_A Manual on Earthwork_, edited by Colonel Maclagan, R.E., gives much
interesting information as to Pise-building and a number of valuable
hints:
_Shutter-ties._--"Cross pieces, as the work proceeds, become so firmly
embedded in the wall, that there is great difficulty in extracting them,
to remedy which iron bars have been substituted. Even these thin iron
bars become so tightly jammed when surrounded by the compact pise earth,
that much labour and risk of injury to the work is incurred in
extricating them, and the expedient of setting them in a bed of sand has
been successfully resorted to. They are then drawn out with care, the
sand also is removed, and the holes which they leave are subsequently
filled with the same earth of which the wall is made, and rammed hard.
"The heads of the opposite uprights are held together by ropes, but in
practice in this country[6] it has been found that, under the immense
pressure exerted upon the plank sides by the earth firmly rammed in the
interior, the ropes are so liable to stretch, and to break, that it is
advisable to use iron rods or bars in this position also. When ropes are
used, the distance between the side planks is measured by gauge rods,
and the ropes tightened when requisite to preserve the proper breadth of
wall. The use of iron connecting rods renders this unnecessary."
[Footnote 6: India.]
_Soil._--"Soil of a medium quality, that is neither very stiff nor very
sandy, is considered best adapted for pise. It may be said that that
which would make good bricks will answer well for this description of
work.
"When the earth is very dry, a sprinkling of water will be necessary."
_Foundations._--"It is usual to begin the work upon a foundation of
brick or masonry; but there seems to be no reason why the pise might not
be used from the commencement, even for foundations under ground; being
carefully guarded from all chance of injury by running water."
_The Building._--"The casing being prepared and erected, and the upper
surface of the old work, when above the first stage, being sprinkled
with water, the earth, well mixed and slightly moistened, is thrown in,
and spread in thin layers of 4 or 5 in. These should, when rammed, be
reduced to one-half their original thickness. The rammers should be of
hard wood and very smooth. The successive layers are similarly treated,
and thus the work proceeds until the top of the casing is reached. The
ends of each portion should be finished with a slope, to which will be
joined the portion next to be added longitudinally. These joinings
should not, in the successive courses, be above those of the lower
stage, but as in masonry and brickwork, should 'break joint.' The seams
are all distinctly perceptible when the work is complete."
[Headnote: Plastering]
_Plastering._--"The wall may have a coating of plaster, or the surface
may be simply smoothed and dressed with a shovel, or similar implement.
When it is to be plastered, it is necessary that the wall should first
be thoroughly dry. If dry only externally whilst damp within, it has
been found that the moisture is apt subsequently to attack the plaster
and cause it to fall off in flakes. Without plaster, good Pise work is
found successfully to withstand exposure to the weather, and after the
lapse of many years to be so compact and hard as to be picked down with
difficulty."
_Protection._--"Where the wall is not that of a roofed building, it
should be provided with a coping, having a good projection to protect it
from rain."
_Rods versus Bars._--"The substitution of iron connecting bars for the
wooden ones has been mentioned above. The evils of the wooden
arrangement were found to be: the starting of the wedges, the fracture
of the tenons, the tight jamming of the bars in the wall, and the injury
to the walls and to the bars themselves from the force requisite to be
applied for extracting them. The lower iron connecting bars are made
3-1/2 in. by 1/2 in.; the upper, 1 in. by 1/3 or 1/4 in. each, having
holes 1/2 in. by 1/4 in., with corresponding pins.
"The mode of setting the bars and arranging the work on each successive
elevation of the casing is to cut on the surface of the completed part
of the wall a groove 1 in. wider than the bar, filling it in, after
placing the bar, with sand, to the level of the wall's surface. The side
boarding being set up, the vacant space left along the bevelled edge of
the previous course is filled up with moist clay to retain the first
layer of the new course. The end pieces are secured by iron bars or
rods, with screws and nuts."[7]
[Footnote 7: "A convenient arrangement might be: to make the
lower and upper connecting bars alike, to raise the side boarding
a few inches above the upper bars, which, when embedded, might be
allowed to remain and become the lower ones of the next course;
the external apparatus being shifted by taking out the pins and
slipping off the stanchions and planks to be reapplied to the
upper bars already in position to receive them."]
_Ramming._--"Gentle and quick ramming has been found most effectual."
_Report on the Pise-work executed at the Etah Jail during 1867-8.
By Mr. H. Sprenger, Assistant Engineer_
"The boxes in which the pise-work at the Etah Jail is being executed
consist of two wooden frames 10 ft. long and 2-1/2 ft. broad, made of
planks, which are nailed on to stout battens. They are held together by
four pairs of posts 3 in. by 3 in., which are connected above and below
with tie-bars of flat iron 1-1/2 in. by 1/4 in. The tie-bars have at
each end a certain number of 1/2 in. holes punched in them to receive
pins for the purpose of preventing the posts from slipping off. By
changing the pins, walls of any given dimension can be obtained, wedges
of hard wood, with longitudinal slots, are introduced between the posts
and the pins, to adjust the breadth of the boxes to a standard gauge.
After the boxes are fixed and adjusted, they are secured in their
position by ropes passing over them, and tied to stakes on each side.
Any deflection from the vertical should be corrected at the commencement
of the work, as it is impossible to alter the position of a box after it
is half full. Any earth which is suitable for brick-making will do for
pise-work. On being dug out it is passed through a screen with 1/2-in.
meshes, and thrown into the boxes in even layers of 6 in. in depth.
[Headnote: The Right Quantity of Water]
"Generally fresh earth contains sufficient moisture to ensure good
consolidation; but if it is found that it jumps up under the rammers, it
should, on being thrown into the boxes, be sprinkled with a little water
out of a tin can with a rose. The watering should be as uniform as
possible, as if it is applied unequally it will liquefy the earth, which
will commence oozing out under the rammers. Pise-work executed with too
much water is worse than if done with dry earth, as, on account of the
elasticity of the wet earth, the effect of the ramming is deadened, and
the earth remains unconsolidated. The men should be prohibited to keep
time in ramming, as it causes vibration, which is injurious to the
stability of the wall. On working over a lower course, it is as well to
let the lower tie-bars about 4 in. into the same to give the boxes a
firm hold on the old work, thereby the joints become imperceptible, and
the upper edge of the lower course is prevented from chipping off.
"The implements used are three different kinds of rammers. The earth is
first beaten down with a V-shaped rammer, and then surfaced with one
with a flat bottom. The sides of the boxes are consolidated with a
spade-shaped rammer. When commencing the pise-work at Etah, considerable
difficulty was experienced in extricating the lower tie-bars. These
were, therefore, supplied with holes 3 in. apart throughout their whole
length. A pin was inserted, against which a crow-bar with a long slot
and well bent at the end was made to work. An equal pressure could
thereby be exerted against the tie-bars; they were thus extracted with
great facility without injuring them or the face of the wall, which was
not the case formerly."
_Supplementary Note by Mr. E. Battie, Executive Engineer,
5th Division, Grand Trunk Road_
"The work at Etah has generally been concluded in the following manner:
In the morning the boxes were taken down, and again put up and filled
during the day; they were left during the night, so that the earth might
detach itself from the sides. It is not advisable to allow a course to
dry thoroughly, as the upper one will not bind well into it, but
probably show a crack. If the earth is well rammed, and only the proper
quantity of moisture admitted, a second course can be commenced
immediately."
* * *
The Report of the Rhodesia Munitions and Resources Committee issued in
1918 contains an interesting paper by Mr. John Hynd on Pise-building,
from which the following is extracted:
[Headnote: Pise Buildings at Empandeni]
"_Pise de Terre Buildings_
"_The Spectator_ took this matter up some two years ago and wrote as
follows:
"'Various schemes of land settlement are in the air. . . . All of them
must, however, be concerned with cheap buildings. That is a _sine qua
non_.' . . .
"The material used for the walls at Empandeni is one-third sand,
one-third ant-heap, and one-third soil, all pulverised and put through a
sieve. Water is then added. The mixture must be neither too wet nor too
dry, just sufficiently damp to bind; a good indication of the correct
consistency being that when squeezed hard by the hand it shows a
tendency to bind. Sufficient of the loose mixture is thrown into the
form to fill it to a depth of about 3 in., and this is thoroughly rammed
before the next layer is put in. Most thorough ramming is essential.
When the frame is rammed full, it is taken apart and shifted along to
make another section and so on until the first layer is complete. The
first layer is, as a rule, sufficiently dry to permit the starting of
the next about three hours after laying. Door and window frames are put
in as the work proceeds, and must be well braced while ramming. In the
top layer hoop iron or fencing wire is let in for fastening down the
wall plates. Arsenite of soda or Atlas Compound is used in the first
layer or two to keep out white ants. The floor can be made of timber,
cement concrete, or rammed earth, and the roof thatched or covered with
corrugated iron as is most convenient.
"The following Pise de terre buildings have been erected at Empandeni:
"A large schoolroom 75 ft. by 28 ft. by 12 ft. high, walls 14 in. thick;
seven boys' dormitories, each 30 ft. by 20 ft. by 12 ft.; twelve
single-room houses, each 16 ft. by 12 ft.; six fowl houses, each 20 ft.
by 10 ft.; a large fowl house 250 ft. long, front walls 7 ft. and back
walls 5 ft. high. This building is divided into fifteen compartments.
"From the foregoing description it is quite evident that cheap and
efficient buildings of this nature can be erected at a very low cost.
"On a farm it is not necessary to employ any skilled labour, as the
doors and windows can be purchased ready-made, and the frame-work,
clamps, etc., put together by the farmer himself. For a roof of thatch
all the necessary material, except iron ridging, if this is used, can as
a rule be procured on the farm.
"Should a cement concrete floor, which is cheaper than a wood one, be
desired, there would be an extra expenditure for cement, the amount
required being about two bags per twelve square yards. Such a floor
should be laid before the walls of the building are commenced, and it is
essential that the site is thoroughly well rammed and consolidated,
particularly below where walls will come, before laying the concrete, to
prevent cracks developing through settlement. The concrete raft should
be carried at least 6 in. beyond the outside walls of the building, and
if the work is properly done, a special ant-course will be unnecessary.
The concrete can be left rough below the walls to give a bond, and it
might be advisable to lay some pieces of hoop iron in it which would be
left projecting to be bedded into the walls.
"Another good type of floor would probably be that suggested in _The
Spectator_, viz. road material laid down and tarred in the same manner
as roads are now made in many places.
"A number of rooms and houses have been erected on the Globe and Phoenix
Mine on much the same principle as Pise de terre buildings, but the
system developed there is different as regards the mixture, which
consists of two parts ant-heap or ordinary dagga which must not be too
sandy, and three parts ashes or clinker sieved free from fine dust.
"A very full description of the method employed on this mine was
forwarded by the courtesy of the Manager to the Committee, and it is
interesting to note from this that the walls are made waterproof by
first making them smooth with dagga plaster, then, when quite dry,
giving one good coat of boiling hot tar. A coat of limewash is applied
three days later. That this is effective is well evidenced by the fact
that the buildings erected have successfully withstood our last
abnormally heavy rainy season.
"The Globe and Phoenix system is the result of a number of experiments
carried out on that mine. Their mixture, which is stated to be
ant-proof, contains more moisture than Pise de terre, and each course is
reinforced with old wire rope, or other suitable scrap. The material is
left in a heap for one or two days before being used.
"Circular huts have been built on the mine of the same material, the
forms being made of two rings of corrugated iron in three or more
sections joined up with cleats at the end laps and held in position with
cross bolts and distance pieces. The inner ring is 9 in. less radius
than the outer one."
[Headnote: Pise Buildings for Settlers]
_Extracts from a paper on Pise in the "Farmers' Handbook,"
issued by the Department of Agriculture, New South Wales, 1911_
"Pise is a material readily obtainable by the settler, of which cheap
and durable buildings can be easily and substantially erected.
"For the construction of pastoral or agricultural buildings, especially
in districts remote from railways, or from towns in which other building
materials are cheap or easily procurable, pise is particularly well
adapted. In the country earth is plentiful and readily obtainable; in
the city or town such is not the case, and this fact, combined with the
very bulky nature of the material, prohibits its use in such centres of
population.
"To the selector or settler, who, like many of our successful pioneers,
is not burdened with a superfluity of hard cash, but who possesses an
abundant capital of energy, combined with a certain amount of handiness,
pise has an additional advantage (which it shares with slabs, wattle and
daub, etc.) over most other building materials, in that it affords him
an opportunity of erecting his homesteading largely as the result of his
own labour.
"As a building material, pise is infinitely superior and more durable
than slabs, galvanised iron, or weather-boards. In fact it is
questionable whether it is not more suitable for our climate, and
therefore to be preferred to brickwork; for pise buildings, properly
protected and finished, are quite as durable and much cooler than
buildings constructed with solid brick walls. This statement may be
questioned by some whose knowledge of pise is limited to buildings so
badly planned that the very elementary principles of building
construction have been neglected. This neglect, which is all too common,
makes things bad enough, but when to it is added, as is sometimes the
case, indifferent workmanship, combined with the use of unsuitable
material, the result does not call for admiration, and it is not
surprising that a bad impression is created. With no other knowledge of
pise it is only natural to condemn it because of such specimens, but
under similar circumstances other better-known building materials of
proved excellence would also be condemned. Brickwork would just as
readily be condemned if its building qualities had to be estimated by
the appearance presented by a brick building which had been constructed
of badly-burnt bricks laid by unskilful tradesmen on an imperfectly
thought-out plan. Just as with other building materials, the
possibilities of this material can only be judged by an examination of
properly planned and constructed examples of the pise-builder's art.
Such are found here and there throughout the country, pleasing to look
at, affording comfort and satisfaction to their owners. A properly
constructed pise building can be finished to suit the taste of the most
fastidious. Even without plaster the walls can be 'floated' down and a
'skin' obtained on them which, when limewashed, resembles stonework.
When plastered inside and out they possess the advantages of a stone
house, and are erected at a fraction of the cost.
"Some idea may be formed of the durability of pise by the fact that
there is a stable built of pise which has been in constant use for over
sixty years, and which at the present time is in good order. The good
condition of this stable is the more surprising because the external
walls are unprotected from the weather, and it is generally recognised
that pise-work, especially if unplastered, should be protected from the
direct action of rain. Pise buildings are said to have a life of a
century and a half.
"The stability of pise buildings is beyond question, as is proved by the
following instance:--At Lambrigg, a second-story brick building, with
14-in. walls, and containing ten rooms, is built upon a lower story of
pise. The bricklayer who had the contract for erecting the brick portion
of the house refused, as it was built upon pise, to guarantee his work.
Some time after the completion of the house he visited it, and after a
thorough examination of the building, declared that it was the most
substantial brick house in the district, as it had not a crack in it,
a feature which was somewhat unusual in that locality. Another case
bearing on the same subject is that of a residence at Temora. When this
building was being constructed the workmen omitted to leave holes for
the bolts which were to secure the verandah plates to the walls, as it
was thought these could readily be bored out afterwards with an auger.
On attempting to bore out these holes on the completion of the building,
and when the pise-work had become drier, the operation of boring proved
so difficult as to be practically impossible, and had to be abandoned.
[Headnote: Builders' Aversions]
"The merits of pise-work have been recognised in France, India, Mexico,
and California for years past, and seeing its equal suitability for our
climate, it is surprising that these merits have not led to its being
more extensively used. The principal reason for this seems to be because
our builders are averse to undertaking this class of work, and in
consequence the bulk of it is placed in the hands of untrained men, who,
whilst quite fitted to carry out the pise-work, are not competent to
undertake the other constructive work of a building. However, they do
not hesitate to do this, as well as to undertake the more important work
(though unrecognised as being so) of planning out the building. The
result is in most cases an improperly planned and defectively
constructed building, which appeals to no one, but has a tendency to
bring pise into disrepute.
"The reason for a builder's unwillingness to undertake pise-work is not
far to seek. For the successful carrying out of his work a builder
relies upon skilled tradesmen; our tradesmen are trained in cities and
towns, and as pise is not a suitable material for such places, tradesmen
do not become familiar with it. A good builder with a reputation to lose
shrinks from placing that reputation at the mercy of a pise-builder, who
is not recognised as a tradesman, and in whom, in consequence of this,
a builder is likely to have little or no confidence.
"The actual erection of pise-work presents so little difficulty that it
can be done by any one who has sufficient strength to shovel earth and
wield a rammer, provided he will exercise care to see that the moulds or
boxes into which the earth is shovelled are kept plumb and in straight
lines. The average settler, even with no previous knowledge of pise-work
or building construction, need have no hesitation in undertaking the
pise-work of his own buildings if he works to a well-thought-out plan
drawn up by somebody competent to do so.
"The necessity of having a plan prepared by some one who understands the
principles and requirements of simple building construction, before
undertaking the erection of any building, cannot be too strongly
emphasised. This great need, which is often overlooked by the settler,
cannot be economically dispensed with. The securing of a properly
prepared plan is of the greatest value towards obtaining a building of
the maximum strength and durability, combined with the best appearance
and greatest convenience, for the least cost. Even when a settler
undertakes the pise-work of his own building, it will only be in rare
instances that he will not have the advantage of trained supervision
during its erection. The services of a tradesman will invariably be
found necessary to make doors and window-frames, construct the roof,
etc. This workman can be engaged when the building is started, and
whilst preparing the timbers of the roof, in readiness for the time when
they will be required on the completion of the pise-work, can supervise
the fixing of the door and window frames, and see they are set
correctly, and in their proper places.
"Pise walls are constructed in sections, the extent of which is
regulated by the supply of casings available.
"Into the moulds formed by the boxes the earth is shovelled in layers of
4 or 5 in., and then rammed until thoroughly solid before another layer
is put in. On the completion of the section, _i.e._ when the mould is
full and well rammed, the keys or pins are knocked out of the 'bolts,'
and the 'boxes' taken apart and erected on another portion of the
building. The top of that portion of the pise-work on which it is
proposed to erect another section should be well moistened and covered
with wet bags some hours before the mould is formed. The bottom of the
mould should overlap the top of the pise-work by about 6 in. After the
'boxes' are put together, the top layer of pise should be loosened with
a pick so as to form a bond with the section about to be built, and if
this section adjoins one already built, the ends of the latter should be
bevelled off so as not to form a straight joint.
"Material which is too sandy will fret away, and one containing clay
will crack when dry. Soils containing these defects should be avoided.
There is, however, such a wide range of soils which are suitable that a
holding of any size on which suitable soils cannot be found will be the
exception. It is possible to remedy the defects found in one soil by
mixing it with another soil, but very rarely will such a course be
necessary.
[Headnote: Number of Men Required]
"The plant required will depend upon the number of men to be employed.
Three is the least number that can be economically employed--two
attending to the boxes and ramming, and one carting earth from its
location to the building and assisting generally. The plant required for
this number of men is given below. If more are engaged, additional plant
of the same character will be found advantageous.
"The necessary plant will consist of--2 wooden rammers, 1 iron shod
rammer, 2 straight boxes, 2 angle boxes, 3 casings for blocking up the
ends of boxes, bolts and keys for same, 12 gauge rods, washers--a
liberal supply of 3/4-in. washers, 2 shovels, 1 spade, a horse and dray
or other means for transporting the material to the building (if
required)."
The following detailed instructions are taken from the same authority:
[Headnote: Pise in New Zealand]