outside render crumbling

[divingmoose]

Hi,
The outside of the house was rendered by the builder before I bought it some 5yrs ago. Large sections of the wall is crumbling the paint has flaked off and now the render is like dust, you can rub it and it crumbles away. This is in varies spots around the lower lever of the wall. The render does not go right down to the floor it has a 6 inch gap from the floor level to were the render starts. Someone has said that the builder has probably not sealed the render correctly and that's why this is happening. Any ideas? Also would I have to chop back up the wall until I reach good render and re do it or will this not work. Its a big area of render and not sure what to do really.
Thanks

 

[ree]

Pics would really help - pic the elevation(s) and some detail, esp. at the foot of the wall(s).

Usually, its best to hack off to the masonry and re-render.

When you say floor, i guess that you mean ground level?

 

[ree]

Perhaps transfer this post to the plastering & rendering forum?

 

[divingmoose]

Yes mate to ground level, it is just really like powder and crumbles to the touch.