Rammed earth arches

rammed earth arches are cheap, effective openings

 
   
 
 
 
   
         

Building arches with rammed earth needs some forward planning. The shape and size of the arch needs deciding, and then the block-out or displacement box has to be made. Once made, the same shape can be repeated indefinitely, giving a different feel and rhythm to what is being built.

There are plenty more images of rammed earth arches.

As with all rammed earth the box is the wall, more detail in the box means more detail in the wall. The more inserts in the wall the less earth, and the less ramming, but also less strength, so this needs to be thought through carefully.

In the job shown formwork was made from 18mm plywood and 75mm x 50mm timber. The two arch blockouts were made from ply facings, cut to the shape of the curve, 50mm x 25mm battens separate the two ply faces and a triple hardboard skin is flexed over to give the inside of the arch its smooth finish.

Also a square facing board was fixed on the outside face of the wall with a chamfered edge as a purely decorative feature, extremely easy to achieve.

 

 

   
     
  These repeating shapes and the indented frame around them are quick and cheap to build  
     
Once the blockouts are made and placed in the formwork material is rammed up either side of the blockout and finally over the top, with ideally at least 450mm of material rammed above the opening for stability. Different arch shapes have different strengths but all of them share certain characteristics, like they don't need a lintel. Lintels work well in rammed earth, in timber, steel or concrete, but not having one saves time and cost.

In the 20th century arches have fallen from favour, but they remain a positive structural element in building and one which works well with rammed earth.

   

 

       

    Crisp surfaces and elements give earth a different feel  

       

     

       

    The same two wooden blockouts produced all these arches  

       

       

 

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