Help, what's this film?

[wheresdonnie?]

I remember seeing a film on TV ages ago, about a woman moving into an apartment/house, which has a stained glass window with a symbol that's like the freemason symbol (eye in a pyramid). There's a love triangle between the woman, a nice guy, and a creepy builder. During the finale they find out the creepy builder is living in the walls, and there's some sort of shutter that kills him at the end.
Can anyone tell me the name of this film, and if it in fact exists?