RIBA Core Curriculum
- Building conservation and heritage
- Design, construction and technology
- General Awareness
The history of English architecture is intertwined with the use of clay tiles with varying periods of popularity. This CPD looks at the roots of traditional heritage roofing and then moves forward to consider the modern challenges associated with heritage roofing and product selection. The course then highlights how designers can recognise potential issues and minimise the risk of damage associated with heritage roofing.
In this section
- Handmade tiles
- Specials and one off productions
- Second hand tiles
Makers of traditional hand made clay tiles work closely with those charged with protecting our heritage, conservation groups, the National Trust, English Heritage, Historic Buildings and building museums.
As well as renovation and restoration, more and more designers of new buildings are realising the aesthetic value of hand made tiles as well.
So what distinguishes a traditional handmade tile? Firstly it is the clay which tends to be local to that particular area. The Weald of Kent and Sussex and the Gault of Cambridge are but two examples.
Secondly in the case of Plain tiles it is the variation in the individual tile. As mentioned before, clay has a memory and as each tile is moulded, the maker’s efforts are highlighted in the subsequent drying and firing processes.
The traditional single camber – as opposed to the more modern double cambered product used by many machine made and concrete tile manufacturers – ensures a unique variation in each tile which gives the roof movement. The tiles do not all sit flat next to each other in total conformity, but in gentle undulations reminiscent of a centuries old cottage.
Thirdly it is the variations in hues within a particular colour range. The firing techniques produce subtle changes over the tiles within a kiln. This adds additional life and texture to the roof.
Lastly, hand made clay tiles improve in looks as they age. The elements combine to weather the tiles, drawing out the natural colours, to further enhance their appearance.
A combination of all the above distinguishes the real hand made clay tile from the imitation.
If you are looking for flat tiles, dull tiles, or tiles that are quick and easy to lay you should not be specifying a genuine handmade product.
When specifying handmade clay tiles, it is very important to consider the skill of the roof tiler. Because of their nature, handmade tiles require a certain amount of sorting and mixing before laying, which brings out the true craftsmanship of the experienced tiler.
It is not recommended to lay true hand made clay tiles on roofs with a pitch of less that 40º. If considering a lower pitch contact the manufacturer for guidance on weathering.
Another important factor when selecting tile is is the life cycle. Handmade clay tiles enjoy long life; clay roofs of over a hundred years old are fairly common. The cost of maintenance of the actual tiles is negligible and with proper care they can also be reused.
Specials and one-off productions
With the advent of modern factory systems mass productions of standard items has greatly reduced the choices available to the architect when designing the roofs of tomorrow.
The range of clay tiles designs in existence 100 years ago had greatly diminished together with most of the manufacturers.
It is especially important with regard to conservation and the environment that architects are given the means to specify one off and special products which either faithfully reproduce the original tile or create a new naturally sympathetic feature on the roof.
The creative ability of architects to design exciting new pitched roofs should not be constrained by the produce’s ability or willingness to manufacture.
Hand made producers, such a Keymer, which still employ individual craftsmen, are able to meet the challenge of almost any project regardless of period or size.
Despite the introduction of standard tiles sizes by Edward IV many sizes and shapes continued to be produced including Spanish style overs and unders. The range of fittings was also varied with many unusual shapes and colours designed to bring a unique character to the roof. As these roofs become due for replacement the trend is to replace them with whatever is easily available.
Second hand tiles
The popularity of genuine hand made clay tiles is set to continue. Discerning clients insist on the real thing, they are looking for the intrinsic beauty of materials used on houses perhaps hundreds of years old.
However despite all the research and development and the launch of yet another “look alike” tile, very few new materials can provide the genuine look, the perceived patina of old age, which is what the hand made clay tile is all about.
This demand for instant “old age” is one of the reasons why second hand tiles have proved continually popular.
The used of second hand clay roof tiles in refurbishment and new building projects can create an inferior roof which threatens the future of Britain’s clay roofscapes.
It flies in the face of manufacturers’ commitment to quality control and any attempt to preserve the beauty of the nation’s traditional roofscapes with top quality hand made tiles. Keymer tiles are produced under a quality assured system.
The cannibalisation of tiles from older buildings, particularly agricultural barns around the countryside is sad to see.
Most secondhand tiles are salvaged by roofing contractors when re-roofing properties. Many are taken from failed roofs and are of dubious quality.
They are bought in as job lots by roofing merchants and then sold out again at vastly inflated prices to builders and their unsuspecting clients.
Secondhand handmades are not cheap by the time they reach the end user. Any price advantage that does filter through to the client specifier should be carefully weighed against the possibilities of early failure. On larger projects it is often difficult to obtain all the tiles in a consistent colour. Ridges and bonnets can also be hard to colour match.
There are no come backs or guarantees with secondhand materials. They are bought and sold in “good Faith” but try telling that to your client when he is saddled with the additional costs for repairs to what he thought was a new roof.
Apart from these inherent risks, good secondhand hand made tiles in the south east of the country are becoming extremely scarce, particularly peg tiles. Fortunately new tiles made from the locally dug Weald clay indigenous to the south east are able to match scarce old Kent peg tiles.
The weathering properties of the clay also ensures that the ridges and bonnet hips blend well into older roofs.
Fortunately there are still some manufacturers who can faithfully reproduce unusual tiles and fittings, including our heritage division. Cost will always be a consideration but as with all genuine articles the best quality does not come at the lowest price.
We all have a responsibility to protect our heritage and the environment but this should not constrain the creativity of architects to design new and exciting clay pitched roofs.
Hand made clay tiles have been used on hundreds of conservation projects, ranging from small working farms to the Royal Palaces.
It is important when specifying for these projects that the source of tiles is known. Many tiles are being imported from places such as, Turkey, Vietnam and Sri Lanka through Import Agents with “British Sounding Names” and with unknown production techniques.
This historic building was a gift from Napolean to Princess Eugene.
Specified by Mr C J Glover, Herring son & Daw, over 34,500 Antique tiles, 5,000 Club tiles & 2,500 Fishtail tiles were used for the project. The roofing was carried out by Ted White.
A mix of two parts Antique to one of Elizabethan was chosen for this project. Around 45,000 tiles were used, chosen for their authentic appearance and ability to blend in with the aesthetics of the building.
The architect was Neil Birchall of Norwich.
Southampton based architect Alistair Hunt and client Sussex Archaeological Society decided traditional hand made clay tiles were a better option than struggling to salvage existing roof tiles. 54,000 Kent Peg tiles used on 12th century building. Work was closely monitored by English Heritage.
You’ve reached the end of the CPD. To make sure you’ve taken on board the key learnings of this course, please fill out the quick multiple choice Q&A below. This will certify that you have completed the CPD and provide you with an email certificate, which, if the course is accredited, you can share with RIBA.