Published · 2026-10-09
A request for a flashing around a ventilation opening can leave several items undefined. Identify whether the opening is in profiled metal sheeting, a standing-seam roof, an insulated roof panel or a membrane assembly. Record the actual roof construction and drawing revision before comparing prices. A flashing quotation is not approval to cut the roof.
A roof opening is more than a hole diameter
Begin with a marked-up plan. Give each opening a reference and show its position relative to the roof slope, sheet joints, supporting members and nearby openings. Distinguish the equipment connection size, required clear opening and external curb dimensions. State units and quantities separately. These are information requests, not standard dimensions offered by ZY.
Ask where the water will go
LYSAGHT's Roofing & Walling Installation Manual discusses drainage around openings through ribbed cladding. Its details depend on the roof arrangement. [1]
Ask for a drawing showing the upstream, side and downstream interfaces and intended drainage route. Give the designer the roof pitch, profile and opening position. Request confirmation of the applicable detail and its limits. A photograph that resembles your roof does not establish compatibility.
Separate opening support from flashing
LYSAGHT's Flashing Guide addresses framing at cut ribs. Treat that as a prompt to identify the support review for the selected roof system. [2]
Identify who reviews the effect of the opening and supplies the surrounding support. Include a support or curb drawing where available. Equipment support, cladding support and the weathering interface each need an identified responsible party.
A price for folded metal does not by itself include structural review, equipment loads, supporting members or installation. Keep those items visible in the comparison rather than assuming that a complete flashing package includes them.
Compare offers against the same boundary
| Item | Information to provide | What to compare |
|---|---|---|
| Roof assembly | Product/profile, layer build-up and drawing revision | Same identified roof system and applicable detail |
| Opening geometry | Reference, location, clear size, curb or connection dimensions | The same measured boundaries and units |
| Drainage interface | Roof pitch, upstream area and nearby junctions for designer review | Proposed drainage route and design responsibility |
| Support | Cut ribs or panels, surrounding members and equipment support | Included framing and engineering review |
| Weathering components | Flashings, closures, seals and roof-layer junctions to confirm | Supplied parts versus separately supplied or installed parts |
| Supply and acceptance | Quantity, materials/finishes, packing and inspection requirements | Explicit inclusions, exclusions and acceptance documents |
Make the accessory schedule usable
Use one reference for the drawing, component schedule and quotation line. Ask for each fabricated component, proposed material and finish, quantity and drawing revision. List seals, closures and fixings where included in the agreed package; mark unconfirmed selections for confirmation. Performance requirements need information identifying the proposed configuration.
Check more than the flashing colour. LYSAGHT's guide asks for compatibility where different materials meet and where water runs from one material onto another. [2] Ask the selected roof-system supplier to identify the flashing material and finish and confirm the contact and runoff interfaces. Record the supporting guidance and drawing revision; matching colours alone does not establish compatibility.
Match the detail to the complete roof assembly
For an insulated roof panel, ask the selected system supplier and project designer to address the complete panel and affected layers. The profiled-sheet references cited here do not verify an insulated-panel penetration detail, fire rating or airtightness result.
Before ordering, reconcile the quotation with the approved project detail and identify open decisions. If only fabrication is included, record who supplies the remaining components, reviews compatibility and accepts installation. This worksheet does not establish stock, a delivery promise or tested performance.
Prepare a roof-opening and flashing enquiry
Fill in known information and keep unconfirmed entries marked for confirmation. Use the same drawing revision for every offer. This worksheet supports procurement and does not replace project design or approval.
- Project reference, contact and destination
- Roof construction, selected product/profile and drawing revision
- Opening references, locations, number and units
- Equipment connection, clear opening and external curb dimensions distinguished
- Roof pitch and sheet/panel joint layout
- Nearby ridge, eave, valley, wall and other opening interfaces
- Intended drainage route and responsible designer's review
- Cut ribs/panels and surrounding support information
- Equipment support, cladding support and design responsibilities
- Fabricated flashing component marks, dimensions and drawing revision
- Proposed material, thickness definition and finish requirements
- Closures, seals, fixings and roof-layer interfaces; flashing material compatibility at contact and runoff interfaces to confirm
- Package inclusions, exclusions and separately supplied components
- Applicable configuration-specific documentation and inspection requirements
- Packing and requested delivery programme, subject to supplier confirmation
- Outstanding decisions, approval status and installation/acceptance responsibilities
Connect the opening to the roof and accessory package
Primary sources and scope
Sources checked on 9 October 2026. The installation manual footer identifies BLY0081_B - 05/2025. The Flashing Guide copy has a 2024 copyright statement; an issue date was not established. Both are LYSAGHT documents, not independent authorities. This is a buying guide, not news.
Manufacturer detail examples are not universal requirements for sandwich panels, standing seams or membrane roofs. This procurement guide is not a cutting instruction, approved roof detail, structural calculation or certification.