HOW TO CLEAN OAMARU STONE:
To clean your house with Hypastat.
Get Prepared -
- Cover any plants against the house and in the vicinity of overspray.
- Use pre-taped masking film and roll of tape 25mm wide to mask up windows and other joinery
- Wear old overalls, and disposable dust mask. (Hypastat will bleach your clothes and burn your skin, so old clothes and a spray suit or a plastic rain coat is cheap and will protect your back from leakage if you use a back pack sprayer)
Mix -
- Make Hypastat solution at a rate of 5 Litres of Hypastat to 10 Litres of water, giving 15litres of solution. Make sure breathing mask is worn.
Spray & Rinse -
- Choose a section 2x blocks wide and spray from top to bottom, moving around the house, lightly but evenly covering all Oamaru stone surfaces, and give extra attention to any areas with mould visible.
- Leave for approx. 1hour. (the moss and mould should be changing colour, possibly to a light reddish orange shade).
- Rinse off with a low- pressure water blaster, taking care to use a wide fan nozzle and making sure the tip is well back from the face of the stone. Use a low pressure water blaster in the 2000-2800psi range, use a 45 degree tip, and keep nozzle at least 300mm away from stone (You are not water blasting the surface, just rinsing it).
- If there is still mould stain evident you can re-apply Hypastat with a 50/50 mix and leave overnight, then re-rinse, and maybe use a wire brush and lightly brush area down to remove any remaining traces of mould, and a paint scraper to dress window sills.
- Thoroughly rinse out the back pack sprayer, to remove any residue of Hypastat.
- Leave house for a couple of days to ensure that all block work has completely dried out before applying any masonry sealer.