AZ024 Lecture 10

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Topic: Overall Maintenance Considerations for Functional and High Quality Buildings Part I: Introduction to Building Maintenance 1.0 Definition of Building Maintenance British Standard BS 3811 defines ‘maintenance’ as: ‘work undertaken in order to keep or restore every facilities, ie. Every part of a site, building and contents to an acceptable standard’ However, this definition is more generally seen in an engineering context and the Chartered Institute of Building supports the following definition:- ‘Building Maintenance is work undertaken to keep, restore or improve every facility, ie, every part of a building, its services and surround to an agreed standard, determined by the balance between need and available resources’ 2.0 The objective of Maintenance

a. Global Objective of a Maintenance System Repair and replacement done when necessary Maintenance budget allocated on a needs basis

b. Objectives for a Social Organization

Maximize, building life Achieve tenant satisfaction Working within constraints of budget available

c. Objectives for a Commercial Organization

Ensure building functions efficiently Building yields an economic return Maximize building life Balance maintenance expenditure and building efficiency

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3.0 Concept of Building Maintenance Maintenance Management can be divided into Building Maintenance Technology and Building Maintenance Management proper. The former essentially deals with the study of the occurrence of building defects, such as deterioration of building finishes/ fabric and the remedies which such defects would require. It involves the application of the principles of the physical sciences to the process of determining the effects on building performances produced by the intrinsic properties of building materials, the loading distribution of the building structure and other related factors. Building Maintenance Management should properly be regarded as describing how a system of maintenance effort could be organized to deal with the problems of building maintenance as whole. It recognizes that, aside from locating and rectifying defects, an effective programme to curb maintenance costs must start with the design of the building itself and must eventually justify itself, not only in terms of minimizing the costs of maintenance, but also in maximizing the benefits of the investment, This means that financial considerations and techniques play a vital role. 4.0 Classification of Maintenance Generally, the nature or maintenance work is divided into three main aspects:

Cyclic or Routine Maintenance Specific tasks carried out at regular-intervals without prior inspection such as clear-out of the curtain walling, flushing gutters, gullies, drains, manholes and replacement periodically of times with a predictable life.

Planned Maintenance (or called preventive maintenance)

Planned maintenance consists of taking corrective or preventive action in order to avoid expected or avoidable failure. In Hong Kong government, ArchSD have a planned maintenance scheme on government building annually, for example, inspect theexternal wall and implement the renovation works. A well-though maintenance plan can save considerable sums of money, although the need for cost effectiveness must be borne in mind. For example, monitoring schemes may be more costly than the periodic replacement of items with a predictable services life. Moreover, planned maintenance may lead to over-maintenance work if life time of building elements isn’t fully understood.

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Emergency Maintenance Emergency maintenance is the speedy action need to rectify failures of the building elements. These can stem from failures in planned maintenance or from natural or other causes, eg, storm, flood, accidents or security. However, it can be reduced to a minimum if routine and planned maintenance are systemically carried out and well-defined. In fact, extensive emergency maintenance is disruptive to occupiers as well as being wasteful. For example, the sudden breaking-down of the electrical switchboard.

5.0 Diagnosis and Investigation Techniques for building maintenance Building diagnosis involved a process in which experts (eg: Building Surveyor, Building Manager) investigate the existing condition of the building or the defect, carry out the necessary tests, evaluate the data collected, make recommendations professionally, and predict the future performance of the building or after repairing. The diagnosis process will involve wide range of techniques from the most simple – visual inspection to some scientific test, like the chloride test in evaluating the strength of the spalling concrete. They all aims at transforming measurable characteristics and properties of the defect or structure into valuable information appropriate to the building condition and performance. 6.0 Principle of Diagnosis In the diagnosis process, relevant professional should be analyzed the obtained data carefully and hypothesis have to be tested to determine which one best explains the causes of the defect. The whole process is never a simple straightforward one. On the hand, it is iterative; the more unusual or complex the cause, the more will be the need to go back and repeat all of the stage previously completed (Figure 1.). In short, the investigation required for the diagnosis of the building defect which has to be carried out thoroughly and systemically. Here are some points to be noted during the diagnosis of the building defect:

A list of the potential cause of a defect would be useful as a reference point to return who unexplained symptoms are found or a diagnosis is challenged

Diagnosis is required to be done step-by-step in a systematic manner. But it is

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essential to recognize that even the most obvious diagnosis may still lead to the wrong conclusions because the symptoms, the investigation and the original assumption of potential causes may all be incomplete.

In real cases, defect is generally believed to be caused by a combination of factors and seldom by a single factor. Some of these factors on their own may not require remedial work, but where they are attacking the material in combination, may need urgent attention.

Figure 1:- Systematic approach to building condition assessment

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7.0 Process of investigation In order to have a complete and all-round investigation of the building defect, a plan of action is required to make sure that the investigation process can progress without causing unnecessary inconvenience to the occupants of the building. This process normally entails the following steps:

1. Desktop Study Documenting survey for which existing information on the building structure and any relevant maintenance record obtaining from design and as-built drawing, specification, suppliers’ record, contractors’ test record during construction, record of defect and repairs, past and present usage of the building, loadings and subsequent alteration, if any, is very important.

a. Drawing and Specification All drawing and specifications, including those produced by the consultants, specialists and sub-contractors, and used during the construction should provide data on the materials used and details of construction. But these documents do not necessarily include all the revisions made during construction. b. Site notes, Minutes and Contractor’s reports Apart from giving information on modifications made during construction, site notes, minutes and reports also give information regarding difficulties encountered during construction; the quality of workmanship achieved; and the precautions taken to protect the materials and the building subsequently from the weather. c. Maintenance Records and Manuals These documents would reveal some useful information such as the history of all defects in building. And it is helpful to find out the root cause of the defect.

2. Interview with the occupants (Optional)

Interviews conducted by the surveyor or other investigator with any party connected with the design, construction, maintenance and use of the building can provide a valuable information on a number of aspects associated with a defect. But such information should be treated with some caution because the party providing the information may not always be true.

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3. Visual Inspection On site investigation should begin with careful visual inspection of the surrounding of the building, which replying mainly on the human sensory perceptions such as sight, hearing. It is at this stage that many of the basic tools such as binocular, hammer, scrapers are used. Graphic and photographic records may also be made of critical members for further analysis.

In fact, from visual inspection, valuable information may be obtained relating to workmanship, structural serviceability and signs of material deterioration. It is particularly important that the surveyor or engineer doing the survey be knowledgeable in these areas.

4. Testing and Monitoring

Many testing technique are available to suit the purpose and may be decided upon after the visual inspection has been completed. These techniques include:

Non-destructive methods, for example, infra-red scanning test, rebounded hammer

Chemical and physical analysis of the material, for example, chloride test on the strength of the concrete

Destructive method, for example: concrete core test

On the other hand, monitoring is also being a useful method of accessing the movement of building structure over a period of time if the structural crack is observed. This can be done by measuring the widths of the fractures or by taking vertical alignment readings of the structure with a theodolite form a datum position. However, monitoring is very time-consuming. The state of the building and the needs of the client must be considered before using them.

5. Evaluations and Recommendations

After obtaining all the required information and test result, the engineer/ surveyor or relevant professional should try to analyze the cause of the defect and make the creditable recommendations in repairing work.

The remedial works often chosen may belong to one of three general categories:

Patching up This recommendation is very often accepted because of relevant lower costs. However, bear in mind, patching up should always believe as temporary measure and employed only while the building has a limited

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functional or economic life and when more extensive rehabilitation or improvement works are planned to be done in the near future.

Replacement of parts This should be the first consideration to give a permanent repair. However, due to the limited time or high costs may give rise to problems to make this recommendation unattractive. However, it is still be the best choice if there is no other alternative.

Complete renewal Obviously, this is the most economics solution for buildings with a longer life, and the process can either involve existing parts for the entire area or providing a complete coverage over existing areas depending on adequate fixing facilities being possible.

* sample condition report is attached in the Appendix for reference. Part II: Main concerns in Building Structure and Building Services Installations (a) Structure

(1) Defective Concrete/ spalled concrete Patch Repair It is the most common repair method for minor concrete defects such as surface spalled or called hairline cracks on the surfaces. Damaged or defective concrete is to be hacked off down to sound substrate and patched up with appropriate repair mortars to protect the steel reinforcement from rusting. Two types of materials are commonly used for patching up by hand:- (i) cementitious mortars such as cement mortar and polyester-modified

cementitious mortar because its properties is very similar to concrete, it can provide a better key between old concrete and new mortar or;

(ii) resin-based mortar such as epoxy resin mortar and polyester resin mortar.

After all defected concrete has been hacked off, rusty reinforcement bars should be properly clean and primed with suitable epoxy based primer (strong anti-corrosive materials) for patching the steel bar if the environmental is aggressive. Furthermore, before patching up with cementitious mortars, the exposed concrete surface and the steel bars must be dust free to allow effective bonding with the new repair mortars.

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Photo 1:- Spalled Concrete

Replacement of reinforcement bars If the diameters of reinforcement bars are found substantially less than their original sizes, addition or replacement of steel bars may be required. The process involves identification of the type of existing steel bars, assessment on the required replacement or additional of reinforcement bars and the required lapping of the new and old bars. Structural calculation may also be required. Partial/ complete demolition and replacement When the defective concrete is extensive and penetrates beyond the steel bars or serious deteriorated, partial or complete demolition and re-casting of affected members may be required. Under such situation, a building professional such as a Registered Structural Engineer is required to give advice on the details of the materials and construction methods, and supervise the works. Precautionary measures such as installation of temporary propping may be required.

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Photo 2:-Spalled concrete – partial removal or re-casting may be required (ii) Structural Cracks

As discussed in Lecture 4, structural cracks deserve immediate attention. Detailed investigation should be carried out first to identify the underlying cause of the cracks. The causes of the problem must be properly addressed before sealing up the structural cracks. Otherwise, the danger of sudden collapse will be occurred.

Identifying the cause of the structural cracks should best be carried out by a structural engineer who should also advise on courses of action to remove the problem and the subsequent repair method. Such repair works should also be carried out by contractors registered under the Buildings Ordinance.

After identifying and addressing the problem causing the cracks, the repair of the cracks is usually done by pressure injects of epoxy resin or by open-up and refill/recast with concrete.

(2) External Wall (i) Wall tiles/ finishes

External wall tiles or panels of wall finishes insecurely fixed to external walls will likely fall off without any further warning symptoms resulting in disasters to pedestrians. All loose parts should first be removed to eliminate the imminent danger and replaced to maintain protection to external walls. A proper key between the existing concrete wall and the newly finished layer as well as the bonding of individual tile to its bedding mortar is crucial to avoid recurrence of the same defects. Proper preparation of the exposed surfaces of the existing wall for a physical key with the new mortar; use of suitable bonding agents or adhesives for the mortar; and special adhesives for the tiles are essential means for this purpose.

(ii) Cracks Crack should be repaired by injection of specially designed chemical or through open up and repair by mortar with the required key mentioned in Lecture 4.

(iii) loose concrete After the external wall tiles or finishes have come off, loose concrete, honeycombing, spalling may be revealed. Loose parts should be thoroughly removed down to the sound concrete substrate. Then,

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suitable repair mortar should be applied in accordance with description in Section (a)(1) of this note. Should the defects be found so extensive that replacement/addition of steel reinforcement bars, partial or demolition and re-casting of certain parts of concrete elements is considered necessary.

Photo 3:- Delaminated mosaic tiles

(3) Windows

(i) Repair Glass panels Any broken or cracked glass panes should be replaced at once with the same type and thickness of glass.

Steel windows

Steel windows are subject to rusting and should be regularly re-painted with primers and re-finished. Putty for holding glass panes should be maintained. Hinges should be regularly lubricated and replaced if necessary to avoid dislodgment of sashes.

Aluminium windows

Bar hinges in aluminium window system is one of the most common sources of problem that leads to dislodgment of sashes. They should be regularly checked for any loose fixings, deformation, cleared of dust and dirt and lightly lubricated to avoid friction causing undue load on the fixing. Should any of the aluminium angle for securing the glass panes be found missing, replacement must be done at once to avoid falling of glass panes.

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In the processing of replacing fixing components such as screws and rivets, measures against bi-metallic action leading to corrosion must be taken to avoid direct contact between two incompatible materials. A common example of bi-metallic action is between aluminium and stainless steel.

Locking devices

Locking devices of window sashes should be replaced if they cannot function properly. Otherwise, damage may result in typhoon.

(ii) Replacing major components Deformed window sashes or frames, usually revealed after typhoon, are unstable and have to be replaced at once.

Replacement of window frames is inevitable if:

the frames have deformed, become insecure, deteriorated to a considerable extent; and

the quality of the frame or its waterproofing materials filling the gap between the frame and the parent structure is in doubt, leading to constant leakage beyond repair.

In the process of installing the new window frames, the following points should be noted:

window frames should be securely and rigidly fixed in place to window opening in walls by fixing lugs;

suitable waterproofing grouting should be properly applied between the window frame and the opening with an additional coat of waterproofing material around the frame;

for aluminium windows, joints in window frames and sections should be properly sealed with suitable sealant. The window frames should be suitably equipped with water bars at its sill to prevent entry of water. A continuous gasket of suitable materials should also be properly applied along the whole perimeter between the window frame and openable sashes; and

glass panels installed to protect against the danger of falling should be designed by an Authorised Person (AP) or Registered Structural Engineer (RSE) and the installation works carried out by a Registered General Building Contractor under the supervision of such AP or RSE.

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(b) Building Services Installations

(1) Electrical Installation Registered Electrical Contractor/ works The repair and maintenance of electricity supply system should be undertaken by registered electrical contractors/workers. Name lists of registered electrical contractors/workers are available for reference at the Electrical and Mechanical Services Department’s (EMSD) Customer Services Office and web site, as well as all District Offices

New installation, additions and alterations. New installations, additions or alterations of electrical installations should comply with the safety requirements of the Electricity Ordinance.

Before carrying out any addition or alteration:

feasibility studies should be carried out by qualified building services

engineer or registered electrical contractor, depending on the scale of the job;

future electricity consumption requirements should be considered; and consent by the electricity supplier and the Owners’ Corporation of the

building must be obtained.

When the electrical work (including new installation, addition, alteration and repair) is completed, the qualified building services engineer and registered electrical contractor should inspect and test the electrical installations and certify that the installations are safe and comply with the safety requirements of the Electrical Ordinance in the Work Completion Certificate (Form WR1).

Periodic Inspection Owners should ensure that the power loading generated by the appliances and installations do not exceed the maximum loading approved by the electricity supply company. Qualified building services engineer or registered electrical contractor should be consulted if in doubt.

Electrical installations with an approved loading exceeding 100 amperes (A) in residential apartments, shops, offices and communal areas of the building should

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be inspected, tested and certified (Form WR2) at least once every 5 years to ensure safety.

Some important issue

All electricity installations should be properly earthed. Concealed electrical wiring of new installations should have mechanical

protection. Distribution boards should have identification labels to indicate the

purpose of individual electrical circuits. Sufficient socket outlets should be installed for individual heavy-current

electrical appliances. Earth leakage circuit breakers must be installed for socket outlets. Socket outlets should be installed as far away as practicable from water

taps, gas taps and cooking appliances to avoid danger of short circuits or fire risks.

No socket outlet should be installed in a bathroom except for electric shavers.

If an electric water heater is installed in a bathroom, the on/off switch should be installed outside the bathroom.

Outdoor socket outlets or electric switches should be of weatherproof types.

(2) Fire Services Installations

Basic fire service installations in the building generally include hose reels, fire extinguishers, fire alarm systems or automatic sprinkler systems. These installations and equipment are for preventing spread of fire, giving alarms or extinguishing fire.

To ensure that these installations work efficiently at all times, a registered fire service installation contractor should be employed by the OC to maintain, inspect and certify the installations at least once every year. When the fire service installation is found not working properly or damaged, immediate repair should be carried out.

(3) Lift and Escalator Installations Reliable lift service not only enhances convenience to residents but can also save lives. A registered lift (and escalator) contractor should be appointed to carry out the following tasks:

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Inspect, clean, lubricate and adjust the lift at least once a month; Test and examine the safety equipment annually; and Test the full load, overload device and the brake once every 5 years.

Apart from ensuring that the lift or escalator meets with the necessary safety standards, building owners should also monitor the following aspects, including:

annual renewal of the permit to use and operate the lift; keeping and updating of records of work for EMSD inspection; inspecting to ensure that no dangerous gaps exist in escalators; and upkeeping the lift machine room and the lift pits in clean and tidy

conditions. (4) Water Supply System

Components The water supply system usually consists of incoming pipes and gate valves, upfeeding pumps, water tanks at various locations, downfeeding pipes, water meters, special valves and accessories.

Fresh water supply systems Many old buildings still use galvanized iron (G.I.) pipes for the fresh water supply. As G.I. pipes are prone to corrosion over time, they are currently prohibited by the Water Authority. Maintenance works in these buildings should include the total replacement of the G.I. pipes by suitable approved materials such as copper pipes or PVC lined G.I. pipes.

Seawater flushing systems Many places in Hong Kong are supplied with sea-water for flushing purposes. Therefore, the Water Authority requires that all flushing systems should be able to withstand the attack of sea water even in areas where fresh water is supplied for flushing. PVC pipes are commonly used for this purpose.

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Part III: Introduction to Buildings Ordinance In Hong Kong, it is a statutory requirement that all proposed building works (which defined under s.2 of the Buildings Ordinance, including extensive addition and alteration works) must be submitted to the Building Authority for approval before their commencement on site. The following part will provide you full picture of the function of the Buildings Ordinance and its implications. 1.0 Buildings Ordinance and its relevant documents Under Buildings Ordinance s.14, all building works*1 should be required to obtain approval and consent for commencement. If any building works were carried out without the BA’s consent, the offender could face a heavy fine or even a custodial sentence under Buildings Ordinance s.40. Moreover, a demolition order will be issued under BO s.2. But it should be noted that some buildings and building works are exempted from the provision of the Buildings Ordinance. *1 Buildings Ordinance s.2: The definition of the building works

"building" (建築物) includes the whole, or any part, of any domestic or public building or building

which is constructed or adapted for use for public entertainment, arch, bridge, cavern adapted or

constructed to be used for the storage of petroleum products, chimney, cook-house, cowshed, dock,

factory, garage, hangar, hoarding, latrine, matched, office, oil storage installation, out-house, pier,

shelter, shop, stable, stairs, wall, warehouse, wharf, workshop or tower, sea-wall, breakwater, jetty,

mole, quay, cavern or any underground space

Exempted Building: These are stated in BO s.41 and include: 1. Buildings belong to government; 2. Building upon any land vested in the Housing Authority or over which the

Housing Authority has control and management; 3. Naval, military , or air force services; 4. Any temporary building to be used as a place of public entertainment. Exempted Building Works: In fact, Buildings Ordinance does not control all building works. Works which may be carried out without approval from Building Authority under BO s.14 include: 1. Not involve the building structure 2. Not contravene to the Buildings Ordinance, for example, the demolition of the

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public toilet in shopping hall, will not reduce the number of the public toilet that required under Buildings Ordinance

3. Drainage works in an existing building if it does not involve: - the structure of the building; - any drain or sewer into which their there is discharged, or it is intended to

discharge, any trade effluent, chemical refuse, waste steam, petroleum spirit, carbide of calcium, acids, grease or oils;

- altering any manhole at which any drain or sewer from the building is connected with a public sewer;

In fact, the main function of the Buildings Ordinance is to lay down the basic requirement of public health and safety in the building development (Figure 2). While the building designer follows the requirement which stated in the Buildings Ordinance, this will ensure the building will give a minimum acceptable standard of safety and health to the end-user.

Figure 2: - The spirits of Buildings Ordinance (CAP.123)

On the other hand, the Buildings Ordinance includes a set of the building regulations which elaborate on the various requirements of Buildings Ordinance: For example: 1. Buildings (Administration) Ordinance: it stated clearly on the statutory period of

approval and consent, the information required to be shown on the submitted building plan

2. Building (Construction) Ordinance: it stated the minimum requirement in the building construction, for example, the height of the railing, the performance of

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the material required, minimum loading capacity of the building structure, etc. 3. Building (Planning) Ordinance: it’s stated the requirement in lighting and

ventilation, requirement of mean of the escape, building height and so on. However, it is not possible to state all the detailed through the Buildings Ordinance (which is passed by legislative council). Instead, the Building Authority has a series of Code of Practice that further explain on the technical requirements of the regulation. For example: 1. Code of Practice on the Provisions of Means of Escape in Case of Fire: in the

Buildings Ordinance s.42, it only lay down that the sufficient mean of escape is required in the building. However, no specific number or design criteria are listed in the Building Ordinance. Thus, the provisions of this Code of Practice stated on the design criteria and number of exit routes, width of the mean of escape in the building and so on.

2. Code of Practice on the Provision of Fire Resistance Construction: it stated the minimum duration of the fire resistance material in the building structure such as the separation between the different usages.

Besides, the Building Authority also issues a series of the Practice Note for Authorized Person (PNAP) in order to classify any ambiguous area in Buildings Ordinance. It is a fast and effective way of communication to inform the designer (or Authorized Person) about the latest interpretation of Buildings Ordinance (as they are issued by Building Authority without going through any legislative process). For example, the provision of exempted gross floor area, under Building (Planning) Regulation s.23 (3b)*2, it does not give the clear view on the exempted gross floor area. In order to classify the ambiguous area, PNAP 13, 68, 116 and 229 give a further justification on the criteria in exempting the gross floor area under different circumstances. *2 Buildings Ordinance s.23(3b) states that:

(b) In determining the gross floor area for the purposes of regulations 20, 21 and 22, the Building

Authority may disregard any floor space that he is satisfied is constructed or intended to be used solely

for parking motor vehicles, loading or unloading of motor vehicles, or for refuse storage chambers,

refuse storage and material recovery chambers, material recovery chambers, refuse storage and

material recovery rooms, refuse chutes, refuse hopper rooms and other types of facilities provided to

facilitate the separation of refuse to the satisfaction of the Building Authority, or for access facilities for

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telecommunications and broadcasting services, or occupied solely by machinery or equipment for any

lift, air-conditioning or heating system or any similar service.

2.0 Statutory Period for Approval & Consent under Buildings (Administration)

Regulation s.30(3) and 32(3) Under Buildings Ordinance s.15, it state solidly that approval of plans or consent for commencement of the buildings work must be obtained from the Building Authority. The statutory time limit for each process is shown below:

60 days*2 for first submission of plans 60 days for re-submission of plan with ‘major’ revision 30 days for re-submission of plan with ‘minor’ revision 28 days for consent to the commencement of approved plan

*2 for A&A works (do not affect the major aspects of the buildings, for example, the lighting and ventilation under B(P)R s.32), the Buildings Department may adapt a fast-track processing to process the A&A work and give the approval within 30days.

Question: Is Addition or alternation works require to obtain the approval and consent from the Buildings Department?

Is it contravened to the Buildings Ordinance? Involve any structural alteration? Is it Exempted building works?

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Appendix - Sample report A comprehensive report usually comprises the following parts:-

Project Title Details of building or structure, for example, location, age, type and

current and past usage. client’s name and name of surveyor or engineer and/or the firm engaged

Preface, which is a brief summary of the important information presented in the report

Lists of contents Introductions, contains the history and subjected matter of the report, the

brief, and scope and limitation of the works. Body, usually includes the background and history of the structure, details

of inspections carried out, results and calculations, and all details of the repairs.

Conclusions, based on firm, reasonable judgment reached after careful evaluation of all information obtained.

Recommendations should tally with the rest of the report and usually include proposals of remedial work, regular maintenance inspection or inspections to detect further deteriorations.

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