per square foot.' For a suitably weathered look to new flint, a solution of fresh cow dung can be painted on to encourage the growth of moss and lichen.

Flint as a building material lasts for thousands of years, provided that water doesn't leak in through the mortar - something much more likely to happen with modern cement mortar than with flexible lime mortar. Bernard, one of few craftsmen with the knowledge and skill to work with flints in this country, believes a revival is under way: 'A lot of younger architects are coming round to the old craft view of things, so things are changing for the better.'

SPECIALISTS

Purcell, Miller Tritton, 14 St Clements Street, Winchester, Hampshire SO23 9HH (0962 868027), specialise in historic building work. Also have offices in Norwich, Colchester, London, Ely and Canterbury.

Bernard Bartrum, SPAB Fellow, 88 Hillcrest Avenue, Toftwood, East Dereham, Norfolk NR19 1TD (0362 696939), see above.

Richard Deane, 11 Ashfield Road, Salisbury, Wiltshire SP2 7EW (0722 330170), is a stonemason based at Salisbury Cathedral who also works on other historic buildings.

Glaven Pits, Holt Road Garage, Thornage, near Holt, Norfolk NR25 7QB (0263 740 848), supplies flints hand-picked from the quarry at pounds 45 per tonne.

H G Clarke, 2 High Street, Weston Underwood, Nr Olney, Bucks NK46 5JS (0234 711358), supplies clunch at around pounds 180 per tonne.

The Lime Centre, Long Barn, Morestead, Winchester, Hants SO21 1L2 (0962 713636), runs one-day courses on the history and practical application of lime at pounds 95 plus VAT per day.

READING LIST

'Conservation of Clay and Chalk Buildings' by Gordon Pearson, published by Donhead. Price pounds 30.

'The Nature and Subsequent Uses of Flint, Volume One' by John Lord, available from Green Lane House, Little Livermere, Bury St Edmunds, Suffolk IP31 1PY. Price pounds 5.50 inc p&p.

'The Masters of Flint' by A J Forrest, available from Terence Dalton Ltd, Water Street, Lavenham, Sudbury, Suffolk CO10 9RN. Price pounds 9.95 hardback, pounds 7.95 paperback.

'Craft Techniques For Traditional Buildings' by Adela Wright, published by Batsford. Price pounds 19.99.

The Society for the Protection of Ancient Buildings, 37 Spital Square, London E1 6DY, has relevant pamphlets.

(Photograph omitted)

Suggested Topics
Arts and Entertainment
At this year's SXSW festival in Austin, Texas

Music Why this music festival is still the place to spot the next big thing

Arts and Entertainment
Russell Tovey, Myanna Buring and Julian Rhind Tutt star in Banished
tvReview: The latest episode was a smidgen less depressing... but it’s hardly a bonza beach party
Arts and Entertainment
Crime watch: Cara Delevingne and Daniel Brühl in ‘The Face of an Angel’
film review
Arts and Entertainment
music Malik left the Asian leg of the band's world tour after being signed off with stress last week
News
Author J.K. Rowling attends photocall ahead of her reading from 'The Casual Vacancy' at the Queen Elizabeth Hall on September 27, 2012 in London, England.
peopleNot the first time the author has defended Dumbledore's sexuality
Arts and Entertainment
‘The Royals’ – a ‘twisted, soapy take on England’s first family’
tv Some of the characters appear to have clear real-life counterparts
News
Brooks is among a dozen show-business professionals ever to have achieved Egot status
people
Have you tried new the Independent Digital Edition apps?
Arts and Entertainment

ebooksNow available in paperback
Arts and Entertainment

ebooks
Arts and Entertainment
A cut above: Sean Penn is outclassed by Mark Rylance in The Gunman
film review
Arts and Entertainment
arts + ents
Arts and Entertainment
James Franco and Zachary Quinto in I Am Michael

Film review Michael Glatze biopic isn't about a self-hating gay man gone straight

Arts and Entertainment
A scene from the movie 'Get Hard'
tvWill Ferrell’s new film Get Hard receives its first reviews
Arts and Entertainment
Left to right: David Cameron (Mark Dexter), Nick Clegg (Bertie Carvel) and Gordon Brown (Ian Grieve)
tvReview: Ian Grieve gets another chance to play Gordon Brown... this is the kinder version
Arts and Entertainment
Benedict Cumberbatch and Martin Freeman in the first look picture from next year's Sherlock special

TV
Arts and Entertainment
Because it wouldn’t be Glastonbury without people kicking off about the headline acts, a petition has already been launched to stop Kanye West performing on the Saturday night

music
Arts and Entertainment
Molly Risker, Helen Monks, Caden-Ellis Wall, Rebekah Staton, Erin Freeman, Philip Jackson and Alexa Davies in ‘Raised by Wolves’

TV review
Arts and Entertainment

TV
Arts and Entertainment
James May, Jeremy Clarkson and Richard Hammond in the Top Gear Patagonia Special

TV
Arts and Entertainment
Game of Thrones will run for ten years if HBO gets its way but showrunners have mentioned ending it after seven

Game of Thrones
Arts and Entertainment
Mans Zelmerlow will perform 'Heroes' for Sweden at the Eurovision Song Contest 2015

music
Arts and Entertainment
Elizabeth (Heida Reed) and Ross Poldark (Aiden Turner) in the BBC's remake of their 1975 original Poldark

Poldark review
Arts and Entertainment
Daniel Craig as James Bond in Skyfall

Mexican government reportedly paying Bond producers for positive portrayal in new filmfilm
Arts and Entertainment
Disney’s flying baby elephant is set to return in live-action format
filmWith sequels, prequels and spin-offs, Disney plays it safe... and makes a pachyderm
Arts and Entertainment
Nazrin with Syf, Camden
photography
News
The QI Elves photographed at the Soho Theatre. They are part of a team of researchers who find facts for the television programme 'QI'.
people
Arts and Entertainment
‘The Royals’ – a ‘twisted, soapy take on England’s first family’
tv0-star review: Sean O'Grady gives it his best shot anyway
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    The saffron censorship that governs India: Why national pride and religious sentiment trump freedom of expression

    The saffron censorship that governs India

    Zareer Masani reveals why national pride and religious sentiment trump freedom of expression
    Prince Charles' 'black spider' letters to be published 'within weeks'

    Prince Charles' 'black spider' letters to be published 'within weeks'

    Supreme Court rules Dominic Grieve's ministerial veto was invalid
    Distressed Zayn Malik fans are cutting themselves - how did fandom get so dark?

    How did fandom get so dark?

    Grief over Zayn Malik's exit from One Direction seemed amusing until stories of mass 'cutting' emerged. Experts tell Gillian Orr the distress is real, and the girls need support
    The galaxy collisions that shed light on unseen parallel Universe

    The cosmic collisions that have shed light on unseen parallel Universe

    Dark matter study gives scientists insight into mystery of space
    The Swedes are adding a gender-neutral pronoun to their dictionary

    Swedes introduce gender-neutral pronoun

    Why, asks Simon Usborne, must English still struggle awkwardly with the likes of 's/he' and 'they'?
    Disney's mega money-making formula: 'Human' remakes of cartoon classics are part of a lucrative, long-term creative plan

    Disney's mega money-making formula

    'Human' remakes of cartoon classics are part of a lucrative, long-term creative plan
    Lobster has gone mainstream with supermarket bargains for £10 or less - but is it any good?

    Lobster has gone mainstream

    Anthea Gerrie, raised on meaty specimens from the waters around Maine, reveals how to cook up an affordable feast
    Easter 2015: 14 best decorations

    14 best Easter decorations

    Get into the Easter spirit with our pick of accessories, ornaments and tableware
    Paul Scholes column: Gareth Bale would be a perfect fit at Manchester United and could turn them into serious title contenders next season

    Paul Scholes column

    Gareth Bale would be a perfect fit at Manchester United and could turn them into serious title contenders next season
    Inside the Kansas greenhouses where Monsanto is 'playing God' with the future of the planet

    The future of GM

    The greenhouses where Monsanto 'plays God' with the future of the planet
    Britain's mild winters could be numbered: why global warming is leaving UK chillier

    Britain's mild winters could be numbered

    Gulf Stream is slowing down faster than ever, scientists say
    Government gives £250,000 to Independent appeal

    Government gives £250,000 to Independent appeal

    Donation brings total raised by Homeless Veterans campaign to at least £1.25m
    Oh dear, the most borrowed book at Bank of England library doesn't inspire confidence

    The most borrowed book at Bank of England library? Oh dear

    The book's fifth edition is used for Edexcel exams
    Cowslips vs honeysuckle: The hunt for the UK’s favourite wildflower

    Cowslips vs honeysuckle

    It's the hunt for UK’s favourite wildflower
    Child abuse scandal: Did a botched blackmail attempt by South African intelligence help Cyril Smith escape justice?

    Did a botched blackmail attempt help Cyril Smith escape justice?

    A fresh twist reveals the Liberal MP was targeted by the notorious South African intelligence agency Boss