An unusual week of sunny June weather here along the central coast is helping us prep the green house for its biennial anointing with oil.
Mildew streaks and stains and dried out chalky areas are restored using a 2 part washing process involving caustic soda (sodium hydroxide), oxalic acid and plenty of water. After drying, everything is sanded to 220 grit. Once the oil stops soaking in, it will be rubbed down to a smooth matte finish.
As we make our way around the building, many areas of interior woodwork will need to be prepped at the same time as the exterior because the washing process can leave its own streaks if the process drips on adjacent wood surfaces without the process being carried through to final rinsing. It is not possible to avoid many leaks of washing solution and rinse water to the interior, so when interior woodwork becomes involved, the scope of our work must include it.
This level of prep is not necessary every time we re-oil, but we're due for it now, and the results I think are going to be outstanding.