Replacing small dormer with large dormer- Loft Conversion

[pgmaverick]

Hi,

I'm looking to replace the existing smaller dormer on the loft with larger dormer with full width of the roof. The loft is already converted from hip to gable.
Will this building work covered under permitted development or planning permission? Will the cost be fairly less than full fledged loft conversion?
I'm London borough of Harrow.

 

[noseall]

Will the cost be fairly less than full fledged loft conversion?
I'm London borough of Harrow.

If you have a Reg's compliant staircase up to the loft, the loft floor has been strengthened to suit and your escape route and electrics/plumbing and fire safety are compliant - then yes, it will be less expensive.

 

[pgmaverick]

If you have a Reg's compliant staircase up to the loft, the loft floor has been strengthened to suit and your escape route and electrics/plumbing and fire safety are compliant - then yes, it will be less expensive.

Thank you.
Any idea if it falls under PD or planning permission?

 

[freddiemercurystwin]

You can do a full width dormer on a hip to gable under PD provided the total additional volume for the additional roof volume ie the hip to gable + the dormer is less than 50m3 for detached and semi detached or 40m3 for terraced. It will need Building Regs, it's likely you'll likely need a structural ridge beam (steel probably) which will need to span between the gable ends.