Brick and tile have been used in construction in Denmark since monks introduced it here in the 1100’s, because it is a robust and natural material. Nevertheless, researchers at The Danish Design School are currently improving on brick as a material, among other things by making it lighter. In an environmentally friendly and aesthetic way, the new material solves some of the problems we face today, such as increased noise problems and poor indoor climate.

By Anna Krarup Jensen

Since 2004, two senior researchers at The Danish Design School, Associate Professor Snorre Stephensen and Architect Peter Mackeprang, have worked on renewing the classic brick expression through a project on ceramic climate screens.

During the first stage of the project, among other things, they developed a completely new type of brick that is capable of solving some of the problems facing the construction trade today. They are now ready to approach stage two, which focuses on ceramic facades.   

With their research project, senior researchers Peter Mackeprang and Snorre Stephensen at The Danish Design School are rethinking the potential of brick, both in technical and aesthetic terms.

“If brick is to be preserved as a material, someone simply has to renew it. It’s an amazing material that’s environmentally friendly, aesthetic and flexible,” says Peter Mackeprang about the motivation behind the project, which addresses both the technical and the aesthetic properties of brick.

The New Brick Material
In stage one of the project, Snorre Stephensen and Peter Mackeprang studied the existing brick materials and their usage. Next, they embarked on the process of developing a new and better brick, which weighs only a third of the classic brick.
“The classic brick is designed for load-bearing constructions. Today, brick is often used for covering, for example in facing walls, and therefore we developed a type of brick tile with special air pores, which is much lighter. This makes it easier to mount, and the constructions don’t need to be as sturdy,” says Snorre Stephensen.

One of the properties of brick is its ability to stabilise moisture in the surroundings, as it absorbs and releases water very easily. Thus, it acts as a so-called moisture stabiliser. In the project the two researchers also experimented with various forms of firing, glaze, reliefs and dye.
“With our light-weight brick it’s possible to use a glaze that forms a hard surface without closing up the pores, so that the brick still breathes and releases water. The firing makes the glaze burn into the brick to form an intermediate middle layer,” says Snorre Stephensen.

A Solution to Energy Problems
The first phase of the project focused on ceramic climate screens, including noise screens. Since the project began in 2004, there has been a sharp increase in the noise problems on Danish roads, and the conclusion from the first phase is that brick has excellent noise-reducing properties.
“We have developed noise screens with brick sheets that form enclosed spaces that act as noise locks,” says Snorre Stephensen. A prototype of a climate screen made in the new light-weight brick has been set up by the entrance to The Danish Design School.

An example of the new type of light-weight brick that the researchers have developed. The tiles have air pores and can be decorated, for example with a relief pattern.

The main focus of the next phase of the project is the use of brick in facades. A few years ago, a new energy act was passed in Denmark, which requires better insulation in buildings, and the new brick tile might be part of the solution to this energy problem.
“The brick industry needs to be innovative. You can’t just continue to put facing walls on top of facing walls, for example when reinsulating buildings. Here, the new tile is very useful as a covering material. Besides, the tile itself also adds insulation because of the air pores,” says Snorre Stephensen.

Available in Large Sizes
With the classic brick material, it is difficult to produce formats larger than conventional bricks, as moisture sensitivity makes the material twist and set when it dries, which means that the large sizes become unstable, and the proportions are distorted. Thus, natural stone, e.g. slate, is often used when a project calls for large-size elements. But the air pores in the new light-weight brick have enabled larger sizes than before.
“The air pores reduce the shrinking; in our brick shrinking is less than 1%, while classic brick might shrink by as much as 10-12%. That allows us to produce tiles in large modules that can be mounted with small joints instead of the rather dominating joints in classic brick walls," says Snorre Stephensen.

This means that the tile’s expression is more distinct, as the tiles are larger, and there are fewer joints. A special dye technique called engobing creates a colour play that gives this light-weight tile a vibrant surface that appears distinctly in both wet and dry weather.

Tried and Tested
The new tiles have undergone testing at the Technical University of Denmark
(DTU) in a series of trials that tested them for frost-proof properties and for their ability to absorb and release water. Even though the air pores make the light-weight tile more porous than classic brick, it complies fully with the Danish requirements for frost-proofing, and water absorption/release also stands up to standard brick.

Diploma students at DTU have also tested the application properties of the tiles.
“Sticking them up with an adhesive on the back, as with bathroom tiles, produced positive test results. But we need to develop an application for the tiles, and we are currently negotiating with the insulation producer Rockwool, among others, to develop an adhesion technique,” says Snorre Stephensen.     
   

The new research results make it possible to produce brick tiles in larger sizes than before, for example for covering facades.

Existing Brickworks Technology
In developing the new light-weight tiles, Peter Mackeprang and Snorre Stephensen kept the existing technology of the brickworks in mind.
“We adhered narrowly to the existing conditions. The new tiles can be produced in the kilns that the brickworks already have, with the same firing technique and work flow. The clay that we used was delivered directly from the brickworks we worked with,” says Peter Mackeprang.

He also emphasises that the new tiles can be cut with a standard hand saw and are therefore easy to adapt.
“If these things aren’t in place, there won’t be any commercial interest,” he says.

Slick Horror Scenarios
The aesthetic properties of brick are also essential to Snorre Stephensen and Peter Mackeprang. They see it as a national characteristic of Denmark. Everywhere in Denmark, we see red or yellow brick houses, while almost all houses in Germany, for example, are plastered. The problem with plastered facades is that they require regular maintenance, and when this is neglected, towns and streets begin to look derelict.
“By contrast, an old farmhouse in wind-swept western Jutland will still have a certain aesthetic appeal, as brick simply improves when it is aged by wind and weather,” says Peter Mackeprang.

One of the reasons why he strives to improve and develop brick is the desire to avoid what he calls the horror scenarios.
“Buildings made of completely slick materials – for instance flow glass, which is a special type of smooth glass sheet – create light reflection, noise reflection, acoustic problems, and high wind speeds. A single building of that type – or a few – can look really great, but when an entire street or area is filled with them, there’s a problem,” says Peter Mackeprang, who feels that such a setup makes the eye hungry for the calm visual expression that brick-clad buildings offer.
“Even if one building uses yellow brick, and the neighbours use red or black tiles, it’s still the same basic idea, and that provides a sense of consistency in the streetscape,” he says. 
 

A special dyeing technique called engobing gives the tiles a vibrant surface.

It’s Actually Safe to Eat...
The reinsulation of facades often uses aluminium, glass or silicate sheets. These sheets are never broken down in nature, and they require surface coating with toxic substances to stand up to the climate. Here, brick offers an environmentally friendly alternative.
“Our tiles are actually safe to eat – if only your teeth could hack it! They don’t contain anything toxic. Brick is a clean, natural material that’s broken down in nature. Once it’s dismantled, it can be recycled or simply dumped in a hole in the ground, so it’s a very sustainable material,” says Peter Mackeprang.

The two researchers are also considering looking into the possibilities of using the new tiles indoors, which might solve some of the problems with poor indoor climate.
“Modern houses are very well-insulated, and people use paint types that practically turn the house into a plastic bag. The materials simply can’t absorb enough water, so moisture collects in the homes, which leads to mildew, etc.,” says Peter Mackeprang, again highlighting the ability of brick to absorb water.

Rethinking Ingrained Habits
Brick is an ancient material, which has been used for construction here since the 1100’s, when monks introduced the “baked stones” to Denmark, for example in the construction of Roskilde Cathedral. Thus, brick is firmly rooted in the minds of architects and builders.
“Although today’s brick and tile industry is very high-tech and modern, the bricks and tiles themselves look largely as they did in Middle Ages, and that’s a habit that we’ll have to change,”  says Snorre Stephensen.

Peter Mackeprang emphasises that architects only use the materials that are available.
“The initiative for new materials is not going to come from the architectural firms. The architects accept things the way they are. However, they are very quick to embrace new materials once they become available. We saw that with laminated wood, for example, when that was introduced,” he points out.

In their quest for innovation, the researchers worked with a couple of brickworks in Denmark. They expect the light-weight tiles to go into production, and, in time, to see additional brickworks follow suit.
“Facing walls are back, although brick was considered obsolete by the 1970’s. That’s because the consumers want brick. But today’s facing walls are over-sized, because they still pretend to be load-bearing, even though they’re simply covering,” says Snorre Stephensen, who therefore predicts a market for the new tiles.

Photos: Snorre Stephensen and Peter Mackeprang.

 

Mind Design #8, 2008