Reflected signal are weaker of signal strength and out of time with the main signal. Broadcast Tv digital tuners have circuits that reject weaker out of phase/time signals , however the tuner can be overwhelmed. With your situation , attics can sometimes help with reception. The roof material will reduce the signal strength of the main signal and the reflected signals. Reducing the signal strength of the reflected signals is important so the tuner not overwhelmed. I recommend try a Winegard HD7000R antenna in the attic aimed at about 305 degree magnetic compass as a starting aim point. Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html. Here are places to buy antennas and etc. ,
http://www.winegarddirect.com ,
http://www.solidsignal.com ,
http://www.amazon.com.