Permitted development rights - extension and review: sustainability appraisal update

Update to the 2019 Sustainability Appraisal on the Programme for Extending Permitted Development Rights in Scotland is concerned with the proposals for phase 1 of the work programme. This document sets out the findings of the further, iterative appraisal of these emerging proposals.

6 Updated Appraisal findings

6.1 Agricultural & Forestry development

6.1.1 The following sections concern new or updated appraisal findings in relation to draft Phase 1 proposals for farm sheds, polytunnels, farm steading conversions, and forestry buildings in turn. 

Farm sheds

6.1.2 Farm sheds can be used for a variety of purposes including grain storage and drying, crop, fodder and equipment storage. They may also house livestock including poultry, pigs, cattle and sheep. Sheds are therefore associated with every farm type and all types of land capability for agriculture. It is assumed that larger farm sheds are most likely to be associated with areas of more productive land. There are already existing PDRs[6] for the erection, extension or alteration of buildings used for the purposes of agriculture. 

2019 SA findings

6.1.3 Section 7.3 of the 2019 SA Report sets out the assessment findings in full, including the likely positive and negative effects arising.  These include (but are not limited to) minor long term negative impacts including on biodiversity, greenhouse gas emissions and water quality where farm sheds are used to house livestock.

Comments received on the SA report

6.1.4 Some public and third sector respondents commented that where PDR leads to an intensification in livestock production this has potential to lead to impacts on environmental receptors as a result of ammonia emissions (both through leaching and air deposition) with potential for associated impacts on air quality.

Updated Appraisal findings

6.1.5 Where sheds are used to house livestock, the SA identified the possibility of negative effects on biodiversity, greenhouse gas emissions and water quality. The 2019 SA identified neutral effects for air quality, however, in light of the comments received, it is acknowledged that ammonia emissions resulting from manure and slurries have the potential to also give rise to negative impacts on air quality. This is because ammonia is converted by mixing with nitrogen oxides and sulphur dioxide, producing ammonium compounds that turn into fine particulate matter. This PM is transported large distances and adds to the suspended background levels of particulates in the atmosphere.


6.1.6 This Update to the SA supports the draft Phase 1 proposal to retain the existing prior notification/approval process that applies to the erection of an agricultural building under PDR (or significant alteration or significant extension of an existing one). 

6.1.7 Further, the updated SA findings support the draft phase 1 proposal to retain the existing restrictions which provide that agricultural buildings erected under PDR may not be within 400m of a protected building where they are to be used to house certain livestock or for the storage of slurry or sewage.


6.1.8 Polytunnels come in a wide variety of shapes, but are typically semi-circular, square or elongated in shape. The structure of the polytunnel is designed to create a micro-climate that provides higher temperatures and humidity by trapping incoming solar radiation, heating up the interior of the building faster than the heat can escape the structure. As such, polytunnels can extend the growing season of various fruit and vegetable plants. The planning status of polytunnels varies considerably. In some cases, the erection or provision of polytunnels may not involve 'development' (for the purposes of the Planning Acts). In other cases, polytunnel schemes may constitute development but be covered by existing PDRs: in particular PDR in relation to agricultural buildings (including farm sheds). Alternatively, larger polytunnel schemes may require a 'full' application for planning permission. To the extent that polytunnels constitute agricultural buildings the proposed amendments to PDR for farm sheds (see above) would allow some larger schemes under PDRs

2019 SA findings

6.1.9 Section 7.4 of the 2019 SA Report sets out the assessment findings in full, including the likely positive and negative effects arising.  These include (but are not limited to):

  • Potential significant impacts in terms of flood risk. Flood risk is recognised as greater if PDR include flood risk areas, however the overall effect is significant for both options;
  • Minor negative but reversible effects on cultural heritage, population and human health;
  • Minor negative impacts in terms of health and quality of life, and flood risk, although these are noted as reversible due to the temporary nature of polytunnels;

Comments received on the SA report

6.1.10 Some public and third sector respondents considered that the impact of polytunnels could be more significant and less temporary than is suggested in the SA

Updated Appraisal findings 

6.1.11 It is acknowledged that there can be considerable variation in the size, extent, scale, movability and permanence of structures or buildings covered by the term 'polytunnel'. Some polytunnels may be small-scale, temporary structures comprising metal hoops that are screwed into the ground and may only be covered with material for part of the year. These are relatively simple to construct, disassemble and move. However, polytunnels can also be substantial, permanent buildings covering multiple hectares of land; they may for example feature concrete footings, foundations and built-in drainage channels.  Further, it is recognised that in some instances polytunnels may be erected repeatedly in the same or adjacent locations.  In light of the above, it is acknowledged that polytunnels can lead to effects which may be more permanent than temporary in nature including for cultural and historic heritage. 


6.1.12 The Phase 1 proposals set out that the Scottish Government is not currently minded to create a specific PDR for polytunnels. To the extent that polytunnels constitute agricultural buildings, the proposed amendments to PDR for farm sheds would allow some larger polytunnel schemes under PDRs. The 2019 SA findings in relation to Farm Sheds, as updated, are relevant in this respect. 

6.1.13 This Update to the SA supports the draft Phase 1 proposal to prepare new guidance clarifying those PDRs under which polytunnels may be erected or provided, and how polytunnels should be treated where a planning application (or prior approval) is required.

Farm steading conversions

6.1.14 Farm steadings are commonly defined as the outbuildings and/or service buildings of a farm. They either form part of a formal architectural composition or a more informal group of farm buildings linked through function. The 2019 SA considered options for the change of use of existing agricultural buildings to dwellinghouses or flexible commercial use. 

2019 SA findings

6.1.15 Section 7.5 of the 2019 SA Report sets out the assessment findings in full, including the likely positive and negative social, environmental and economic effects relating to farm steading conversions. These include (but are not limited to):

  • Permanent minor negative effects in terms of biodiversity, flood risk, greenhouse gas emissions, and cultural heritage;
  • Minor positive effects in terms of soil through re-use of existing buildings;
  • Mixed minor long term effects in terms of landscape, sustainable economic growth and the rural economy

Comments received on the SA report

6.1.16 Some respondents expressed concern regarding the SA findings generally in relation to flood risk. In particular, respondents commented that where farm steading conversions lead to an increase in people living in areas of flood risk, impacts for flooding could be considered significant.

Updated Appraisal findings 

6.1.17 In relation to farm steading conversions, the 2019 SA identified minor negative effects related to flooding. In light of comments received, we consider there is potential for significant negative effects for flooding where PDR leads to an increase in the number of people living within areas of flood risk.


6.1.18 To address the above, this Update to the SA supports the draft Phase 1 proposal that the relevant PDRs would be subject to a prior notification/prior approval process in respect of flood risk.Conversion of forestry buildings

6.1.19 Scotland's forests and woodlands cover more than 1.4 million hectares and consist of different woodland types and tree species. Diverse and versatile forests and woodlands are located across Scotland and serve both Scotland's rural and urban communities. When managed appropriately they can provide considerable economic and environmental benefits, as well as helping to improve people's quality of life.  

What are the new proposals for Forestry buildings?

6.1.20 Typically many forestry buildings, like agricultural ones, are a legacy of previous land use practices and may have fallen out of active use or be unsuitable for current land management practices. In addition to options for agricultural PDR considered in the 2019 SA, the phase 1 consultation includes proposed PDRs for the conversion of forestry buildings (that is, buildings on land used for the purposes of forestry, including afforestation) to residential and commercial uses. The proposals closely follow those for the conversion of farm steadings. 

 Updated Appraisal findings

6.1.21 The proposals for the conversion of forestry buildings closely mirror those for farm steading conversions, and we have therefore reviewed the findings of the 2019 SA in relation to options for relevant agricultural developments. We consider proposals for the conversion of forestry buildings to result in the same effects as identified in the 2019 SA for relevant agricultural development, as updated by the findings in paragraph 6.1.17 above in relation to flood risk.


6.1.22 Similar to mitigation proposed for farm steading conversions, the Update to the SA supports the draft Phase 1 proposal that the relevant PDRs would be subject to prior notification/prior approval in respect of flood risk.

Reasonable alternatives considered

6.1.23 SEA requires consideration of alternative policy positions (referred to as 'reasonable alternatives'). The 2019 SA identified and assessed options for PDR for each development type. Those options were developed through an iterative process in discussion with Scottish Environment Protection Agency (SEPA), Scottish Natural Heritage (now Nature Scot) and Historic Environment Scotland and with a virtual review group.  We consider that the options and associated effects identified in the 2019 SA for relevant agricultural development also apply to the conversion of forestry buildings.   

6.2 Developments relating to active travel

6.2.1 Development relating to active travel is identified as the physical infrastructure required to support this, such as cycle paths and pedestrian crossings. 

What are the new proposals for developments relating to active travel?

6.2.2 The 2019  SA considered the likely effects arising from PDR for physical infrastructure to support active travel including creating new walking and cycling routes; surfacing cycle paths and footpaths; providing safe crossing points for pedestrians and cyclists, docking stations for electric bikes; and other developments (e.g. car share parking spaces). In addition, options for PDR for ancillary buildings (including bike sheds) within the curtilage of a property were explored under Householder developments (Section 17.8 of the 2019 SA Report refers). 

6.2.3 The draft Phase 1 proposals seek to clarify existing PDR relating to the above-mentioned physical infrastructure; they also set out new options for PDR for on-street cycle and scooter storage in public spaces subject to certain size restrictions. Finally, to encourage ownership and use of bicycles the draft phase 1 proposals include PDR for ancillary buildings (bike sheds) for flatted properties. Finally, the draft Phase 1 proposals include provisions for a power supply to any bike store. 

Updated appraisal findings

6.2.4 The erection of communal cycle and scooter storage and associated power supply is considered likely to lead to minor positive effects for climatic factors through encouraging a modal shift to cycling instead of private car use which has the potential to contribute to reducing GHG emissions as well as traffic volume and consequently congestion. In relation to this, minor positive effects are identified for air quality due to a reduction of pollutants emitted from vehicular traffic. Furthermore, the provision of electricity/ power supply will enable e-bike charging which can further help support a modal shift. E-bikes are significantly heavier than pedal bikes and provisions of ground level storage can help to encourage e-bikes as a mode of mass transport and can also contribute to better quality of life.

6.2.5 No new or additional effects have been identified in relation to water (surface run off); biodiversity; soil or landscape. 

6.2.6 PDR for communal cycle and scooter storage is most likely to have negative impacts on cultural and historic heritage.

Reasonable alternatives

6.2.7 The following reasonable alternatives have been considered in relation to on-street cycle and scooter storage:

  • no PDR 
  • PDR excluding Conservation Areas

6.2.8 Applying PDR in Conservation Areas could lead to unsympathetically designed structures that impact on the appearance, and setting of buildings within these areas. No PDR will avoid effects on cultural and historic heritage but positive effects including for climatic factors, air quality and quality of life would not be realised.

Mitigation and enhancement

6.2.9 In terms of additional impacts identified on cultural and historic heritage, we consider these could be minimised through design guidance (for example, ensuring that  the colour or materials used for storage are sympathetic to the area).

6.2.10 There is an opportunity to enhance positive effects for air quality and water through best practice design[6] on the use of green roofs, helping to decrease surface water run-off and contributing to the removal of air pollutants.

6.3 Peatland restoration 

6.3.1 Peatland can become degraded as a result of drainage, forestry, grazing, peat cutting or erosion. The 2019 SA appraised actions to restore peat  including: Blocking channels and ditches, stabilising large areas of bare peat through mats or vegetation regeneration, and scrub clearance or tree felling, but excluding access tracks for the purposes of peatland restoration.

What are the new proposals for peatland restoration?

6.3.2 Rather than defining specific activities to which PDR would apply, the consultation proposes applying PDR to a general description of 'peatland restoration' without further definition. Views are invited specifically on PDR for the transfer of peat for the purposes of peatland restoration (but excluding the extraction of peat outside the restoration site and the removal of peat from the restoration site).  

Updated appraisal findings,  mitigation and enhancement

6.3.3 The 2019 SA identified potential significant permanent positive effects in terms of biodiversity, the water environment, reducing greenhouse gas emissions, climate adaptation, soils and the landscape; minor positive long term effects in terms of economy, quality of life, education and training; and, mixed permanent effects on cultural heritage and we consider that these findings remain valid in light of the updated proposals.  The consultation paper sets out the likely oversight that will apply to peatland restoration projects, including from Peatland Action or validation under the Peatland Code, and invites views on whether there are any forms of development which should be restricted or controlled.

6.3.4 In addition to the consideration of any restrictions or controls, it is considered that there is opportunity to further enhance positive effects through guidance or advice on PDR for peatland restoration. 



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