Pebble dashing falling off

Hi there, just need an opinion. My garage was pebble dashed about 15 months ago. I will hopefully attach pictures but it is coming off in large patches, the builder has said the frost must have got behind it but he currently doesn't seem to be accepting responsibility. The stuff coming off it very crumbly. Surely the dashing is to protect against the weather. Am I right to expect this to be rectified? It surely should have lasted for years!

 

Is the background structure unstable?

 

Was it done in hot sunny weather?

Are all sides the same?

 

Can you remember what the weather was like when he did it? I e- was it freezing cold etc. The ratio looks very suspect. To much sand

 

Thanks for the replies, is the background structure the stuff you can see underneath? That seems to be staying on ok.
Yes it is happening on all sides.
I can't remember what the weather was like, I'd have hoped that if the weather wasn't right they would have left it for another day. The stuff that has come off definitely seems very sandy

 

It looks like he's use building sand and not plastering sand.

 

Thanks guys, now I just need to persuade him to come and put it right!