Friday 26 June 2020

David Cufley on sustainable building materials

David Cufley is President of  North West Kent Family History Society and has been to talk to GIHS on a couple of occasions.  However he is really the local authority on bricks and building materials. So – when GIHS was asked about by Mr.P. about local sustainable materials for the built environment we put the enquirer in touch with David.

First David asked “What do you mean by sustainable?Let me know your definition of sustainability and I’ll think again of materials. As a starter:-

Include Clay used for bricks and tiles.

Sand used for mortars and other industrial purposes.

Gravels used for concrete

Chalk for plasters, mortars and Cement. Thus, cement for concrete. Chalk was also used as a fertilizer and is not therefore your built environment.

I assume for the built environment you are including roads, bridges and infrastructures.


Mr P replied. “As there are different interpretations of the term 'sustainability' I will start with that used by the Alliance for Sustainable Building Products (ASBP): "...building products that are low embodied carbonnatural, non-toxic, locally made and healthy in use." Another definition is "... a material that will be available for future generations and has the lowest impact on human health and the environment."

It can also include renewables such as timber, straw and wool if an equal amount is replacing the amount being used but I will focus mainly on housing stock.


All of the materials you mentioned - clay, sand, gravel, chalk - will get a mention as locally available resources, regardless of their sustainability, not least because there is some research going on into the use of existing buildings as a 'material bank' for future construction (part of a design for deconstruction idea).


Any thoughts on sources of info I could search regarding the historic use of clay, sand, gravel etc in the London/Kent/Surrey area? I want examples of historic as well as contemporary use.


Also, you mentioned the use of chalk as a fertilizer; any links you can suggest to find out more about this?


David wrote:


Thanks for the explanation of sustainable. I like the ‘building products that are natural, non-toxic, locally made and healthy in use (not always i.e. limes). Don’t like ‘low embodied carbon’ and ‘material that will be available for future generations …” Example, historically the use of timber and later coal to burn bricks means that they were known for fumes and smoke coming off the clamps and you can find newspaper references (see British Newspaper Library online) to deaths of tramps that slept on or close to the clamp for warmth and in the morning were found dead. The other example that once materials are excavated or quarried for buildings they are not available again except in their new form and not as originally manufactured. The pits once depleted may return to farmland or fishing lakes but the landscape will have changed.

I struggle with the following.The renewable element is fine but such as clay and chalk once used are no longer available, unless you apply your ‘material bank’ idea. One of my fellow MSc students did her dissertation on reclamation of building materials and this is with the Weald and Downland Living Museum (WDLM) as a York University dissertation in the museum’s library.

A problem with bricks and their reuse is their original classification as taken out of the clamp and their use depended on their burning. Bricks used originally only for internal walls and temporary works are not good for use as facings because they will quickly deteriorate when weathered and the structural quality will not accept loads that modern bricks will take. They are too soft. The use of modern mortars will also cause them problems. While they are okay with lime mortars, OPC mortars can be too strong and don’t allow them to breath.


There are other reclaimed and demolition materials that react to modern materials and it’s a case of knowing your materials and where and in what combination they can be used.


Jerry building is not a new phenomenon and can be found in 18th c references. I’ll leave it to you to research the use and misuse of building materials.


Let us consider clay, sand, gravel, chalk, timber and straw/reed in London/Kent/Surrey areas.

Clay pits used for brick, tile (roof) and chimney pots were all made on the brickfields. See my map produced for a talk to Greenwich Industrial group]. I’ve done similar maps for LB Bexley, Dartford, Swanley and at present Eynesford and Farningham for a talk in 2021. Historically brickfields served approx. 5 miles radius (one horse and cart load, out and back in a day). Until canals and railways changed the landscape. However, Greenwich was slightly different as it has the Thames, which allows heavy materials to be carried not only in larger quantities but also further. Example Vanburgh Castle on Maze Hill used bricks from the Medway towns and Fulham areas, only needing carting up to the site from the river. See history of Vanburgh Castle and its accounts.

The North Kent brick industry using clay and chalk mix to form London Stocks was killed off by the fletton brick industry from late 1800s. The threemain factors being, land values for housing becoming higher than returns on brickmaking, industrial manufacturing mechanisation and then labour shortage part of the WW1 factors.

Between the wars people like Stephenson the developer of housing in the Welling, Bexleyheath, Barnhurst, area [See Bexley Library publication]. Bought up the sites of building materials i.e. sand and gravel pits as well as brickfields. Not only did he have sources for his building materials, he could manage costs and deliveries. Not a new idea as Durtnals, builders since the late 16th c to 20th century had sons that not only followed their ancestors’ carpentry/building trade but also ran the brickfield at Sevenoaks, Otford, Kent.

Dawson family at Plumstead, East Wickham, Woolwich and previously Dartford produced not only bricks but also a wide range of clay products; i.e chimney pots, sugar moulds, tiles and drain pipes. The East Wickham brickfield that Stephenson eventually took over also had a chalk mine that extends under Rockcliffe Gardens and Alliance Road. OS Maps of this brickfield will show you they also had a lime kiln. OS maps are very good for locating and discovering the structures used on the sites. The maps are freely available from the National Library of Scotland.

Henry Ward a civil engineer did a paper with illustrations on the East Wickham brickfield (known then as the South Metropolitan Brickfield) describing its equipment and process as an article in the Institution of Civil Engineers proceedings c1890.

For chalk mines see Kent and East Sussex Underground by Kent Underground Research Group. The East Wickham mine they call Plumstead Chalk Mine. The Dartford mine was owned by C N Kidd who was also a brickmaker and a brewer. You will also discover from the historic maps details of the sites along Thames Road to Crayford and Erith area that had chalk, sand and brickfields. Stephenson owned some of these eventually.

Now you have to travel down to Faversham area to find a brickmaker trading under the old ‘Smeed Dean’ name for their London Stocks. See George Smeed book published by Meresborough books (I’ve attached my brick bibliography for the references) that tells of his business including barge building to carry bricks he made up to London. London refuse was brought back to the brickfields on the return journey to be used to temper the clay and fuel the clamps.

You might also like to read ‘Bricks and Brickies’ by F G Willmott that talks about Eastwoods and transporting bricks into London and Refuse out to the brickfields. Willmott also wrote ‘Cement, mud and muddies’ the history of APCM barges and the cement industry. The ‘Blue water’ shopping centre is built in the old chalk quarries used for cement manufacture. The prices for the clay in the 20th c are given by Willmott in this book.

Because of the link of the Medway and Thames to the brick and cement industry it was easy to transport materials into London and most of these sites are now developed as industrial sites or housing.

You might like to read Jim Preston’s book ‘Industrial Medway an historical survey’ that talks about all the industries that used the Kent materials that found their markets in London and further affield. The period covered is up to the 1940s. The same can be applied to the Thames and I expect you have seen Mary Mills book on the Peninsular down river as far as the Thames Barrier. Few of these were sustainable industries but might give you a glimpse into their products.

I’ve mentioned above sand and gravel pits on Thames Road but there was a very fine sand used for cleaning among other things in the 18th and 19th century excavated at pits on the Woolwich Road, near Marion Wilson Park.

The geological OS maps gives the head materials and some areas’ materialsthat have provided for industries. The gardeners at Hall Place, Bexley mentioned in a personal conversation some years ago they had used the spoil, which is sand and gravel, from foundation trenches mixed with cement to form the concrete of their structures and it was returned to the trenches. You can still see sand and gravel being extracted as you travel between Crayford and Sidcup by rail adjacent to Bexley, Hall Place and the Black Prince area. I’m not certain the company name but it might be ‘Bexley Sand and Gravel’.

In regard chalk as a fertilizer it was used on the fields around Wilmington, Joydons Wood and Birchwood. In fact the Birchwood Road was known at one time as fire pit lane. The chalk pits having fires in them to break up the chalk.

The book by Bexley Library publications on Dene and Swallow holes, (sorry cannot remember its author) talks about their excavation of chalk for fertiliser and other uses.

Timber as a sustainable home grown material is no longer a large part of the British Industry, now most of the woodland areas have been cleared. However, there was a resurgence of planting trees for softwoods some years ago; they are quick growing; because of the grants (EU?). I’ve got no references for this for you. Certainly nothing within 25 miles of Greenwich.

I seem to remember part of the decline of the Wealden iron industry was the lack of fuel (timber) and expense of transporting coal in addition to the decline in the iron ore quality and quantity that moved the industry into the midlands.

Thatch and the use of straw and reed was never a big part of construction in London; and Greenwich; after the Great Fire of London when building regulations required tiles, slatesand bricks in favour of replacing more combustible materials.

A discussion I had with a thatcher at the WDLM mentioned most of today’s thatch is imported from Europe although some is still produced in East Anglia. He was very busy working in Sussex and south Surrey area, but I’ve not seen many buildings closer to Greenwich that use this material. Most have been reclad with slate or tile.

Finally, I should mention ‘conservation’ and ‘Building Conservation Philosophy’ by John Earl published by Donhead. There are a couple of pages (P34 etc. ‘Guarding resources ‘Green’ issues) that you might like to read.

A quote by Michael Cope, Head of Planning, English Heritage 2002 leapt out of the page when I first read it. “If sustainability means anything at all our mentality has to change … … we need a mindset where we think carefully before we knock things down and don’t always blame the buildings for problems’.

With that thought I hope I’ve given you the information you want.