hello, i'm a newbie here but wanted to ask some of the more knowledgeable folks a few questions about waterproofing.

i bought a modern/new construction home a couple of years ago in chicago. the front and back of the home are steel and windows. the sides are mostly CMU/masonry. the masonry was painted with some grey paint which i thought was waterproof however this past summer i've had rain come through the flashing above one of the windows in the living room. this windows is a narrow window that is in the cmu/masonry. my contractor tore out the drywall above the window and noted that the flashing was incorrectly installed. he did a water yest on the masonry wall and also suggested that we re-seal or seal for the first time, given that we don't know what the gray paint is on the outside.

i was wondering if anyone had any thoughts on re-sealing over an a presumably sealed paint and if any other options there are to waterproof the masonry by adding a cladding system and/or fiber cement.

do the rainscreen cladding systems work over masonry?
will fiber cement boards without the rainscreeen cladding system over masonry make it waterproof?

is the cheapest way to just re-seal?

thanks so much for your input.

i hope my questions made sense.

chicagowinters