What made you want to direct Sunshine Cleaning?
"At the core of the family was the story of two sisters who had the same experiences as children but then we make different choices and try and run our lives, so I was really interested in the dynamic between those characters, the subtext. There's a lot of stuff that goes on that's unspoken which is fun to play with."
Was it nice to do this as an antidote to Sylvia, which was quite a tragic story?
"Absolutely. I was also drawn to the fact that it had some humour in it and I really exploited that in terms of making things - obviously it had a humanistic side and an emotional side that I really enjoyed - the scenes like the mattress, and I added in things that would add to the film without detracting from the story."
Also you have the Little Miss Sunshine connections with the film. Did that add pressure when you took the film to Sundance?
"Well, I think people were really excited about Amy and Emily pairing together, and Alan Arkin of course and Clifton Collins Jr. It was such a great cast, I think people were really excited seeing what it was all about. I think if there's anticipation for a film, it's nice sometimes to come out left of field and just be quiet about things."
How much research did you do into crime scene clean-up?
"Quite a bit actually - not myself in particular! When we were in Albuquerque we found there were two real crime scene cleaning businesses there so we contacted the main one and a guy called Enrique came in and he was an amazing resource to us. We all sat around and asked him a lot of questions but also, in particular our production designer Joe Garrity spent quite a bit of time with him going through his files and then he was also a consultant on set to make sure things were realistic."
Are they usually a very small crew of people?
"I think so - I'm not sure how many employees he had. He had quite a few people - different teams working I think. So more than just two people, but they seemed really busy and it's a very professional thing. I was surprised - all the different techniques they use like, 'Do we need to cut this up to remove it?' They just put things back like they should be. I was also intrigued to hear things like how they have to be efficient, for example turning round hotel rooms, which I'd never really thought about but sounded kind of scary!"
Did you have the luxury of getting Amy and Emily together beforehand?
"Yeah, we had a week. We rehearsed with Alan Arkin and Jason [Spevack] as well, which was really important in terms of a young boy with a screen mother - there's a lot of intimacy there so you can't just assume it, you really have to build it through getting to know each other. I mean they loved each other and had a lot of fun. Alan was really fantastic with Jason."
Do you think Amy's character is a bit naïve? At high school she was a popular cheerleader. Did she think she was set for life?
"I think life certainly didn't turn out how she envisaged it. She's very much at a crossroads and struggling on all kinds of levels - she's not emotionally satisfied, her self-esteem's very low, she's struggling with her son - but I think she's got a very strong sense of what's right and what's wrong. She's almost quite black and white about some things and also, I don't know if it's naïve or not, but blind to the fact that her relationship's going nowhere. It's something that's comfortable for her but she's deceiving herself about it. Norah says that to her when she gets out of the car - Norah is the truthsayer in the family and even though she's the most random one she's the one who cuts through all the lies and says, 'This is what's happening, actually.'"
Norah is on equal footing when it could have been easy to place her as a pot-smoking sidekick. Was that always how you wanted the relationship to be?
"I think it also evolved through the way Emily took on board the part and made her character three dimensional - finding what drives her. I think the stoner thing would have been a bit boring. At her core she's essentially random, but finding that she had that honesty that no-one else in the family has because they're kidding themselves. She would say things and say them with some kind of conviction about the truth and how everyone else is deluding themselves. For me, focusing on that made her an interesting character and gave that randomness a dimension and a really strong heart."
How did the scene where Norah goes tressling come about? Emily has to go through a lot of emotions in it and it begins to tie together the ending.
"We did storyboard that sequence. It was really freezing - I think the lenses on the camera froze - and it was quite difficult to get her under the train so we had to build three different areas. There was a wide shot where we could have her climb up and another area which was a bit safer for when she was lying under the train. It was kind of tricky and low budget so we were working really fast. Emily - that shot when she's lying underneath and she starts laughing and then she starts crying - it's a beautiful performance and she went really deep. I could have held on that forever - it's amazing the kinds of transitions she did in it were wonderful."
Sunshine Cleaning opens in UK cinemas this Friday.