A 1926 bungalow on Grey Street in Hamilton East taught me the cost of doing an exterior repaint in the wrong order. In 2019 the owners had the weatherboards painted in November, a good job, three coats. In February they had the roof washed and painted. The wash brought forty years of chalk, lichen and rust off the long-run and down every wall, and the runoff left tide marks in three-month-old paint that no rinsing shifted. Two elevations had to be redone. I priced the rework at NZ$4,200, which was more than the roof wash had cost in the first place.
Roof first, always
Everything on a roof ends up on the walls. Water blasting at 15 to 20 MPa lifts chalk, moss and oxidised paint and sends it down the sheets, over the spouting in a heavy wash, and down the cladding. Rust from fixings and cut edges leaves orange streaks that stain fresh acrylic permanently. So the roof gets washed, treated, primed and top-coated before a brush goes near a weatherboard, and it gets a week to cure so the last of its dust has blown off.
The one exception is bare timber taking on water: those boards get primed first, the roof is done, and the wall topcoats follow, so the primer takes the staining and the topcoats never see it.
Then spouting, fascia and soffit
This band is where the two trades meet and where most sequencing arguments happen. My order is: roof coating finished and cured, then spouting removed if it is being replaced or thoroughly cleaned if it is staying, fascia and soffit sanded and painted, spouting refitted, and only then weatherboards. Painting a fascia with the spouting still on it leaves an unpainted strip behind the back of the spouting that rots first. On a 1920s bungalow with a 300 mm boxed eave, that strip is where I find the soft timber every time. New spouting goes on after the fascia paint has cured for 48 hours, not before.
Waikato weather sets the calendar
Hamilton’s problem is not rain so much as fog and dew. From May to September the Waikato basin sits under inversion fog until mid-morning on many days, and relative humidity stays above 85 per cent well past noon. Acrylic paint applied onto a damp board or a cold sheet does not coalesce properly; it dries with a chalky, weak film. Steel roofs are worst, because the sheet is colder than the air until the sun has been on it for two hours.
The workable window is October to April. Within it, roofs get coated between 10 am and 2 pm, when the sheet is above 10 degrees and there are still four hours of drying before the evening dew. Shaded south walls get the middle of the day too; north walls can go earlier and later. The painters who last in Hamilton schedule elevations around the sun, not around the van.
What sequencing does to the cost
For a 150 square metre single-storey bungalow with a 170 square metre long-run roof, the pieces price roughly like this in Hamilton: roof wash, treat, prime and two coats NZ$5,000 to NZ$7,500; spouting clean and fascia, soffit and barge paint NZ$2,000 to NZ$3,500; weatherboards prepared and painted with three coats NZ$11,000 to NZ$18,000. Done as one sequenced job, the roof and walls share the same edge protection and the same set-up days, which usually takes 10 to 15 per cent off the combined total. Done in the wrong order, add NZ$3,000 to NZ$5,000 for rework and a second round of edge protection. Weatherboard prices vary far more than roof prices because preparation on old rusticated boards ranges from a light sand to burning off six layers of enamel, so ask for that preparation to be described, not just priced.
One contractor or two
Roof coating and weatherboard painting are related but not the same trade, and plenty of good wall painters will not go on a roof. Where one outfit does both, the sequencing is their problem. Where it is two, the owner has to hold the order. If you are engaging a Hamilton house painter for the walls and someone else for the roof, get the roof date fixed first and have the wall painter start no sooner than a week after it.
Frequently asked questions
Should the roof or the weatherboards be painted first? The roof, always. Washing and coating a roof sends chalk, lichen and rust down the walls, and that runoff stains fresh paint permanently. Give the roof a week to cure before wall painting starts.
What time of year is best for exterior painting in Hamilton? October to April. Waikato winter fog keeps humidity above 85 per cent past midday and leaves roofs and boards damp, which stops acrylic paint curing properly.
How much does a full exterior repaint cost in Hamilton? For a single-storey bungalow, roughly NZ$5,000 to NZ$7,500 for the roof, NZ$2,000 to NZ$3,500 for fascia and soffit, and NZ$11,000 to NZ$18,000 for weatherboards, with a 10 to 15 per cent saving when sequenced as one job.