Will Brick acid damage a flat roof with felt and gravel?

[darkan9el]

Hi all, I have a wall that is above a flat roof extension, the flat roof is felted and gravelled, I have to remove some very poor mortaring from the brickwork, the mortar will eventually need removing as it is a different colour to the rest of the mortar but for now all I have to do is remove the mortar on the bricks to tidy it up bit.

Do I need to protect the felt or will the brick acid not react with the felt, I'll probably mask it up anyway but I just wanted to know what effect it may have etc.

 

[foxhole]

You have to protect roof or you will have all the cwap removed mixed with gravel.

 

[darkan9el]

I have some old dust sheets I don't mind binning so I'll cover up with those, its not a big job but nevertheless don't want corrosion of the felt nor the bitumen.