The first is The Cottage starring Reece Shearsmith (The League of Gentlemen, Psychoville) and Andy Serkis (y'know Gollum). The UK trailer's here.
The other is [REC], the original Spanish horror film that was adapted domestically as Quarantine. [REC] is superior (imho) and has spawned a sequel in Spain with more in the works. (I'm a Balaguero fan and suggest you track down Los sin nombre, Darkness, Fragile, and To Let as well.) (Mike)