Part 3 (2/2)

”The cob was made of the stiff sand found on the site; this waswheat straw trodden into it The walls were built 3 ft thick, pared down to 2 ft 6 in, and were placed on a plinth standing 18 in above the ground floor, and built of cobble stones found aiven a coat of plaster and a coat of rough-cast, which was gently trowelled over to sed on the cobwork, so in on to the top of the walls It took them about three months to reach the wall plate; the cost was 6s a cubic yard, exclusive of the plastering No centring was used

The joists rested on plates, and above them the walls were reduced to 2 ft 2 in in thickness to leave the ends of the joists free The beams also rested on wide plates and the ends were built round with stone, leaving space for ventilation Tile or slate lintels were used over all openings The cost of the whole house was 6d a cubic foot Building with cob is soon learnt--of the eight men, only one of them had had any previous experience, and, I believe, he had not built with it for thirty years This is the only house I have built of cob”

What isin this narrative is the workmen's lack of experience, which seems to have been no hindrance Anyone who proposes to revive the use of cob e fro the walls was reasonable and the cost low It reater in proportion, if as great, when compared with brickwork The natural charm of the wall surface is enhanced by the crown of thatched roof,so certainly to their task as Mr

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-- II METHOD OF BUILDING

_Composition_--Cob is a mixture of shale and clay, straw and water

Shale is a common and widely distributed stratified formation of a slaty nature, and there are few types of clay soil that would not serve for cob-

The precise relative proportion of the first two ingredients varies, depending on their individual peculiarities

Local custoenerally be found to have adjusted itself to the peculiarities of the soil

The following extract is from an analyst's report on a sa:

”The material when placed in water fell to pieces On analysis, it was found to consist of:

Per cent

Stones (residue on 7 by 7 mesh sieve) 2440 Sand, coarse (residue on 50 by 50 h 50 by 50 mesh sieve) 3250 Clay 2060 Straw 125 Water, etc 155 ------ 10000 ------

”The ravel with a very sandy clay, to which mixture a small proportion of straw has been added

”The clay acts as an agglutinant, and the straw as a reinforcement

”Efficient protection from frost and rain would be necessary before such material could be considered weatherproof”

[Illustration: +A Devonshi+re Cob Farmhouse, probably between 200 and 300 years old+]

[Illustration: +A Cob-built Village+]

(NB--Lime is occasionally added to the clay-shale, but this is not usual)

_Mixing_--The oldby hand is as follows: A ”bed” of clay-shale is formed close to the here it is to be used, sufficient to do one perch A perch is superficial h, and the a to the thickness of wall required Fourstones are picked out The ed in a circular heap about 5 or 6 ft in diae theand treading on the material all the time One man sprinkles on water, and another sprinkles on barley straw from a wisp held under his left arain in the other direction, treading continuing all the ti” is usually considered sufficient Straw bands s of the men to keep them clean, and these are re is done in a rough trough, whilst a power-driven ”pan-h one would think that the use of such a th of the straw sub

[Headnote: Implements]