Yes, as a homeowner you can carry out a basic visual inspection of your roof framing — and it's a smart thing to do periodically. Accessing your roof space and looking for signs of sagging, rot, or structural damage doesn't require a licence, but it does require care. Knowing what to look for can help you catch problems early before they become costly repairs.
Safety First Before You Go Up There
Before you even open the manhole, take a moment to think about safety. Roof spaces can be dark, cramped, hot in summer, and full of hazards including:
- Fibreglass insulation — wear a long-sleeved shirt, gloves, safety glasses, and a P2 dust mask
- Electrical wiring — never touch or move any cables; if you see damaged or exposed wiring, contact a licensed electrician immediately (electrical work is restricted work under the Electricity Act and must be done by a registered electrician — check EWRB)
- Weak or missing ceiling battens — only ever step on the structural framing members (rafters and ceiling joists), never on the plasterboard ceiling below
- Low light — use a good head torch and take a second torch as backup
- Heat — on warm days, roof spaces can reach dangerous temperatures; inspect early in the morning
If your roof space is too confined to move around safely, or you have a low-pitched roof with limited access, don't push it — this is a job for a professional.
What You're Looking For
Once you're safely inside the roof space, here's what to inspect:
1. Sagging or Bowing Rafters and Purlins
Rafters are the sloping timbers that form the main roof structure. Purlins run horizontally across them. Sight along each rafter from one end — they should be straight. Any visible bow, sag, or curve could indicate overloading, undersized timber, or structural failure. Under NZS 3604, timber-framed buildings must meet specific span and load requirements, so any deviation from straight is worth investigating.
2. Signs of Water Damage and Rot
Look for:
- Dark staining or discolouration on timber — often a sign of past or ongoing leaks
- Soft, spongy, or crumbling timber — probe suspect areas gently with a screwdriver; healthy timber is firm
- Mould or fungal growth on framing or sarking
- Rust staining around nail or bolt connections
Water ingress is one of the most common causes of roof framing damage in New Zealand, particularly in older homes or those with ageing roof cladding.
3. Broken, Split, or Missing Timbers
Check for cracked, split, or completely broken rafters, ceiling joists, or struts. Also look for notching or drilling that may have been done by previous tradespeople — if these cuts are too large or in the wrong location, they can significantly weaken a structural member.
4. Ridge Board and Collar Ties
The ridge board runs along the peak of the roof. Check it's straight and well-supported. Collar ties (horizontal timbers connecting opposing rafters) should be present and intact — missing or cut collar ties are a red flag.
5. Connections and Fixings
Look at how timbers are joined. Check for:
- Loose or missing hurricane ties (metal framing connectors)
- Corroded or missing bolts and nails
- Connections that appear to have pulled apart or shifted
6. Insulation and Ventilation
While you're up there, check that insulation isn't blocking eave ventilation. Poor ventilation leads to moisture build-up, which accelerates timber decay. BRANZ has good guidance on roof space ventilation requirements.
Doing a Quick External Check Too
From the ground (or safely from a ladder at eave height — never walk on the roof unless you're trained and equipped), look at the roofline from several angles. A sagging ridgeline or uneven roof plane visible from outside is a strong indicator of structural movement that needs professional attention.
Keeping a Simple Record
Take photos of anything that looks unusual, note the location, and date your inspection. This is useful if you later engage a building inspector or need to make an insurance claim.
| What to Check | Healthy Sign | Warning Sign |
|---|---|---|
| Rafters | Straight, firm | Bowed, cracked, soft |
| Timber colour | Light/golden brown | Dark staining, black mould |
| Connections | Tight, no rust | Loose, corroded, pulled apart |
| Ridge board | Straight | Sagging or deflecting |
| Collar ties | Present and intact | Missing or cut |
When to Call a Professional
A DIY visual inspection is a great starting point, but it has real limits. Call a licensed building inspector or Licensed Building Practitioner (LBP) if you find:
- Any broken, rotted, or significantly bowed structural timbers
- Evidence of ongoing water ingress
- Anything you're unsure about
- A sagging roofline visible from outside
Structural repairs to roof framing may require a building consent depending on the scope of work — always check with your local council before starting any structural repairs. You can find more guidance at MBIE Building Performance. For repairs that involve restricted building work, you'll need a Licensed Building Practitioner.
A qualified local building inspector can give you a thorough, professional assessment and a written report. You can find experienced building inspectors and tradespeople in your area at tradedirectory.co.nz.
Licensed Building Practitioner (LBP)
BCITO Qualified
