Non-structural elements refer to edifice elements which are non responsible for back uping the burden in a edifice. For illustration, non-load bearing wall ( or divider ) , its coating, completing to ceiling and floor. Defects are ever found in such elements during their life. In this chapter, the symptoms, causes and redresss of some common defects in non-structural members will be covered.
3.1 External Wall Appendages:
External extremities are extra fond regards to the external wall, normally they are cantilevered constructions which include canopies and balconies, architectural projecting characteristics, air-conditioner supporting frame and drying racks. Although the structural designs of these elements have already ensured suited for their cantilevered public presentation, hapless craft, deficiency of care and fix to contend against natural weathering would pull development of defects, unduly shorten their life-span and finally ensue in prostration. In a worst instance, such prostration might be sudden without prior obvious symptoms such as desertion taking to tragic effects.
Except for canopies which are largely found in dais degrees, other extremities are normally thin and little in size but big in Numberss which are hard to look into and supervise. Therefore, equal resources should be allocated for regular review and fix in order to forestall them from going falling jeopardies.
Balconies and Windowss of single units normally provide good points for review of defects in the outside of the edifice. Owners descrying any defects in the outside of the edifice should describe to the belongings director or the Owners ‘ Corporation ( OC ) for their action, irrespective of whether the defects are at the outside of their ain units or other units.
Symptoms:
Cracking at junctions
Peeling-off of picture
Loosening of fond regards
Spalling concrete or denudation ( exposure ) of steel support
Corroding of metal parts
Water ooze
Vegetation growing or damaged by fungus
Possible Causes:
Junction is the weak point of the construction where taking the highest burden
The extremities are exposed to endure onslaught
Lake of regular picture and other care
Canopies and balconies are RC cantilever constructions, support bars are placed near the top surface where clefts will besides foremost get down to develop. ( the chief supports are placed near the underside of the component in conventional strengthened concrete constructions )
If sealing at the top is unequal or damaged by the clefts leting immersion of H2O, corrosion will cut down the effectual cross-sectional country of the support bars. Then the strength of support saloon for keeping the cantilever slab will be lowered and do sudden prostration.
Repair Methods:
Carry out item probe to look into whether it is structural cleft. If yes, it may be required to pulverize and retrace, depends on the Registered Structural Engineer ‘s ( RSE ‘s ) recommendation.
Cover up the surface clefts with cement sand howitzer or grouting injection
Remove the peeling-off coatings and use with a new one
Remove the relaxation of fond regards, piece up or replace the corrosion parts
Repair the spalling concrete and cover up the steel support
Remove the rust of metal and repaint or replace it if necessary
Apply waterproofing stuff to the characteristic ‘s repairing point on the external wall
Remove the flora or fungus, and so reinstate any amendss
3.2 Advertising Signboard
Some of the advertisement signboards are fixed under the soffit of the canopy and some of them are fixed on the external wall as a type of cantilever construction.
Symptoms:
Relaxation of Connection
Corroding of steel
Damage on the edifice constructions
Cause nuisance or make obstructors to the populace or residents of the edifice
Dangerous to the populace
Possible Causes:
Lack of care
Atmospheric corrosion due to muffle and pollution
Chemical corrosion
Water trapped between the laps and articulations of metals
Abandoned or no longer in usage
Repair Methods:
Re-fix the articulations decently and transport out regular review and care
Eliminate cause of moist conditions
Spot or replace the corroded parts and avoid contact from caustic chemicals
Repair the damaged edifice constructions.
Using a protective coating to metals
Remove unsafe signboards instantly
3.3 Curtain wall
Refer to the treatment in window and partly will be farther discussed in following degree.
3.4 External Coating
3.4.1 External Wall Tiling
Figure 59 – Crack of tiling on external wall
Symptoms:
Crack of wall surfaces
Bulging with hollow base
Loosening of parts
Falling off
Produce ‘hollow sound ‘ when tapped with a cock
Possible Causes:
Aging
Structural motion such as differential colony
Thermal motion
Defective or losing enlargement articulations
Poor craft ( e.g. non adequate coverage of adhesive to tile, honeycomb concrete substrate etc. )
De-bonding between tile and bedding howitzer ( substrate straight reach the concrete ) , tile with bedding howitzer and concrete substrate, ensuing in ‘hollow sound ‘ when tapped with a cock
Repair Methods:
If no hollow tiles found but checking merely, it can be repaired by injection of grouting or through unfastened up and fix by retiling.
For debonding tile, all loose parts should be removed instantly to extinguish the at hand danger.
If merely debonding found between the tile and the bedclothes howitzer, take the loose tile and re-tiling to the faulty country with suited adhering agents or adhesive in order to keep protection to the external wall. A proper bonding of single tile to its bedclothes howitzer is important to avoid return of the same defects. Adequate enlargement articulations should be allowed for thermic motion.
In instance debonding is found between the bedclothes howitzer and concrete wall, both tile and bedding howitzer should be removed. Then use a new bedclothes howitzer bed to the concrete wall before retiling. A proper key between the bing concrete wall and the freshly applied bedding howitzer is really critical, it can be formed by using spatterdash and slurry coat of adhering agent on top of concrete wall before laying of bedding howitzer. Allow equal enlargement articulations excessively.
When hapless substrate such as honeycomb, loose concrete or spalling concrete found after remotion of bedding howitzer, the loose parts should be removed down to the sound concrete substrate, and so rectify the concrete defects before application of new bedding howitzer. If the defects found are so extended so replacing or add-on of steel support bars, partial or destruction and rewording of certain parts of concrete elements will be considered necessary.
3.4.2 Rendering
Symptoms:
Crack of wall surfaces
Loosening of parts
Falling off
Produce ‘hollow sound ‘ when tapped with a cock
Possible Causes:
Aging
Structural motion
Thermal motion
Defective craft
Missing enlargement articulations
Debonding between render and concrete substrate
Repair Methods:
If no hollow render found but checking merely, it can be repaired by injection of grouting or through unfastened up and fix by re-rendering.
All loose parts should be removed instantly to extinguish the at hand danger.
A proper key between the bing concrete wall and the freshly applied render is really important to avoid return of such defects. The key can be formed by using spatterdash and slurry coat of adhering agent on top of concrete wall before re-rendering.
When hapless substrate such as honeycomb, loose concrete or spalling concrete found after remotion of render, the loose parts should be removed down to the sound concrete substrate, so repair the concrete before application of new render. If the defects found are so extended so replacing or add-on of steel support bars, partial or destruction and rewording of certain parts of concrete elements may be required.
3.5 Paintwork on Rendering
Symptoms:
Blisters or bubbles formed
Flaking ( little pieces of pant )
Skining ( larger in size )
Figure 60 – Skining off painting on the wall
Possible Causes:
Moisture in the render had non dried out before application of painting
Chemical onslaught on the pigment
Repair Methods:
Eliminate all beginnings of H2O or wet affect the render
Remove the bing picture and allow the render dried out
Repaint on the prohibitionist, clean and sound substrate of render
3.6 Window
3.6.1 Aluminium Window
Symptoms:
Deformed or unbarred window frames or sashes
Window sashes/hinge bars excessively tight to open or shut
Loose or losing stud or prison guard
Loose flexible joint saloon
Grey white pulverization looking at the flexible joint, paths, studs and prison guard, bespeaking corrosion of aluminum
Water escape between window frame and sash
Locking device of window sash non working decently
Broken glass window glass
Missing aluminum angle for procuring the glass window glasss
Falling off
Possible Causes:
Aging
Lack of care and preventative steps
Poor design
Poor craft
Misuse of the window
Preventive steps:
Regularly clear the dust or soil in the flexible joint bars
Keep the path and upper portion of the sash prohibitionist
Lubricate the flexible joint saloon on a regular basis ( e.g. WD40 )
Should non hang any objects including apparels on the window sash to avoid doing extra burden on the flexible joint saloon
Do non enforce force per unit area to the window sash when cleansing windows to avoid overemphasizing the flexible joint saloon
Exercise cautiousness when cleansing
Do non coerce to open the window
Ask for review and fix instantly one time defects found, and inspected on a regular basis by experient contractors ( e.g. one time per 3 old ages )
Repair Methods:
Replace any broken or cracked glass window glasss at one time with the same type and thickness of glass
Replacement of aluminum angle must be done at one time to avoid falling of glass window glasss.
Replace or re-fixing the repairing constituents such as prison guard and studs
Replace the lockup device which can non work decently to forestall harm consequence in typhoon
Replace the window frame at one time if the window frame is deformed or unbarred. The window frame must be firmly and stiffly fixed to the gap by repairing Lugs. Otherwise, it will be really unstable after typhoon and may do harm
Replace the window frame if the frame have deformed or deteriorated to a considerable extent
Replace the window frame if the quality of the frame or its waterproofing stuffs make fulling up the spread between the frame and the parent construction is in uncertainty, which taking to changeless escape beyond fix
Suitable waterproofing grouting should be decently applied between the window frame and the gap with an extra coat of waterproofing stuff around the frame
Joints in window frames and subdivision should be decently sealed with suited sealer. The window frame should be appropriately equipped with H2O bars at its sill to forestall entry of H2O. A uninterrupted gasket of suited stuffs should besides be decently applied along the whole margin between the window frame and openable sashes.
3.6.2 Steel Window
Figure 61 – Rusty steel window Figure 62 – Broken glass window glasss
Symptoms:
Rusty frames, grip or wicket
Deterioration or loss of sealer to keep the glass panels
Broken glass window glass
Dislodgment of sashes
Possible Causes:
Aging
Lack of care and preventative steps
Repair Methods:
Repaint the frame and wicket to protect the window from corroding
Regularly lubricate the flexible joints or replace if necessary
3.7 Internal Coating
3.7.1 Hairline and shrinking clefts
Symptoms:
Hairline clefts in plaster
Multi-directional clefts ( shrinking clefts )
Cracks between panel wall and structural elements such as wall or column
Figure 63 – Hairline clefts in plaster of the wall
Possible Causes:
Surface shrinking clefts in plaster or other coatings will impact the visual aspect merely and do non make large safety jobs. Surface clefts are little hairline clefts developed within the completing bed non perforating down to the strengthened concrete construction.
Insufficient clip for the hardening of plaster
Repair Methods:
Cut and make full up the person clefts with fix howitzer and redecorate to fit the bing coatings.
Resurfacing may be required if snap is excessively serious.
Let sufficient clip for bring arounding procedure to be completed in resurfacing
3.7.2 Differential motion clefts
Symptoms:
Cracks occur at the junction of two different stuffs in the background construction, e.g. concrete and brickwork
Cracks typically found in the junction between the column and wall, and the junction between the external and internal component.
Possible Causes:
Differential motion occur in the background stuffs such as concrete and brickwork
The background stuffs respond otherwise to the alterations in humidness and temperature
Repair Methods:
Provide flexible/expansion articulation by bring forthing a channel, or make fulling up the spread with joint filler and sealer
Supply a screen strip which fixed to one background component merely in order to cover the spread between different stuffs
3.7.3 Plaster Delamination
Symptoms:
Full thickness of plaster loose and come off from the background
Produce ‘hollow sound ‘ when tapped with a cock
Cracks occur
Plaster bumps
Figure 64 – Plaster loose and falls down from the wall
Possible Causes:
Poor craft
Lack of good key between the concrete background and the underseal plaster
Repair Methods:
Hack-off all of the debonded plaster from the affected country and clean the loose stuff
Supply a good key to the background concrete by using spatterdash, or roughening the concrete surface. Using a slurry coat of adhering agent on the concrete surface before re-plaster.
3.7.4 Tile Loose or Falling Off
Lapp as external wall tiling, refer to subdivision 3.4.1.
3.8 Floor
3.8.1 Timber Floor
Symptoms:
Falsifying ( distorted ) of lumber floor
Gaps appear between lumber boards
Edges curl upwards
Possible Causes:
Gaps looking is normally because the lumber strips have non dried out adequately before being fixed, shrinking occur go forthing spreads between strips
Expansion of timber strips and deficient enlargement spreads between the strips lead to borders curl upwards
The enlargement of timber strips may due to extra H2O used for cleansing.
Repair Methods:
Timber floor can be sanded to an overall level surface
Replace with new lumber floor if it is excessively serious
Sufficient spreads between the strip should be allowed for enlargement
3.8.2 Plastic Floor Tiles
Symptoms:
Bulging and impairment
Tiles are loose or borders lifted
Defects may be localized or a big country
Possible Causes:
Poor stuff and craft
The slab is non wholly dried out before puting tiles
Excess H2O used for cleaning intent ( from above )
Repair Methods:
Find out the wet beginning
Apply damp-proof membrane if necessary
Relay or replace the plastic tile with proper craft such as using sufficient adhesive to the exhaustively dried slab.
3.8.3 Floor tiles
Symptoms:
Produce ‘hollow sound ‘ when tapped with a cock
Loose / lifting of tiles
Continuous cleft in tiles
Falsifying of tile coatings
Figure 65 – Crack and broken tiles due to deficient enlargement articulations
Figure 66 – Lifting of mosaic tiles
Figure 67 – Lifting of vinyl tiles
Possible Causes:
Poor stuff
Poor craft
Insufficient enlargement articulation
Repair Methods:
Replacement of faulty tiles
Retiling
Addition of enlargement articulations
3.9 Plumbing and Drainage System
3.9.1 Defective Plumbing System ( fresh H2O supply pipe )
Symptoms
Insufficient H2O force per unit area or flows
Brown H2O and sedimentation
Arrest of H2O supply
Water escape
Dirty H2O ( soil and sedimentation ) or algae growing
Sudden rise in ingestion
Noisy H2O pumps
Possible Causes:
Obstruction or escape of constituents of H2O supply system
Rusty of galvanized Fe ( G.I. ) pipes or soiled supply armored combat vehicles
Pump failure or breakage of supply pipe
Defective H2O armored combat vehicles, pipe articulations or valves
Defective or missing H2O armored combat vehicle screen
Escape occur in the system after H2O metres
Defective H2O pumps, H2O force per unit area may be excessively high
Repair Methods:
Everyday review and care of plumbing system
Regular cleansing of H2O armored combat vehicle
Water armored combat vehicle should covered decently with locks
Replacement of faulty pipe and its accoutrements including connections and valves
Re-plumbing with Cu pipe or PVC lined G.I. pipes
3.9.2 Defective Drain System
Symptoms:
Rusty of dramatis personae Fe pipes
Broken piping
Water ooze
Stinky smelt
Possible Causes:
Lack of proper care such as picture
Accidental harm
Obstruction of drains by rubbish collected in the system
Insufficient no. of brackets
Aging, ultra-violet ( UV ) onslaught to uPVC pipe
Figure 68 – Obstruction of drains by trash
Repair Methods:
Regular picture of shrieking
Regular cleansing and remotion of rubbish
Provide sufficient bracket to keep the down pipe steadfastly
Replacement of faulty drain pipes
Replacement of the whole system
3.10 Seepage
Water ooze usually occur at bottom of roofs, underside of light Wellss, fanlight, ceiling below bathroom, kitchen, balcony, window, external wall, cellar and buried piping.
Symptoms:
Water staining
Skining off of pigment or wall paper
Water dripping
Growth of fungus
Defective concrete, plaster or tiles
Rust staining
Possible Causes:
Defective sealing membrane
Poor design
Failure of sealer
Hairline cleft in rendering
Honeycomb of concrete
Spalling concrete
Service pipe leaked or blocked
Damage of gasket
Repair Methods:
Re-roofing or spot fix
Better the design of floor drainage system
Reapplication sealer
Seal the cleft and use H2O repellent agent
Divert H2O to run out system
Replace faulty piping
