Soft washing vs pressure washing-cleaning gable siding
I like soft washing because: 1) Control, 2) Will not destroy caulking/sealant, 3) Will not deform face of siding/brick, 

1) Controlling the direction of the nozzle is important so the spray does not go where it can leak into the house. Often high pressure sprays will “push” a water stream in cracks, around trim, etc. causing leaks inside the house. 

2) A high pressure spray can “blow out” the caulking and sealant around windows and doors. 

3) A high pressure spray can easily deform (gouge) the surface of the siding or brick. When we clean historic structures, it is especially important not to “over clean” the surface because it can get damaged easily. 

I use a siding cleaner. First, I pre-soak the siding and the spray the cleaner on the surface of the siding/brick. The instructions on the cleaner will tell you how long to let it sit before you clean it off by spraying it. 

The comment regarding not aiming the spray upwards is referring to the possibility of pushing water up under building paper and moisture barriers. This is especially important at corners, joints in siding or trim, where the building paper may not be lapped properly. 

Remember, brick needs a clear sealant installed over it just like siding needs to be painted. The sun and rain will wear the protective coating off over time, so it needs to be reapplied every 3-5 years.