Conservatory subsiding

[Gordy_1]

My father's conservatory is approaching 3 years old now. It was built by a reputable company with a 10 YEAR guarantee. Since it was built it has begun to subside. The company has been monitoring the subsidence and adjusting the building plastics accordingly over the last 3 yrs but the subsidence is still continuing, to the point now where it is not possible to open the doors or windows. The builders have said that there is no more adjusting that they can do. The bungalow it was added to was built on 9ft deep concrete piles because of the type of soil in the area. The builders were aware of this but have now said the conservatory will need underpinning, but appear to me to be trying to wriggle out of this work, hinting to my father that he could claim on his house insurance (and having to pay 1K excess). They are using delaying tactics here.

What rights does my father have, does the company have an obligation to put things right properly? and does anyone have links to sites where I can find more information on these issues?

Thanks in advance, Gordy.