Inadequate foundations are frequently an issue and can cause subsidence or movement of your conservatory.
Just because the structure of a conservatory is 'lightweight' it doesn’t mean a foundation should be shallow or isn’t needed at all.
Foundation movement and differential settlement between the conservatory and the existing house will cause cracks in the structure that can lead to water finding its way in.
Signs that you have a subsidence problem are:
- New cracks (especially diagonal ones) on the walls and floors or your conservatory (or existing ones getting bigger).
- The door and windows getting stuck or difficult to open.
- Leaning of the conservatory itself toward or away from your home.
- A slope in the floor of the conservatory.
If you're worried, have a qualified building surveyor or structural engineer look it over.