A/C bracket interferes with painting

Soliciting opinions only ...

I am installing brackets to help support a window air conditioner.

Is it desirable to have a gap between the bracket and the windowsill?

Advantages of a gap:
* Rain water won't wick between the bracket and the windowsill and persist and cause rot,
* Easier to repaint the underside of the windowsill when needed.

Disadvantages of a gap:
* Blocking and shimming (marked in red) the outer edge of the air conditioner is more obtrusive,

Unscrewing and removing the brackets has the disadvantage of wearing out the screw holes and possible stripping of the screws and failure of the bracket.

 

Is it desirable to have a gap between the bracket and the windowsill?
You don't have much of a choice. The brackets must go where they can properly support the AC. I would say it is too low in both your photos. You will probably have to notch the bracket to get around the window trim. Or, you can install blocks on top of the bracket to get the height you need.

 

The red boxes are blocks (shims) in his picture.

I would not like the look of a large shim at my home.
If I was worried about water getting between the mount and the windowsill.... I'd use a bit of caulk at the point where they touch.

 

Caulking, great idea, I wasn't thinking about that.

Thanks.