A roof penetration is an opening through the roof assembly for a component such as a ventilation duct or pipe. Its interface with the covering requires a suitable waterproof junction.
What does this mean on your roof?
A penetration interrupts otherwise continuous roof layers. Consequently, insulation and vapour control may be involved as well as the outer covering.
When reporting a concern, identify the component’s purpose and location without dismantling it to inspect inside. Photographs should show its relationship with the surrounding roof rather than only the pipe itself.
New equipment may require new penetrations or reuse existing ones. Agree who creates the opening, who completes the roofing junction and who checks the result. Installers and roofers may handle different components. Clear responsibility prevents the waterproof interface from falling between separate commissions and leaves a usable record of the agreed arrangement.
Frequently asked questions
Is every ventilation pipe a rainwater outlet?
No. Establish the component’s purpose; different pipes and ducts perform different functions.
Who completes the waterproof junction?
Agree this explicitly between the client and relevant contractors before equipment is installed.