Repair Systems — 04
Penetration plinth systems — raised pipe surrounds
Technical product reference for penetration plinth systems — raised Colorbond or Zincalume box enclosures for pipe and service penetrations through flat or low-slope sections of pitched tiled roofs. Covers design requirements, fabrication, overflow provision, and base flashing.
What are penetration plinth systems?
Penetration plinth systems are raised box enclosures — typically custom-fabricated from Colorbond or Zincalume sheet by a licensed roof plumber or sheet metal fabricator — that create a weathered elevation around a pipe or service penetration where a standard pre-formed collar flashing cannot be used. Plinths are required where the pipe exits through a flat or low-slope area of the roof and the surrounding roof surface is at or near the same level as the pipe exit point, exposing the penetration to ponding water or water flow.
Product Reference
2 products — 2 brands — penetration plinth systems — scroll to view all
Custom Colorbond / Zincalume Fabricated Plinth
Custom-fabricated raised penetration plinth — Colorbond or Zincalume
System Description
A custom-fabricated raised plinth is the standard solution where a pipe, mechanical service, or conduit penetrates through a flat or low-slope area within a tiled or metal roof and a standard pre-formed collar cannot be used. The plinth is a raised box — typically fabricated from Colorbond or Zincalume sheet by the roof plumber or a local sheet metal fabricator — that creates a raised weathered enclosure around the penetration. The height of the plinth above the adjacent roof surface is determined by the drainage falls, the adjacent tile course height, and the risk of water ponding at the penetration point. The base of the plinth is flashed into the roof sarking and waterproofing layer below the tile course. The pipe or service penetrates through the top or side of the plinth box, which is then flashed or sealed at the penetration. There is no proprietary product for a custom plinth — the plinth is described by a specification, fabrication drawing, and installation detail prepared by the roof plumber or structural engineer. Colorbond is specified for colour-matched or aesthetic requirements; Zincalume (unpainted) is specified for concealed applications or where painting is to follow. Confirm Colorbond colour and Zincalume gauge with BlueScope Steel product documentation before ordering sheet.
Technical Properties
- Custom-fabricated raised box — size and height determined by project conditions — no standard size
- Colorbond (prepainted) or Zincalume (unpainted) steel sheet — BlueScope Steel product
- Described by specification, fabrication drawing, and installation detail — not a proprietary product
Limitations
- Not a proprietary product — design must be documented by a specification or fabrication drawing before fabrication — do not fabricate without a drawing
- Fabrication quality varies by fabricator — inspect finished plinth before installation for dimensional accuracy and watertight seam quality
- Overflow provision must be considered — if ponding occurs at the plinth base, an overflow weep or drainage point must be incorporated in the design
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Deks Elevated Pipe Collar System
Pre-formed elevated pipe collar / plinth accessory — Deks
System Description
Deks Industries manufactures a range of penetration flashing accessories and may offer elevated collar or plinth adapters for situations where a standard D-1 or Deks 45 collar is insufficient on a low-pitch roof area and a raised elevation around the pipe is required. This product listing is a placeholder — the owner must confirm with Deks Industries the current product name, part number, and technical specifications for any elevated collar or plinth accessory in the Deks range. Confirm with Deks technical whether the current product range includes an elevated or extended collar product for low-pitch applications, and confirm the pitch range, pipe OD range, and installation requirements before specifying. If Deks does not currently offer an elevated collar/plinth product for the application, revert to the custom-fabricated Colorbond plinth described on this page.
Technical Properties
- TODO — confirm current Deks elevated collar product name and part number with Deks Industries technical
- Pre-formed — if available, no site forming of the main flashing element required
- For low-pitch roof areas where standard D-1 collar cannot be used without elevation
Limitations
- TODO — product existence, name, and specifications must be confirmed with Deks Industries before specifying
- If no Deks elevated collar product is confirmed, use a custom-fabricated Colorbond or Zincalume plinth instead
- Do not specify this product without first confirming with Deks Australia that a current elevated collar product exists in their range
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side comparison of penetration plinth approaches. Plinth design must be engineered for the specific application — confirm with a licensed roof plumber.
| Product | Brand | Type | Material | Fabrication | Size flexibility | Weatherproofing | Cost |
|---|---|---|---|---|---|---|---|
| Custom Fabricated Plinth | No proprietary brand | Custom-fabricated box | Colorbond or Zincalume | By sheet metal fabricator or roof plumber | Fully flexible — any size | By specification and detailing | Higher — custom fabrication |
| Deks Elevated Collar | Deks | Pre-formed (if available) | Confirm with Deks | Factory pre-formed | Limited to available sizes | Pre-formed seal | Lower if standard product available |
Do not confuse penetration plinth systems with:
- Penetration flashing collars (listed on the Flashing collars page) — pre-formed EPDM collar systems used for round pipe penetrations through the main tile field on a standard pitched roof — collars are the standard system for most residential tiled roof pipe penetrations and do not require a raised plinth
- Most penetrations on standard pitched tiled roofs (above approximately 15°) use collar flashings, not plinths — a plinth is required only when the penetration occurs in a flat or low-slope section of roof or where ponding water reaches the penetration base
- Roof penetration sleeves or fire-rated pipe collars — intumescent or fire-rated sleeves around pipe penetrations through fire-rated roof assemblies — a separate scope from weatherproofing plinth flashings
Disclaimer
Plinth design must be engineered for the specific application. Confirm with a licensed roof plumber. Final product selection and fabrication must be confirmed against the project specification, drainage conditions, and roof membrane compatibility. Do not rely on this reference as a substitute for professional roofing consultant or engineering advice.