Presentation on Conservation – Restoration of Exposed Concrete Façade of Heritage Buildings in City Centre, Sector-17, Chandigarh prepared by Prof. Jagjit Singh Ghuman, Formerly Chief Town Planner and Head T&CP Deptt., Govt. of Punjab in the Heritage Conservation Committee 4th Meeting on 22nd May, 2014 organised by Chandigarh UT Administration.

1. CHANDIGARH UT ADMINISTRATION
HERITAGE CONSERVATION COMMITTEE
4th Meeting: 22nd May, 2014
Agenda Item No. 1
Conservation – Restoration
of
Exposed Concrete Façade of Heritage Buildings
in City Centre, Sector-17, Chandigarh
Presentation of HCC Sub-Committee Report
by
CCA Research Cell Team Chandigarh

2. UNESCO: WORLD HERITAGE OVERVIEW
The International Charter for the conservation and restoration of
monuments and sites (The Venice Charter 1964) adapted by ICOMOS
(Intentional Council on Monuments and Sites) resolved to uphold age-old
traditions-cultures to bring “unity in human values”, regard ancient
monuments and safeguard its heritage for future generations.
It enlarges the scope, concept and definition of historic monuments to
include the more modest works of arts which have acquired cultural
significance and values in the fold of conservation and restoration of sites
and heritage buildings.
It lays recourse to all sciences and techniques to safeguard its legacy and
architectural heritage buildings, streets in the city landscape.
The UNESCO World Heritage Convention (Paris, 28th-29th October, 1999)
resolution adopted by the 12th General Assembly of the State Parties, DOC:
14GA-WHC-03/14.GA/INF.8 dated: 16th July, 2003, highlights:
“The cultural and natural heritage is a function in the life of the
community and to integrate-protect its heritage
in comprehensive planning programmes”.

3. Glossary of Words
Archaeological site and remains: As defined u/s 2(d) of the Act 1958, means
any area which contains or is reasonably believed to contain “Ruins or
Relics of Historical or Archaeological Importance” which have been in
existence for not less than one hundred years, and includes
i. Such portion of land adjoining the area as may be required for fencing or
covering in or otherwise preserving it, and
ii. The means of access to, and convenient inspection of the area;
Natural -Building Structure: A composite free standing natural or manmade
structure, a rock or geological formation, building or other object (e.g. a
bridge or a dam across a river), comprising of several parts and components
made of different building material e.g. earth soil (mud), lime or cement,
wood, brick, stone, steel or glass, including cement concrete, or Reinforced
Cement Concrete (RCC) or other natural building material.
Culture/Cultural:
The arts, customs and institutions, related to ancient or modern
intellectual achievements of a society or a nation. The structured
way of life and living conditions of the people in a city, including
heritage buildings, streets in the city landscape.

4. Conservation: Careful use of man-made or natural resource, art,
architecture or cultural heritage, to preserve, restore or repair a piece of art
or culture, archaeological or historical or heritage sites, monuments, and
buildings, or the natural environment. This includes, truthfulness of
building material used in the city development process.
City Structure/Landscape: Refer to the structured shape, size or composition,
of a city landscape, optimum utilisations of land, space or buildings in an
urban settlement, equitable distribution of various city functions and
activities or building structures in a healthy living environment.
Heritage: Refer to events, activities or a legacy the citizen inherit, places and
objects we want to protect as our historic culture / cultural identity for
future generations. Moveable e.g. piece of art or custom or tradition, or
Immovable e.g. natural heritage sites, monuments or buildings inherited or
passed down from earlier generations and includes a street / buildings in the
city landscape.
Habitable Building: A structure built as a place of work or living, fit safe &
suitable for habitation i.e. such portion of a building in direct contact or
used as a place of work or living. It also include such fixtures
and infrastructure i.e. water supply, drainage or solid waste etc.

5. Insects & Mites: Insects are any of the numerous usually small arthropods,
creatures in the class “Insecta” that live & survive on the exposed surface of
buildings. In adult stage the insects or mites are characterized by three or
more pairs of legs and a body. Mites are any of the various small or minute
arachnids in the class of “Acarina”, parasitic on animals and plants or
exposed concrete surfaces, a serious health hazard-transmit diseases.
Modern Concrete: Made of gravel (crushed stone/pebbles), sand, and
modern cement, mixed with water as slurry, laid or cast in a mould forming
a stone like mass when dry, a physical form or structure.
Microbial Agents: A minute life form; a microorganism, especially a
bacterium that live & survive in moist exposed surfaces in buildings.
Generally, these are formed on moist / damp or fissured concrete surfaces
and are also a health hazard and cause infective diseases. These also act as
food for growth of insects and mites.
Surface Texture: The word texture means: what things are made of and how
they feel. Textures can be described as “rough”, “smooth”, “hard”, “soft”,
“liquid”, “solid”, “lumpy”, “gritty” etc. The word “texture”, here includes
the physical form, shape, size or composition of building material, colour,
or healthy finish of exposed cement concrete surfaces in heritage buildings.

6. CHANDIGARH: CITY LEGACY OVERVIEW
Chandigarh City is a symbol of India’s freedom, an expression of citizen’s
faith in its development, i.e. Architecture, Urban Form, City Landscape.
It Nurtures a Way of Life for the people in the machine age civilisation,
unfettered by the traditions of the past and the citizen’s faith to sustain its
legacy for the future.
The Chandigarh City Charter – Edict, enlightens the citizens on its basic
urban design concepts and architecture with a view to protect its legacy /
inheritance, namely;
i. “The Age of Statues is Gone”, commemoration of events to be confined to suitably
placed bronze plaques.
ii. Protect and conserve its “Modern Age Architecture” and “Truthfulness of
Building Material” in the city landscape.
The presentation aims to protect / restore its architectural heritage,
Conserve / Restore the Exposed Concrete Façade of City Centre Heritage
Buildings in, Sector-17, Chandigarh
.

7. CHANDIGARH HERITAGE SUB-COMMITTEE: TERMS OF REF.
The Chandigarh Heritage Conservation Committee (CHCC) in its meeting
held on 14th Jan, 2013, constituted sub-committees i) to study / prepare draft
on enabling Heritage Laws-Regulations, ii) study and formulate a plan for
action to conserve-restore exposed heritage concrete structures / buildings in
the Chandigarh City Landscape.
The sub-committee in its meetings in Nov / Dec, 2013 with the CCA
Conservation Team, chalked-out a course of action and prepare a report on
conservation-restoration of the Façade of Heritage Buildings / Precincts in
City Centre (Jagat Cinema Site-TDI Mall), Sector-17, Chandigarh i.e.
i. Undertake detail study of altered / damaged exposed brick / concrete surfaces of
heritage buildings / precincts jointly with CCA Conservation Team.
ii. Accept / protect and preserve the Chandigarh City Heritage Legacy on
“Truthfulness of Building Material” in restoration of heritage buildings / precincts.
iii. Create awareness, identify viable natural building material, skills / techniques and
train skilled / unskilled workers in conservation / restoration of heritage buildings.
iv. Evolve norms, standards and specifications for treatment / restoration of exposed
concrete surface textures of heritage buildings in City Centre, Sec-17, Chandigarh.
Evolve a strategy for a suitable / cost-effective future course of action for
citizen participation to sustain the City Landscape in Sec-17, Chandigarh.

8. The Draft Master Plan 2031,
enlists buildings in Capitol
Complex, CCA in PEC
Campus, Sector-12 etc. and the
City Centre / Jagat Cinema and
other buildings in Sector-17 in
the “Heritage Zone” Grade-I
i.e. of historic importance,
excellence in architectural style,
design and use of natural
building material. It does not
permit intervention / alteration
of the concrete façade / surface
textures of concrete structures
in the city landscape.
Chd Adm. Engg. Deptt. tests of
structural stability of concrete
structures in Capitol Complex,
show that they are safe for
habitation purposes.
HERITAGE BUILDINGS SECTOR-17 CHANDIGARH
Census 2011
Area of Chandigarh City (UT) - 114 km2
Elevation above MSL - 350 m (1,150 ft)
Population Metro - 1,025,682 persons
Density - 8,400/km2
(22,000/sq mi)

9. Le Corbusier’s Chandigarh: Capitol Complex
Siting of the Capitol Complex
in the Chandigarh City Landscape
A View of the Jan Marg Looking Towards the
Shivalik Hills: the seven-storey blocks add a touch of
urban habitat in a City Landscape

10. Chd. Adm. Planning Deppt. /
CCA Research Cell study of the
structures in the City Centre,
show that 80840.31 m2 i.e.
3.80%, constitute “altered /
damaged concrete structures”
due to human intervention i.e.
alteration of the exposed
concrete surface with cement
plaster / paint / hoardings etc.,
which require repair and
restoration.
The entire external or internal
exposed concrete surface i.e.
2127376.52 m2, constitute
“damaged surface textures” due
to effects of air pollution /
carbonation / algae / microbial
action which require
restoration, sustainable
treatment and regular
maintenance.

11. Physical Survey of Heritage Buildings / Precincts
Of the total 500 public / privately owned heritage buildings, 23.40% are
structurally safe i.e. telephone exchange, GPO, banks, cinemas, SCOs. The
original architectural building façade, shuttering pattern-formwork is
visible. 49.60% have altered / damaged exposed concrete façade due to
painted surface (cement plaster or enamel oil paint). 22.80% show signs of
weathering action carbonated / blackened surface, 0.40% show signs of
alteration / damage due to microbial action or green algae on surface. 3.80%
have developed visible cracks and are structurally damaged, which require
structural restoration, see table below:
Sr.
No.
Description of Heritage Buildings No.of
Bldg.
Percentage
1. Stipulated exposed concrete building façade: visible shuttering pattern
/ formwork. Surface texture show signs of carbonation / black streaks 117
117/500 x 100
= 23.40 %
2. Stipulated exposed concrete building façade: altered / damaged
surface due to high carbonation / blackening 114
114/500 x 100
= 22.80 %
3. Stipulated exposed concrete building façade: altered / damaged due to
cement plaster or painted surface 248
248/500 x 100
= 49.60 %
4. Stipulated exposed concrete building façade: altered / damaged due to
microbial action / green algae surface 2
2/500 x 100
= 0.40 %
5. Stipulated exposed concrete building façade: structurally damaged
due to spalling / cracks and exposed reinforced steel bars 19
19/500 x 100
= 3.80 %
Total No. of Buildings Surveyed including Telephone Exchange /
GPO, 17 Bay Off., Additional Town Hall and Jagat Cinema Bldg.
500 100%

12. Agents of Change: Altered / Damaged Heritage Building Façade
Conservative assessment carried-out by the CCA Conservation Team show
that 60% to 65% of the altered / damaged concrete façade has been done by
banking institutions or public / private corporates. The break-up of the
agents of change, effecting the altered or damaged exposed concrete façade
or the concrete surface texture, either intentional or incidental due to
absence of awareness of the heritage status of the City Centre Landscape.
Sr.
No.
Description of Heritage Buildings Agents of Change /
Ownership
Percentage
1. Stipulated exposed concrete building façade i.e.
concrete columns / architrave / parapets: altered /
damaged due to cement plaster or painted surface
which require restoration by sand / shot blasting, use
of proportionate mix of natural building material.
Govt. / public or
private owned bank
corporate buildings, e.g.
bank square, GPO /
telephone exchange and
17 bay office building
60 to 65 %
2. Stipulated exposed concrete building façade i.e.
concrete columns / architrave / parapets: altered /
damaged due to cement plaster or painted surface
which require restoration by sand / shot blasting, use
of proportionate mix of natural building material.
Private / individual or
joint ownership small
holdings, i.e. cinema,
SCOs, retail, shop /
commercial buildings
40 to 35 %

13. The HCC Sub-Committee report focuses on cleaning / restoring the façade
of heritage buildings / precincts by active participation of the private sector /
shopkeepers / owners of the properties. It also focuses on the need to accord
priority to protect and conserve the Government owned Public Buildings
Bank Square etc. as a demonstration exercise and thereafter take-up the
Private Commercial Buildings in City Centre, Sector-17, Chandigarh. The
study of the physical condition of building structures related to conservation
of the City Centre, Sector-17 are highlighted as follows:
•Poor construction of RCC structures in the private sector with alterations and
changes made by human interventions, damaging the exposed concrete surface
building façade.
•Pitting / spalling, cracks and fissures in exposed concrete surfaces, RCC column.
•Carbonation / blackening of building architrave, parapet facia due to dampness and
deposit of salts and fungus on its surface.
•Some of the parapets partly broken, damage concrete cover, exposing steel
reinforcement at many places.
•Vegetation growth, algae, microbial growth, carbonation etc, on exposed concrete
surfaces of building architraves and on roof top.
•Concrete surface façade painted with variety of cement / oil based applicants
damaging the exposed concrete surface building façade.
•Structural changes in use of natural building material, making it unsafe
for pedestrian movement in front covered / paved corridors.

15. Damaged concrete façade:
Heritage Building Central
Plaza, Sector-17, Chandigarh
Damaged roof top
architrave: SCO Concrete
Building, Central Plaza,
Sector-17, Chandigarh

16. Altered / damaged
concrete façade: Heritage
Building Central Plaza,
Sector-17, Chandigarh
Altered / damaged concrete
façade: Unauthorised covered
verandah in Heritage
Building, Sector-17

17. Damaged concrete
façade of Cinema
Building along
newly constructed
Fly Over: Sector-
17, Chandigarh
Altered / damaged
concrete façade /
verandah flooring:
Heritage Buildings,
Sector-17, Chandigarh

18. Altered / damaged
concrete façade of
Bank Square Heritage
Buildings: poor or
unhealthy street City
Landscape,
Altered / damaged
concrete façade of
Heritage Buildings:
poor or unhealthy
street City
Landscape,
Sector-17,
Chandigarh

19. Altered / damaged
concrete façade of
Heritage Buildings:
poor or unhealthy City
Landscape,
Sector-17, Chandigarh
Altered / damaged
concrete façade of
Heritage Buildings:
poor or unhealthy
City Landscape,
Sector-17,
Chandigarh

20. Altered / damaged concrete
façade of Heritage Hotel
Buildings: poor or unhealthy
City Landscape, Sector-17,
Chandigarh
A View of the Jan
Marg Looking
Towards the
Shivalik Hills: the
seven-storey blocks
add a touch of urban
habitat in a City
Landscape

21. RESTORATION OF JAGAT CINEMA / TDI MALL HERITAGE
BUILDING: DEMONSTRATION EXERCISE
Pursuant to the CHC meeting held on 24th Jan, 2013, the Chief Architect
Urban Planning Deptt. followed-up action in the Sub-Committee meeting
held on 24th Dec, 2013 for feedback from conservation experts i.e. the
architect members of the CHCC – Sh. SD Sharma, Prof. Rajnish Wattas,
the CCA Conservation Team comprising of Prof. Jagjit Singh Ghuman and
Prof. Prafulla Janbade.
It was also noted that the case of TDI Mall falls in the Chandigarh Heritage
Zone V and a detail case study / demonstration exercise taken-up by and the
CCA Conservation Experts and TDI Mall Representatives.
Aerial View of Jagat
Cinema Site and N-E
Facing Front
Exposed CC Façade
of Heritage Building
before its Re-
construction and old
Jagat Cinema
Exposed CC Façade
/ TDI Mall, Sector-
17 Chandigarh.

22. It is noted that, the ICS Hotels Pvt. Ltd. revised building plans / application
to erect / re-erect / add to / alter the Jagat Cinema Site / Building in Plot No.
32, Sector 17-A, Chandigarh u/r 5 of the Punjab Capital (Dev. & Reg.)
Building Rules 1952 were sanctioned vide Memo No. 52713/SDO(B)/CP-949
dt. 25th April, 2011.
In the course of its re-construction the stipulated exposed cc façade was
altered i.e. RCC walls with steel shuttering pattern façade has been
constructed in cement / brick work, exposed surface cement plastered and
further coated with acrylic off-white colour paint.
The proposal to regularise it was not accepted and TDI Mall representative
submitted details of alterations in the exposed concrete façade as follows:
• The surface has been thoroughly cleaned, by removing all motor droppings, algae,
fungus, greens and all other foreign matters.
• Base preparation has been done by cleaning the surface with sand paper.
• Pitting of surfaces have been filled with cement putty and rubbed with sand paper
to make the surface clean and level (smooth).
• Coat of water proof cement paint @ 3.84 Kg./sq. mtr. has been applied.
• Exterior grade primer, make Berger applied @ 2.2 Kg./10 sq. mtr.
• Finish with Acrylic smooth exterior paint, make Berger @ 1.67 Ltr./10 sq. mtr.
external building surface.

23. N-E Facing
Front Exposed
CC Façade of
TDI Mall
Heritage
Building after
its Re-
construction
with Altered /
Painted
Exposed CC
Façade, Sector-
17 Chandigarh.
Efforts made by TDI Mall representatives from Oct’2013 to Jan’2014 to
restore the stipulated concrete façade comprising of the GF cc columns-
architrave, side walls , front and rear parabolic façade by i.e. 7 samples for
columns-architrave and 3 samples with cement plaster and use of synthetic
colours / paints to restore the texture / colour of the concrete façade were
examined at site and discussed in the Heritage Sub-Committee meetings.
The samples were not approved / accepted / un-satisfactory due to mismatch
in use of restoration material, application technique, texture / colour

24. i. Sand / shot blasting, dry process cleaning / restoration of altered / damaged
concrete surfaces.
ii. After (i) above, wet process cleaning with sponge and clean portable water.
iii. Restoration / treatment of exposed concrete with a workable mix of concrete
i.e. cement, sand and grit for walls and cement-putty mix for exposed columns.
The TDI proposal /
paint work was not
acceptable as it did
not meet the
conservation /
restoration
techniques i.e.
satisfactory cleaning
/ removal of paint
work from concrete
surfaces etc. The
CCA Conservation
Multi-Disciplinary
Team recommended,

25. 1. Chief Architect UT
Chanidgarh with
Heritage Committee
Members, CCa
Conservation Team
and TDI Mall
Representatives.
2. Members inspecting
the sand blasted
column surface with
partially treated
concrete mix.
3. Sand blasted column
exposed concrete
surface.

26. Different restoration
techniques for concrete
columns and walls have to
be used i) workable mix of
OPC grey / white cement,
sand, grit is suitable for
restoration of concrete walls
only, and ii) the circular
surface for the columns
suitably restored with OPC
grey / white cement-wall
putty mix only.
1 sample of the exposed
concrete wall surface and 1
sample of the exposed
concrete column surface
was accepted and approved
by the Heritage Sub-
Committee / CCA
Conservation / TDI Teams
on their joint visit / meeting
on 21st Feb, 2014.

27. Area
a) Surface area of 39 columns @ 5.15 m2 /
column = 201 m2
b) Surface area of architrave – Length
202.5 m x surface parameter 1.075 m =
217.68 m2
c) Total stipulated concrete surface area
for columns and architrave=418.68 m2 .
Cost Effective Restoration: Column / Architrave Concrete Surface
Cost
a) Dry process cleaning: sand blasting 10 Kg. psi, including sand, labour
etc. Rs. 250 / m2 i.e. Rs. 23.23 / ft2
b) Restoration: OPC grey / white cement with white cement based putty
mix, labour etc. Rs. 301.22 / m2 i.e. Rs. 27.98 / ft2.
c) Silicon surface protective coating, Rs. 120.00 / m2 i.e. Rs. 11.15 / ft2.
d) Misc. expenses: scaffolding, taxes etc., Rs. 177.60 / m2 i.e. Rs. 16.50 / ft2.
e) Total Effective Cost is Rs. 848.82 / m2 i.e. Rs.78.86 / ft2

28. Area
a) Side walls surface area FF = 1508.12 m2
b) Front / rear parabolic surface area =
366.66 m2 .
c) Total area for walls and parabolic
surfaces = 1874.78 m2
Cost Effective Restoration: Wall Concrete Surface
Cost
a) Dry process cleaning: sand blasting 10 Kg. psi, including sand, labour
etc. Rs. 250 / m2 i.e. Rs. 23.23 / ft2
b) Restoration: OPC grey / white cement with sand / grit concrete mix,
labour etc. Rs. 712.23 / m2 i.e. Rs. 66.17 / ft2.
c) Silicon protective surface coating, Rs. 120.00 / m2 i.e. Rs. 11.15 / ft2.
d) Misc. expenses: scaffolding, taxes etc., Rs. 861.18 / m2 i.e. Rs. 80.01 / ft2.
e) Total Effective Cost is Rs. 1943.41 / m2 i.e. Rs.180.55 / ft2

29. RESTORATION: NORMS / STANDARDS /
SPECIFICATIONS
There are no norms, standards or specifications to grade concrete surface
textures in heritage buildings. It is also noted that the stipulated exposed
concrete surfaces of TDI Mall Heritage Building has been altered / damaged
in the construction process. Its effective cost for a) columns-architrave and
b) side walls-parabolic front & rear façade given by TDI Mall
Representatives are at page no. 20 & 21 of the Report. The norms,
standards and specifications for restoration of altered / damaged concrete
surfaces are as follows:
1.Dry Process Cleaning: This refers to cleaning of the exposed concrete surface with a
piece of cloth, coir / nylon soft brush, for smooth concrete textures, steel wire brush or
sand / shot blasting for rough concrete textures, altered / damaged concrete surfaces,
see IS Code: 4988 (Part IV). NB: Sand / shot blasting cleaning process on unaltered /
undamaged concrete surfaces invariably damages the fine surface texture.
2.Wet Process Cleaning: This refers to cleaning of the exposed concrete carbonated
surface with clean portable water, scrubbed with a sponge / bucket or gently washed
with water hose pipe. NB: Do not use any detergents / corrosive
additives with water in wet process cleaning of concrete surfaces.

30. 3. Restoration of concrete wall surface texture: Truthfulness of material;
• Grey Ordinary Portland Cement (GOPC), 43 Grade, IS Code : 8112-2013, initial
setting time 30 minutes. Do not use Portland Pozzolon Cement (PPC) due to fly
ash and other additives / ingredients.
• White Ordinary Portland Cement (WOPC), IS Code : 8042-1989, surface fineness
IS : 4031 Pt 2: 1999, initial setting time 80 minutes.
• Washed River-bed Sand (medium grains), IS Code : 383.
• Coarse River-Bed Grit 2 to 4 mm for restoration for concrete mix, IS Code : 383.
4. Restoration of concrete wall surface texture: Composition of concrete mix;
• Grey Ordinary Portland Cement (GOPC) 1 part
• White Ordinary Portland Cement (WOPC) 1 ½ part
• Washed River-bed Sand 2 part
• Coarse River-Bed Grit 2 to 4 mm 3 part
5. Restoration of concrete column surface texture: Truthfulness of material;
• Grey Ordinary Portland Cement (GOPC), 43 Grade, IS Code : 8112-2013, initial
setting time 30 minutes. Do not use Portland Pozzolona Cement (PPC) due to fly
ash.
• White Ordinary Portland Cement (WOPC), IS Code : 8042-1989, surface fineness
IS : 4031 Pt 2: 1999, initial setting time 80 minutes.
• White Wall Putty (cementing agent), IS Code : 63 , initial setting time ≥100
minutes, tensile adhesion >1.0.

31. 6. Restoration of cc column surface texture: Composition of concrete mix;
• Grey Ordinary Portland Cement (GOPC) 1 part
• White Ordinary Portland Cement (WOPC) ½ part
• White Wall Putty 3 part
7. Formwork: No formwork required for restoration of concrete columns-
architrave with cement / putty mix. Restoration of wall and parabolic concrete
surface shall ensure shuttering pattern 10 mm joints in flat steel frames 10 mm x
32 mm.
8. Placing of concrete: Concrete mix to be securely placed on suitably treated
exposed concrete surface of the wall with formwork of flat steel frame (without
steel plate).
9. Grouting of joints: The 10 mm x 32 mm steel frame joints to be grouted with the
concrete mix and ensure uniform concrete texture / colour.
10. Workability: Use of natural building material shall ensure workability. Control
water content, IS Code : 456 for workability of concrete mix for wall / parabolic
surfaces.
11. Workmanship: Trained, skilled, dedicated workman engaged in
conservation / restoration process shall ensure uniform concrete surface
texture / colour.

32. 12. Surface Texture: Smooth / soft concrete surface texture for columns,
architrave ensured by 2 coat process application / cleaning of cement-putty mix
with 80 to 120 grade sand paper 2 coat silicon based sealant / water repellent.
The side walls, front-rear parabolic surfaces laid / finished with concrete mix in
shuttering pattern, grouting of the joints and protected with 2 coat silicon based
sealant / water repellent.
13. Colour: Uniformity of natural colours for standard grey / white cement
concrete or putty mix shall be ensured for all restored surfaces i.e. sustain
truthfulness of building material.
14. Curing: The restored concrete mix wall surfaces in concrete mix only require
curing with clean portable water as per IS Code : 456. The concrete columns and
architrave restored with cement and putty do not require curing with water and
will require 24 hours for its setting before the next coat is applied.
15. Durability: Restored exposed concrete wall surfaces with concrete mix of
cement, sand and grit, enhances the stability and durability of the concrete
structure. Similarly the cement-putty mix restored columns also ensures
uniform surface texture and colour of the concrete façade. The concrete surface
of heritage buildings is also improved with application of silicon based
sealant / water repellent protective coating.

33. FINDINGS / CONCLUSIONS
Detail study of exposed concrete surface structures require periodic examination of
its structural stability, assessment of the extent of structural alteration / damage and
exposed corroded steel bars treated with protective anti-corrosive agents. The study
also assess available options in the cleaning / removal of carbonation by dry / wet
process, repair or restoration of altered / damaged concrete surfaces. Removal of
cement mortar plaster or paints or other synthetic agents on concrete surfaces, which
permanently alter / damage the “texture of exposed concrete surfaces”. All such
alterations or damage need to be stopped / totally prohibited and timely efforts made
to protect / conserve the concrete surface texture of heritage buildings in the
Chandigarh City Landscape.
It is noted that the City Centre is regulated by specific zoning and architectural
controls for concrete and brick structures. There are two types of controls, a) shop
cum office buildings i.e. brick façade on the V4 road and b) the rest of the banking /
commercial privately owned properties in the City Centre are in exposed
concrete façade. As per Edict of Chandigarh, any form of alteration / change
in its façade is not permitted and “Truthfulness of the Building Material” is to be
maintained.
(NB. Use of detergents, chlorine,
caustic soda or other corrosive agents
in the dry or wet process cleaning is
totally prohibited).

34. Of the total 500 public / privately owned heritage buildings surveyed, only 23.40%
are maintain the original architectural building façade (shuttering pattern-
formwork). The concrete surface texture however show signs of weathering action /
carbonation / black streaks. 49.60% have altered / damaged exposed concrete façade
due to painted surface (cement plaster or enamel oil paint). 22.80% show signs of
weathering action carbonated / blackened surface, 0.40% show signs of alteration /
damage due to algae, microbial action. 3.80% have developed visible cracks and are
structurally damaged, which require restoration.
Conservation of cement concrete façades in heritage buildings begin with the
assessment of the extent of structural damage or alteration of exposed concrete
surfaces by paint, plaster, effects of carbonation, algae, microbial action etc. in
buildings. Findings of the study on use of “Truthfulness of Material” help build the
use of skills and techniques in the Restoration Process. The conservation of cement
concrete structures and its relationship with structural damage vis-à-vis surface
texture damage is given below:
Dry or wet process cleaning without sand / shot blasting and application of petroleum
mix on concrete surface is simple and cost-effective. This is possible with periodic
cleaning of outdoor or indoor concrete surfaces damaged due to weathering action
or effect of carbonation.

35. The process of conservation / restoration of the
exposed concrete façade carried-out with
natural building material namely; cement,
sand, grit or white cement based putty has
been successfully achieved to restore
truthfulness of concrete surface texture /
colour, of concrete heritage public / private
buildings in Sector-17, Chandigarh. The
accepted cost effective sustainable
conservation / restoration technique for
sustaining a healthy City Centre Landscape is
given below:
i. Sand / shot blasting, dry process cleaning IS Code:
4988 (Part IV).
ii. Wet process cleaning with clean portable water with
hose pipe or bucket-sponge.
iii. Restoration / treatment of exposed concrete with
natural building material only, i.e. a workable mix of
concrete i.e. cement, sand, grit or putty (white
cement based filling agent).
iv. Application of protective coating with silicon,
polymer or petroleum based mix on concrete / putty
mix.
Repair or restoration of altered or
damaged concrete surfaces require
careful handling by a multi-
disciplinary conservation team.

36. THANK YOU