Exterior Covering and Finish
=49. Sheathing or Sheeting.=--After the frame work of a building
is erected and the openings made in the frame for windows and doors,
the sheeting is to be placed. Sheeting is placed either horizontally
across the studs or diagonally, sometimes both ways, depending upon
the specifications of the architect. The diagonal is somewhat stronger
but is more expensive. The horizontal is satisfactory upon ordinary
frame dwellings, especially where the building is braced at the corners
by studs cut in diagonally, or by sheeting placed diagonally at the
corners as in Fig. 90. Such sheeting should be matched and well nailed
with two 8d nails to each stud. Building paper should be placed upon
the sheeting to further protect the interior from cold.
[Illustration: Fig. 90. Sheathing]
Roof sheeting for shingle roofs may best be of unmatched boards spaced
about 2" apart. For slate, matched stock should be used and this
covered with a tar or asphalt paper.
[Illustration: Fig. 91. Setting T-bevel for Roof Boards]
In making the face cut on roof boards for hips or valleys the framing
tool or the T-bevel may be made use of, being set to the complement of
the angle used in making the side or cheek cut on jack rafters. The
complement angle in this case equals 90 less the angle of the side cut
of jack. Or, if the framing square is to be used, the same numbers
used in making the side cut of the jack will be used in laying out the
face cut of roof boards, with the scribing being done along the tongue
instead of along the blade as in the case of the side cut.
A second T-bevel may be set as in Fig. 91, the beam being placed across
the edge of the jack and at right angles to it, with the blade adjusted
to the cheek or sawed surface of the jack which is to fit against hip
or valley rafter. A framing tool might be used.
Carpenters more frequently, however, get the angles for sawing roof
boards by laying the board to be cut out over the hip or valley rafter,
then sawing along the side the rafter as in Fig. 92.
In warm climates, weather boarding is often applied directly to the
studs, no sheeting being used; the frame being strongly braced at the
corners.
=50. Scaffolding.=--Cornice is placed after sheeting. To do this
advantageously it is necessary to erect scaffolding or staging. Fig.
93 illustrates a common type. Stock 2" × 4" is used for the uprights,
and 1" × 6" for the horizontal members and braces or stays. Planks
are placed upon these horizontals as shown. Fig. 94 illustrates a
substitute for staging, a scaffold bracket upon which planks are laid.
[Illustration: Fig. 92. Sawing Roof Boards]
[Illustration: Fig. 93. Scaffolding]
[Illustration: Fig. 94. Scaffold Bracket]
=51. Cornice.=--Cornices are generally classified as open or
skeleton, and box, Figs. 95 and 96. Each of these types will be found
constructed in almost endless variety of forms. The illustrations shown
will serve the purposes of this text. The student should familiarize
himself with the various common forms, details of which may be got from
any good, modern book on building details.
[Illustration: Fig. 95. Skeleton Cornice]
[Illustration: Fig. 96. Box Cornice]
In making the various cuts on cornice work, a miter-box must be
available for mouldings. The old type of wood miter box, with the
various necessary cuts laid out in its sides is satisfactory. Some
experimenting will be necessary upon the part of the beginner to
determine the manner of placing the moulding in the box to give the
correct cut.
The cuts for the plancher, which rests in the planes of a hipped roof
and which must be membered around a corner are determined in a manner
similar to that described for roof boards, Sec. 49, from the cuts of
the jack rafter cheeks.
[Illustration: Fig. 97a. Skeleton Cornice]
[Illustration: Fig. 97-b. Box Cornice.]
Fig. 97 illustrates the manner of "framing in" the lookouts on' gables
where a skeleton cornice is used. Also there is illustrated the manner
of placing lookouts in gables for a box cornice. Unless the cornice is
quite wide, these blocks are merely fastened to the underside of the
roof boards at intervals of 3 or 4 feet. The depth of these blocks will
depend upon the manner of framing the tail ends of the rafters.
Metallic gutters made to assume the form of the crown mould, no wood
crown mould being used, will be found in common use upon ordinary
house construction. A fall of ½ inch to every 10 feet is usually given
gutters.
=52. Raked Mouldings.=--In all cases where a moulding resting in
one plane, as crown or bed moulding at the eaves, is to be membered
with moulding swung up out of that plane, as up a gable, one of two
things must be done to make the surfaces of the mouldings match or
member properly at the joint: (1) The moulding at the eave may have
its top edge tipped forward until its top edge lies in the same plane
as the top edge of the corresponding gable moulding; (2) a moulding
with a new face may be worked which will member with the eaves moulding
when their reverse surfaces are fitted to the fascia or, in case of bed
moulding, to the frieze.
[Illustration: Fig. 98. Laying out Gable or Raked Moulding]
To member by means of the second method proceed as follows: (1) Make
a full sized drawing of a cross-section of the moulding, Fig. 98. (2)
Draw a number of lines thru the more important reference points of
the moulding at an angle equal to the pitch of the gable. (3) Draw
horizontal lines thru the points of reference and erect a perpendicular
thru these passing thru the back of the mould as _A-B_. (4) Lay
off a line _C-D_, Fig. 98, perpendicular to the oblique lines. (5)
Using the lines _A-B_ and _C-D_ as reference lines, transfer
the distances of the various points on the eaves moulding, measured
horizontally from _A-B_, to pitch lines measured obliquely. A
curve traced thru these points will give the shape of the moulding
required for the gable. Since this moulding would, in all probability,
have to be worked up especially for any particular job, this practice
is not followed except upon large or important work. Cornices are
usually designed so as to avoid such work.
[Illustration: Fig. 99. Miter Box for Raked Gable Moulding Cut at Eaves]
[Illustration: Fig. 100. Miter Box for Plumb Cut of Gable Mouldings]
Figs. 99 and 100 illustrate two miter-boxes constructed for use in
cutting rake mouldings in gables.
In making the miter cuts on mouldings of the eaves, the horizontal
members, no special box is needed. The moulding will be set on the
far side of the box, upside down. The box will have the side cuts
perpendicular to the top edge and the angles across the top edges
will be determined by the miter of the plate, sill, or corner of the
building. On a square cornered building this miter will be one of 45,
12" and 12" being taken on the square. Two cuts of each kind, but
reversed, are made in each box so that the moulding for each side of
each gable may be readily cut. On the octagonal building 5" and 12"
would be used in laying out the miter, with scribing done along the 5"
member of the square.
For the miter cuts of the rake or gable member, special boxes would
best be constructed. For the cut of the gable member where it joins
the eave moulding: (1) Lay off across the top of the miter-box, right
and left, the miter of the plate, sill, or corner of the building. (2)
Down the sides of the box lay off the slanting lines as shown in Fig.
99, at angles determined by the plumb cut of the common rafter. (3) Lay
the moulding in the box as indicated by the cross-section, Fig. 99,
being careful to keep the backs of the mouldings adjusted to the side
and bottom of the box. A good plan is to drive a nail or two in the
bottom of the box against which the moulding may be made to rest, once
the proper position is determined by trial.
For the plumb cut of the gable moulding, (1) lay off lines across
the edges of the box as in Fig. 100, using on the framing square the
numbers which give the plumb cut of the common rafter. Lay off a right
and a left cut as shown. (2) Square these lines down the sides of the
box and saw. (3) The moulding will be placed in the box as shown in the
cross-section view of Fig. 100, especial care being taken to have the
backs of the mouldings adjusted to the back of the box.
Manifestly, one box may contain all these cuts to advantage instead of
having three boxes.
These cuts, Figs. 99 and 100, serve in cutting the miters on ends of
the gable fascia. A little consideration will make clear the remaining
cuts upon ordinary cornice work.
In splicing mouldings, corner boards, etc., a mitered joint is best and
should be made so as to shed water from the joint, Fig. 101.
=53. Shingling.=--The reason for placing cornice before base or
window frames, etc., is to allow the workmen to work inside should
inclement weather overtake building operations at any time. Shingling,
therefore, will follow cornice work.
[Illustration: Fig. 101. Spliced Comer Boards and Moulding]
The amount of shingle to be exposed to the weather will depend in
general upon the pitch of the roof. In no case should this exposure
exceed 5 inches. The shingle most used is 16 inches long, and each
shingle should lap two courses beneath it. The usual amount of lay is
from 4" to 4%", by quarters. When nearing the ridge or comb of a roof
in shingling, the dimensions used on the main body of the roof should
be increased or decreased so as to make the final layer show under the
comb or ridge or saddle boards properly. The worker should begin such
calculations when within about four or five feet of the ridge so that
changes of exposure of the different layers may not be noticeable and
so that the line of shingle butts may be kept parallel with the ridge.
[Illustration: Fig. 102. Beginning Course]
The first layer of shingles should be a double one with joints properly
broken, and with the butts projecting over the crown moulding about 1½"
to 2". Lay the shingles at the gables first, then at intervals of about
ten feet. Stretch a chalk line between these fastening it to the butts
by shingle nails driven into the butts, Fig. 102.
The remaining courses may be laid by means of a straight-edge or by
means of a chalk line. Both practices have ardent advocates. Where
a straight-edge is used, it is usually a piece of lap siding or
clapboard, and is held in place by being lightly tacked.
[Illustration: Fig. 103. Shingling. Toe Hold]
In using the chalk line a man for each end is required. The line is
chalked and snapped for three courses at a time. The mechanic, after
a little practice, is able to keep the butts of the shingles straight
and to sight them so that they shall follow the chalk line mark. On
long courses a third person may be utilized in chalking and in laying
shingles. In chalking, this person holds the line to the roof as
sighted by an end man and the snapping is done on each half of the line.
The chalking of a line so as to conserve the chalk is one of the tricks
of the trade which must be mastered early. It consists in rotating
the chalk about its hemispherical axis while being worked backward and
forward along the line, the line being held between the chalk and the
ball of the thumb. Otherwise the line would soon sever the chalk.
[Illustration: Fig. 104. Shingling. Toe Holds]
Cut nails should be used in preference to wire nails because of their
greater rust-resisting quality. Dry shingles should not be laid tight
together, ⅛ inch between is not unusual with dry shingles. It is best
to split shingles over 10 inches wide before laying them. Each shingle
should have at least two nails, the average is two nails for every four
to six inches of shingle.
Scaffolding for roof work, or toe hold, is usually constructed by
nailing shingles to 2" × 4" as shown in Figs. 103 and 104. Other
forms are equally common. Apparently the holes left by the nails
used to fasten the toe hold to the roof would cause a leak in the
roof. To avoid any such danger, tho such danger is slight because
of the swelling of the wood fiber upon the application of moisture,
the shingles having such holes are driven down the roof slightly by
striking their surfaces a glancing stroke.
=54. Shingling Hips and Valleys; Flashing; Saddle or Comb
Boards.=--Hip and valley shingles are usually sawed to shape before
being taken to the roof, the face cut being the same as that used
across the face of the roof boards and plancher members intersecting
about a corner of a hipped roof where plancher lies in the plane of the
roof. The cut across the edge of such shingles is made square to the
face.
[Illustration: Fig. 105. Shingle Tins]
[Illustration: Fig. 106. Valley]
Of the many ways of protecting the intersection of hip shingles when
in place upon a roof, the simplest is that of employing tin shingles.
Such shingles should be of sufficient length to allow the corners to be
turned under as shown in Fig. 105, and still extend far enough under
the next course of shingles to permit the nails holding the tins to
be covered. It is not good practice to nail thru these tins after the
roof has been covered, that is, to place these tins after the roof has
been shingled because the action of the weather "lifts" the nails when
exposed thus.
Valleys are covered with a strip of metal to a width of 20 inches. Upon
steep roofs and short valleys this width may be reduced to 16 inches.
Space must be left between the edges of valley shingles as shown in
Figs. 106 and 107. The amount will depend upon the length of the valley
and the steepness of the roof. For a ½ pitch with a length of twelve to
fourteen feet of valley, the space at the top of the valley may well
be 1 inch to each side of the valley center line, widening gradually
toward the lower end to 2½ inches to each side. Chalk lines snapped
upon the tin or other metal forming the valley indicate the location of
shingle edges. Nails in valley shingles should be kept well back from
the valley edge of the shingles.
[Illustration: Fig. 107. Shingling Valley]
Flashing consists in placing tin shingles or other material about
the members making up a joint so that the joint shall "turn water."
Counterflashing consists in placing a double layer of tins in such a
way as to doubly insure turning water from a joint.
Fig. 108 is an illustration of flashing where shingles meet lap siding.
Shingle tins are forced under the siding on one side and either under
or over the shingles, several inches of lap being allowed all about.
Fig. 109 illustrates a counterflashed chimney. A layer of tins is
placed as in flashing against siding except their top edges are not
inserted. Over these tins a second layer is placed as shown, the
top edges being inserted ¾" between the layers of brick, the mortar
being raked out so that this can be done. These turned edges are held
in place by the insertion of a wedging nail or tack, after which
the cracks are filled with cement, or better, an elastic roofing
composition.
Tins should be carried high enough to prevent drifted snow from
entering; 2½ or 3 inches at the narrowest place.
[Illustration: Fig. 108. Flashing Fig. 109. Flashed and Counter-flashed]
Saddle or comb boards are of various forms. They are used to give the
ridge a finished appearance and to turn any water which might happen to
strike thereon; also to hold the last course of shingles in place. A
simple form is obtained by creasing to the appropriate angle a strip of
tin eight inches in width. Place this on the ridge and nail its edges
at intervals of 3 or 4 inches. Where boards are used, one board should
overlap the other and extend a half inch beyond to turn water from the
joint so made. Galvanized ridge rolls may be purchased in stock styles.
=55. Finishing Exterior Walls.=--With the roof completed, side
walls are next covered except where porches are to be attached.
Fig. 110 illustrates the manner of constructing an exterior wall having
a water table and lap siding, also the relation of the various parts of
an exterior wall.
[Illustration: Fig. 110-b. Exterior Wall Detail]
A belt course is sometimes used between the first and second stories of
a building. Such a course is often constructed like the water table.
Like the water table or base, this belt course is furred out in order
to throw the course into greater relief. In case this furring is not
done, the lower edge of the belt board must be rabbeted to receive
the top edge of the siding. Frieze boards, too, are frequently furred
instead of being rabbeted. More elaborate belt courses are common.
Building paper should be stripped about the openings for doors and
windows before the frames are set, to insure warmth; also about corner
boards and cornice.
Corner boards and casing edges should be very slightly beveled so that
the siding may take a slight squeeze as it is placed. Care in setting
frames and in making casing edges true will insure a saving of time in
placing siding.
=56. Setting Window and Door Frames.=--Two men usually work
together in setting frames, as in fact they do on much other carpentry
work. In setting door frames on outer walls (1) the rough floor, etc.,
must be cut away so that the top of the sill may rest on a level with
finished floor when that is in place. (2) When this is done the door
sill is carefully leveled, Fig. 111, and shingle points inserted under
the sill where needed to give solidity and support. (3) The casing is
given a nail close to the sill at each side of the frame and (4) the
sides of the jambs, are plumbed and the casings finish nailed. If the
work is carefully done the frame should be square.
[Illustration: Fig. 111. Leveling Door Sill]
Where heads of several windows are a given distance from the floor,
a stiff stick may be cut this length and used in placing windows in
position for height. The window sills will be leveled as are door
sills; the jambs are plumbed, Fig. 112, and casings nailed at intervals
of about a foot.
[Illustration: Fig. 112. Plumbing Frame]
[Illustration: Fig. 113. Using Siding Stick]
=57. Siding.= Preparatory to siding, a siding stick should be
made. Such a stick is made by planing parallel edges upon a piece of
Y% inch stock about 1 inch in width. Upon this stick marks will be
made which will indicate the spacing of the siding; these marks being
transferred to corner boards and casing edges, Fig. 113. To lay off
this stick a given space is taken, water table drip cap to the lower
edge of a window sill for example. (1) This space may be transcribed
upon the stick easiest by setting the stick upon the drip cap and
against the casing edge, marking under the sill upon the stick. (2)
This space is "stepped off" by means of a pair of dividers set to the
amount of exposure desired. Exposures will run from 4¼ to 4¾ inches on
ordinary lap or bevel siding. (3) Should there be a remainder, and
there almost always is, the exposure must be increased or decreased,
whichever is necessary, an amount sufficient to give an equal or even
number of divisions. In practice this amount is found by stepping off
as suggested and then making necessary adjustments by guess and again
stepping. This is continued until the desired result is attained. The
difference is thus divided equally over the whole space instead of over
the last courses as in shingling.
[Illustration: Fig. 114. Marking Length of Siding Fig. 115. Using
Siding Hook]
In a similar manner a stick, or another space of the same stick is
laid off and stepped for the space between the bottom of the window
sill and the top of the drip cap above the head casing of the window,
etc. On long lateral spaces this stick will be used to keep the lower
edges of the boards in position between the casings, by transferring
its marks to the building paper, stepping down from one of these marks
with a pair of dividers to the lower edge of the siding board being
placed. (4) A bunch of siding boards should have one end of each sawed
square across the face, but sawed under on the back side slightly so
as to insure a fit on the surface. (5) One end is next fitted, with
block plane if necessary, after which (6) the length is marked by
turning the board upside down and marking on the lower edge of the
board, which is uppermost, with a knife, Fig. 114. Another way to mark
length is indicated in Fig. 115. This tool is called a siding hook or
tool and this method possesses the advantage of caring for any lack of
squareness in the frame or trim.
In nailing, care must be taken to place the nail so that it shall pass
thru both boards where lapped. Under windows it will be necessary to
trim off part of the upper edges of the siding boards. Saw kerfs at
either side of the part to be cut, and a sharp, deep knife scoring
along a straight-edge should be used to outline the part to be removed.
To determine the amount to be removed, set the dividers to the amount
of spacing used for the boards in the space under the window, plus the
depth of rabbet, or groove in the under side of the window sill into
which the upper edge of the siding board must fit. Set off this amount
on the siding board from the butt or under edge at each end of proposed
cut, and connect with straight-edge; scoring with knife.
[Illustration: Fig. 116. Siding Circular Tower]
Occasionally the carpenter is called upon to side a circular tower or
rounded corner of a building. That the lower edge of each board may
rest in a horizontal plane it will be necessary to shape that edge
before applying the board to the side of the building. To determine
the amount of curvature to give such an edge proceed as follows: (1)
Plot a curve to represent the plan of the tower, Fig. 116. Draw this
upon a scale sufficiently large and make use of accuracy such as
will insure a result equal to the requirements of the occasion. (2)
Draw the line _A-B_ of indefinite length. (3) Place a section
of a clapboard in the position it will have on the sheeting, as at
_abc_, Fig. 116, and (4) extend a line along the face surface to
meet _A-B_. (5) With a radius equal to _B-C_ describe an arc
with _B_ as a center which shall cut the siding board as shown,
taking an equal amount off the edge at each end.
Occasionally it becomes necessary to fit a casing against a sided
wall. This casing is scribed as indicated in Fig. 117, a pair of sharp
dividers being made to follow the contour of the wall with one point
while the other marks or scribes the casing. A saw will be used to cut
to these lines, sawing under slightly to insure a fit at the face.
[Illustration: Fig. 117. Scribing against Irregular Surface]