Designing House Extensions - draft Supplementary Planning

Document (SPD) for consultation

Eleanor Parker, Development Management

Background to new SPD

• Officers consulted on areas which needed clarification based on their experiences

• Consultation letter sent to agents and community groups in Sept.2009 asking what they would like to see in new guidance document

• Developed draft and been waiting for the City Policies and Sites document, to consult alongside.

Reasoning for new SPD

• Necessary to formalise current ‘informal’ guidelines on developments such as Juliette balconies, extensions greater than 3metres and corner plots for consistency.

• To address issues which are a concern in design terms, such as the terracing effect.

• To promote good practice, and standardise our approach for matters such as where the 45 degree angle is taken from on ground floor window.

• To try and make householders ‘think’ a little bit more about the development they are creating and how it will look and work, rather than just the internal dimensions of the room.

• Tried to reflect areas of concern and the clarification requested at consultation stage. BUT, also needs to be a document that works for Architects, Designers, Builders, Neighbours, Planners and the ‘I’ll have a go at drawing the plans’ householder.

– Guidance needed for consistency, and to reflect the needs of all those who use the guidance; can’t help but be prescriptive at times!

– ‘Where appropriate’ gives flexibility to designers/architects as requested, for making a case for design if it is appropriate; but also gives the LPA ability to control the varying qualities of schemes that can be submitted.

Topics covered in new SPD

• Design Principles• Side Extensions and the

Terracing Effect*• Corner Plots• Front Extensions• Dormer Windows• Cellar Conversions*• Overshadowing and

Overdominance*• Privacy and Overlooking

• Gardens and Outdoor Space

• Bin Storage*• Green Belt• Trees• Garages and

Outbuildings• Parking and Highways• Safeguarding

Accessibility*

*Significant new areas of guidance

The Terracing EffectTwo-storey side extensions should be:

(a) subservient to the original dwelling house; and

(b) set back at least 0.5metres from the front elevation of the property and the ridgeline of the extension should be set below the ridge line of the main house.

• Extensions encouraged which are set away from the side boundary. But not required.

• Will be less restrictive to detached properties which are set well within their own grounds.

Cellar ConversionsCellar conversions to form additional living

accommodation should:

a) Provide a suitable and sufficient source of natural light, ventilation and outlook;

b) Not require the excavation of more than 35% of the front garden area.

c) Allow at least one metre between the window to the cellar room and any wall facing it;

d) Achieve a 30 degree line of sight. With no obstruction form the centre of proposed window. The cill height of the window should be no greater than 1 metre above floor level.

• The enclosure of a light well for safety should not restrict light into the room and be appropriate to the character of a property.

Overshadowing and Overdominance

Two Storey Rear Extensions:

• Should not breach an angle of more than 45 degrees, when measured vertically from the neighbour’s nearest main ground floor window.

• Angle to be taken from the centre of the window and at a height of 1.5 metres above finished floor level.

• Where a conservatory has been added to neighbouring property, line to be taken from estimated position of former rear window.

• Should not breach an angle of more than 45 degrees when measured horizontally on plan from the centre of the neighbour’s nearest main ground floor window.

Single Storey Rear Extensions (taking account of new PD)

• Temporary approach to take account of temporary PD where a Prior Approvals application is sought.

• Extensions greater than 3metres( semi detached) and 4metres( detached) will be permitted where it can be clearly demonstrated that the extension will not be unreasonably harmful to the amenities of the adjacent properties.

• In considering larger extensions will take account of factors such as:

- Orientation and siting of the extension in relation to neighbouring properties

- Level difference between the properties

-Height of extension

We will review this approach in May 2016 when the government review their permitted development criteria.

Bin Storage

• New developments should provide adequate bin storage where an extension would prevent access to existing bin storage locations.

• Where these stores are visible from a public highway they should be of a high quality and made from a durable material to complement the proposed development. Should also be integrated into the site.

Safeguarding AccessibilityWhere a property alreadyincorporate features to meet the needs of disabledpeople these should be:

• safeguarded for future generations of disabled and older people; and

• incorporated into the extension, so that the whole of the extended dwelling meets the same standard.

(If built to Mobility Housing or Lifetime Homes Standard)

• 6 week consultation period commencing around early July.

• Members of Agents Forum to be consulted along with all who regularly submit planning applications and community groups with interest in planning.

• Comments to be made using the online commenting facility.

• Aiming for adoption Autumn/Winter

Next Steps….