How do we insulate an old cavity wall to convert our garage?

I want to submit a plan to the local authority for a permitted development (PD) extension. Do I need to include a proposal for all future PD developments which we may wish to add later – for example, a pool area - or can we apply for that later? For clarity, my reason for submitting a PD proposal to the planning department is purely for the benefit of a certificate of lawfulness.

It is always wise to get a certificate of lawfulness from the council in order to confirm your proposals are indeed permitted under PD. However, bear in mind that a certificate of lawfulness refers to the status of the project at the time it was issued.

For instance, if you plan to add a pool area in five years’ time, there’s no guarantee it would still be PD when you come round to building it. One way around this is to include the pool plans in the certificate of lawfulness application and then, once granted, start the works in a small but material way.

PD is, in legal terms, a blanket planning permission. So, if you start your scheme now, that keeps the consent alive indefinitely, just as it would for standard planning permission.