How to paint cubby with mould coming through?

[Triodia]

Hi,

A couple months back we got a timber cubby built in the backyard. Construction was delayed until just before the Perth winter rains hit. 

Some patches of wood already had some signs of mould spores, like they'd been stored on mouldy ground. We scrubbed/sanded the whole thing and started painting whenever I had a few hours free on a non-rainy weekend.

Most of it now has one to two coats of oil-based primer. Mould is coming through some patches with one coat. And some of the unpainted bits also show signs of mould. 

I can't scrub with antifungals, dry and paint all within a week as there is not enough dry weather.  

Also the tops of some pieces will never be painted as the roof makes them impossible to reach.... likewise the base of the stilts at the bottom of the cubby. 

What is my best approach? Plough ahead with painting, or leave it till Spring when the weather dries?

[JacobZ]

Hi @Triodia,

Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

Unfortunately, simply painting over the mould is not going to be sufficient to prevent it returning. Covering it up with paint will likely create an environment that promotes mould growth.

It is likely that the timber used in the cubby house is untreated, so there is no fungicide present in the timber. If there was, the mould would not be able to grow in the timber so easily.

With this being said, you'll need to remove as much of the mould as possible with a cleaner such as Selleys 750ml Rapid Mould Killer Remover and allow the timber to dry before painting.

I'd suggest trying to keep the mould growth to a minimum to prevent any damage to the timber and in Spring when the weather gets better, give it a thorough clean to remove any visible mould and allow it to dry thoroughly before painting.

Let me know if you have any further questions.

Jacob