Purpose Of Miranda Roof Inspection

Provide a roof condition report to N.C.C 2016 Vol.2, AS 1562.1, AS 1562.3, SA HB 39 2015 The Installation Code for Metal Roofing and Walling and Manufacturer’s Instructions. For more information about our South Sydney roof inspection services, click here.

Findings Detailed In Miranda Roof Inspection Report

No spreader on the downpipe of the lower roof and the outlet is discharging onto roof flashings, noncompliant to SA HB 39 refer 5.7.7. Likely cause of ingress in this area is due to the flashing being turned up onto the wall without an over flashing, pressure flashing required as shown below.
Chase flashing has failing silicone due to silicone having no longevity, chase flashings also break down due to the cement attacking the metal and pressure flashings as shown above give better longevity if installed correctly. Unsure if the flashing connection has been undersealed compliantly due to the silicone overseal.
Vertical line of sealant cracked to dwelling framed and cladded wall abutting the Duplexes’ central masonry partition wall of the dwelling. If the eaves gutter overflowed, it would likely run into these cracks.
Severe ponding occurring the central parapet cap of the lower roof, this will result in corrosion over time.
Although installed to manufacturer’s instructions the Velux skylights give limited flashing cover of the roof with the minimum required coverage to be 150mm.
Flashing is lapped against direction of water flow here with ingress potential, non-compliant to SA HB 39 refer 8.2. A tray flashing to the apex will remedy this.
Screw not tightened on capping above central partition wall of duplex.
Rivets have sheared on the ridge capping connection; this is likely due to not being silicone undersealed. See item #6 for compliance on flashing connections.
Parapet capping between dwellings on the upper roof is ponding. See item #4 for compliance.
Ponding occurring to small roof areas. See item #4 for compliance.
Sealant roof/flashing sheet joint exposed to ultraviolet radiation to small roof at 2nd storey wall stepback. Silicone should be sandwiched between the lap to protect it from the sun’s UV rays. Note there is also ponding occurring at this join.
Vertical line of sealant cracked to the framed FC sheet nib wall of dwelling abutting the framed and cladded wall of the dwelling above the small roof at 2nd storey wall step back 3.5 CORNERS.
An internal corner requires a 6mm gap between sheets that is filled with James Hardie joint sealant. See Figure 14: Installation Guide – EXTERIORS Australia May 2019
Vent pipe penetration is affecting the anti capillary of the sheet lap, this will likely lead to ingress. Dektite also has insufficient fasteners. Flashing connections throughout the roof are poorly done with no evidence of silicone underseal taking place, rather the silicone has been applied on top which gives no longevity due to the silicone breaking down under the sun’s UV rays. See items #6 & 11 for flashing join compliances.
Aerial upstand is corroded and is starting to affect the flashings below, it would be prudent to replace the aerial to prevent the spread of corrosion. Flashing connection above the aerial has insufficient fasteners.
Although installed to manufacturer’s instructions the Velux skylights give limited flashing cover of the roof with the minimum required coverage to be 150mm. See item #5 for compliance.

References To Australian Building Codes & Manufacturers Instructions

5.7.7 Spreaders

Spreaders may be used to drain rainwater from a higher roof surface with a catchment area not exceeding 15 m2 provided the following conditions are satisfied:

When discharging onto a tiled roof, the lower section is sarked a minimum width of 1800mm either side of the point of discharge extending down to the eaves gutter.
When discharging onto a corrugated roof, a minimum width of 1800 mm on either side of the point of discharge is sealed for the full length of the side laps.
The increased roof water volume from the upper roof is not to enter any seam of the roof covering of the lower roof.
No spreader is to have its discharge entering any part of any building.
Spreaders are to discharge all roof water onto roof coverings in the direction of flow, avoiding discharging onto laps on lower roof sheets and tiles.
When discharging an upper roof catchment onto a lower roof, the total roof area including the additional upper roof catchment area is to be considered for inclusion when sizing the lower roofing, gutters and downpipes.
Spreaders do not discharge on sheets or tiles discharging to valleys.

8.7 All Other Flashings and Cappings

b) Parapet cappings: Parapet cappings to be fixed to parapet walls at intervals not exceeding 500 mm with masonry anchors and cleats that permit longitudinal expansion and contraction. A minimum fall of 3 degrees to be provided across the width of the flashing, to divert water back onto the roof coverings so as to prevent the water from dripping down the fascia causing unsightly staining.

8.2 Fastening

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

(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.

5.8.3 Fastening and sealing with sealants

Joints in aluminium/ zinc, aluminium/zinc/magnesium alloy-coated steel, prepainted steel flashings and cappings are to be fastened at intervals not exceeding 40 mm 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.

8.6.1 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