What is a side extension?
A side extension builds into the space beside a semi-detached or detached house, often over a driveway or side passage. It can be single-storey, for a utility room, downstairs toilet or study, or two-storey to add a bedroom above.
How much does a side extension cost in Prestatyn?
In Prestatyn, a side extension typically costs £1,550–£2,450 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £43,500–£68,500. The guide for Prestatyn reflects typical costs in Wales, roughly 8% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £31,000–£49,000 |
| Typical project (28 m²) | £43,500–£68,500 |
| Larger project (39 m²) | £60,500–£95,500 |
| Rate per m² | £1,550–£2,450 |
The biggest cost drivers are:
- Steel work where the side wall is opened
- Single or two storeys
- Boundary walls and access for materials
- Roof design and tile matching
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a side extension in Prestatyn?
Here is how the rules work for a side extension in Wales. In Wales a single-storey side extension can be permitted development if it is no more than 4 metres high and the widest part of the house ends up no more than 50% wider than the original. Two-storey side extensions must be at least 10.5 metres from the side boundary and set back 1 metre from the front, so most need planning permission. In conservation areas single-storey side extensions are limited to 3 metres.
The Party Wall etc. Act 1996 applies in Wales, so notices must be served before work on a shared wall, on the boundary, or excavation close to a neighbour’s foundations.
We check this for your address before design work starts, so there are no surprises later.
What we handle
The work we manage on a side extension:
- Foundations and drainage alterations
- Walls, roof and windows to match the house
- Structural calculations
- Opening into the existing house
- Building control completion
- Electrics, heating and plastering
How long does it take?
Build time is typically 10 to 16 weeks on site depending on size and storeys. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Prestatyn
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
Our Prestatyn coverage includes postcode districts LL19, and we also work in nearby places such as Rhyl, Flint and Colwyn Bay.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about side extensions in Prestatyn
Do I need planning permission for a side extension in Prestatyn?
In Wales a single-storey side extension can be permitted development if it is no more than 4 metres high and the widest part of the house ends up no more than 50% wider than the original. Two-storey side extensions must be at least 10.5 metres from the side boundary and set back 1 metre from the front, so most need planning permission. In conservation areas single-storey side extensions are limited to 3 metres.
Will I lose my driveway?
A side extension often takes the side drive. We look at whether parking can be kept at the front and whether a dropped kerb is needed.
Who approves a side extension in Prestatyn?
Planning matters in Prestatyn go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How much does a side extension cost in Prestatyn?
In Prestatyn, a side extension typically costs £1,550–£2,450 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £43,500–£68,500. Your fixed price depends on the survey and drawings.
How close to the boundary can I build?
You can build up to the boundary, but the eaves height near it is limited under permitted development, and planning officers often want a gap at first floor. If you build on or near a shared boundary, party wall rules may apply.
Will a two-storey side extension look odd?
Not if it is designed well. Setting it back from the front and keeping the roof lower than the main ridge usually gives a natural look and is what most councils ask for.