Ebook Interior design principles and practice - M. Pratap Rao: Phần 2

Part 2 ebook present the content:drawing; lettering & scales; figures & projections; building material symbols; space standards; external parts; nternal parts; kitchen design; staircases; theory of colours; rendering techniques; three dimensional views; interior design method; introduction to computer aided drafing (cad). For more details please refer to the ebook.

I LETTERING

All the headings, explanatory notes and dimensions should be neatly written on the drawing Ordinary writing is not good for presentation A student c'interior design should devote enough time to practice lettering before starting the drawing To do good lettering, the work must be done slowly The presentlettering style is known as single-stroke lettering Other styles of lettering\can also be used but this is an easy and acceptable form of lettering Insingle-stroke lettering a line of the required thickness is made with one stroke The letters must be well formed with good relative width and uniform spacing.There is no standard relation between the height and the width of a particular letter The actual width of the letter will depend on the space available forwriting Proper proportions of the various letters are estimated by eye The rounded letters require most care and attention Good jqdgement and practise arerequired to obtain proper spacing of the letters in a work

Writing method

There are basically three types of letters normally used They are:

I Block letters like A, B, C

2 Small letters like a, b, c

3 Numbers like I, 2, 3

Try to write all the letters with free-hand with pencil grade 'B' Avoid using T-square and set-squares for writing letters Choose proper spacing betweenthe letters depending on the availability of space

1 Block letters - Make rectangular boxes equally spaced with three horizontal lines as shown to any scale in the proportion of 1:1.5 (1 width and 1.5

length) Try to write all the letters within these boxes as shown Take care in writing letters I, J & W proportionately because they may not fit exactly

in the box

2 Small/etters - Ma~ rectangular boxes equally spaced with four horizontal lines as shown to any scale in the proportion of 1: 1.5 (1 width and 1.5length) Try 'to write all the letters within these boxes as shown Take care in writing letters i, j, m & w proportionately because they may not fitexactly in the box

3 NumIJers - Make rectangular boxes equally spaced with three horizootal lines to any scale in the proportion of 1:1.5 (1 width and 1.5 length) Try to

write all the numbers within the boxes as shown

LETIERING AND SCALES 3

l Take.~ ordinary 30 eentimeter~ (em) scale

J For seale CDmark I 'em.as equivalent to 1 meter (m); 2 em =3 m; 3 em =3 m; 4 em =4 m; 5 em =5 m; 6 em =6 m; 7 em =7 m; 8 em =8 m; 9 em .

= 9 m; 10em =.10 m; 11em = 11m; 12em = 12 m; 13em = 13 m; 14em = 14m; 15 em = 15 m; 16 em = 16 xn;17 em = 17 m;18 em = 18 m;

19 em = 1911\l;20em= 20 m ~d so pn Now, it is a seale of 1 em=1 m (or) 1:100 .

4 For scal~ @ n1.ark2.em as equivalent to 1 meter (m); 4 em =2 m; 6 em =3 m; 8 em =4 m; 10 em = 5 m; 12 em = 6 m; 14 em = 7 m; 16 em = 8 m;

1~ em = 9 m;20 em = 10 m; and s() on Now, it is a seale of 2 em =1m (or) 1:50.

5 For seale:;<IDmark 5 em 'as equivalent to 1 meter (m); 10 em =2 m; 15 em =3 m; 20 em=4m and so on Now it is a seale of 5 em =1 m (or) 1:20 .

6 For seale'@ mark 10 em as equivalent to 1 meter (m); 10 em=1 ni; 20 em =2m and so on Now, it is a seale of 10 em=1 m (or) 1:10

7 For seale@ mark 20 em as equivalent to 1 pleter (m) and so on Now, i.tis a seale of 20 em=1 m (or) 1:5

8 For seale @ mark 10 em as equi'(~eQ~to 3 meters; 5 em=1.5 m; 4 em =1.2 m; 3 em = 0.90m; 2 em =0.60 m; 1 em=0.30 and based on this

higher digits should be worked out' NQw, it is a seale of 10 em =3 meters (or) 1:30

9 Simill!J'ly any type of $eale can be made and u~ed for metrie units

,

:-A General assumptions

l The followingobjectsare drawn: .

2 Plan means appearance from the top of the object

3 El€~vation means appearance from the side of the object

4 Only one surface is seen at a time

3 Rectangle

6 Octogan

B Object dimensions

I The square object has six surfaces They are top, bottom and four sides Length: 2.50 m Width: 2.50 m and Height: + 2.59 m

2 The triangular object has five surfaces They are bottom and four sides Length: 2:60 m Width: 2.60 m and Height: + 2.60 m

3 The rectangular pbject has'six surfaces They are top, bottom and four sides Length: 2.50 m Width: 5.00 m and Height: + 2.50 m

4 The hexagonal object has eight surfaces They are top, bottom and six sides Regular hexagon of 1.30 m and height: + 2.50 m

5 The circular object has three surfaces They are top, bottom a.'ldside Radius: 1.30 m and Height: + 2.50 m .

6 The octagonal object has ten surfaces They are top, bottom and eight sides Regular octagon of 1.30 m and height: + 3.00 m,

C Drawing method

Steps

1 Visualise each surface how it appears on that particular side

2 Draw plan to scale 1:100 (or) 1 em =1 meter as shown, otherwise choose any convenient scale

A General assumptions

1 The structure ;s standing on the ground level and all elevation heights are given from 'the ground level as + 1.2 m.:!t means 1.2 m above the groundlevel Similarly + 3.7 m means 3.7 m from the ground level and -+4.9 m~\means 4.9 m from the ground level Normally all heights of any structure:should be indicated as (+) or (-) from the ground level, which is treated ~:f: O

2 The structure is composed of the following shapes:

(a) Rectangle of+ 1.2 m height forms the b~e.

* On the left side: (b) Square of + 3.7 m height over the rectangular base.

(c) Diamond shape of + 4.5 m height over the squ~ base

* On the right side: (d) Square pyramid of + 4.9- m height over the rectangular base.

3 Three different views are marked as L (left), F (front) and R (right):

B Drawing method

Steps

1 Draw to scale 1:100 (or) 1 cm =1 meter as shown, otherwise'choose any convenient scale

3 Draw the 'F' side elevation directly below the plan so that orthographic projections ffom the plan can be t*en Add the heights for the elevation

4 Similarly draw 'L' and 'R' side elevations l'Qaintl,riniQga total height of + 4.9 m f~m ground'1evel ,

5 While drawing the elevations from three different sides, it should be observed that from each side elevation some parts of the structure are hi~den

Drawing Method

Steps

1 Draw to scale I: 100 (or) 1 cm =1 meter as shown, otherwise choose any convenient scale

2 The structure is composed of the following shapes:

(a) Rectangle of + 1.2 m height forms the base.

(b) Regular octagon of + 2.4 m height over the rectangular base.

(c) Square shaped' pyramid of + 5.00 m height over the octagon

* On the right side: (d) Square of + 5.00 m height over the rectangular base.

3 Draw the plan as per the measurements

4 Draw the 'F' side elevation directly below the, plan so that orthographic projections from the plan can be taken Add the heights for the elevation

5 Similarly, draw 'L' and 'R' side elevations maintaining a total height of + 5.00 m from the ground level.

12 INTERIOR DESIGN PRINCIPLES AND PRACTICE

1 Draw to scale I: 10 (or) 10 cm =I meter as shown, otherwise choose any convenient scale

2 Draw the 'F' (front) side elevation directly below the plan, so that orthographic projections can be derived from the plan

3 Only the front and the side elevations are drawn, because the back and other side elevations are the same as front and side elevations

2 ORTHOGRAPHIC PROJECTIONS

Orthographic projection is normally used to represent an object or structure, so that any line or angle can be measured directly and accurately A line orsurface is projected upon a plane by drawing perpendicular lines from points on the line or surface to the plane, and then joining them The plan and threedifferent sections of two structures and one room are worked out for conceiving the construction details with the help of orthographic projections

A General assumptions

1 The structure is simple and easy to start learning of the orthographic projections

2 The structure is standing on the ground level (GL) and all heights shown in the brackets in the plan as + ] 0, + 1.5, + 2.0 and + 4.0 meters are givenfrom the ground level; which is assumed as:t O

3 The structure is composed of the following shapes

(a) A base of + 1.5 m height.

* On the left side: (b) A sunken square of + 1.0 m height within the base.

* On the right side: (c) Two rectangles of + 2.0 m and + 4.0 m heights over the base.

4 Three different cross sections are taken for orthographic projections

(a) Section-XY looks upwards.

(b) Section-PQ looks towards the left side.

(c) Section-AB looks towards the right side.

Across section shows the imaginary cutting line and its viewing direction This helps to understand the construction details of the structure

B Drawing Method

Steps

1 Draw to scale I: 100 (or) I cm =I meter as shown, otherwise choose any convenient scale

2 Draw the plan as per the measurements Take the outer dimensions of lOx 5.50 m to start the plan, so that it fits within the given dimensions First,draw the base of the structure and then the innt::r parts

3 Draw the cross section~XY below the plan While cutting the structure along the XY line, the visible parts are' the base, the sunken 'square and thesmall rectangle.laJ(e-ihe orthogr<ij)hic projections shown in dotted lines from the plan and give the heights mentioned in the plan The portions of thestructure which are cut in the imaginary cross section line should be shown in hatched lines

4 Similarly draw cross sections AB and PQ on the left and right sides by using orthographic projections

5 Sections are particularly drawn for easy visualisation while drawing The left side (Section AB) and right side (Section PQ) are mirror images, whilethe front side (Section XY) is a true image

16 INTERIOR DESIGNS PRINCIPLES AND PRACTICE

(b) Structure -2

1 Structure - 2 is made of different shapes than square and rec\angles of the eariier exercis~ This exercise helps to understand the use of orthographic

projections for shapes other than square and rectangle

j

2 The structure is composed of the following shapes:

(a) A base of + 1.0 height.

* On the left side: (b) A square pyramid of + 3.0 height over the base.

* On the right side: (c) An open cylinder of + 4.0 m height over the base.

3 Three different cross sections are taken for orthographic projections:

(a) Section - XY looks upwards

(b) Section - PQ looks towards the left side.

(c} Section - AB looks towards the right side.

A cross section shows the imaginary cutting line and its viewing direction This helps to understand the construction details of the structure

B Drawing Method

Steps

1 Draw to scale 1 : 100 (or) I cm =1 meeter as shown, otherwise choose any convenient scale

2 Draw the plan as per the measurements Take the outer dime:nsions of 10 x 5 m to start the plan so that it fits within the given dimensions First drawthe base of the structure and then the inner parts

3 Draw the cross section-XY below the plan While cutting the structure along the XY line, the visible parts are the base, the cut pyramid and the cutopen cylinder Take the orthographic projections shown in dotted lines from the plan and give the heights mentioned The portions of the ~ructurewhich are cut in the imaginary cross section line should be shown in hatched lines

4 Similarly draw cross sections AB and PQ on the left and right sides by using orthographic projections

5 Sections are particularly drawn for easy visualisation while drawing The left side (Section AB) and right side (Section PQ) are mirror images, whilethe front side (Section XY) is a true image

18 INTERIOR DESIGNS PRINCIPLES AND PRAcrlCE

(c) Room

A General assumptions

I This exercise of the room helps to understand the use of orthographic projections for drawing building cross sections

2 The room is made of brick wall, a door, four windows, ordinary cement flooring, RCC roof slab and a brick parapet Note the direction of the northpoint, which shows the direction of north side in relation to the room North point should be marked in any building drawing

3 Three different cross sections are taken for orthographic projections

(a) Section- XY towards north side

(b) Section - PQ towards west side

(c) Section - AB towards east side

A cross section shows the imaginary cutting line and its direction This helps to understand the construction details of the building

I Draw to scale 1:50 (or) 2 cm =I meter as shown, otherwise choose any conyenienrscale

2 Draw the plan as per the measurements Take the outer dimensions of 4.50 x 3':s0 m to start the plan, so that it fits within the given dimensions First

draw the external wall thickness of 25 em then mark the door (DI) and windows (WI) in the centre of the walls Similarly mark windows (W2) to the

corners of the wall

3 For dimensions refer door & window schedule

4 Draw the cross section - XY below the plan While cutting the room along the XY line, the visible parts are the walls, flooring, windows, roof slaband parapet Take the orthographic projections shown in dotted lines from the plan and give the heights as shown

5 Similarly draw cross sections AD and PQ on the left and right sides by dsing orthographic projections

6 Sections are particularly drawn for easy visualisation while drawing The left side (Section AB) and right side (Section PQ) are mirror images, while

-Interior design depends upon the relationship of the following lihree aspects:

2 Space - The given space is always fixed The area and dimensions cannot be changed except marginally However narrow spaces can be made tolook spacious by providing mirror walls It is only an optical illusion and does not increase the real space When the space is inadequate and small,

minimum area should be provided for circulation or movement of the people

.

3 Equipment - - To perform any activity within a given space, some furniture is required For example, in a dining rom, a dining table and chairs areneeded Based on the available space and number of persons to be accommodated, the size and shape of the dining table should be decided Similarlyfor a bed room, the bed and wardrobe should be properly planned

Thus for good interior design, there is a need to co-ordinate these three aspects effectively The following space standards are useful for good interiordesign

The above space standards are extremely useful for il}terior design These standards are derived out of practical experience and useful fot Indian

conditions However they are not rigid Whenever there is any doubt about the provision of any space, it is useful to take the measurements of that particularactivity as we perform in our daily lives

ExERCISE

1 Prepare an existing interior layout of your residence

2.Plepare an existing interior layout of your classroom.

Before knowing brick bonds, there is a need to know various brick sizes used in brick bonding and their technical terms Even though we may not use

Drawing Method

Steps .

1.)fraw to scale 1:10 (or) 10 cm = i meter as shown, otherwise choose any convenient scale

2 Assumptions made in the drawing:

.

(a) Brick size 250 x 125 x 75 mm (or) 10" x 5" x 3"

(b) l\llthe sizes of bricks are shown as parts of a full size brick like 1/4, 1/2 and 3/4 of the whole brick This makes the understanding easy than

showingactual measurements.It is also the normalpractiseof cuttingthe brickson the site.

3 Normal brick sizes available in India are

(a) 250 x 125 x 75 mm (or) 10" x 5" x 3"

1"

(b) 225 x 113x 75 mm (or) 9" x 42" x 3"

4 The brick has six faces, which are known as top, bottom.J!eader and stretcher faces The top face has 'frog' in the case of pressed or machine-cut

5 The various brick sizes shown are used for brick bonding depending on the need because without cutting the brick, brick bonding is not poSsible

6 For all the brick si7es full size bricks should be drawn The differaat.sizes should be cut from the full size bricks

Drawing method

Steps

1 Draw to scale 1:10 (or) 10 cm=1 meter as shown, otherwise choose any convenient scale

2 Assumed brick size is Lx B x H =250 x 125 x 75 mm (or) 10" x 5" x 3"

3 The drawing is divided into two parts The ~ttom part shows the isometric view of 1, 2, 3 & 4 brick courses and their overlapping with queenclosers (half) to break the continuity and increase bonding capacity

4 The upper part shows the elevation view from')l side

5 English bond is compact and strong for walls having thickness of more than one a~d half bricks It does not require strict supervision and skill forexecution When compared to Double Flemish bond, it is more costly and less pleasing in appearance

Drawing Method

Steps

1 Draw to scale 1:10 (or) 10 cm=1 meter as shown, otherwise choose any convenient scale

2 Assumedbrick size is Lx B x H= 250 x 125x 75 mm (or) 10" x 5" x 3". ,

3 The drawing is divided into two parts The bottom part shows the isometric view of 1, 2, 3 & 4 brick courses and their overlapping with qUfenclosers (half) to break the continuity The bricks are placed in a different way than English bond to increase the strength of bonding

4 The upper part shows the elevation view from')l side

5 Double Flemish bond is less compact and stronger than English bond but requires good workmanship and careful supervision When compared toEnglish bond it is cheaper in cost because more brick bats are used for one and half and two bri~k walls It has better face appearance

Fig Eel DilIerentBrieks sizes (Scale 1:10 or 10 em =1 Meter)

Brick bonding is the interlacement of brick courses with mortar It should have minimum vertical joints in any part of the brickwork because it is a weak part of the brickwork with uneven distribution of load There are many types of brick bonds like Stretcher, Header, English, Flemish etc., Most frequentlyused brick bonds are English and Double Flemish bonds The use of these two bonds for one brick wall is.shown in the drawings One brick walls arecommonly used at present for exterior and interior construction of buildings.

30 INTERIOR DESIGN PRINCIPLES AND PRAC1'ICE

3 TYPICAL WALL CROSS SECTIONS

A There are basically two ty~ of building constructiC'D

(a) Load bearing wall construction - Most of the residential buildings and small structures are constructed with load bearing walls for economy and easy

(b) Plinth level- It is above ~e ground level.and to the surface of the immediate floor level

(c) Plinth area - It is the built-up covered area at the plinth level.

(d) Superstructure - The structure constructed above the plinth level

(e) Storey - The portfon of a building between any two floors.

if) Sill level - The lower part below the window and the floor

(g) PCC footing - Plain Cement Concrete (PCC) in the proportion of 1:5: 10 or in any other desired proportion is used as foundation footing to the loadbearing wall construction The base width of PCC should be twice the width of wall

(h) Brickfooting - Brick footing is stepped over a concrete bed The number of brick steppings depends on the proposed width and loading of the wall

(i) Column footing - These footings are used to support individual columns They can be stepped or have projections, as shown, in the concrete base

(j) RCC - In reinforced cement concrete (RCC) the concrete and reinforcing metal (normally steel is used) act together as one material Concrete has

good compressive strength and steel has got good tensile strength In RCC, both these qualities of the materials are combined together to produce a

(k) RCC plinth beam - RCC plinth beam is usw to tie the columns at the ground level or plinth level The wall can be constructed on this beam

(I) DPC - Damp proof course (DPC) is a layer of water repellent material like bitumen, plastic, metal etc It is used wherever water entry is anticipated

This is normally used at the plinth level and over the roof level

(m) Flooring - The flooring is normally done with cement, stone or tiles The thickness of the floor depends on the material used.

(n) Skirting - Skirting is made with the same material used for the flooring Skirting is made to protect the wall finish while washing the floor.

(0) Door - A door can be defined as a movable barrier fixed to a wall opening for providing an access to the building or internal rooms The door isfixed to the wall with door frame, and a movable shutter is used for closing and opening Doors are made of different materials like wood, plywood,glass, metal etc.,

(P) Lintel- It is a horizontal supporting member used to span the openings of doors, windows, ventilators corridors etc., The use of a lintel is exactly thesame of an arch but it is preferred because of easy construction and stability for small spans They are made of wood, stone, brick and RCC RCC

(q) Window - A window can be defined as an opening in the wall of a building to bring natural light, air, vision with protection from sun, rain and other

extremities of weather They are normally fixed to the wall with movable shutters for opening and closing Windows are made Qf different materials

(r) Sunshade - It is a sloping overhang provided over openings like doors and windows to provide protection from sun and rain beating

(s) Throating -It is a channel or groove under the sunshade to prevent rain water from ruooing inside the walls

EXTERNAL PARTS 31

(t) Ferro-cement - It is made of cement and steel mesh It is thin, light weight and easy to construct than brick wall It can be made totbe requiredarchitectural design

(u) Parapet - It is that part of the wall constructed above the top roof slab

(v) Coping - Top of every wall not protected from the rain should be built to prevent the penetration of rain water with a slope Known as coping.

C Drawing method

Steps

I Draw to scale: 1:5 or 20 cm =I meter as shown, otherwise choose any convenient scale

2 Draw the ground level line and divide the drawing into two equal parts for load and non-load bearing walls

3 Visualise the vertical cross section ofa wall with door and window

4 Draw the total height (755 cms) of both the buildings

5 Divide the buildings into plinth (45 cms), ground floor «310 cms), first floor (310 cms) and terrace (90 cms) levels Thus the building levels becomevery clear for further internal detailing

6 Draw the door (200 cms) and window (120 ctns) levels, excluding the floor thickness, for both the walls with lintels and sunshades

7 For non-load bearing wall, draw the balcony projection (90 cms) with ferro-cement walls cf 8 ems thickness

8 Draw the internal parts of both the buildings and notice the different parts The load bearing wall does not have column footing, RCC beam, balconyand ferro-cement wall of the column structure Half-brick wall can also be used in column structure because the load is taken by the columns andbeams

9 Finally draw the foundation below the ground level as per the measurements and notice the difference in footings

EXTBRNAL PARTS

33

4 ARCH AND LINTEL

There is a need to understand the difference between an arch and lintel

A Ardl

Arch is a structure consisting number of small wedge shaped units joined together with mortar This is constructed to bridge across the openings meantfor doors, windows, ventilators, cupboards etc., and to support ~e weight of the superimposed masonry in building construction The wedge shaped unitssuch as brick or other masonry blocks are arranged along a curved line to balance the load and exert a vertical pressure to be sustained by the supports below.The arches made of RCC and steel- are built of single unit

It is a horizontal structural member used to span the openings for doors, windows, corridors and recesses to support the weight of the structure above if.The function of a lintel is exactly the same as an arch but it is preferred to arch because of easy construction Though lintels are made of various materialssuch as wood, stone, brick, RCCand steel, RCC lintels are widely used these days

C Technical terms in arch work

1 Crown - Highest point of an arch.

2 Voussoirs - Wedge shaped or tapered-units forming the COUNeof an arch.

3 Soffit - Under surface of ail arch.

4 Intrados - Inner curve of an, arch.

5 Impost - The projecting course at the upper part of an abutment to stress the springing line.

6 Centre - Geometrical- centre point of an arch.

7 Rise - Vertical distance between the springing line and the highest point of an arch.

9 Frontface - Front face of an arch

10 Extrados - External curve of an arch.

11 Haunch- Lower portion of an arch

12 Springers - Lowest voussoirs of an arch.

13 Spring;ng line - Imaginary horizontal line between two springers.

14 Span - Clear horizontal distance between the supports.

15; Abutment jamb.-- Outer most supports Qfan arch

'E Drawing method of arch

Steps

I Draw to scale: 1 : 50 or 1 cm =1 meter as shown, otherwise choose any convenient scale

34 INTERIOR DESIGN PRINCIPLES AND PRACTICE

2 The arch is assumed to be made of stone

3 The measurements of arch:

/

(a) Span: 5.50 m.

(b) Rise: 2.55m.

(c) Impost projections from the wall on either side : 0.40 m.

(d) The actual scale measurements may be taken for crown and voussoirs

4 First take the span 5.50 m and draw the imposts on either side

5 Mark the centre of the arch and take the rise 2.55 m to draw the intrados

6 Take 3.55 m radius from O1ecentre and draw the extrados

7 Take 3.1 m facIius from the centre and draw the middle curve between the voussoirsJ

8 Finally draw the crown and two rows of voussoirs as per the scale measurements

F.Construction of a lintel

Lintels can be classified into various types like wooden, brick, stone, steel, RCC (Reinforced cement concrete) and Keinforced brick lintel RCC lintelsare extensively used in modem building construction in India, because they are economical, strong, durable, fire-proof and easy to construct RCC lintels areconstructed usually with a concrete mix proportion of 1:2:4 (1 cement, 2 sand and 4 stone aggregate) with reinforced steel bars RC(: lintels may be eitherpre-cast or cast on the site Pre-cast lintels are preferred for small spans upto 2.0 meters Depending on the span and load, proper steel reinforcement should

be provided

G Drawing method of lintel

1 Draw to scale 1:20 or 5 cm =I meter as shown, otherwise choose any convenient scale

2 All measurements are -given in centimeters

3 The brick size is assumed as 10" x 5" x 3" or 25 x 12.5 x 7.5 cm

4 Draw the span of 200 cm and draw the RCC lintel 230 x 15 cm over it The overlap of 15 cm on either side gives the necessary support to the lintel

-

5 Finally draw the exposed brick wall as per the given measurements

36 INTERIOR DESIGN PRINCIPLES AND PRACfICE

* Draw to scale 1:50 (or) 2 cm =1 meter as shown, otherwise choose any convenient scale .

1 Equilateral arch - Draw a straight line with two centres of 'A, B' 200 em apart Take' ftl as centre and draw an arch of 200 em radius Similarly

take 'B' as centre and draw an arch of 200 em radius Both these cut.at '0' forming an 'Equilateral arch' for the span 'AB' of 200 em

2 Lancet arch - Draw a straight line with two centres of 'ftl, 'B' 400 em apart Take 'A' as centre and draw an arch of 300 em radius Similarly take

'B' as centre and draw an arch of 300 em radius Both these cut at '0, X, Y' forming a 'Lancet arch' for the span 'XV' of 200 em

3 Triangular arch - Draw a straight line 'AB' of 200 em Take an angle ()f 60° at point 'A' and draw a straight line 'AO' of 200 em Similarly take an

angle of 60° at point 'B' and draw 200 em straight line 'BO' Thus a 'Triangular arch' is formed over the span' AB' of 200 em .

4 Obtuse arch - Draw a straight line with two centres of 'ftl, 'B' 150 crn apart Take 'A' as centre and draw an arch of 200 em Similarly take 'B' as

centre and draw an arch of 200 em Both these cut at '0, X, Y' forming an 'Obtuse arch' over the span 'XV' of 250 em .

5 Semi-circular arch- Take a centre point 'ftl and draw an arch of 150 em radius cutting at points 'X', 'V'; which are in line with point 'ftl Thus a

6 Segmental arch - Take a centre point' ftl Then draw a straight line at gOem distance above point' ftl Taking' ftl as the centre point, draw an arch

of185 cm cutting at 'x, Y' Thus a 'Segmental arch' is formed over the span 'XV' of 325 em

7 Basket arch - Draw a straight line with two centres of 'ftl, 'B' 200 em apart Take the centre point and draw a perpendicular line below Takeanother centre point 'C' on this line at a distance of 80 em from' AB' Draw the first arch 'XP' of 50 cm radius with' ftl as centre The point 'P' isobtained by taking an angle of 45° from 'Xftl Draw the second arch 'QY' of 50 cm radius with 'B' as the centre Finally, draw the third arch ~PQ'

.of 185 em radius with 'c' as the centre Thus a 'Basket arch' is formed with three centres over the span 'XY' of 300 em

8 Stilted arch - Take a centre point 'A' and draw an arch of 150 em radius cutting at 'PQ' Draw another parallel straight line 'XY' at a distance of 90

em below 'PQ' Join 'PX' jIlld 'QY' Thus a 'Stilted arch' is formed OYerthe span 'XV' of 300 em .

9 Horseshoe arch":' Take a centre point' ftl, and draw a straight line 'PAQ' !>raw another parallel straight line below this at 50 em distance Taking

'ftl as centre, draw an arch of 155 cm radius cutting at 'PQ' and 'XV' Thus a 'Horseshoe arch' is fonned over the span 'XY' of 290 em

10 Four~centred arch - Draw a straight line with two centres 'ftl,'B' 160 em apart Take the centre point of the straight line and draw a perpendicularline below Then draw below another parallel straight line with two centres 'C', 'D' 200, cm apart !It a distance of 180 em below' AD' Draw thefirst arch 'XP' of 50 cm radius with 'ftl as the centre Draw the second arch 'QY' of 50 cm radius with 'B' as the centre Draw th<?third arc4 'PO'

of 300 cm radius with 'D' as the centre Finally, draw the fourth arch 'QO' of 300 cm.radius with.'C' as the centre Thus a 'Four-centred arch' is

11 Shouldered arch - Draw a strai~ht line with two centres' ftl, 'B' 200 em apart Draw the firSt arch 'XP' of 50 em radius with 'A' as the ccm~.

Then draw the ~d arch 'QY' of ~Q cm radius with 'B' as the centre Draw perpendicular lines 'PM' of 20 em and 'QN' of 20 em.,' and join'MN' Thus a'Shouldered arch,' is farmed oYer the span 'XV' of 300 ern.

(c) Chamfering - It is the process of planing the edges or corners of a wooden piece to fonnnormaIly 45° angle.

(d) Bevel - In the process of chamfering, if the angle fonned is not 45° ,then it is called as, bevel

(e) Moulding - It is the process of shaping the wood as various units for construction by hand9r machine

if) Metring - It is the process of joining two wooden pieces at an angle.

(g) Scribing -If one end of the wooden piece is cut to suit the shape of ~other wooden piece, it is known as scribing

(h) Rebating - It is the process of cutting to sufficient depth a rectangular portion of a wooden 'piece to fit in apother wooden piece.

(I) 'Shooting - It is the process of dressing the edges of the wooden piece to make them even

(}) Housing - It is the process of sinking the edge of one piece into another.

(k) Groove - It is a recess fonned in a wooden pieCe The groove may have different shapes to fit another wooden piece

(I) Bead - It is the semi-circular projection fonned at the ~ges of the wooden pieces. , d','"

(m) Grounds - it is the process of fixing roug~ wooden blocks into the waIl to act as finn base lining for pictures 9r other ornamental things The

surfaces of the grounds should be flushed with the surface of the wall

(n) Laminating - It is the process of covering the structural woodwork wi~ )lect>rative laminates

INTERNAL PARTS

(4) WoodeDJoiDts -1Drawing method

Steps

1 Draw of scale -1 : 5 (or) 20 em=1 meter as shown, otherwise'choose any convenient sf81~'

The two members are Jomed by lappingooe over the other and binding them oy strap aPd boltS These Jomts are used where no projections at the

joints are required.Four types of joints are shown. ", s.

All the joints are drawn in isometric view and the dimensions are as shown First draw the ",ttom 'part and then the upper part to fit in.

,

3. Mi!ered joints -These joints are formed by cutting the members at an angle and joinin~' Mitered joins of different forms are used to hide the ~nd

All the JOlOts are drawn 10 180° x 30° angles, and the dimensions are as shown Observe the cross JOlOts while ~wmg.

4 PaaelliDgjoints - These joints are formed by joining two wooden members as sh~wn 'ftIreC' types of joints are, shown:

All joints are drawn in 180° x30° angles and the dimensions are as s~_own.Observe the "ointP while drawing.

S Corner joints- The~e joints are formed by connecting the ends and edges of dte~ber' parallel or at ri~t angles to their grain~ There may be

several types b~t one, Important type, Dovetail joint,' is drawn It is'drawn in isometric v' IN and the dimensions are as shown First !draw the grpove

Ie