Hertfordshire
Roof lanterns and rooflights for rear extensions in Hertfordshire
Lanterns, flat rooflights and walk-on glass that bring light deep into the plan. We design and build rear extensions across Hertfordshire, from Watford and Hemel Hempstead to Stevenage, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.

Rear extensions in Hertfordshire gain most from a rooflight placed against the old back wall, where the room would otherwise be darkest. Hertfordshire mixes Victorian terraces with 1930s semis, so both side returns and full-width kitchen extensions suit houses here.
What does it cost in Hertfordshire?
As a guide, £2,200–£4,500 including VAT. These are guide ranges; the written quote after the survey is the figure that counts.
What approvals does it need in Hertfordshire?
New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.
Where in Hertfordshire do we work?
- Watford
- Hemel Hempstead
- Stevenage
- St Albans
- Welwyn Garden City
- Cheshunt
- Hatfield
- Bishops Stortford
- Borehamwood
- Hitchin
- Hoddesdon
- Letchworth Garden City
- North Watford
- Harpenden
- Bushey
- Hertford
- Rickmansworth
- Potters Bar
- Berkhamsted
- Ware
- Enfield Lock
- Royston
- Croxley Green
- Broxbourne
- West Watford
- Batchworth
- Tring
- Chorleywood
- Codicote
- Baldock
- Abbots Langley
- Waltham Cross
FAQ
Questions people ask
Lantern or flat rooflight?
A lantern gives height and a feature; a flat rooflight is cleaner and lower-profile.
Do rooflights count towards the 25% glazing limit?
Yes, in England's simple route; more is possible with a calculation.
Can a rooflight open?
Yes, manually or electrically, with rain sensors.
Do you cover all of Hertfordshire?
We cover 32 towns and districts in Hertfordshire, including Watford, Hemel Hempstead and Stevenage.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.