Boarshurst Lofts

Design Renovation  

Plans for Dormer Extensions and Windows

Design & Plans for Roof Dormers & Planning Rules

We provide an extensive planning service throughout mainland UK. We also provide a free loft assessment and competitive, fixed price quote for construction in the Greater Manchester region.

Boarshurst Building Plans

We actively design, plan and construct dormers to maximise space, meet householder requirements and complement the existing house style.

Given the complexity of working with existing buildings, UK building and planning regulations and the construction itself, we are proud to have hundreds of satisfied clients. This allows us to confidently say, we are one of the best loft conversion companies around.

How To Plan A Dormer?

All dormer lofts & windows need plans that show the what, where, how and from what of construction.

These detailed drawings are called either architectural, building or floor plans and they are used by local Building Control, inspectors and the construction team who follow the plans faithfully. All Boarshurst plans and construction meets current UK Building Regulations.

Our plans are structurally accurate and sufficiently detailed for competent tradesmen to follow.

Do I Need Planning Permission?

No, Permitted Development rules assume dormers will not need Planning Permission so long as they meet and don't exceed certain criteria.

Our experience enables to accurately assess a home and design a dormer to within these criteria.

Permitted Development

"A loft conversion for your house is considered to be permitted development, not requiring an application for planning permission, subject to the following limits and conditions:*

  • A volume allowance of 40 cubic metres additional roof space for terraced houses or 50 cubic metres additional roof space for detached and semi-detached houses. (i.e. 2-4 bedroom houses generally will be OK for dormers)
  • No extension beyond the plane of the existing roof slope of the principal elevation that fronts the highway (i.e. no dormer to face the street)
  • No extension to be higher than the highest part of the roof, (i.e. dormer does not increase the roof height)
  • Materials to be similar in appearance to the existing house. (i.e. in-keeping with house and street)
  • No verandas, balconies or raised platforms; and side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor (prevents over-looking and for safety)
  • Roof extensions not to be permitted development in designated areas. (i.e. excludes National Parks, A.N.O.B., Conservation Areas)
  • Roof extensions, apart from hip to gable ones, to be set back, as far as practicable, at least 20cm from the original eaves"

*Source: planningportal.gov.uk (opens new tab/window)

This planning change makes it simpler and quicker to add a significant amount of space to your home. Building Regulations Approval is still required - to ensure the extension is constructed properly - and a key measure is the minimum height rule.

Minimum Loft Height Rules

Minimum Loft Height
© Crown copyright

Building Regulations state that loft conversions need to meet minimum height rules for the access and entry point. These are: 1.8 metres at the edge of a stair with 1.9 metres at the centre line if the ceiling is sloping.

During our free loft assessment we accurately measure the loft to determine the existing and eventual internal height. Where margins are tight we are often able to design in solutions that gain the required height.

However, if Planning Permission is unavoidable, say to raise a roof ridgeline, we have an excellent record obtaining permissions.

Loft Survey

During our initial survey we measure and discuss the requirements and feasibility of various design options.

We then create a draft design and discuss to an agreed design before we submit for relevant approvals.

Hard and electronic copies of the Approved plans are then supplied.

NB. Additional fees and costs that are not covered include structural calculations (required for larger dormers) and Local Authority fees. See our table on plan costs.

Top Top Design Renovation


Dormer Loft Plans
from £650 +vat


UK Plans Only Service

Design and Build - Greater Manchester


A phone call

Free Consultation

Initial Design Scheme

Submissions to Local Authority

Plans Approved