There are a large number of so-called “half-timbered” houses in Normandy. The main reason was that timber was plentiful while stone was rare and expensive. They consist of a skeleton of beams whose interstices are filled with cob (a mixture of clay and straw) covered with lime. The oldest half-timbered houses date from the Middle Ages, the Renaissance, and the 18th century. The Seine-Maritime, Eure, eastern Calvados, and Orne departments are the areas with the most of these homes.