Which notice type applies?
A loft conversion requires a Section 3 (Party Structure) notice whenever steel beams or joist hangers are inserted into a shared wall. This is true for almost every dormer, mansard, hip-to-gable and L-shaped loft on a terraced or semi-detached property. If the conversion involves raising the party wall (to accommodate a new ridge height) a Section 3 notice is also required for that work. Section 6 only applies if there is also excavation within 3 m of a neighbouring building — uncommon for lofts.
Common scenarios where this notice is needed
- Inserting steel ridge beams into the party wall.
- Inserting purlin beams supported by joist hangers in the party wall.
- Raising the party wall to gain head height in the loft.
- Cutting flashings or chasing for ducts into the party wall.
- Removing chimney breasts in the loft that form part of the party structure.
The notice period and what to expect
A Section 3 notice requires two months of notice before works begin. The clock runs from the date of service.
Once served, the adjoining owner has fourteen days to respond. If they consent, you can proceed once the notice period expires. If they dissent (or fail to respond), the Section 10 surveyor process begins and a Party Wall Award is produced before the relevant works can start.
Typical cost for this project type
The notice itself costs £48 inc VAT through our generator (less for multiple notices). Surveyor fees only apply if the adjoining owner dissents — typically £600–£1,200 for an Agreed Surveyor or £1,200–£3,000 for two-surveyor matters on a standard domestic project. For a full breakdown, see our cost guide.
How to generate the right notice
Our notice generator walks you through the relevant questions for your project type and produces a statutorily compliant notice ready to print and serve. The wizard recommends the right section automatically based on what you describe — there's no need to know which section applies before you start.
Frequently asked questions
Do I need a Party Wall notice for a Velux-only loft conversion?
Usually no. If the conversion does not insert any structural element into the shared wall and does not raise the wall, it is not notifiable. However, many 'Velux conversions' do still bed a small steel beam into the party wall to redistribute loads — check the structural drawings, not just the description.
What if my neighbour also wants to do a loft conversion?
If you both proceed, you each serve a notice on the other. It is common for adjacent owners doing similar works to agree to use the same Agreed Surveyor for efficiency.
How early should I serve the notice?
Two months before the planned start date is the minimum. We recommend serving as soon as you have your structural drawings, because a dissent leads to a four-to-eight week surveyor process before works can lawfully begin.