Building regulations for two-storey extensions in the Isle of Wight
Our building regulations service covers the whole of the Isle of Wight. Choose your town below, or get in touch to talk your project through.
The Isle of Wight at a glance
- Nation
- England
- Price region
- South East England
- Postcode areas
- PO
- Towns covered
- 8 listed below, plus surrounding villages
- Site visits
- By arrangement, with travel costs agreed in writing first
What a building regulations application involves
Building regulations approval for a two-storey extension involves preparing technical drawings and a specification that show how the extension meets the rules on structure, fire safety, insulation, ventilation, electrics and drainage, getting them approved and having the work inspected. At the end you receive a completion certificate.
Across Isle of Wight we cover Newport (Isle of Wight) (PO30), Ryde (PO33), Cowes (PO31), Sandown (PO35), East Cowes (PO32) and Shanklin (PO37), plus the smaller places around them.
Fees
Technical drawings and specification are a guide of £1,500–£4,000. The council's building control fee depends on the value of the work; we confirm every fee in writing before the design stage starts.
Rules in England
In England, building regulations approval comes from council building control or a registered building control approver, using the Approved Documents. Full plans are recommended for two-storey work. New editions of Approved Documents L and F take effect generally from 24 March 2027 and are not yet in force, so current projects follow the 2021 standards.
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
The Party Wall etc. Act 1996 applies, so notices may be needed for work on or near a shared wall or boundary.
Getting the design right
Fire escape from the first floor
In England, first-floor habitable rooms need an escape window, with a clear opening of at least 0.33 m², at least 450 mm wide and high and its bottom no more than 1,100 mm above the floor, or a protected stair. Adding a storey above 4.5 m means a protected stairway or an alternative.
Insulation and U-values
In England, Part L sets limiting U-values for extensions: 0.18 W/m²K for walls, 0.15 for roofs, 0.18 for floors and 1.4 for windows. Glazing is normally limited to 25% of the new floor area plus windows removed, unless SAP or compensating calculations are used.
How we work in the Isle of Wight
Visit by arrangement
We agree a visit to your home in the Isle of Wight and any travel costs with you in writing first, then look at the structure, access and boundaries.
Get it approved
Once you're happy with the design we submit it to the council for the Isle of Wight and deal with any questions from the planning officer.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Towns we cover in the Isle of Wight
Building regulations for two-storey extensions in the Isle of Wight: questions
Do I need building regulations if I have planning permission?
Yes. Planning permission and building regulations are separate. Planning covers what the extension looks like and how it affects neighbours; building regulations cover how it is built and whether it is safe, warm and healthy. A two-storey extension needs both, unless permitted development replaces the planning part.
What is a build-over agreement?
A build-over agreement is permission from your water company to build over or near a public sewer. Many rear extensions sit near shared drains, and the water company will want access protected and the pipe checked. We check sewer records early so the agreement does not delay the start.
Are the new 2027 building regulations going to affect my extension?
New editions of Approved Documents L and F take effect generally from 24 March 2027 in England, and are not in force yet. Projects approved under the current rules follow the 2021 standards. If your build will start after that date, we check whether transitional arrangements apply.
Neighbouring areas
- Building regulations for two-storey extensions in Hampshire
- Building regulations for two-storey extensions in Dorset
- Building regulations for two-storey extensions in West Sussex
- Building regulations for two-storey extensions in Berkshire
All extension services in the Isle of Wight · About building regulations for two-storey extensions
Ready to see what a second storey could do for your home?
Visits here are by arrangement, with any travel costs agreed in writing first. We'll look at your house, talk through options and explain the approvals you'd need.