Sambucus nigra is just the plain green leaved European Elder, which makes a tree about 26 feet high, sometimes taller. I doubt that's what you mean so I'll assume you mean Sambucus nigra Black Lace - this also becomes tree like, though not so tall as the basic species, but is usually kept pruned to control its size/shape. If you kept it pruned to 8/10 feet, the roots are unlikely to be much of an issue, but it does depend on your definition of 'close to the house'.

Elder trees do not make deep or penetrating roots as they are best regarded as shrubs, especially if you keep them well pruned, which will be best for the foliage and flowers. I would say you have nothing to worry about.

Thank you.