Im kinda new at this cake stuff, im doing a tombstone cake, and i want the frosting to have a cement look to it. Any suggestions?

Hi. Today I made a haunted castle and I was kinda going for the cement look as well. I colored my buttercream grey. I then frosted the cake and did not do any special smoothing. I then took some black wilton icing spray and gave it a kind of airbrushed look. I think it would have turned out better with an actual airbrush machine...but it did not turn out bad. The other option would be to use a patterned paper towel to give you some texture.
traci

A clean, broken piece of sponge or a sea sponge might do it too and I think it might work better if you're using crusting bc.

do they make a grey colored dye? The black tends to look a little too purple when using only a little bit.

I would sponge paint it and then use some a paintbrush with black and make little cracks.