Lap marks on a hip roof are one of the most frustrating results of a DIY paint job — and one of the most avoidable. They happen when a freshly painted edge dries before you overlap it with the next pass, leaving a visible ridge or darker band. With the right preparation, product selection, and a disciplined working method, you can achieve a smooth, professional finish on all four faces of a hip roof.
Understand Why Hip Roofs Are Trickier
Unlike a simple gable roof with two large flat faces, a hip roof has four sloping planes that meet at angled ridges and hips. This means you're constantly working up to and away from edges, and each face is relatively small — so you can be tempted to stop and start too often. Every stop-start is a potential lap mark. Planning your sequence before you pick up a brush or roller is essential.
Safety First
Before anything else, roof work carries serious fall risk. WorkSafe NZ requires that anyone working at height has appropriate fall protection in place. For a typical residential hip roof this means:
- Scaffolding around the perimeter (strongly recommended and often required for steeper pitches)
- Non-slip footwear rated for roof work
- A roof ladder or chicken ladder hooked over the ridge
- Never working alone — have someone on the ground
Do not attempt roof painting in wet, frosty, or windy conditions. Most roof paints have minimum application temperatures (typically 10°C and rising) — check your product's datasheet.
Preparation: The Step Most DIYers Skip
Lap marks are made worse by an uneven or porous surface. Proper prep is non-negotiable.
- Clean thoroughly — Pressure wash the entire roof to remove moss, lichen, dirt, and chalky old paint. Allow at least 24–48 hours to dry completely.
- Treat biological growth — Apply a moss and mould treatment and allow the dwell time specified on the label before rinsing.
- Repair before you coat — Fix any cracked or lifted iron, replace rusted screws, and seal around flashings with an appropriate sealant such as a product from Sika.
- Prime if needed — Bare metal, heavily weathered surfaces, or surfaces switching from oil-based to water-based coatings need a compatible primer. Check with your paint supplier — Resene and Dulux both offer roof-specific primer systems.
Choose the Right Paint and Tools
| Factor | What to look for |
|---|---|
| Product type | Water-based acrylic roof paint (longer open time, easier blending) |
| Sheen | Low-sheen or flat — high sheen amplifies lap marks |
| Applicator | Long-pile roller (18–20 mm nap) for corrugated iron; brush for edges |
| Quantity | Buy enough to complete each face in one continuous session |
Water-based acrylic roof paints from brands like Resene, Dulux, and Wattyl generally have a longer open time (the window before the paint skins over) than solvent-based products, giving you more time to blend edges before they dry.
The Key Technique: Work Wet-Edge to Wet-Edge
This is the golden rule for avoiding lap marks. Never let a painted edge dry before you overlap it.
Plan your sequence
- Work one complete face of the roof at a time, from ridge to eave.
- On each face, start at the end furthest from your exit point so you're always rolling back towards fresh paint.
- Work across the roof in strips parallel to the corrugations (up-and-down the slope), overlapping each strip by about 100–150 mm while the previous strip is still wet.
Rolling technique
- Load the roller generously but not dripping.
- Roll from the dry area back into the wet edge — this is called rolling into the wet and is the single most effective way to eliminate lap marks.
- Finish each strip with light, long strokes in one direction (up the slope) to lay off the paint evenly.
- Keep a pace that lets you complete each face before any edge has time to tack off. On a hot NZ summer day, work early morning when temperatures are cooler and the paint stays open longer.
Avoid stopping mid-face
- If you must take a break, finish to a natural break point such as a hip ridge or the full width of a face — never stop mid-panel.
- Keep a wet rag handy to wipe the roller frame and avoid drips on finished sections.
How Many Coats?
Most quality roof paints require two coats for full coverage and durability. Allow the first coat to dry fully (check the datasheet — typically 2–4 hours recoat time in good conditions) before applying the second. Apply the second coat in the same direction as the first. Two thin, even coats will always look better than one thick coat.
NZ Building Code Considerations
Painting an existing roof is generally maintenance work and does not require a building consent under Schedule 1 of the Building Act. However, if you're replacing roofing material or making structural changes at the same time, consent may be required. Always confirm with your local council. For guidance on the NZ Building Code, visit MBIE Building Performance.
When to Call a Professional
Roof painting is physically demanding and carries real fall risk. Consider hiring a qualified roof painter if:
- Your roof pitch is steep (generally above 25°)
- The roof is high off the ground or difficult to scaffold safely
- The surface has significant rust, damage, or complex flashing details
- You're unsure about product compatibility with your existing coating
A professional roof painter will have the right equipment, insurance, and experience to get the job done safely and without lap marks. You can find qualified local roof painters on tradedirectory.co.nz.
Master Painters NZ member
Licensed Building Practitioner (LBP)
Roofing Association of NZ (RANZ)
