Clay Lump Green Building

Clay Lump Green Building was the sophisticated way to build an earth home created totally by natural materials making any repairs to an old home or a new build to be an Eco Friendly green home improvement project!

Building homes from earth, before clay lump, started out by making up the mixture and then throwing lumps of cob to a 'master cob builder' who would be balanced on the three foot wide cob wall and he would catch the big lump with a three pronged fork and then settle the natural material onto the wall, walking backwards as he built it up over days, let layers dry and then build it up some more...

So progressing onto Clay lump green building methods was a really big change in the way country homes and farm buildings were constructed at the time, not only in the time that it took to complete the build but also because it was easier to learn the trade of Clay Lump over Cob and so allowed semi skilled work men to build a home...

We don't have to go far to find a natural option to home building materials, with all the energy required to make cement blocks or fired red bricks, Clay Lump from the 1800's meant that the natural clay mixture, prepared in the same way as for Cob building, was then formed into "lumps" or blocks - the first natural building blocks.

Clay Lump Green Building Material

Unlike Cob, where just about everything on the ground was mixed in, Clay Lump Green Building Material of olden days was just basically clay and straw bind together with water.

Graphic showing making clay lump green building materials

Clay Lump was mixed up in the same traditional way as Cob...

with men with forks breaking up bigger pieces of clay and adding water and mixing in broken straw bits...

while horses walked across the circle of mixture breaking up the rest of the lumps.

Clay Lumps or 'Clay Bats' were made while the mixture was still nice and wet and easy to form into shape.

Clay Lump Mould

Wooden 5 sided moulds were about 1 1/2 feet long (18 inches) less than a foot wide (about 10 inches) and about half a foot deep (6 inches) so Lump blocks were surprisingly big, really the maximum comfortable weight and size that strong men could lift into place all day long on what really was a green building site.

Graphic showing a simple clay lump mould

The eco friendly clay lump mixture was pushed into the mould - which was conveniently big enough to get a boot in to compress the mix.

The mould was then turned over and lifted and the perfecty formed Clay Lump was left on the ground to dry.

The clay lumps changed color as they dried so it was easy to be able to judge when a soft lump brick was set enough to be handle so that it could be turned over to allow the other sides to dry.

In this way you can begin to imagine rows upon rows of single bricks on the ground drying out in the spring and summer sunshine and towers of clay lump bricks stacked up and ready to use on the home building project.

The enemy for any Clay Lump building site was rain, water and dampness as clay lump disintegrates and brick deteriation was quick.

Building with Clay Lump Green Material

Once the Clay Lumps were formed and dried and ready to use the actual build was a lot quicker than using Cob which was build it layers and then had to be left to dry, but that isnt the only advantage...

Building with Clay Lump Green Materials was also quick because the walls were build to the thickness of the clay lump brick - where as with loose cob earth walling the walls had to be thick to create stability and so much more clay had to be dug up and brought to the site in the first place.

Another important advantage was that clay lumps could be prepared (with shelter) throughout the year and so a stock could be prepared ready for the good weather of the dryer, spring and summer months when the actual build could be started.

In the look and feel of the buildings of either type of traditional mud construction, although materials were basically the same, a cob construction was much inferior to that of a clay lump home of which the smooth even walls were much favoured and sought after in the mid 1800's.

a foundation wall of stones or bricks was first built about a foot high up from the ground to make sure that the Clay Lumps were kept well high and dry and away from any ground puddles of water.

Brick Chimney on Clay Lump

With stones or bricks used as foundation stones the only other time that something other than clay lumps were used on this type of house was in the construction of the chimney.

Although some chimneys were built of clay lump up to the roof level and then the stack finished off with red bricks, it was more usual for the entire chimney stack to have been built of brick because of their strength, purity of clay and ability to withstand great heat.

Rendering Clay Lump Green Building

As we know clay lump has to be protected from the elements to prevent brick deteriation.

The first clay lump buildings were rendered in more clay and straw and then rendering progressed to the use of lime plaster.

Old farm buildings are seen to be of a dark surface almost as if they had been burnt and this is because gas tar was used to coat the outer surface and protect the shell of the construction.

Clay Lump Green Building

For all the weakness and vulnerbility in Clay lump as a clay bat block building material we may ask if it is at all viable and the best answer to that question is to look at the hundreds of examples that have stood the test of time for hundreds of years and are still used as family homes today.

Timber frame construction is back in vogue when using wood from sustainable sources and together with locally formed clay lump green building material it really is possible to create an Eco friendly home with a very small footprint.

If you have the right plans and the time and the money and the right building site - and local building regulations permitting!, working on an earth walling through Clay Lump Green Building could be a dream home come true.

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