Breakdown of A casa está a ser pintada.
ser
to be
a casa
the house
estar
to be (temporary / location)
pintar
to paint
Questions & Answers about A casa está a ser pintada.
Why do we have both está and ser right next to each other in this sentence?
This sentence combines two grammar structures. First, the European Portuguese continuous tense uses estar a followed by an infinitive to show an action is happening right now. Second, the passive voice uses the verb ser to show an action being done to a subject. Put them together, and you get está a ser (is currently being).
Why does the verb end in -a (pintada)?
In the passive voice, the past participle acts like an adjective. Because the subject receiving the action is A casa (a feminine, singular noun), the standard past participle pintado must change to pintada to agree with it perfectly.
Could I say A casa está sendo pintada instead?
You will hear that in Brazil, where the gerund (sendo) is commonly used for ongoing actions. However, in Portugal, the standard rule for ongoing actions is to use estar a followed by the infinitive, giving us está a ser.
Is this passive structure the most natural way to say this in Portugal?
While this sentence is completely correct, Portuguese speakers often prefer the active voice in everyday conversation. It is very common to hear Estão a pintar a casa (They are painting the house) instead, using a generic "they" when the specific painters do not matter.