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Date Posted: 12:14:17 11/21/06 Tue
Author: ��Z�ر��P+�w�וּ�\: jameslam@hkpro.com.hk
Subject:

�b�x��Z�ر��O+�w�וּ�\: nancychow@hkpro.com.hk
In reply to: andy 's message, "viper alarm" on 19:47:29 06/18/06 Sun

(c) .During the course of any works, if the Project Manager is of the opinion that any of the Approved Specialist Roofing Applicator employed by the Contractor for this contract is incompetent or negligent or fails to execute the Proprietary Roofing System in accordance with this clause, he may instruct the Contractor in writing to remove such Approved Specialist Roofing Applicator from the works. After receiving notice in writing of such removal, the Contractor shall forthwith remove the Approved Specialist Roofing Applicator and shall not thereafter employ him again on any works and shall within 14 days submit the name of the replacement Specialist Roofing Applicator for the Project Manager's approval as laid down in sub-clause 6.4 above. The Contractor shall not be entitled to any extension of time and/or additional costs whatsoever for any replacement of Approved Specialist Roofing Applicator under this circumstance.

6.5 Letters of Intent to be Submitted

Upon approval by the Project Manager of the Specialist Roofing Applicator, the
Contractor shall within 7 days submit to the Project Manager the letters of intent from the Approved Roofing Applicator, indicating his willingness to carry out the proposed Proprietary Roofing System included in the contract.

6.6 Workmanship

(a) The Proprietary Roofing Systems shall be applied strictly in accordance with the manufacturer's specification and recommendations and in accordance with the details and sequence as approved by the Project Manager. Particular care should be taken to ensure that all junctions, joint details such as skirtings, covering to kerbs, edges, etc. and all joints around pipes, rainwater outlets and the like are properly executed.

(b) The Contractor shall ensure that moisture will not be entrapped between
the existing roof structure and the Proprietary Roofing System. All necessary precautions shall also be taken by the Contractor to ensure the full integrity of the Proprietary Roofing System.

6.7 Detailed Specification to be Submitted

(a) Upon approval by the Project Manager of the Specialist Roofing Applicator, the Contractor shall within 21 days submit to the Project Manager the following information for approval:

i) Detailed specification and standard details of its selected
Proprietary Roofing System, sequence of laying, details of any proposals for dealing with existing flashings, expansion joints , joints around pipes, rainwater outlets and the like, together with his proposed method for executing work in any problem areas as may be informed by the Project Manager.

ii) Certified engineering data and samples.
iii) Job references.
(b) Approval of any details by the Project Manager shall not relieve the
Contractor from any of his obligations and liabilities under the contract.

6.8 Demonstration on Site

Before commencing any works, the Contractor shall demonstrate on Site that the proposed Proprietary Roofing System, including all adhesives and waterproof roofing materials, are fully compatible and this must be certified by the manufacturer in writing. Re-roofing work may only commence upon satisfactory demonstration and accepted as such by the Project Manager.

6.9 Warranty

Upon completion of any works involving the execution of any Approved Proprietary Roofing System, the Contractor and the Approved Specialist Roofing Applicator executing such Approved Proprietary Roofing System shall submit the executed joint and several Certificate of Warranty for a period often (10)years in strict accordance with the format at Appendix VI to the PS to the Employer. Such Certificate of Warranty for the Approved Proprietary Roofing System is required and any such works will not be considered as completed without having such Certificate of Warranty duly completed and submitted to the Project Manager by the Approved Specialist Roofing Applicator concerned.

6.10 Removal of Existing Surface Finishes

(a) Where floor finishes are to be removed, break up all floor finishes, and
clear away from site. Clean substrate, remove all deleterious materials and leave the base and upstand surfaces clean, dry, and even, ready to receive new floor screed and/or floor tiling, all to the satisfaction of the Project Manager.

(b) The existing wall skirting shall be completely removed up to 300mm
(minimum) measured from concrete surface.

6.11 Protection Against Overloading of Roof Structures & Inclement Weather

Before proceeding with the works, the Contractor is required to submit a method statement to the Project Manager for approval. The method statement must include details of the lifts and hoists to be provided, details of how the waste is to be removed from site and the precautions that will be taken to avoid the risk of overloading the roofs structure.

Ensure that all necessary precautions are taken to prevent overloading of the roofs structure. Materials should not be stored in isolated locations, particularly in respect of heavy materials such as concrete or other cementitious tiles and paving.

The Contractor shall provide adequate protection to the exposed substrate during wet and/or inclement weather to the entire satisfaction of the Project Manager.

6.12 Resurfacing Work

a) Before commencing the application of any screed, take all levels and calculate the correct level for all critical points of the new finishes. All points shall be marked with permanent markers to ensure consistency and accuracy throughout the course of the works. Take particular care with existing levels and drainage gullies to ensure the accurate matching of floor levels.

Ensure that an even, straight pattern with parallel lines is achieved for
tiled finishes and that all work joints meet neatly. Take all
measurements to ensure that such true square patterns can be achieved, and refer all discrepancies to the Project Manager who shall issue an instruction as appropriate.

Supply a record of all existing and proposed levels and present the same to the Project Manager for approval, and agree the setting out at a formal meeting, to be convened at a time to be agreed with the Project Manager with a minimum of two days notice.

Failure of the Contractor to seek approval of the setting out may result in the Contractor being instructed to break out the work and relay the floor if it does not achieve the desired standard.

b) Lay screeding to falls (1:80) to drain with a minimum of thickness of
30mm and carried up skirting 300mm high.

c) All wall/floor intersections and internal/external angles shall be
reinforced with expanded stainless steel lathing. A 50mm x 50mm cement sand angle fillet shall be provided to all external angles.

d) Adequate movement joints for the roof tiles, mosaic tiles and screeds on the roof shall be provided at positions approved by the Project Manager for every 15 m2 or as may be directed by the Project Manager.

6.13 Expansion Joint

a) Rake out existing concealed expansion joints along roof parapet wall ,
external wall, and podium deck and to form a 25mm groove.

b) Form a 150mm x 25mm recess along the expansion joints to receive
waterproofing layer.

c) Lay a 25mm dia. bond backer rod into the groove and filled with
polyurethane sealant to form mega joint.

d) After sealant cure, apply one layer of �� Thane coat W302" or approved
equivalent liquid applied waterproofing membrane reinforced with polyster mesh and allow to cure.

e) After cure of waterproofing membrane, lay a second bond backer into the joint and apply second layer of �� Thane coat W302" or approved equivalent liquid applied waterproofing membrane reinforced with polyster mesh and allow to cure.

f) Fill the groove with 25mm (W) x 13mm(D) �� Dow Corning 790" neutral
silicone sealant or approved equivalent.

g) Conduct intermittent water test to the expansion joint at parapet walls
and podium decks by water jet for 20 minutes per hour during 9:00 am to 6:00pm at one working day.

h) The contractor shall make good all affected finishes to match existing to
the satisfaction of the Employer.

i) Unless otherwise specified, install a 1.2mm thick stainless steel cover
with screw 200 mm centre to centre over the expansion joints.

6.13Expansion Joint Cover

1. Sample of expansion joint cover to be submitted to Surveyor prior to
ordering of material.

2. Expansion joint cover to be of stainless steel to BS 3019 of non-skid
pattern to be approved by Surveyor.

3. Stainless steel screw to be to BS 4174 or of an approved proprietary product fixed strictly in accordance with the manufacturer's recommendation.

4. Stainless steel anchor bolt to be of an approved proprietary bolts fixed
strictly in accordance with the manufacturer's recommendation.

6.14Water Test for Roofs

On completion of the waterproofing works or each section thereof and prior to the subsequent application of surface finishes, the Contractor shall inform the Project Manager for water test to be carried out to the roofs in accordance with the following procedures: -

a) Flat Roof

The Contractor shall temporarily block all outlets, constructing dams to compartmentalise the test area, and flood the roof area with clean water and approved dyeing agent to a minimum depth of 50mm or to the top edge of skirting or kerb all as directed by the Project Manager. The test shall be run for a period of not less than 48 hours, which may be extended at the discretion of a period of not less than 48 hours. At the end of the period, the Contractor in conjunction with the Specialist Roofing Applicator shall make a careful inspection of the underside of roof for leaks. Where repairs are necessary the area shall be drained and allowed to dry, the defects rectified and the area tested again for membrane integrity to the satisfaction of the Project Manager. The Contractor shall submit a detailed report after testing, carried out on the completed roofing to the Project Manager for record purposes.

c) Pitch Roof

The Contractor shall apply water to the pitch roof at a rate of 3.41/min/m2 so as to completely cover the pitched roof.

The following pressure load should be applied: -

(i) Pre-wet the pitched roof surface for 1/2 hour at zero pressure.

(ii) Spray water onto the pitched roof surface at static pressure at 1.20
kPa for 1/2 hour.

(iii) Zero pressure for inspection.

No water leakage should be allowed through the roofing system and the Contractor shall submit a detailed report on the inspection with photo records.

d) Roof Void

The Contractor shall temporarily block all outlets, constructing dams to compartmentalise the test area, and flood the roof area with clean water and approved dyeing agent to a minimum. depth of 50mm or to the top edge of skirting or kerb all as directed by the Project Manager. The test shall be run for a period of not less than 48 hours, which may be extended at the discretion of a period of not less than 48 hours. At the end of the period, the Contractor in conjunction with the Specialist
Roofing Applicator shall make a careful inspection of the underside of roof for leaks. Where repairs are necessary the area shall be drained and allowed to dry, the defects rectified and the area tested again for membrane integrity to the satisfaction of the Project Manager.

All temporary works necessary to perform the above test or as may be directed by the Project Manager shall be carried out by the Contractor at his own expense.

6.1.5Non-destructive Test

The Contractor shall employ an Approved Infra-red Scanning Contractor as Specialist Contractor to carry out non-destructive tests to establish waterproof
integrity of the roofing installation including any Proprietary Roofing Systems executed by the Contractor and/or Approved Specialist Roofing Applicators. For flat roofs, the tests shall include sealing of all outlets and if necessary constructing dams to compartmentalise large roofs. The roof shall be flooded for 24 hours. After flooding, all outlet blockages and dams shall be removed to drain the roof. At a period between 24 and 48 hours from release of water, an infra-red scanning test shall be undertaken by the above Specialist Contractor to establish if there was penetration through the roofing installation including any Proprietary Roofing Systems. For pitch roof, the Contractor shall apply water to the pitch roof at a rate of 3.41/min/ m2 so as to completely cover the pitched roof. The pitch roof surface shall be pre-wetted for 1/2 hour at zero pressure and then sprayed with water at static pressure at 1.20 kPa for 1/2 hour. After the surface water dry out, an infra-red scanning test shall be undertaken by the above Specialist Contractor to establish if there was penetration through the roofing installation including any Proprietary Roofing Systems.

The test results are to be sent direct by the above Specialist Contractor to the Surveyor. The Contractor shall allow all costs in connection with this provision for the non-destructive testing to be carried out by an Approval Infra-red Scanning Contractor.

In the event of failure, the Contractor shall be required to carry out repairs at his own expenses and the expense of all subsequent infra-red scanning tests shall be borne by the Contractor. Infra-red scanning tests shall be carried out until the roof is shown to be watertight.

For the Contractor's information, the Infra-red Scanning Contractors currently known to the Surveyor are listed below. These contractors are subject to approval by the Surveyor. The Contractor shall not be entitled to any additional costs for any variation in this respect whatsoever.

6.16Maintenance Manual

Upon completion of any works, the Contractor shall submit a maintenance
manual for such works , identified with the project name, location, date of certified completion, type of roofing installation applied and surface to which the installation was applied, including sketches where necessary. The manual must provide details on periodic inspections, care and maintenance and must identify common causes of damage with instructions for temporary patching until permanent repair can be made.

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