请教 mold 问题：(自住房)

建自住房, 发现wood framing中有十多根 mold 严重。工人 sand 处理了，工程继续进行。几天后， mold 又生长了。 请问应如何处理方能清除彻底？Online search found bleach actually doesn't work for wood. Should we request builder to hire mold cleaning company? In general, is it a serious problem if molded framing exists in a house?