Unfortunately there is little that can be done for flies already inside the attic and walls.
House fly infestation in attic.
Another thing that can really help with a house fly infestation is to do some serious cleaning indoors and outdoors around your property.
You should probably look at your windows screens and even in your attic so that you can find any area that isn t sealed tight.
Space sprays and fogs into the attic have little if any affect as the flies are usually under insulation or deep in cracks and crevices.
A house fly infestation can be annoying at best and dangerous at worst but with the correct sanitation prevention measures and right extermination methods the problem is easily fixable.
Therefore fly paper fly strips and bug zappers are of no value.
Rotting garbage and pet feces can attract flies and cause an infestation.
If you have a large infestation in your attic then you probably need a large solution.
If you suddenly see a swarm of flies that means dozens of eggs have already hatched and developed into flies.
The one highlighted above is made for fast flying insects.
Place traps around attic windows to catch flies.
If this is the case for you your best option to get a good sized bug zapper.
They do not fly around much in attics.
Solutions include disposing of the attractants and using repellents to keep the flies away in the first place.
They enter houses through cracks in the roof or in the walls cracks in door and window jambs and open doors and windows.
The most effective way to get rid of attic flies is to make sure that they stay outdoors.