Cottage Building in Cob, Pisé, Chalk and Clay: A Renaissance (2nd edition)

Roof.—Though thatch is the traditional roofing material of chalk cottages, any other will serve that is permanent and good of its kind.

The only special demand that chalk walls make is that the eaves shall be generously overhung for their better protection from the weather.

Where, in later years, the boldly projecting thatch has been thoughtlessly replaced by a slate roof with meagre eaves, or with none at all, the walls have suffered accordingly.

Garden Walls

Garden Walls.—A chalk garden wall must be afforded just as much protection as the wall of a house and on both sides.

The hat with which it is provided is of the highest importance to the health and longevity of the walling.

Examples of garden wall copings are given in the sketches shown below.

WALL COPINGS.

House Walls.—Chalk conglomerate walls rarely exceed 18 in. in thickness, and are usually the same upstairs as down.

A plinth of the same thickness as the chalk wall it supports is usually carried up 6 in. to 18 in. above the ground level in rubble-work, flint, or brick, being known as the “Underpin Course.” Any of the stock damp-courses are suitable, but they must be well and truly laid, as damp feet are nearly as deleterious to a chalk wall as a leaky or inadequate hat.

No special tools are required for this method of building, an ordinary farm fork for lifting and a spade for the final chopping down of the wall faces being all that are necessary.

A house built during the summer is usually fit for occupation the same autumn.

Old Examples.—Those who may wish to see buildings in chalk conglomerate, both old and new, would do well to visit some such typical chalk district as that lying about Andover in Wiltshire.

It should, however, be constantly borne in mind that most of the old cottages were somewhat unscientifically erected by their original jack-of-all-trades occupiers, that damp-courses and Portland cement were unknown, and that the advantages of proper ventilation and the causes of dry-rot were discoveries yet to be made.

Secondly, a large number of these cottages have been sadly neglected either recently or in the past, and they bear the disfiguring marks of their ill-treatment upon them now.

But a chalk cottage that is well found in the beginning, and that is reasonably well cared for subsequently, has nothing to fear from comparison with cottages built in the most approved manner of the more fashionable materials.

Mr. James Thorold gives the following particulars of a block of three chalk cottages recently built for Sir George Cooper on his estate at Hursley, near Winchester:

“The chalk walling was done by Messrs. A. Annett and Son, of Winterslow, near Salisbury, where this method of building has been kept alive from olden days. It consists of working up the soft upper strata of the chalk by putting a bed of it 4 ft. 6 in. thick on the ground, watering and treading it to a sticky consistency with the feet, working in shortish straw at the same time. When thoroughly mixed by the builder’s mate, he lifts up a forkful to the builder working on the wall immediately above him, the latter catches the chalk, dumps it down on the top of the wall, building an 18 in. course all round. As soon as the weather has dried this sufficiently he goes round with a sharp spade squaring up both sides of the wall. As this work is greatly dependent on the weather it is well if the men have other work to fall back on, and that building operations should be commenced in the spring or early summer. The wall is built 18 in. thick to the first floor joists and 14 in. above. Chalk in itself being very absorbent of moisture, the usual plan is to render the outside of the wall with a lime mortar, which, however, requires renewal every few years. To obviate this we fixed with long staples 1¼ in. mesh wire-netting over the outside surface of the wall to give a reinforcement for a rendering of hair mortar and cement gauged in proportion of 1 to 2 respectively, and left rough from the trowel. This rendering was done at a cost of 3s. 3½d. per square yard, which is a substantial addition to the cost of the walling, but so far there is no sign of a crack or hollow place behind it, and the cottages have kept very dry. The walls were finished off with a limewash containing Russian tallow and copperas.9

Cost of Three Cottages

“As regards the cost of this block of three cottages, the result is obscured by the fact that tall chimney-stacks with ornamental bricks and appropriate foundations were built and reinforced leaded lights were used in the windows to keep the building in character with the other cottages on the estate, but at the time we estimated that the chalk walling saved a sum of £54 as against the amount we should have had to have spent in carrying out the building with bricks made on the estate, and this had to include lodging money and profit, the builders being independent men. The ornamental chimney-stacks were put in for the sake of appearance, flues built up in the chalk being entirely satisfactory and fireproof. The foundations are either flint or brick with a slate damp-course.

“I consider that for a chalk country this method of building has many advantages.

“(1) It saves cartage.

“(2) It can be carried out by a skilled labourer who can be otherwise employed during unsuitable weather.

“(3) No fuel is required as in burning bricks.

“(4) If a suitable rendering is employed to keep it weatherproof, and a good damp-course on the foundations, the cottages are nice and dry and keep an equable temperature, chalk being a good non-conductor.

“Sir George wonders if any method could be devised by chemical means to harden the chalk and make it weatherproof; if this could be done it might save the expense of the cement rendering.”

CHALK CONGLOMERATE

From Country Life, February 23rd, 1901:

“Soft chalk is practically mud, yet Dr. Poore, one leading authority on rural hygiene, had his model hygienic cottage built with it at Andover, just outside the boundaries, in order to escape the tyranny of the bye-laws. In several other places this material has been used time out of mind.

“The white cottages on the Wiltshire Downs are as good as any in England.”

 

Three Chalk Cottages at Hursley Park

THE WINTERSLOW COTTAGES

From Country Life, April 6th, 1901:

“The white chalk cottages of the scattered straggling village are found in every sort of position. They must not be confounded with the cottages of rock chalk at Medmenham. You might almost call them mud cottages.

“The house is generally both planned and constructed by the owner.

“. . . The soil is only a few inches deep, soft chalk lies close to the surface and can be dug out with a spade. This is a very suitable material in the district and costs nothing but the labour of digging. . . .

“On the downs there is a constant lack of water; that which falls in the shape of rain is therefore very precious, and in some cases is indeed the only kind available. But a large tank or artificial well is needed to contain it, and the pit from which the chalk is dug out can be made to serve the purpose. . . . One was made watertight by means of a lining of concrete, and held enough water to keep the family going through all the dry season.

“In another house . . . the chalk-pit had been utilised to form a large and convenient cellar. . . .

“Most of them (the cottages) . . . are on two floors, with parlour, kitchen, back kitchen and so forth on one, and the bedrooms on the other. In the preparation of the chalk, the method followed is that of treading it into a kind of rubble, and adding a proportion of straw and a small quantity of lime.

Expensive Scaffolding Avoided

“There is a local builder who will run up the shell of a house for a matter of £100, more or less, according to its size. . . . Most of the cottages are literally hand-made. A skilful architect who visited the Winterslow cottages felt sure that boards must be used to keep the walls straight, but he was wrong. The chalk is shovelled up and the walls are kept straight without line or plummet. No expensive scaffolding or machinery is employed. Yet the walls come out beautifully in the end, the colour being an exquisite soft white. They are about 18 in. thick, and the slowness of their construction has one good effect, it gives them time to dry. No point is of more importance than this. It is advisable not to put on any rough-cast, plaster, or paper for at least twelve months, as doing so will prevent the moisture from exuding. One or two of the little cottages were slightly damp, but the majority were as dry as tinder. The thickness of the walls helps to render the cottage more comfortable, to make it cool in summer and dry in winter.

“One word should be added in regard to soft chalk as a building material. Where it can be obtained in the garden at a few inches depth, and especially where the cottager is his own architect and builder, it can be most heartily recommended, but there are obvious objections to its transportation to districts where it is foreign.

“The village itself is a very homely and irregular one without a single dwelling of any pretence. The country lying adjacent to Salisbury Plain consists of broken, sparsely peopled downland, and very ornate or finished cottages would be out of keeping, but they would not look so well copied in a very rich, heavily timbered country.”

RATS AND CHALK

Note.—Conglomerate chalk is, like cob, vulnerable to the attacks of a really determined rat.

The outer defences provided by the exterior rendering can be backed up by the mixing in of broken glass or sharp flints with the substance of the wall, where such attacks are likely.

 

Marsh Court, Hampshire.

 

Brick-and-chalk Vaulting at the Deanery Garden, Sonning

Block Chalk

BLOCK CHALK

“Chalk” is a term somewhat loosely used to denote the soft white limestone—the “Creta Scriptoria”—that is cousin to Marl on one side and to Ragstone on the other.

In its purest form chalk consists of over 95 per cent. of carbonate of lime in the form of fine granular particles held together by a calcareous cement, its organic origin being clearly traced in the remains of the minute sea creatures with which it abounds.

Hewn blocks of chalk have been used for walling and vaulting from immemorial times, and, where not exposed to direct erosion by the weather, remain to this day as clean-cut as when they were first quarried and a very great deal harder.

The filling in of the great vaults at Salisbury Cathedral and in the Bishop’s Palace are of chalk, whilst innumerable lesser buildings of more or less antiquity still remain to us as monuments to the excellence and durability of this stone.

Chalk, too, was often used in combination with flint or brick to build the engaging chequer-work walls that embellish so many downland villages.

At Medmenham there are cottages both old and new of hewn rock chalk, and both the Berks and Bucks banks of the Thames have many buildings to show of this beautiful material.

Amongst present-day architects Sir Edwin Lutyens was the first to give hewn chalk an opportunity of showing its quality in serious architecture, Marsh Court in Hampshire being an instance of more than local celebrity.

In the great walls at the Bishop of Winchester’s palace, Farnham Castle in Surrey, the old builders appear to have used bricks, limestone and chalk proper, according as the several materials were delivered, quite indifferently, and with results altogether delightful.

Not all chalk is suitable for building, that near the surface being often far gone in decay and much too friable for such a purpose.

Even when apparently sound blocks have been gotten they are not infrequently found to be crossed in all directions by planes of weakness along which they are apt to fall to pieces in the handling.

From this cause the “waste” is sometimes considerable.

The well-known building “stones” from the quarries of Beer, Sutton, and Tottenhoe in Devonshire are really chalk, but in a form not readily distinguishable from ordinary free-stone.

The longer that chalk blocks are kept to dry before building-in the better, and the sun and wind of at least a year should be allowed free play upon them to dry out their natural sap and render them “frost-proof.”

During the drying-out process the chalk should, if possible, be protected from the rain.

For years after being built into the walls of a house, chalk will continue to dry and harden.

But it is essentially a somewhat porous material, and will quickly revenge itself on those neglecting its just demands for a sound roof and a proper damp-course.

In exposed situations new chalk walling is liable to allow the penetration of moisture under the pressure of the wind unless a cavity is provided or unless the surface is treated with a silicate or other “vitrifying” fluid.

Chalk, however, has one shining virtue in common with its great antithesis—it improves mightily with keeping.

Chalk walls sometimes have youthful vices in the way of porosity that entirely disappear with advancing years through the closing up of the surface pores, which eventually makes a cavity and inner lining superfluous.

9 See recipes for Whitewash in Appendix (I).

IV
UNBURNED CLAY AND EARTH BRICKS

IV
UNBURNED CLAY AND EARTH BRICKS

Sun-dried Bricks

The use of sun-dried bricks in this country, is, for no very apparent reason, almost entirely restricted to East Anglia. There it has been used for generations with entirely satisfactory results.

Mr. Skipper of Norwich writes of the material as follows:

“Who, travelling from Norfolk to London, whether by the Ipswich or Cambridge line, has not noticed the numerous colour-washed or black (tarred) cottage, farmhouse and agricultural buildings scattered practically all along the countryside? Some of these are of studwork and plaster, some of wattle and daub, but many are built of clay made up into lumps, sun-dried, and built into the walls with a soft clay-mixture as mortar. No lime need be used, though sometimes it is mixed with the clay mortar. The preparation, digging, exposure and mixing with short straw are similar to the Devonshire ‘cob’ work, but in these parts the worked clay is thrown into moulds, and lumps are formed of, say, 18 in. by 12 in. by 6 in., or 18 in. by 9 in. by 6 in. for large sizes, and for inside walling or backing to brick-faced walls, 18 in. by 6 in. by 6 in. The walls, naturally, are rough in texture and the joints are generally stopped up and besmeared with a thin coating or almost a wash of clay. This coating sometimes has lime mixed with it, but it is not necessary. This is all that is needed to complete the walling, and there is a building—a malting, that any one can see at Tivetshall Station on the Ipswich line, about 200 ft. long, 45 ft. or 50 ft. wide and three floors high, built of lumps 18 in. by 12 in. by 6 in.—that has stood the weather and weight of its roof for forty years built in this way; 12 in. is the thickness of its walls. A further stage in finish is to give the walls two or three coats of coal tar, but it is not essential, though desirable where stock are kept, as cattle are rather fond of licking the clay, and they do not use their horns much when walls are tarred. The highest finish in this work is to cast sand on the last coating of tar before it is quite dry, and then to colour or whitewash on this. This accounts for the variety of colourings seen in these buildings, some even of a kind of pink or red; while some yellow or buff, beside the white and the black or tarred buildings, and all huddled together or standing apart, whether covered with thatch or red pan or flat tiles, look remarkably in harmony with their surroundings. These lump walls are, of course, built on a base of brickwork, about 18 in. or 2 ft. high, to keep them free from damp. This kind of walling can be built for at least 15 per cent. or 20 per cent. cheaper than ordinary 9 in. brickwork. Thin as these walls are compared with those of ‘cob’ houses, they are noted for being warm in winter and cool in summer. When suitable clay is procurable a local builder almost invariably uses clay lumps when building a house for himself, though to gratify a whim perhaps, he will case the outside walls—especially the front next the street or road—with brickwork. But clay lumps he carefully reserves for inside walls and weight-carrying linings to the outside walls, bonding the two together very much in the same way as two 4½ in. ‘cavity walls’ are bonded. I am not suggesting that this walling is as interesting artistically as ‘cob,’ but I do suggest it is a practical, sensible and dry walling, and if properly done it will ‘last for ever,’ as a local builder repeatedly said to me when speaking of it. One can easily see why the cost is light—the sun and the winds do the drying in the spring months, and no coals are required, and also the clay is often found on the building site, hence no cartage. Actual building work naturally goes quickly, as the lumps are large. There is another important point to notice. One may see a building complete with its roof on and occupied by its tenant while still awaiting an outside casing of brickwork to be built round it, either with a view to greater protection or for the mere vanity of the owner, for while thus left unprotected the lump walls take no harm from even winter exposure. Now to be quite practical in these extremely practical days, I venture to suggest that the use of clay lumps at least for inside walls and linings of outside walls would be an immense boon to the numerous cottage-building schemes now being projected. We must not forget that comparatively few bricks will be available this year, while the cottages are wanted at once. Can these few bricks be better used than by forming foundations and chimneys for the clay-lump walls of these cottages? I think not. The cottages could, of course, be occupied in the late summer or autumn of this year, and next year when bricks will be more plentiful perhaps the brick casings could be added, if brickwork must complete them. I make this strictly utilitarian suggestion solely to meet a very urgent and deep national need. Personally, I prefer the sight of a cottage built and finished in the old-established method of the locality. Unskilled labour only is required, working under intelligent supervision, hence immediate employment for a great number of men would be provided.”

Use for Unskilled Labour

 

 

The use of sun-dried bricks for the interior partitions of cob and pisé cottages is worth consideration, as the nature of these materials demands a thickness of wall which is too wasteful of space to be acceptable in mere partitioning.

Of the strength of clay-lump walls, there is no question. It was recently necessary to cut a new doorway in the old clay-lump wall of a large traction-engine garage, and the blocks removed were thrown into a heap upon the ground.

The clay happened to be needed for other purposes, for which it had first to be broken up.

Ordinary hammers proved entirely ineffective, and it was not until heavy sledges were used that the lumps could be smashed.

The tractor-house in question is a large building some 25 ft. by 100 ft., carrying a heavy roof and constantly subjected to vibration by the coming and going of the tractors.

The walls are only 12 in. thick, without piers or reinforcements of any kind, and yet the whole building, which is 26 ft, high at the gables, is as perfect to-day as when first erected some twenty years ago.

 

In the same town as this tractor-house, East Harling in Norfolk, is a council school built of clay lump (converted from the old Corn Hall), apparently not a pin the worse for a century of hard wear.

Near by there are a number of private houses built of the same material, some of them reputed to be upwards of 200 years old and certain of them having considerable architectural merit.

“Substantial and Cool”

(Extract from “The Farmers’ Handbook,” issued by the Department of Agriculture, New South Wales, 1911)

“Adobe,” or Sun-dried Bricks

“As their name implies, these buildings are constructed of sun-dried, but unburnt bricks. For buildings of this character, material like clay, which is unsuitable for pisé-work, can be used. The bricks are made in a wooden mould, and are 16 in. long, 8 in. wide, and 6 in. thick. A man can mould about 100 per day. They are laid in a similar manner to other bricks, the mortar used being wet loam, or even the material of which the bricks are made. The cost of making and laying is estimated at about 15s. per 100. Buildings constructed of these bricks are substantial and cool, and very similar in character to pisé buildings.

“A school-house built of these bricks eighteen years ago by Mr. Nixon, of Reefton, is still in an excellent state of preservation; in fact, little, if any, the worse for wear, despite the fact that walls are unprotected by verandahs or overhanging eaves. During its existence it has had, first one coat of oil-paint, and later a coat of coloured limewash.”

“Clay lump,” then, is one of the many good old building methods that needs no proving, but only revival and perhaps improvement.

APPENDIX

I
WHITEWASH

Whitewashing has been frequently referred to in the foregoing pages as the most suitable treatment for the exterior of chalk and earth buildings.

There is, however, a certain prejudice against lime-whiting amongst both owners and occupiers, owing to the frequent renewal that its adoption usually implies.

With a view to removing this drawback from a treatment otherwise so effective, the following recipes are suggested as improvements on the usual practice.

Ordinary whitewash is made by slaking about 10 lbs. of quicklime with two gallons of water.

The following recipes are taken from “White Paints and Painting” (Scott), and are reliable:

(1) “Factory” Whitewash (interiors), for Walls, Ceilings, Posts, etc.:

Mix (b) and (c), then pour into (a), and stir until all is well mixed. This is the whitewash used in the large implement factories, and recommended by the insurance companies. The above formula gives a product of perfect brush consistency.

(2) “Weatherproof” Whitewash (exteriors), for Buildings, Fences, etc.:

Pour (b) into (a), then add the milk (c), and mix thoroughly.

(3) “Light House” Whitewash:

Pour (b) into (a), and then add (c).

Note.—Alum added to a lime whitewash prevents it rubbing off. An ounce to the gallon is sufficient.

Flour paste answers the same purpose, but needs zinc sulphate as a preservative.

The following are from “1,000 More Paint Questions Answered”:

(4) Durable Whitewash for Outside Use.—A whitewash that will not rub off or wash off in rainy weather can be made by mixing one half-pint of flour to a batter with cold water, then stirring into this boiling water until it becomes a thick paste.

While still hot it is poured into a pailful of ready-made lime whitewash and well stirred in.

(5) Another simple method is to add to 2 gallons of ready-made lime whitewash one half-pint each of molasses and table salt. Must be stirred frequently while being used.

Whitewash for Exterior Surfaces.—A formula for a durable whitewash for out-buildings of rough lumber. The following is reprinted from “Popular Mechanics”:

(6) Place 1 bushel good fresh lime in a barrel with 20 lbs. beef tallow; slake with hot water and cover with sackcloth to keep in steam. When the lime is slaked, the tallow will have disappeared, having formed a chemical compound with the lime. Dry colours may be added to produce any tint desired.10

It is better to add colour before slaking the lime, but if this is not feasible mix the colour with alcohol and add it to the strained whitewash. Thin to easy flowing consistency with clear water.

Distempers and Limewashes

Cold Water Paint that will stand the Weather.—A formula for making a white outside coating that will resist the action of the weather and remain hard even under the influence of moisture and rain. Experiments with different brands of cold water paints have proved failures.

A really effective cold water paint, in order to resist the elements and remain white, should contain a white pigment of good body and some oil in addition to the water, and with this purpose in view the following is suggested:

(7) To make 100 lbs. of such paint, mix 10 lbs. white, pure in oil, with 10 lbs. bolted whiting, 8 lbs. raw linseed oil, 6 lbs. soft soap (made with potash), and 26 lbs. soft water.

One quart of pale copal varnish will improve the preparation. The formula given is of the right consistency to apply on dressed lumber with the brush. For application on rough lumber or with the spraying machine it requires more thinning with water and varnish.

The following is taken from Pearce’s “Painting and Decorating”:

(8) A London recipe for distemper has the following proportions: 4 “balls” whiting, 2 lbs. Young’s patent size, and sufficient water to cover the whiting.

(9) A Scotch distemper is described as: 12 lbs. whiting, size as given previously, 2 ozs. alum, 2 ozs. soft soap. It is very fast, for passages, schools, etc. Tinting colours for limewash should be restricted to ochres, umbers, lime blue, lime greens, charcoal or lamp black, and earthy reds (as Venetian).

(10) External limewash for farm buildings, etc., may be made as follows: Lime, ½ bushel, slaked with 1 gallon of milk and remainder of water, 1 lb. salt and ½ lb. sulphate of zinc to make it withstand the weather.

Experiments with and practical tests of these and other kinds of whitewash are being carried out, and the author hopes that he may find opportunity at some later date of announcing the results obtained.

10 Experiments and tests carried out for the author by the Department of Scientific and Industrial Research place this receipt at the head of the list.

Local Materials

II
THE IMPORTANCE OF USING LOCAL MATERIALS

(Extract from “Country Life,” November 9th, 1918)

300,000 Cottages would Entail the Transport Of 60,000,000 Tons of Material

In carrying out any considerable scheme of house building two difficulties will have to be met. The first arises from the scarcity of building material; the other from the cost and difficulty of transport. These, to some extent, can be obviated by the use of local material, which is to be commended on other grounds as well. Local material fits into the character of the neighbourhood in which it is found and maintains its traditions.

Very few people realise the bulk of materials, and in order to help them the following statement has been prepared to show the materials needed for each cottage and the total for 300,000 cottages:

Materials.	Weight.
	Per One Cottage.				Per 300,000.
	Tons.	Cwts.	Qrs.		(Tons.)
Ballast, sand, gravel	78	17	0		23,655,000
Lime	5	18	0		1,770,000
Cement	12	8	0		3,720,000
Bricks	85	0	0		25,500,000
Slates for D.P.C	0	10	2		157,500
Chimney-pots	0	0	3		11,250
Tiles	7	2	2		2,137,500
Carcassing timber	7	0	0		2,100,000
Complete joinery timber	1	12	0		480,000
Cast-iron rain-water goods and sundries	0	9	0		135,000
Stoves, copper, ash-bin, etc.	0	5	2		82,500
Nails, screws, etc.	0	1	2		22,500
Hair for plaster	0	1	0		15,000
Lead flashings, etc.	0	2	1		33,750
Sink, waste pipes, draining boards, etc.	0	2	1		33,750
Sanitary goods	0	1	0		15,000
Whitening, distemper and paint	0	3	1		48,750
Total	199	14	2		59,917,500

It will be seen that to carry out the scheme for 300,000 cottages a total of close on 60,000,000 tons of material will have to be shifted. In addition to that, it must be remembered that the cost of material is very small in comparison with that of building. This will be apparent from an analysis of the items employed for actual cost and the percentage which that cost bears to the total cost.

Cottages erected 1912 (semi-detached): total interior area of cottage, 772 ft. super, (parlour, kitchen, scullery and three bedrooms, coal and W.C.):

		Per House.
No.	Item.	Actual Cost.		Per cent. of Total Cost.
1.	Sundries	8		2.66
2.	Foundations	16		5.28
3.	External and party walls (a)	77		25.41
	Windows and doors (b)	23		7.59
4.	Internal partitions	36		11.88
5.	Ground floor	18		5.94
6.	Upper floor	22		7.26
7.	Roof and rain-water goods	34		1.22
8.	Chimney and fireplaces	30		9.90
9.	Sanitary fittings, water supply and drainage	19		6.27
10.	Staircases	11		3.63
11.	Fittings	6		1.98
	Total	£300

These facts help to clarify the problem. The weight of the building materials required for an ordinary cottage with living-room, parlour, scullery, three bedrooms, etc., the house containing cubic contents of about 11,500 ft., would come approximately to 200 tons per cottage; and even assuming that there is only an average transport of fifty miles, this would give 10,000 ton-miles per rural cottage, which is taking it at a very low average. In each cottage the weight of the brickwork represents about 42 per cent. of the total weight. It is, therefore, apparent that every effort should be made to lessen the transit of materials required for the external walling. If, on the other hand, local materials are employed, this carriage would be saved and a great economy effected. Even if this utilitarian consideration were not so important as it is, the desirability of making all possible use of local materials is very great from other points of view. It would stimulate local interest in building and, in addition to retaining the traditions of the district, give greater hope of retaining and maintaining the proper architectural aspect of our villages.

It is scarcely necessary to summarise the advantages that may fairly be expected to flow from this endeavour to make a real start at finding a solution for the housing difficulty. First and foremost must be placed the saving in transport. A casual reader may easily imagine that the difficulties of carriage will vanish with the end of the war, but that is not so in reality. Any one who has travelled in France must have noticed engines bearing such names as Liverpool Street, King’s Cross, Euston, Birmingham, and so on. The meaning of that is that a great deal of our rolling stock was sent over to France, and at the best will not be available here for a long time to come. Even the ordinary work of upkeep and repair has necessarily been neglected owing to the scarcity of men and other causes incidental to war-time. Transport difficulties are bound to last for a very considerable period after the peace settlement, and it would not be at all advisable to delay the construction of houses so long. The returned soldiers will make us vividly conscious of the shortage. Nothing could be imagined more likely to make them look for chances of going abroad than to learn that there is not sufficient housing accommodation for them in the village in which they lived before the war, and to which they hoped to return on its conclusion.

Cost per Foot Cube

III
EXTRACT FROM A LETTER TO THE EDITOR OF COUNTRY LIFE, JULY 27th, 1918

“Shortly before the war I had occasion to demolish some very old cottages at Clovelly for the reconstruction of the New Inn. I was so much struck with the stability of these (although by no means first-class samples of cob work) that I collected some facts and notes on the subject from different parts of the county of Devon. Where bye-laws have been adopted, cob is no longer being used. It is difficult, therefore, to give an accurate comparison of costs, but after careful investigation I did arrive at the following results for North Devon and Scotland. The prices were in 1913, and in both cases for a five-roomed cottage (assuming four to be built at the same time, including internal water supply, but omitting any special work necessary to procure supply, and omitting fencing).

		Cost per foot cube cob at 2 ft. 6 in. thick.		Cost per foot cube 11 in. hollow brick.
North Devon		6½d.		5⅞d.
Scotland		6d.		6d.

These prices assumed suitable material on or near site, and allowed something for the difficulty of getting at least one experienced cob-worker to instruct the unskilled men. Since 1913 the cost of brick has risen so much that cob would now be much cheaper, probably as much as 1d. or 1¼d. foot cube in both cases, and this is likely to be the case for many years. Suitable material exists in many parts of the country. If reed straw cannot be had, other reinforcements can be used. I have seen various materials in use, of which heather was perhaps the best and most easily procured. I can endorse from experience the comfort of these old buildings, and the affection of Devon people for them. The thick walls give all that a house should—protection from heat in summer and cold in winter. For the contrast, visit the new Garden City at Rosyth. Many of the houses are attractive, but their thin brick walls, tile and slate hanging are not suitable to the north and east coasts. Ask the opinion of the occupants of these new houses. Many of them are Devon born and bred, and imported from the dockyards of the three towns. They nearly all complain of the cold, and their views form an interesting comment on modern construction.”

IV
PISÉ TESTS

(With acknowledgements to “The Spectator”)

Through the courtesy of Messrs. Alban Richards & Co. we are able to publish the results of certain very instructive tests that have been carried out on Pisé during the past winter. Messrs. Richard’s experience and Report bring out two points with especial clearness, (1) That Pisé work, though not impossible under winter conditions, is not ordinarily desirable unless some means of artificially drying the earth be resorted to. (2) That the strength of Pisé increases with surprising rapidity as the work dries out. It should be remarked that none of the samples tested were made from really good Pisé soil, such for instance as the red marls or brick earths. With such materials or anything approaching them, the results would have been even better, as the Report points out:—

“In conjunction with Mr. Williams-Ellis, we have made certain tests with a view to satisfying ourselves as to the practicability of pisé de terre for house construction. In order to obtain what we might term the minimum or ‘worst’ tests, we decided to erect walls for this purpose in the winter. This we have done for the last three months, which has been a very wet period, and the following is a short description of the tests we have made:—

“1. Two walls were erected measuring 14 ft. long, 9 ft. high and 18 in. thick, spaced 20 ft. apart, with short return ends to each wall. Wall plates were placed centrally along the top of each wall, on which were placed 9 in. by 3 in. wood joists, at 16 in. centres, across the 20 ft span. In order to obtain the minimum results we allowed the shutters to remain until the test was ready to be applied, so that walls did not have an opportunity of drying or hardening. This condition was thought necessary, as it is quite reasonable to expect that if pisé de terre cottages are erected, considerable weight might be placed on the walls immediately the shuttering is struck. We then proceeded to test the walls to destruction. The floor space provided for by the joists referred to above measure 220 super. feet, the load was then applied gradually. The load applied totalled 16½ tons, which is equivalent of 168 lbs. per super. foot of floor space, under which the wall collapsed, which, in our opinion, provides a factor of safety of three to the normal load which a cottage floor would have to bear.

“We are convinced that very much better results can be obtained in this method of construction with walls which were first dried before the load was applied. Further experiments are to be made to procure further data on this subject. In addition to the above tests, we have submitted to the National Physical Laboratory, blocks made of pisé de terre, from poor to medium soil, for testing purposes, and the following are the results which have been obtained:—

“The following Report shows results of Tests made by the National Physical Laboratory.

Pisé Tests

“Report on Tests of Building Blocks of Pisé de Terre sent for test by Messrs. W. Alban Richards & Co., Ltd.

“Tests made on January 14, 1920.

“First set of three blocks sent in November 1919.

“These blocks were composed of a fine gravel containing very few and very small stones. The material was said to be similar to that used at Merrow Down, near Guildford, Surrey. It appeared to be very similar to Farnham gravel.

“The blocks were tested in compression, one within twenty-four hours of arrival at the laboratory, and the others after drying for a time in the laboratory. For results of tests see Table I.

TABLE I

No.	Marks.	Dimensions in inches.	Age in days. *	Area in sq.ft.	Density lbs. per c.ft.	Load.		Remarks.
						in tons	in tons per sq.ft.
UT1	3	9×9×9	1	.562	131	0.70	1.66	Cracked
						1.04	2.47	Collapsed
UT2	1	8.9×8.9×8.9	9	.550	125	4.27	10.50	Collapsed
UT3	2	8.95×8.95×8.95	16	.556	117	2.31	5.57	Small cracks appeared
						4.23	10.20

* Age after arrival at laboratory.

“Second set of blocks sent in December 1919.

“This set consisted of six blocks in three pairs, each pair having been rammed with a different quantity of water.

“One of each pair was tested within twenty-four hours of arrival at the laboratory, and the others after drying in the laboratory for twenty-six days.

“The material used was not homogeneous, and the mixture consisted of a very clayey loam, a fibrous loam, sand and large stones. The clayey material gave rise to surface cracks as the blocks dried.

“For results of tests see Table II.

“From the second set of blocks it would appear that it is better to ram with too much moisture than with too little. It will be noted that the density of the wet block was 30 per cent. more than that of the dry block, so that a wall could be carried higher with the dry material than with the wet, although such a wall would never gain the strength which a wet one would upon drying.

TABLE II

No.	Marks.	Dimensions in inches.	Age in days. *	Area in sq.ft.	Density lbs. per c. ft.	Load.		Remarks.
						in tons	in tons per sq.ft.
VW1	1 dry	8.9×9×8.5	1	.555	106	0.45	0.81	Cracked at one corner
						0.51	0.92	Collapsed
VW2	2 dry	9×9×9	26	.562	105	2.15	3.84	Collapsed. Material quite dry in interior
VW3	3 wet	9.1×9.1×8.9	1	.570	134	0.55	0.96	Collapsed
VW4	4 wet	8.8×8.8×8.9	26	.546	110	3.20	5.86	Collapsed. Material quite dry in interior
VW5	5 medium	9×8.9×9	1	.558	126	0.60	1.08	Bulged and cracked
						0.69	1.24	Collapsed
VW6	6 medium	8.8×8.8×7	26	.546	109	3.33	6.10	Collapsed. Material slightly damp in the interior

* Age after arrival at laboratory.

Seal of
NATIONAL PHYSICAL LABORATORY Signature of Director

Conclusions

“We are of opinion, having regard to the fact that the house at Newlands Corner (Guildford four miles) has weathered the winter, without showing any signs of dampness, that pisé de terre will make a thoroughly dry house.

“We consider that the tests made are satisfactory, and prove that this form of construction is of a sufficiently sound nature to be employed in the building of houses. With really suitable material, such as a light brick-earth or marl, it is considered that the results already obtained might well be 100 per cent. better.”

We are informed that additional tests are now proceeding with regard to the water-proof and weather-resisting qualities of Pisé, the results of which will be duly published.