CONSTRUCTION OF THE HOUSE.
In preparing to build a house, or in entering into a house already
built, the following requisites should each receive careful attention:—
1. The site of the house should be healthy, and its relation to
surrounding objects in accordance with the laws of health. (See page
201).
2. The house should be warm in winter, and cool in summer.
3. It should be always dry.
4. There should be an abundant and uninterrupted supply of air.
5. The water supply should be abundant, conveniently arranged, and pure.
6. The excreta and waste-water should be immediately removed from the
house and its annexa.
The three last requisites have already received consideration. Of those
still to be considered, =dryness= is the most important. A damp house
is certain to be an unhealthy one. It is this for two reasons:—1st, it
is a cold house, as damp walls, like damp clothes, conduct the heat of
the body away much more rapidly than dry walls; 2nd, if the pores of
the bricks are occupied by water, air cannot pass through, and thus the
ventilation and purification of the house are greatly impeded. Damp may
arise from the ground on which a house stands, or from the rain beating
against the walls, or from a defective roof. Unless special means are
taken to prevent it, moisture rises by capillary attraction through
brick after brick.
The =Foundation= requires to be solid and substantial, otherwise
sinking occurs, with cracking of the walls, resulting in an unsafe
condition, and an exposure to rain and wind.
In making the foundation for a house, the ground should be excavated,
so as to secure a solid bed of earth or rock not liable to be affected
by the weather. A continuous bed of the best cement concrete should
then be laid, not only under the walls, but covering the entire site
of the house, and extending on every side at least 6 inches beyond the
footings of the wall; and for footings it should never be less than 18
inches thick. The concrete serves two purposes: it, to a large extent,
cuts off the entrance of the ground-air through the basement floor
into the house; and prevents the entrance of damp into the house from
below. To further ensure dryness where the floor is below the level of
the adjacent ground, a _dry area_ is frequently provided, that is, a
closed chamber lined with stone or cement below the ground level of
the house, and surrounding the underground part of its four walls, or
a hollow wall is built below the ground-level, as shown in Fig. 38.
Neither a dry area nor a hollow wall constitutes the best arrangement,
as the cavity is usually inaccessible, and rather aids than hinders the
entry of the ground air into the house. The best plan is to provide a
solid wall, impervious to both moisture and air. A vertical layer of
roofing slates is sometimes used for this purpose; or, still better, a
narrow cavity about 1∕2 to 3∕4-inch wide is provided in the body of the
wall, and this is run full with molten asphalte.
The =Walls= of the house must be provided with a “=_damp-proof
course_=” carried through their whole thickness, slightly above the
highest point at which the ground is touched. It may be formed by (1)
sheet lead, which possesses the disadvantage of being costly; (2) two
layers of ordinary roofing slate, set in cement, with broken joints,”
_i.e._ the joints of the upper layer over the centre of the slates
below them; (3) a layer of good asphalte, about ¾-inch thick; (4)
perforated glazed stoneware slabs; or (5) two or three courses of hard
blue Staffordshire bricks, laid without mortar. The use of asphalte is
an excellent plan, and is now commonly adopted in good buildings.
[Illustration: FIG. 38.
DOUBLE DAMP-PROOF COURSE AND HOLLOW WALL.
_a_, _a_—Damp-proof courses. _b_—Level of neighbouring ground.
_c_—Floor-boards. _d_—Floor joist. _f_—Vertical space in wall.
_g_—Concrete under foundation and over site of house.]
This suffices when there is no basement. If there is a basement an open
area around the house is desirable. Where for a given wall this cannot
be secured, the vertical damp-proof course already described must be
made to extend from the foundations well above the ground level. The
open area, however, should be insisted on whenever practicable. The
damp-proof course protects the walls from damp proceeding from the soil
around or beneath the house.
It is necessary also that the walls above the level of the ground
should, as far as possible, be kept free from damp. =_Damp walls_=, not
due to ascent of moisture, =_may be caused by_=
(1) Rain falling on window-sills which do not project beyond the walls,
and consequently do not throw the water clear of them. This is remedied
by constructing the window-sills so as to project beyond the walls, and
“throating” them to prevent rain from running along the bottom of the
sill. The throat is shown at _a_, Fig. 39.
(2) Rain falling on cornices and other projecting portions of the wall
itself. The evil from this source may be diminished by sloping the top
of the projection, downwards from the face of the wall.
(3) Parapet walls, gables, etc., not being properly covered with
coping. All such walls should be topped with a projecting slab of
stone, or with a damp-proof course under the top course of bricks,
which should be laid on edge.
(4) Overflow from defective roof-gutters or rain-water pipes. In this
case, either clearing out, repairing, or renewing is required.
(5) Rain beating against the walls. This as a rule produces no great
harm, if the walls are well constructed. Most of the water runs off as
it falls on the surface. It is advisable, however, to protect a much
exposed wall by a coating of Portland cement, or in extreme cases with
slate. Various impervious paints have also been employed.
[Illustration: FIG. 39.
SECTION THROUGH WINDOW.
Showing stone sill “weathered” at _i_, and “throated” at _a_.
_b_—Wall. _c_—Inside plaster of room. _d_—Window-board. _e_—Oak sill.
_f_—Beading and _g_—bottom rail of window-sash. _h_—Window. _j_—Iron
tongue let into slot in _i_ and _e_ to prevent rain driving in.]
If it is not proposed to coat exposed surfaces of brickwork, the
wall may be formed of two parallel walls, two inches apart, and tied
together by a sufficient number of bonding-ties of iron or glazed
stoneware, or some other non-absorbent material. This arrangement is
shown in Fig. 40.
An excellent plan is to fill in the narrow space between two such
walls, as the building proceeds, with asphalte or slab slate, thus
forming a _vertical damp course_, in the same way as below the ground
level. The evils arising from damp can be avoided in every new house
by proper methods of construction. In an old house, however, they are
much more difficult to remove. The dampness is indicated on entering,
by a peculiar mouldy smell, and by the discolouration and destruction
of wall-papers, and dry rotting of floor timbers. In such a case a damp
course may, with care and patience, be inserted in the wall, and the
soil under the basement may be covered with concrete, and a dry-area
excavated around the basement. Free ventilation under the floor-boards
of the lower floors also helps in keeping the house dry.
[Illustration: FIG. 40.
SHOWING HOLLOW WALL AND BONDING-TIES OF GLAZED STONEWARE.
_a_—Cavity. _b_—Tie. _c_—Floor-joist. _d_—Wall-plate. _e_—Concrete
foundation of wall.]
The _thickness_ of the walls of a house requires to be sufficient to
ensure stability, to keep out the damp, and to prevent a too rapid loss
of heat from the walls. The relative merits of the different materials
employed for these purposes have been already considered. A thin-walled
house is hot in summer, and cold in winter. The upper stories of houses
are often built with too thin walls, the result being chilly bedrooms.
A single-brick wall (9 inches thick) will rarely keep out the weather
effectually, and frequently a brick-and-a-half wall (14 inches thick)
is insufficient for this purpose. The bricks should be so interlaced
as to “bond” or tie the wall together in all directions. The strength
of walls may be increased by the introduction of hoop-iron between the
courses of brickwork.
In the construction of fire-places and chimneys, it is important to
avoid the proximity of timber and wood-work to the inside of flues, as
this is a common cause of fires.
Inside Coverings of Walls.
=Plaster= is made of lime mortar, or cement mortar; the former is
generally preferred for domestic dwellings because it remains porous
and moisture does not condense on it.
In houses built by speculative builders, the plaster commonly used
consists of a mixture of lime with road scrapings. The result is a
composition which unless supported by the wall-papering, is soon
damaged.
Ordinary plaster consists usually of three layers. The first is laid on
with a mixture of about equal parts of lime and sand with long ox-hairs
if required for ceilings. The second coat consists of slaked lime,
mixed to the consistency of cream. The last or setting coat consists of
a thin layer of slaked lime called plasterers’ putty. Some plaster of
Paris (gypsum) may be added, to ensure rapid setting, but it should
only be used in small quantities. For the internal plastering of rooms
_serapite_ (a form of cement) is now commonly employed. This is not so
absorbent as mortar, but is sufficiently so to prevent condensation
of moisture on the walls. Its chief advantage over plaster is that
it hardens quicker and is smoother, and can be used in a single thin
layer. This, however, diminishes the impermeability of ceilings for
sound.
Keene’s cement and Parian cement are mixtures of calcined gypsum and
other substances; Keene’s cement being the hardest, and capable of
receiving a high polish.
Selenitic cement contains a small proportion of plaster of Paris
ground along with lime. Lime may also be selenised by the addition
of any other sulphate, or of sulphuric acid. The presence of the
sulphate causes the lime to set rapidly. Selenitic cement is useful in
plastering, as a backing of cements, such as Parian.
The treatment of the =internal wall-surface= of a room differs
according to circumstances. =Lime-washing= is suitable only for
stables and other outbuildings. It is made by the addition of water
to quicklime, no size being added. It is an excellent germicide and
insecticide. =Whitewashing= is quite different from limewashing.
“Whiting,” _i.e._ finely-ground chalk, to which a certain proportion of
size and alum had been added is mixed with water. The size and alum are
added to prevent the whitewash from being rubbed off. =Distempering=
is identical with whitewashing, except that pigments are added. It is
distinguished from =painting in oils=, by the fact that the pigments
are mixed with size, instead of with linseed-oil and turpentine.
Painting in distemper is practically limited to plaster, which should
first receive a coat of whitewash to diminish its porosity. Oil-paints
are impervious, distemper is as absorbent as plaster or whitewash.
Various =washable distempers=, as duresco, are made, which are more
durable and non-absorbent. =Water-glass= consists of silicate of
potash, which in the gelatinous form is soluble like size in hot-water,
but when allowed to dry forms an impervious film. It can be used for
protecting porous stone from the effects of weather; and renders
internal surfaces of walls non-absorbent and washable.
=Oil-painting= renders wall-surfaces impervious, and enables them
to be easily washed. The importance of this in the event of any
infectious disease occurring, is obvious. The question arises whether
distempered or papered walls, which are porous, or painted walls,
which are non-porous, are preferable from the standpoint of health.
The difference between the two is seen during damp weather, when
moisture condenses and runs down the latter and is invisible in the
former. In practice in domestic dwellings the former are preferred;
but although some advantage is thus secured in ventilation through the
wall-substance, there is the serious disadvantage that particles of
dirt accumulate and may seriously interfere with the purity of the air
of a room. Hence the importance of rubbing down the internal surface of
a room, whether distempered or papered, at intervals with bread crumb
or dough (see page 332). This effectually removes all accumulations of
dirt. A painted wall presents the enormous advantage that it can be
frequently washed; while the loss of ventilation may be ignored, if
windows and doors be properly utilised for this purpose. The presence
of poisonous pigments in oil-paints is of importance to the workman,
but not to the householder except during the painting, as paint, unlike
distemper, does not rub off the wall. Lead is the chief poison present,
as white lead (carbonate of lead). Various substitutes for lead paints
have been introduced.
Painting wood or iron-work is valuable, not only as a preservative from
the effects of the weather and the oxidising action of the air, but
also because it tends, to a large extent, to prevent the absorption of
organic matters; and its surface can be frequently cleansed.
=Paper= is the material most commonly employed for covering walls. It
is more absorbent and retentive of moisture than distemper.
Light-coloured papers should be chosen, as they are more cheerful,
and are not so likely to harbour dust. Glaring patterns are
objectionable, as they tire the eyes. The paper should not present any
surface-projection for the lodgment of dust.
In bathrooms and water-closets, the wall-surface should be
non-absorbent. Paper, unless varnished, should therefore be avoided.
The best covering for these places is glazed tiling, or painted cement.
Not uncommonly, a new paper is pasted over an old one; and this may
be repeated several times. Under these circumstances dangerous dirt
accumulates. Before new papering is put on, the walls should be cleared
of all vestiges of the old, thoroughly washed down, and subsequently
coated with size (that is, “clear coloured”). The sizing diminishes the
absorptive power of the wall, and gives a good surface for applying the
paper.
Bed-room papers require to be more frequently changed than those of
other rooms. Bed-rooms in regular use should be re-papered at least
every two years. It is still better to use distemper for such rooms,
as this can be washed off in a few hours with comparatively little
expense, and can be made of any tint desired.
Rooms in the basement should not be papered, as the walls require
frequent washing down and cleaning. Here also a washable distemper
colour can be used.
Various kinds of sanitary paper are now sold which are washable, and
relatively non-absorbent. Some of them require varnishing; others do
not. Such papers are certainly cleaner than ordinary paper; but it
would not be safe to trust to their non-absorptive character. Lincrusta
Walton is non-absorbent, and can be scrubbed with soap and water; but
it is expensive. Other cheaper materials possessing the same properties
can now be bought.
=Arsenic in Wall-Papers and Paints= has until a few years ago been a
not uncommon source of prolonged ill-health—the cause of which has
possibly not been detected until the illness disappears, when the
offending room is vacated for a period. Arsenical pigments are now
only rarely used for wall-papers. The symptoms produced vary greatly,
and may closely simulate those of different diseases. In some cases
repeated attacks of diarrhœa and abdominal pain occur. Or there may
be nausea, headache, frequent griping pains, and loss of appetite.
In other cases restlessness, loss of sleep, and general malaise are
the chief symptoms, with the occasional addition of conjunctivitis
(superficial inflammation of the eye). Out of 100 cases collected and
reported on by a Committee of the Medical Society of London, diarrhœa,
nausea, and intestinal mischief occurred in 85; severe depression in
16; conjunctivitis in 19; and cough, asthma, etc., in 9.
The severity of the symptoms produced will vary with the amount of
arsenic contained in the paper, and the length of time daily that the
patient is exposed to the fumes.
Some persons again are much less susceptible to the influence of
arsenic than others. This will explain why some escape while occupying
the same room in which others suffer severely. More commonly, however,
the exemption is due to shorter exposure.
The most dangerous preparation occasionally employed in wall paper
printing is Scheele’s green (arsenite of copper). Emerald-green—an
aceto-arsenite of copper—is sometimes used to produce more delicate
tints. Aniline dyes, especially the red, may contain much arsenious
acid (white arsenic). The arsenic compound is made to adhere to the
paper by size or some other material. When dry, it cracks and peels
off, and minute particles get into the air as dust. In addition,
arsenic compounds easily volatilise, and become diffused in a
gaseous condition throughout the atmosphere of a room, even when its
temperature is not greatly raised. The virulence of the arsenical
colouring is in proportion to its volatility. Arsenic seems to be
much more dangerous when associated with size. It has been shown
that a mixture of white arsenic and starch paste, or other organic
substance, leads to the formation of gaseous arseniuretted hydrogen,
while this does not occur when no organic matter is present (Dr.
Fleck). Distemper frequently contains arsenic, and as it also contains
size, arseniurretted hydrogen is liable to be given off at any time.
Size is largely used for fixing colour; thus, the proper conditions
for the development of arseniurretted hydrogen—the most dangerous
compound of arsenic—are present. As much as 17 grains of arsenic have
been discovered in each square foot of a wall-paper. Now, arsenic is
sometimes given internally for certain skin and other diseases, but the
dose is only from 1∕60 to 1∕12 grain; the capacity for poisoning of
such a paper as the above will therefore be evident.
Papers of other colours than green have been found to contain
dangerous quantities of arsenic; thus blue, mauve, red, and brown
may contain large quantities; the delicate greys often yield a
considerable amount, and some white papers are heavily loaded with
it. Arsenic is occasionally present in stockings and other wearing
apparel, artificial flowers, toys, etc. In these cases, it may produce
irritation of the skin, and even eczema.
The presence of =arsenic may be detected= by the following tests:—
(_a_) _Reinsch’s test._ A portion of the suspected paper (two or three
inches square) is cut into small pieces, and placed in a good-sized
test tube; water is added until the tube is about a third full and
then one or two teaspoonfuls of pure hydrochloric acid, and a small
piece of pure copper foil. If the test tube is now heated for a few
minutes over a spirit lamp, arsenic, if present, will be deposited as
a black or dark steel-coloured coating on the copper. A mere tarnish
of the copper must not be accepted as evidence of the presence of
arsenic, but an almost complete obliteration of the colour of the
copper.
(_b_) Take the copper covered with arsenic, dry it, and then heat it
in a perfectly dry test tube. Crystals of white arsenic, which may be
identified under the microscope, will be deposited higher up in the
tube.
(_c_) _Marsh’s test._ The ordinary apparatus for developing hydrogen
by the action of diluted sulphuric acid on zinc is employed, the
suspected paper being inserted in the bottle. The hydrogen coming off
is burnt, and a clean porcelain surface is applied to the flame. If
there is arsenic in it, it is deposited on the porcelain in a black
patch.
=Windows= are required to open directly into the external air in every
habitable room. The window area according to the model bye-laws of the
Local Government Board and the London Buildings Act of 1894, must be at
least one-tenth of the floor area, and half of this at least must be
made to open. The following rules have also been given. (B = breadth, L
= length and H = height of room.)
_Area of window_
(B × L)/10 _London Building Act_
(B × L × H)/100 _Gwilt_
√(B × L × H) _Morris_
In a room measuring 15 × 20 × 12 feet, the preceding rules would give
a superficial area of window space of 30, 36, and 60 square feet
respectively. Plate glass dissipates heat less quickly than sheet glass.
Objection may be taken to plate glass windows, in passing, especially
for shops, banks, etc., in view of the fact that they are commonly made
without any arrangement for ventilation (see also page 148).
The hygienic necessities of =Floors= are that they shall be impervious
to moisture and to dust. On the =ground floor= the ordinary arrangement
is to provide a joisted and boarded floor raised about a foot above the
ground. Dry rot is one of the dangers in connection with such =boarded
floors= on the ground floor. The chief causes which tend to induce
rotting, are damp walls, lack of ventilation, contact with mortar, damp
earth, or vegetable mould, and worst of all, alternations of damp and
dryness, or wet along with heat.
In order to avoid these dangers in connection with boarded floors, the
ends of all timbers resting on walls should have a clear air-space
around them, and communicate with the external air by means of
perforated bricks. The larger timbers, girders, etc., should rest
on stone templates, and the smaller joists on hoop-iron bonds. In
all cases, the timber used should be well seasoned, and properly
ventilated. The ends of oak posts, which are to be driven into the
ground, should be charred, if the timber is old, or steeped in a
solution of chloride of zinc.
The ends of the joists should be trimmed, so as not to come too near to
chimney flues.
The best plan for flooring is to place an impervious flooring resting
on the solid ground. This is more secure against rot than the boarded
floor, and affords no space for dirt and vermin to lodge. Such an
impervious floor may be formed of concrete over a layer of asphalte,
as in the well-known terrazzo flooring. This is very suitable for
corridors, pantries, etc. For living-rooms =wood-block flooring= is
placed over the cement, molten pitch connecting the two. The blocks
are 2 to 3 inches thick. If the wood is soft, as deal, it must be kept
clean by washing; if hard, as oak or teak, it can be wax-polished.
_Parquetry_ consists of small pieces of hard woods carefully fixed and
polished.
For =upper floors= the ordinary flooring is of floor-boards supported
on wood joists, beneath which are wood laths and plaster. The
floor-boards should be thoroughly seasoned, otherwise they will shrink,
and the joints be filled with dirt. This dirt may accumulate for years
between the floor and the ceiling of the room below, vitiating the air
and helping to increase the stuffiness characteristic of dirty houses.
Various plans are adopted for uniting the edges of floor-boards and
preventing dust from dropping between the boards.
[Illustration: FIG. 41.
TONGUED FLOOR.]
The one most commonly employed is the _ploughed and tongued floor_
(Fig. 41). In this, both edges of the floor are grooved so as to
receive strips or tongues of iron or wood, an equal half of each strip
being in the groove of each of two boards when they are in place.
A less expensive method than the above is to _splay_ the ends of
the boards so that they slightly overlap each other. This is not so
efficient as the above, but is much better than simply placing the
boards side to side as is commonly done.
_Solid wood floors_ resting on a bed of concrete are free from the risk
of harbouring dust, and are relatively fire-proof.
Oak or teak in narrow boards, made with close joints, and then
oiled and beeswaxed and rubbed to a polish, makes a good and almost
non-absorptive floor. One of the best floors is made of concrete, with
iron joists, and oak boards laid above this.
=Carpets= are commonly made to cover the entire floor of rooms. This
cannot be too much deprecated. Carpets, like curtains, are mere
dirt-traps, which become loaded with filth of every description. This
is abundantly proved when a carpet is swept, and the dust allowed to
settle on all the articles in the room. Such dust, if examined, will
be found to consist not only of mineral matter, but also of every
description of vegetable and animal impurities. The inhalation of such
dust, which may contain particles of fæcal matter, as well as the dried
expectoration from consumptive or other infectious patients, is a not
infrequent cause of infection to healthy persons.
The substitution of a central carpet, for one covering the entire
floor, is a great improvement.
The carpet should be easily removable, in order that it and the floor
may be thoroughly cleaned at intervals.
In bedrooms, the less carpet the better. Good Chinese or Indian
matting is serviceable, as it does not retain the dust and other
impurities which are apt to become fixed in the woolly texture of the
carpet. Oil-cloth, linoleum, and similar materials are in common use
for covering halls, passages, etc. They are particularly useful in
preventing dust from gaining access to the spaces between floor-boards.
The =prevention of dust= should be the great aim of the householder,
as dirt frequently carries infection. =Sweeping= as ordinarily done
scatters dirt over the room, and =dusting= with a dry cloth fails to
remove it. Mechanical sweepers, in which the dirt is collected in a
box are valuable. The best plan is to have movable carpets, roll them
up for shaking or beating at a distance from any house, and wipe the
boards with damp cloths. All wooden and leather furniture, picture
frames, etc., should be wiped down with cloths rung out of water so as
to be just damp.