Planning permission

[Extensionrebellion]

We are in the middle of some building work. It involves improving the insulation of the flat roof over our breakfast room and a small single storey extension out the back. The side wall is along the boundary with our neighbours and we have shared the plans with them and they are happy. We didn't think we needed planning permission as we thought we were within permitted development. The rest of the house is 2 storey.

However the builder wants to put on a warm roof rather than a cold roof which raises the level a small amount. Due to us having a roof lantern added we are now worried that we will be over the 3m height limit. We are not sure whether we need to apply for retrospective permission. The planning regulations don't seem very clear and when we phoned for the 15 minute consultation the planning department didn't seem sure either. Has anyone else been in this situation please?

Ignoring for the moment that you have an existing extension, would the remodelled extension you’re going to end up with meet the requirements of PD or not? What will be the new height?

What did the planning department actually advise you to do?

Do you have any neighbours who would be likely to object to your works?

Thank you for responding. I don't think any neighbours will object.

The planning department were really unclear and said it would probably be OK. But since then it is going to be a little taller.

The flat roof will have a small incline for water drainage but height with the roof lantern isn't completely clear.We think it might be higher than 3m in the centre but not at the edges. As there is a garage with the same roof in front the roof lantern won't be obvious from the front of the house.

We have been told that there was not previously an extension but that it was the original design of the house.

Honestly, I’m that situation I would just go ahead and not apply for any planning permission. The worst that could happen is that you would be made to apply after the fact. But the only reason that would be likely to happen is if a neighbour complained.

*in that situation

I'm not sure if this is relevant. However if you live in England or Wales you may need to take notice of the info in the below link:
www.fmb.org.uk/find-a-builder/ultimate-guides-to-home-renovation/party-wall-agreements-what-you-need-to-know.html#what

Permitted development is 3m high at the eaves (the edge of the roof) but can be higher elsewhere. Read the technical guidance document on the planning portal.

If you’re simply modifying the roof of an existing building and not changing the footprint I don’t think anyone will care. If you spoke to the planning department and they didn’t tell you an application was required I think you can go ahead.

So the lantern is in the original roof not the extension?
If this is the case it is allowed to project upto 15 cm beyond the original roof without planning permission. Anymore and PP is required.

Thank you for your help. We have read the technical guidance but find it quite difficult to understand. We are increasing our footprint, but only by a small amount so this is definitely within permitted development. The height at the eves is changing very little but will be a little higher due to the insulation, but as it is on our boundary with our neighbours, I think it needs to be under 3m.

The roof lantern is the issue as it is in the part of the roof that was existing (although within the room that is being extended) so we may need to put in a flat roof light rather than a lantern to avoid having to apply for planning permission. This is a shame, but I'm not sure we want to go through the planning process due to the cost, getting further elevation drawings done and the wait. Thank you all again for your thoughts.