We’ve just had an offer accepted on a chalet-style semi-detached home in Lemsford Village, Welwyn. We had hoped to make it our forever family home. the current footprint is a too small for our needs, but the has substantial land-plot I hoped to extend the rear ground and upstairs. However its on a Greenbelt which comes with huge restrictions
Property Details/Context
- Address:Lemsford Village, Welwyn, AL8 7TN
- Is within Green Belt (not within a Conservation Area)
- Retains Permitted Development Rights
- Currently Extending 65% of original dwelling volume
- Note There is no hard specific rule for Welwyn Council regrading Green belt, they follow guidance from national policy
- Planning History:
- 1976 – Alterations to dormers (unsure what this is, no drawings available)
- 1971 – Ground floor rear extension (no drawings)
- 1956 & 1980 – Garage (there is no garage, unsure if this refers to current side extension)
- Existing side/rear extension is already approx. 65% extended
Attached
- Sketch of proposed layout and photos
- Existing Plans and property details
There’s a lot of conflicting information on the web so I’d like to check whether
elements of my proposa;l fit within Permitted Development (PD) and whether my Planning proposal liklihood against GreenBelt restrictions?
Questions - Permitted Development
Ground floor rear extension (6m deep)
- As a semi-detached house, would this require 'Householder Planning' or fall under 'Prior Approval (Larger Home Extension)' and therefore not be subject to Green Belt volume limits?
- Can I extend 3.3m beyond the existing 2.7m extension (totalling 6m) across the ‘full width’ of the original dwelling?
- If neighbour refusal: The extension would sit behind an existing 3m-high parapet wall along the neighbour’s boundary causing minimal impact — would this reduce risk of neighbour objection and help my argument forward?
First floor side extension (1m)
- Would extending an existing dormer sideways by 1m (above original footprint) qualify as PD?
Questions - Planning Proposal
First floor rear extension (3m deep)
- Would this definitely require full planning or other planning type? Should it be submitted alongside PD applications or afterwards?
- Are the following good arguments/precedence/trade-in against Green Belt restrictions and what would you deem likelihood of success with Welwyn Council/ Green Belt
- Trade-in Volume: can request trade-in volume for
- demolishing existing ground rear extension (as we will rebuild under PD) (highlighted in yellow)
- Omit a potential ground side extension under PD (highlighted in blue)
- Omit existing ground side extension and claim the side PD later
- No New Footprint: I am Enclosing existing roof terrace (terrace in regular use 25+ years). No change in existing footprint - minimal impact to GreenBelt
- Minimal openness impact — terrace is already visually contained between existing walls. Enclosing it will have negligible effect on the perception of openness from public vantage points
- Privacy Improvement (VSC Very Special Circumstance): current terrace allows direct overlooking of attached neighbour’s garden. Enclosing it removes this issue, improving privacy for both households — a tangible planning benefit.
- Sustainability (VSC): Replacing an exposed terrace with insulated habitable space will improve the dwelling’s thermal efficiency and reduce energy loss, contributing to sustainability goals under the Local Plan and NPPF §152–158.
- Precedent: Multiple properties in Lemsford Green Belt have been extended with first-floor / two-storey rear additions (see attached table) demonstrating such development can be
- Character Preservation: use integrating materials and design with dwelling, avoiding undue prominence in the Green Belt as required by Policy RA3 and draft Policy SADM34
- Subordinate Design: subordinate to the host dwelling in height, scale, and form, preserving the visual dominance of the original house.