We brought our dormer bungalow 3 years ago and discoved that it was built in the 1960s on a small gravel works and did suffer from some subsidence approximatley 10 years ago (a brick built garage next to the house began to crack and was demolished, and the corner of the house has been rebuilt at is sufferd cracking). We currently have plans to extend on to the side of the house (2 storey extension on to where there was once a garage). I am concerned that whilst we have not had any movement since we have been in the house, what the impact of extending the house would be, given that the extension is likely to be built on much deeper foundations than the existing house/dormer bungalow. I would be grateful of any thoughts on whether we should go for it, or are there any considerations that the builder could impliment in the extension to reduce any further movement? Best regards Andy