I have a terraced house, which already has a 6m back extension. Can I still build a glass conservatory under Permitted Development Rights (PD) ?

You cannot build the conservatory under PD, you will need to apply for this under a full planning application, it makes no difference what materials you use to build an extension, whether it’s a glass conservatory or brick, whether you use light materials or heavy it is considered an extension either way

If you did not already have arear extension then you could benefit from the use of the PD rights as follows:

A 3-meter conservatory is Permitted development even in a conservation area, and there is no need to apply for any planning permission, however a Certificate of Lawfulness (LDC) would be advised as written in a previous #askaplanner column for a few reasons:

1) For re-mortgage purposes

2) Just to make sure that the sizes and the extension does actually comply with the PD rights (basically to help you sleep better at night)

3) Because even if you built wrongly after a certificate of lawfulness, the council won’t make you take it down, as they will have to bear the cost of remedying the breach

A 6-meter conservatory will need a Prior Notification application, notifying the council that you intend to build, they will send out letters to your adjacent neighbours, and if there are no objections or response from the council for 42 days after submitting the application, you can just go and build it

Please note all of the above is for a terraced or semi-detached house, however for a detached house the sizes are 4m for Permitted Development (PD) and 8m for a Prior Notification application