How to paint a cement wall thats peeling?

[remagenman]

Buddy asked me about painting a cement wall, exposed to elements and never painted before. It's basically the bare cement that was poured as a retaining wall, about 10 feet tall x 20 feet wide. It has a cracking surface but not in the cement, like a surface peel crack. I don't know exactly what surface material was used.

Anyhow, contractor wants to charge him $1500 to paint it, half to sandblast surface and half to paint.

Is this a good price or can he just power wash, scrape the surface and primer/paint it?

Thanks.

 

[Adaylate]

Is it sealed on the backside?

 

[remagenman]

Is it sealed on the backside?

The backside is the 2nd floor of the house, so its filled in to the top. So living room area, outside sidewalk then it drops down to the basement area. Thats the wall.