gioc presentation

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RISING DAMP IN GHANAIAN BUILDINGS: AN ISSUE WORTH

ADDRESSING

By

Kofi Agyekum

(PhD, MPhil, BSc., MGIOC, MIIE, MISDS)

ISSUES TO THINK ABOUT

• How will you feel if a building specialist tells you that your building is very sick and needs to be demolished?

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ISSUES TO THINK ABOUT CONT’D

• Such was the fate of some Israelites about 2000 years ago.

• They were aware of mouldattacks on their buildings, but unaware of the causes of the problem.

• They would report such incidences to the Rabbi who would tell them what to do.

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ISSUES TO THINK ABOUT CONT’D

• Mould attack and clean up is mentioned for the very first time in Leviticus 13 and 14

13: 1-46- isolation and purification of people with skin diseases.

13: 47-59- mildewed clothing should be burnt

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ISSUES TO THINK ABOUT CONT’D

• The mildewed walls were

to be remedied (Chapter

14) by:

Tearing out thecontaminated stonesand throwing them outinto unclean placesoutside the town.

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Throw the unclean stones outside the town

OUTCOME OF THE INSPECTION Scrape the remaining

inside walls and throw the scrapes in unclean places.

Replace the old stones with new ones, replasterand monitor to see whether the trouble recurs.

Such buildings were classified as suffering from leprosy.

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ISSUES TO THINK ABOUT CONT’D

• 14: 33-48- mildew withgreenish or reddishdepressions on theinside wall of a house.

• These inspections werecarried out by the Priestor Rabbi.

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ISSUES TO THINK ABOUT CONT’D

• But if after all these inspections the priest finds out that the mildew has still spread,

It must be torn down, all

its stones, timbers, and

plaster must be discarded.

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BACKGROUND• Buildings are composites of different materials and

forms of construction, each having their own specificperformance characteristics (Watts et al., 2001).

• Old or modern types of construction are susceptible tonatural and man-made mechanisms of deterioration

• Of all defects associated with buildings, moisture is themost frequent and dangerous and contributes morethan 50% of all known building failures (Halim et al.,2012; Trotman, 2004).

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BACKGROUND CONT’D

• When moisture which

should not be present in a

building accumulates in

that building, it is said to

be suffering from

dampness (Burkinshaw

and Parrett, 2004).

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WHAT IS DAMPNESS?• The penetration of water

through the walls and certain elements of buildings (Halim et al.,2012).

• An excessive moisture contained within building materials and components (Hamid and Ngah, 2010).

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EFFECTS OF DAMPNESS

PHYSICAL EFFECTS

• Timber rot

• Water staining

• Cyclic wetting/drying

• Electrics made unsafe

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Source (Riley and Cotgrave, 2005)

EFFECTS OF DAMPNESS CONT’D

CHEMICAL EFFECTS

• Efflorescence

• Corrosion of ferrous metals

• Chemical attacks

• Loss of cohesion

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Source (Riley and Cotgrave,

2005)

EFFECTS OF DAMPNESS CONT’D

HEALTH EFFECTS

• Ambient air conditions

• Mould growth and spores

• Viruses and infections

• Rot and infestations

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Source (Riley and Cotgrave, 2005)

SOURCES OF DAMPNESS• Sources of dampness in buildings have been

extensively studied.

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THE THEORY OF RISING DAMP

• It is the most frequently encountered cause of damage to masonry walls.

• It results from the capillary flow of water from the ground (Oxley and Gobert, 2011)

• Ground water reaching the foot of a wall which tends to rise in the walling material and continues to do so due to capillary action to varying degrees of intensity (Melville and Gordon, 1998).

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THE THEORY OF RISING DAMP CONT’D

• Caused by a natural phenomenon called capillary action.

• Ground water is drawn vertically upwards through fine pores in a material.

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THE THEORY OF RISING DAMP CONT’D

• Majority of construction materials are porous

• Because they are embedded in, or in contact with the ground, they will encourage the migration of water from the ground by capillary action.

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Source (Riley and Cotgrave,

2005)

THE MECHANISM OF RISING DAMP

• For water to rise in a wall, a supply must be available at the base.

• If the ground surrounding the wall is saturated this condition is achieved.

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THE MECHANISM OF RISING DAMP CONT’D

• If the ground is not saturated, the soil will exert a suction that will oppose the upward capillary pull on the water in the wall.

• If the water table falls, the height of the moisture in thewall will drop to a new level provided there issufficient time for equilibrium to become established

• Each period of heavy rain on the ground at the base of the

wall will produce a temporary condition of saturation and

the water level in the wall will begin to rise again.

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THE MECHANISM OF RISING DAMP CONT’D

• The extent to which a wall is affected by rising damp differs and is dependent on:

The level of moisture in the ground;

The features of the wall enabling or restricting

evaporation from its surface;

The porosity of the material; and

The chemical composition of the migrating water.

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HOW DOES RISING DAMP DAMAGE MASONRY?

• In masonry that is affected by rising damp, moisture is

continuously transported upward through the capillaries.

• The water evaporates on the surface and more moisture

follows.

• This process leads to an increase in the concentration of

salts on the surface.

• Most evaporation takes place in the area between the dry

(top) and the damp part of the wall (bottom).

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Adopted from Koster Waterproofing Systems; www.kosterusa.com

SYMPTOMS ASSOCIATED WITH RISING DAMPNESS IN BUILDINGS

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SALTS IN MASONRY MATERIALS

• Salts in buildings are either

present in the masonry during construction or

are absorbed from the atmosphere or groundwater during the life of the building (Jordan,2001).

• Efflorescence is a deposit of soluble salts whichusually appears as a fine, white crystalline powderon the surface of masonry as the internal waterevaporates.

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WHAT DOES SALT HAVE TO DO WITH RISING DAMP?

• The water which is transported into and through awall, contains salt. These salts can have differentsources:

Salts are present in the ground. They can be dissolvedin ground water or ground moisture and can then betransported with the ground water into the wall.

• Salts are present in the brick/block itself. These saltscan be dissolved by the rising damp in the masonry.

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HOW DOES SALT CAUSE DETERIORATION IN BUILDINGS?

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Lstiburek (2009)

HOW DOES SALT CAUSE DETERIORATION IN BUILDINGS?

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Lstiburek (2009)

EFFECTS OF SALTS ON BUILDINGS

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Adopted from Koster Waterproofing Systems; www.kosterusa.com

CAUSES OF RISING DAMP IN BUILDINGS

• Mainly caused by bridging of existing damp proof courses and membranes installed in buildings.

• Bridging is caused when water by-passes damp proof courses which are installed in buildings.

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• Most common form of bridging is:

when the ground level

outside a solid wall becomes higher than the installed DPC.

Internal plastering and external rendering extending down over the DPC line.

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Trotman, 2004

• If soil or paths are allowed to touch the wall above the level of the DPC,

ground water will be in contact with the wall and rising damp can occur.

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CAUSES OF RISING DAMP CONT’D

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Trotman, 2004

THE SITUATION OF RISING DAMP IN GHANA

• In a tropical region like

Ghana characterized by

high rainfall with

relatively high and even

temperatures, rising

damp is a very common

problem among many

public and private

buildings.

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Agyekum et al. (2014)

THE SITUATION OF RISING DAMP IN GHANA CONT’D

• Studies carried outhave shown that risingdampness has assumedan alarming dimensionin buildings in Ghana.

• This is because one outof every ten buildings isaffected by theproblem, some of whichare visible.

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Agyekum et al. (2014)

THE SITUATION OF RISING DAMP IN GHANA CONT’D

• Generally, the level ofawareness of the problemamong building occupantsand constructionprofessionals in Ghana isvery high.

• This has led to the adoption of various methods such as the tiling of wall bases, replastering among others to control the problem.

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PATCHED WALL BASES

APRONS AT WALL BASES

THE SITUATION OF RISING DAMP IN GHANA CONT’D

• The significance of the problem is also reflected by the diversity of products on the market.

• Owing to the scarce scientific information on the effectiveness of such methods, it has become very difficult for professionals working in the field to choose suitable interventions on sound basis.

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TILED WALL BASES

TILED WALL BASES

EMERISDA, 2014

THE SITUATION OF RISING DAMP IN GHANA CONT’D

• This issue has left the

general public in shock

as the problem of

dampness keeps

escalating with no sure

ways to combat it.

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REPLASTERED WALL BASE

TERRAZZO USED TO CURE DAMPNESS

THE PROBLEM IN GRATER ACCRA REGION

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THE PROBLEM AT AXIM

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THE PROBLEM IN CAPE COAST

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THE PROBLEM IN EASTERN REGION

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THE PROBLEM IN ASHANTI REGION

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THE PROBLEM IN BRONG AHAFO REGION

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THE PROBLEM IN BRONG AHAFO REGION CONT’D

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THE PROBLEM IN WESTERN REGION

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THE PROBLEM IN NORTHERN REGION

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THE PROBLEM IN UPPER EAST REGION

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HOW THE PROBLEM IS BEING CONTROLLED WORLDWIDE

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HOW THE PROBLEM IS BEING CONTROLLED WORLDWIDE CONT’D

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Bailey damp

proofing co.

Dryzone technology

HOW THE PROBLEM IS BEING CONTROLLED IN GHANA CONT’D

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HOW THE PROBLEM IS BEING CONTROLLED IN GHANA CONT’D

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THE ARGUMENTS SURROUNDING THE PROBLEM

• Stephen Boniface,former chairman of theconstruction arm of theRICS, told the institute’s40,000 members that‘true rising damp’ is amyth and chemicallyinjected damp-proofcourses (DPC) are ‘acomplete waste ofmoney’.

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THE ARGUMENTS SURROUNDING THE PROBLEM CONT’D

• Elaine Blackett-Ord,chair of the Register ofArchitects Accreditedin BuildingConservation, has alsospoken out againstrising damp, saying itwas as rare as‘rocking-horse shit’.

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THE ARGUMENTS SURROUNDING THE PROBLEM CONT’D

• Jeff Howell, a qualified bricklayer and author of The Rising Damp Myth (2008) said trials in the laboratory confirm the falsehood.

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THE ARGUMENTS SURROUNDING THE PROBLEM CONT’D

• Terry Brown, of GMW Architects, said:

‘Of course there is no reason why inherited conventional wisdom shouldn’t be challenged. [But] the challenge has to be scientific and not anecdotal.’

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DOES THE PROBLEM REALLY EXIST?

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BEFORE 4 MONTHS AFTER

WHAT IS THE WAY FORWARD?

• Currently there is a study on-going in Europe which seeks to examine the effectiveness of methods against rising damp in buildings.

• This is a co-operation between research institutes, conservation authorities and SMEs guarantees.

• It started on 1st February 2014 and it is expected to end on 31st January 2017.

• Total project budget: ₤ 596, 194.00

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• The participants include:

Italian National Research Council;

Dutch Cultural Heritage Agency

Delft University of Technology, faculty of Architecture;

Ca’ Foscari University of Venice

Environmental Research and Consulting Centre Medingneria

Special Restoration Ltd. of Pambianco; among others.

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CONCLUSION

• Rising damp truly exists and has come to

stay with us.

• This issue is still an open challenge.

• WHAT IS THE WAY FORWARD FOR GHANA?

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THANK YOU FOR YOUR ATTENTION

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