Preserving the Timeless Elegance of Oamaru Stone
Spring signals renewal, and your Oamaru Stone deserves the same gentle refresh. This remarkable natural stone responds beautifully to a little seasonal care, especially once the drier weather settles in.
From the ornate Victorian facades of historic Oamaru buildings to striking contemporary homes, Oamaru Stone carries a character all its own. Its warm honey hues and the sculptural qualities of limestone make it both distinctive and enduring.
Like any premium material, however, it benefits from thoughtful maintenance. With the right approach, your stonework will continue to look refined and stand strong for generations.
Preparing and Waterproofing New Oamaru Stone
Once construction is complete and the site is tidy, the final step is protecting the exposed stone with a high-quality water-repellent sealer.
We recommend premium New Zealand–made products such as Aquellux S or RTS No.4. These advanced siloxane and polysiloxane treatments make porous materials water-repellent without altering the stone’s natural appearance.
Before Sealing
If you notice any discolouration, address it promptly. Organic growth should be treated early, even if full sealing must wait until summer.
- Initial clean
Wash all stone surfaces to remove construction residue. A soft-bristle brush and clean water are usually sufficient. - Treat moss or mould
Apply a moss and mould treatment (such as Hypostat and Moss Kill mixed 50:1). Spray generously and leave for 24–48 hours before rinsing with a hose. Repeat if needed.
Because sealing locks in the stone’s appearance, so ensure you are happy with how the surface looks before proceeding. The stone must be thoroughly dry, which is why winter sealing is not advised.
Applying the Sealer
In settled, dry conditions, apply the water-repellent sealer at a rate of approximately 1 litre per 1-1.5 m². Professional application is recommended, but guidance is available if you wish to do it yourself.
Properly treated, Oamaru Stone can remain water-resistant for up to 10 years.
Resealing and Maintaining Existing Oamaru Stone
If your building is several years old, begin by checking whether resealing is needed.
Simple Water Test
Lightly spray water onto the stone:
- If droplets bead on the surface, the seal is still effective.
- If the stone darkens and absorbs the water, the protective layer has worn away and resealing is needed.
Visible moss, mould, or lichen is another clear sign that treatment should not be delayed.
Cleaning Before Resealing
Use a moss and mould treatment (50:1 mix) and apply generously so the surface is fully wet. Leave it to work for 24-48 hours, then rinse. Stubborn areas may need gentle agitation with a firm nylon brush. Heavier build-up may require more intensive brushing, and professional help is strongly advised to avoid damaging the stone.
Important: Never use a pressure washer or water blaster on Oamaru Stone. High pressure can loosen pointing and permanently harm the surface.
This is also the ideal time to carry out minor repairs, such as fixing loose pointing.
Resealing
Once the stone is completely dry and the finish looks even and clean, apply Aquellux S or RTS No.4 as described earlier. Because Oamaru Stone is more porous than concrete, it requires a slightly heavier application of sealer.
Enduring Beauty, Minimal Effort
Oamaru Stone asks for only modest care, yet rewards it with lasting elegance and strength. When maintained correctly, it continues to offer warmth, texture, and architectural presence for decades, even centuries.
If you are considering Oamaru Stone for an upcoming project, professional advice and product support are always worth seeking to ensure the best long-term results.