Re-plastering question

[danbo]

Our pool needs replastering. I've received a number of quotes for the job. One contractor says all existing plaster should be removed down to the gunite - and the other contractor say its better to only sandblast the existing plaster surface before replastering. Cost is about the same for both. Which is the better method? Thanks.

[Guest]

Same answer to your question to another buletin board.

[geeman]

A pool only needs to be sandblasted if it is currently painted. Sandblasting will not remove plaster. Waterblasting will remove plaster but is expensive, not necessary, and you didn't mention it so we won't get into it. Before replastering, the entire existing plaster surface should be cheked with a hammer for hollow sounding (loose) areas that can then be removed with a hammer. If the existing plaster is the original, you may find just a few hollow spots. If the existing plaster is already a replaster or if the pool was left empty for a long time, you may have a lot more hollow spots. So, NO not all of the plaster has to be removed (unless it is falling off the walls in sheets). The pool should be drained, chipped, remove hollows, cleaned and acid washed, apply a BONDCOAT, plastered and filled with water within 24 hours. Sandblasting as a means of roughing up the surface to be plastered is unacceptable. Be sure that any contractor is going to use a "bondcoat" material. Bondcoat is a thin cement and glue mixture that is applied rough and should sit for at least one day before plastering. It is what keeps the layers of plaster together.