Washing wall?

[PixiePromises]

Please can you settle an argument?

We're about to start on painting our new house.

OH says we should wash the walls first. I've never heard of this!

Do you wash yours or just crack on with the paint brush?

Always wash down with sugar soap.

Wash down with a diluted sugar soap solution first, then another wash with plain warm water.

I've only ever done it on a kitchen splashback area which will have oil etc. but it's definitely a thing with sugar soap.