Commercial Roof Inspection Checklist Christchurch

Why Roof Inspections Matter

A commercial roof in Christchurch protects your building, tenants, and stock every day. But it's under constant attack from sun, rain, wind, and temperature swings. Regular inspections help you catch issues early before leaks spread or costly damage occurs.

Summary

• Inspect your commercial roof at least once a year and after major storms

• Internal gutters are the most common leak source in Christchurch

• Check fixings, laps, penetrations, and membrane edges for movement or cracking

• Look for ponding, rust, shrinkage, or blocked outlets

• Early detection prevents business disruption and extends roof life

What to Check on Metal Commercial Roofs

Metal roofs are durable, but Christchurch conditions push them hard. Check for:

• Loose or missing fixings – a common sign of wind stress

• Rust on sheets, laps, or flashings – especially where paint has failed

• Lifted sheet laps – high wind pressure can loosen overlaps

• Peeling or chalky paint – UV damage exposes the metal

• Ponding water – common near HVAC units or low-slope areas

Pro tip: Take reference photos from the same corners each year to spot changes.

What to Check on Membrane Commercial Roofs

Inspect for:

• Shrinkage or cracks along edges or upstands

• Blisters or soft patches – signs of trapped moisture

• Lifted seams or joins – especially near penetrations

• Failed patch jobs or incompatible coatings

• Wear in high traffic paths used by maintenance crews

Touch test: If it feels spongey, moisture is likely below.

Internal Gutter Inspection Checklist

These are leak-prone zones in commercial roofs. Look for:

• Blocked outlets or downpipes

• Standing water – test with a ball to check if the fall is correct

• Cracked or shrinking membranes like Butynol

• Rusting in steel gutters

• Lifting or bubbling old repairs

Liquid membrane relining (e.g., WaiSeal) is often the most effective fix.

Penetrations and Plant Platform Inspection

Check around all roof penetrations:

• Vents, flues, and pipes – look for sealant cracks or movement

• Skylights – ensure edges are intact and sealed

• Mechanical platforms – verify watertight seals beneath

• Cable or pipe movement – can open gaps over time

Snap close-up photos for your records leaks often start here.

Perimeter Edge and Parapet Inspection

Water often finds its way in at the edges. Check:

• Gaps at parapet joins or corners

• Loose or rusting flashings

• Cracked membrane upstands

Rain and wind often concentrate here vulnerable zones during storms.

Interior Inspection – Signs of Trouble

Don’t forget the inside:

• Ceiling stains or bubbling paint

• Mould growth on upper walls

• Watermarks near internal gutters

• Damp smells or discoloured ceiling tiles

Interior signs usually mean the leak has been active for a while.

How Often to Inspect

• At least once a year

• Before and after winter

• After major storms or wind events

• More often if your building has internal gutters, trees nearby, or flat areas

FAQs

How often should a commercial roof be inspected?

Once a year, minimum. Twice yearly is better. After major storms is essential.

What’s the most common leak source in Christchurch?

Internal gutters due to poor falls, old membranes, or blocked outlets.

Can I do my own inspection?

Basic visual checks are fine. But for safety and full condition reports, call a pro.

What happens if I ignore roof issues?

Small issues grow into major leaks, interior damage, and costly repairs or reroofing.

Next Step

Regular inspections are one of the simplest ways to protect your building, tenants, and stock. If you want expert eyes on your roof especially internal gutters or aging membranes book a professional roof inspection.

🔗 Book your commercial roof inspection: https://www.roofmasterschristchurch.co.nz/contact