Bonville Roof Inspection Purpose:

Provide a roof condition report to AS 1562.1 AS 1562.3 And SA HB 39 2015: The Installation Code for Metal Roofing and Walling. Also provide recommendations to extend longevity.

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Findings & Recommendations Report For Bonville Roof Inspection

  • Flashing coverage in some areas is under the required 150mm minimum to be compliant, although we do note this is minor as there is a dry pan provided under the flashing and should not cause ingress.
  • Hole presents at location shown although undersealed, all flashings should be flush fitting to prevent moisture getting into the laps and reducing the lifespan of the connection.
  • Flashings lapped onto the roof against the flow of water and heavily reliant on silicone which has no longevity, potential for future ingress from ponding corrosion. Non-compliant to SA HB 39 refer 8.2.
  • Flashing join not undersealed or fastened sufficiently, non-compliant to SA HB 39 refer 5.8.3. See item #2 for compliance.
  • Batten has not been fastened in location shown, incomplete works.
  • All areas:. Barge cappings throughout the roof have no sliding cleats/fasteners, noncompliant to SA HB 39 refer 8. 7.
  • Potential for future ponding corrosion and ingress to occur at location shown, given the low pitch of 8-degrees it would be prudent to tray flash this vent pipe penetration.
  • Flashing joins still have plastic protective coating evident this will affect the silicone seal and is non-compliant to SA HB 39 refer 5.8.3. See item #2 for compliance.
  • Apron flashing does not go behind the wall cladding and is not waterproof, also note the upstand is under the minimum 50mm required.
  • Ridge capping joins not undersealed and have insufficient fasteners, non-compliant to SA HB 39 refer 5.8.3. See item #2 for compliance.
  • Roof sheets have not been fastened to the top batten and not installed to manufacturer’s installation instructions. Given this type of structure has limited battens it would be prudent to ensure this is fastened down compliantly.

Building & Installation Code References found in Bonville roof inspection report:

5.8.3 Fastening and sealing with sealants

Joint in aluminium/zinc, aluminium/zinc/magnesium alloy-coated steel, prepainted steel flashings and cappings are to be fastened at intervals not exceeding 40mm and silicone sealed with neutral cure silicone sealants.

Sealants are to be sandwiched between the laps of the joint to provide a positive seal and to protect the silicone sealant from exposure to ultraviolet radiation.

8.2 Fastening

Roof flashings and cappings are to be fastened as given in Table 8.2(A) and the following:

(a) Roof flashings and cappings to be fastened to withstand wind pressures and thermal
movements.

(b) Roof flashings and cappings to be tightly notched and fastened at the intervals given
in Table 8.2(8).

(c) Intersections, laps and mitres are to be fastened and sealed as per Clause 5.8.

(d) Joints in flashings and cappings other than straight joints to be accurately mitred,
fastened and sea led.

(e) Joints in flashings and cappings to be 25 mm and fastened at intervals not exceeding 40 mm. Joints are to lap in the direction of fall.

(f) All joints are to be watertight on completion of the installations.

8.7 All Other Flashings and Cappings

c) Barge Capping

Barge capping to be installed as shown in Figure 8.7 (B)

8.1.3 Expansion Provision

Roof flashings and cappings are to be installed to permit longitudinal expansion and contraction without detrimental effect to the flashing themselves and other roof components, structures and covers.

Roof flashings and cappings fastened to metallic roof covering materials are not to be fastened to other building materials with other than sliding cleats or fixings.

8.6 PENETRATIONS

8.6.1 Collar Flashings

Where any part of the roof surface is penetrated by any pipe, pole, duct, flue, shaft, cable or tank support, the penetration is to be flashed to prevent the entry of rainwater, and to permit the roof surface and penetrating object to expand and contract without detrimental effect to any part of the roof. In addition, particular attention is to be paid to the following:

Pondage Colar flashing to permit the total drainage of the area above the penetration

7.2 Roof Sheet Span Information

The roof sheet support spacing for the various profiles are listed in the typical span information of the manufacturer’s product literature. This information varies depending on whether it is an end span, internal span or overhang.

The typical span charts are based on the ability of sheeting to withstand the wind loads specified in AS/NZS 1562.1 and the NCC. All sheeting is to be fixed to each and every roof support unless otherwise approved by a structural engineer

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