Building Surveying: Advice for Loft Conversions

The following case study report is based on an exercise from the RICS certificate in building surveying practice. The template that is provided in the course was based on English legislation so I had to start from scratch to tailor the recommendations from the Scottish context. I enjoyed researching for this case study because I have been working with an unauthorised loft conversion recently so it was very relevant for me.

Whether you are looking to complete the certificate in building surveying practice or if you are dealing with an unauthorised loft conversion in Scotland  hope you find some of the information below useful. I have made adjustments to the report like removing the contents page and the stock photos to streamline it to the blog format as best as possible.

Case Study Report

The following report examines the partial construction of a loft conversion to a single storey bungalow after work was stopped following a visit from the local authority building inspector. The work has been started by a local building contractor without any statutory approval or design documentation. The scope of work was scheduled to include an additional bedroom with en-suite toilet and sink. An initial inspection of the photographs taken from site show the current progress of work which shows the framework of internal partitions and a dormer window.

This report has been written with limited information provided. It would be advised that a site visit is completed to examine the full extent of the work that has commenced which will allow us to present a more tailored and specific report. This report will therefore speak in broad general terms on what will need to be done to seek compliance of your loft conversion.

Where specific advice is given this will be outlined separately, where assumptions have been made these will also be made clear.

01 Statutory Approvals

Planning Permission

Question: Do you need planning permission?

You may need planning permission if:

  • you want to build something new
  • you want to make a major change to your building – like building an extension
  • you want to change the use of your building
  • your building is in a conservation area (you may need ‘conservation area consent’)
  • your building is a listed building (you may need ‘listed building consent’)

Planning Permission for Roof Alterations

Many additions or alterations do not need a planning permission application, because most meet a set of rules called ‘permitted development’. The permitted development rules are:

  • They are not on the front or side of your house and facing a road
  • The distance between the dormers and the boundary of your curtilage they face is more than 10 metres
  • The development would not be higher than the existing roofline (when measuring the height of the roofline, do not include chimneys)
  • All your dormers combined cover less than half the width of the roof
  • The distance between the dormers and any edge of the roof is at least 30 centimetres
  • It’s not within a conservation area

The local development plans for different local authorities may be slightly different which is why close liaison with the local authority planning / building department is crucial. In East Ayrshire, where permission is required, you may find the following general rules will apply:

General Principles

  • Dormers shall be of a scale and design appropriate to the building on which they are proposed and, in all cases, the design and positioning of the windows shall reflect the position, character and proportion of other windows on the same elevation;
  • Dormers shall take account of the design of other existing dormers on the building and of dormers on adjoining properties;
  • Side and, if appropriate, front panels should be finished externally in the same materials and colours as the roof covering of the existing house. Notwithstanding the above, the front face of the dormer should be predominately glazed;
  • Dormers should, collectively, occupy no more than 50% of the area of the roof plane;
  • Dormers shall be set a minimum of 0.3 metres away from gables and hips, and down from the roof ridge in order that the roofline remains unaltered. Under no circumstances shall a dormer rise above the ridge of the roof;
  • Dormer extensions should be built in the roof, not in wall;
  • Dormers should not breach or wrap around roof hips;
  • Continuous box dormers (i.e. two or more rooms linked) will not generally be permitted in situations exposed to public view, other than in non-sensitive areas and/ or where such dormers are already prevalent;

General Guidance Planning Diagram

planning rules

Important Note: The above information is for guidance only. You should always check with your council’s planning department to see whether you need to apply for planning permission. Even if you meet the permitted development rules, there may be other approvals you’ll need to get.

Important Note: If your project needs planning permission and you do the work without getting permission first, you may be served an ‘enforcement notice’. It’s illegal to ignore enforcement notices.

Note: Additional rules may apply for dormers constructed on traditional / listed properties.

From the photographs you have provided, the dormer looks to be side facing and to be within 10 metres from a boundary (based on the presumption that the gutter seen to the left of the photo is a neighbouring property). It also looks to be within 300mm from the edge of the roof and looks very close to being more than half the width of the roof. Therefore, for all of the reasons outlined, planning permission will be required.

As the dormer has been constructed in line with the roof ridge it may be denied planning permission, if this is the case the design may need to be altered or the dormer removed and put back to standard.

Applications for planning permission can be made online using the ePlanning Scotland website.

Relevant Legislation

  • Town and Country Planning (Scotland) Act 1997
  • Town and Country Planning (Appeals) (Scotland) Regulations 2013

Building Regulations

Scottish Building Standards are rules that cover things like making sure building work is safe and complies with building regulations

To ensure your work complies with the regulations, you will need to apply for a building warrant. A building warrant is required for all major building works such as:

  • Alterations
  • Extensions
  • Conversions
  • Demolishing part or the whole of a building
  • Building a new home
  • Changing the structure of a building

Question: Does a loft conversion require a Building Warrant?

A building Warrant is required for nearly every construction project, large or small. A full description of work that does not require a warrant can be found in the Building standards technical handbook 2019: domestic. Generally speaking, loft conversions will always need a Building Warrant.

If you only propose to floor the roof space for light domestic storage without overloading the roof structure and access from the lower storey is by way of a retractable/removable ladder then Building Warrant approval is not required.

Important Note: It’s an offence to start building work without a building warrant. If you do, you could be fined up to £5,000. Non-compliance with the building regulations could leave your property unsafe and may impact on your building insurance as well as your ability to sell the property.

Note: Consider using an Approved Certifier of Design and/or Construction. These are Scottish Government approved scheme providers that can certify to your local council that the building work meets building standards.

Your loft conversion will require a Building Warrant as it is a full conversion with structural alterations and the addition of a bathroom and bedroom area.

Online submission of applications and other related forms to local authorities can be made on the eBuildingStandards.Scot website.

Relevant Legislation

  • Building (Scotland) Act 2003 with all amendments
  • Building (Scotland) Regulations 2004

02 Further Points of Consideration

Planning Application – Certificates of lawfulness

Where planning permission is not required, you should consider applying for a certificate of lawfulness. This is a planning determination with legal status which demonstrates that the work has been completed lawfully. This can hold various benefits but is not a mandatory requirement.

General Health and Safety Considerations

It is important that all relevant health and safety legislation is complied with when constructing the loft conversion. All of the below issues should be covered in the construction phase plan which is mentioned in more detail below. Health and Safety considerations should include:

  • Working at Height (Work at Height Regulations 2005)
  • Electrical Safety
  • Gas Safety
  • Structural Safety Considerations
  • Good Housekeeping
  • PPE (for example when removing insulation or to protect against dust)

Risk Assessments and Method Statements

General assessment – employers are required to make an assessment of the health and safety risks to which employees and others are exposed on construction sites. The significant findings must be recorded where five of more people are employed.

Specific assessments – certain regulations require risk assessments for specific hazards and state in more detail what is required. These include: work at height; hazardous substance (COSHH); manual handling; noise; vibration and lead.

Method statements – The arrangements for carrying out demolition, dismantling or structural alteration must be recorded in writing before the work begins. This is usually achieved by means of a method statement that can be generated from a risk assessment. While not required by law, method statements are also prepared for many other construction activities and are proven to be an effective and practical way to help plan, manage and monitor construction work.

CDM 2015

The Construction (Design and Management) Regulations 2015 helps all involved in a project to plan work and manage risks from the beginning, to ensure the right people are involved and to communicate effectively across the project.

As per the CDM regs, before the work starts, a construction phase plan must be written. If the project involved more than one contractor, a construction health and safety file has to be produced by the Principal Designer. Welfare facilities must also be provided on a domestic project. A loft conversion is unlikely to be deemed a notifiable job unless It will exceed more than 500 person days or It will last longer than 30 days and involve more than 20 workers at the same time.


Remember to inform your mortgage lender and insurer if you go ahead with a loft conversion an extra room could result in a higher buildings insurance premium. Depending on the work you are planning to have done, your insurer may amend the terms of your policy, or cancel your existing cover. Among other things, your insurer may consider the cost of the work, how long it will take (and how long the property may be unoccupied while it is carried out), and whether your builders have adequate public liability insurance.


The general duties in Section 3(1) of the Health and Safety at Work etc Act 1974 apply to protect householders from any risks from work activities being carried out in their homes. Where work being done involves asbestos-containing materials then the Control of Asbestos Regulations 2012 will also apply.

From the pictures presented it looks likely that the property was constructed before the year 2000. Whilst there does not look to be any visible asbestos from the photos provided, there is a chance that there may be asbestos present within the property. Unless you have documentation showing that there is no asbestos present it would be prudent to get an asbestos refurbishment survey completed.

Party Wall Issues

The Party Wall etc. Act 1996 only applies to England and Wales. Scotland and Northern Ireland rely on common law rather than legislation to settle party wall disputes. You must tell your neighbours if you want to carry out any building work near or on your shared property boundary. Advice and guidance can be found online on the following link:

It is not clear from the photographs that there are any party walls involved. I am taking the view that the property is a detached bungalow so the above will not apply. If this is not the case you will need to follow the above guidance.

Real Burdens

It may be worth checking if there are any real burdens imposed on the land. A real burden (which is the Scottish equivalent of a “restrictive covenant” in England and Wales) is an encumbrance on the title of property (“burdened property”) which benefits neighbouring property (“benefited property”). Real burdens typically prohibit certain activities, impose building restrictions, oblige owners to build to specified plans, or allocate responsibility for maintenance and repair.


We assume the client is the owner of the property and the property is not being rented or leased. If the property is being leased or rented you must have the property owner’s permission to alter the building and thus should not continue with the conversion.

Approved Certifiers

An approved certifier is a building professional who has approval to certify that plans or building work comply with building standards. Currently there are two schemes approved by Scottish Ministers:

  • Certification of Design (Building Structures) operated by SER Ltd.
  • Certification of Construction (Electrical installations to BS 7671) operated by SELECT and NICEIC.

Structural Engineers Registration Ltd (SER) has been appointed by the Scottish Government’s Building Standards Division (BSD) to administer a scheme for Certification of Design (Building Structures). Once an application for Building Warrant is ready to be made, the Approved Certifier of Design (Building Structures) generates a certificate from the SER system.

Using an approved certifier should speed up the application process, as the building standards department will have less to check.

03 Compliance with the Building Regulations

A Building Warrant is a legal document in Scotland that gives you permission to carry out building work. Your Architect or Designer will produce detailed technical drawings for submission to your local authority Building Standards department. These plans should tell your local building services department the location of the building work, what the building work is and how it will affect any adjoining or existing buildings. The drawings will be assessed against the requirements of the Building (Scotland) Regulations.

The Domestic Technical Handbook 2019 (in force from 1 October 2019) gives guidance on achieving the standards set in the Building (Scotland) Regulations. The handbook is broken into sections which are as follows:

  • General
  • Structure
  • Fire
  • Environment
  • Safety
  • Noise
  • Energy
  • Sustainability
  • Appendix A & B

Some of the items of compliance that are most applicable to a loft conversion are as follows:

Section 1 Structure

In order to be safe, a building should be capable of resisting all loads acting on it as a result of its intended use and geographical location. To achieve this, the structure of a building should be designed with margins of safety to ensure that the mandatory functional standard has been met.

Section 2 Fire

Domestic buildings should be designed and constructed in such a way that the risk of fire is reduced and, if a fire does occur, there are measures in place to restrict the growth of fire and smoke to enable the occupants to escape safely and fire-fighters to deal with fire safely and effectively.

Section 3 Environment

This section covers items such as; site conditions, the effects of moisture, ventilation, drainage, sanitary facilities, heating etc.

Section 4 Safety

The intention of this section is to give recommendations for the design of buildings that will ensure access and usability, reduce the risk of accident and unlawful entry. It covers things like stairs, electrical safety etc.

Section 5 Noise

The purpose of this section is to limit the transmission of sound to a level that will not threaten the health of occupants from sound transmission emanating from attached buildings and a differently occupied part of the same building. It covers things like noise separation and noise reduction between rooms.

Section 6 Energy

The intention of this section is to ensure that effective measures in place for the conservation of fuel and power. In addition to limiting energy demand, by addressing the performance of the building fabric and fixed building services, a carbon dioxide emissions standard obliges a designer of new dwellings to consider building design in a holistic way. It covers things like insulation, heating, lighting etc.

Plan Design Showing Some Points of Consideration

building regs considerations

04 Main Structural Areas of Concern

We would strongly recommend that a Structural Engineer is appointed to complete the new structural design for the loft conversion, there is no ‘one size fits all, solution. Each project will be unique so therefore a structural design specific to the project will be required.

Some areas of concern particular to your loft conversion would be as follows:

  • Dormer Walls
    • The front wall of the dormer can be supported off the external wall, or if it is to be set back from the external line of the house, it can be supported off the new floor joists, which should be designed to cater for the extra load of this wall. The new dormer wall will need to be supported sufficiently from the existing structure. Adequate provisions will need to been made to strengthen elements such as ceiling joists, external wall etc.
  • Removal of Rafters
    • It is important to ascertain what impact the structural alterations will have on existing structural members. Roof supports may have been removed to form the loft area space thus weakening the structural support members of the roof.
    • To enable a window, rooflight or dormer to be installed when creating new rooms it is normally necessary to cut an opening in the existing rafters. The new openings must be designed in such a way to support any new openings.
  • Floors and Timber / Steel Beams
    • It is unlikely that the existing ceiling joists will be adequate to support the weight (loads) that arise from the construction, contents and use of a typical habitable room developed in a loft.
    • The structure will need to be designed in such a way to adequately support the new alteration and intended use. This may come in the form of new floor joists and other additional supports such as steel or timber beams.
  • Walls
    • New walls will form the perimeter of the new rooms and will help support the existing and new roof where existing roof supports have been removed. Such new support for the roof will normally take the form of low level walls towards the eaves of the premises, helping to reduce the span (unsupported length) of the existing rafters. Other walls, typically loadbearing , will separate the new rooms from other areas of the home. These walls may need to be fire resisting.
  • Opening for New Stairs
    • This would normally be formed by cutting away some of the existing ceiling joists between the existing habitable areas of the home and loft-space. As these joists support the existing ceiling and restrain the pitched roof from spreading, replacement support should be provided.
  • Redesign / reinstatement
    • If the current dormer does not comply with planning / building requirements a redesign may be required. The structural engineer will need to evaluate the impact of any proposed changes on the existing structure. If the dormer is to be completely removed and reverted back to standard a structural assessment will still be required and recommendations followed.

05 Process to Achieve Compliance

The following points will need to be followed with to ensure compliance:

  1. Obtain an initial structural assessment. On the provision the current set up is structurally sound, a contractor can then be brought in to make the site safe for the meantime as well as making the roof opening wind and watertight.
  2. Organise a suitably qualified person to produce an inventory of the existing work.
  3. Arrange for an architect / technician to prepare design drawings and specifications for work to show how the works will comply with Building Regulations. The architect will consult with the planning department to ascertain whether the partly constructed dormer design can remain. If the current design would not gain planning approval the architect will alter the design to conform with planning rules.
  4. Planning application should then be lodged with the local authority and approval gained.
  5. A structural engineer should be sought to design the structural elements for the chosen design. This could be steel or timber or a combination of both. The structural engineer will send the final drawings and Certification of Design for Building Structures (or SER certificate) to the architect.
  6. Architect / technician will complete the Building Warrant application whilst liaising closely with the building inspector to ensure that the drawings and application are compliant.
  7. Organise an asbestos refurbishment survey (if required) and follow recommendations.
  8. Organise a contract to be set up and contractor to be used for the work (tendering process to be followed unless client has a preferred contractor selected). The work will then commence with all relevant health and safety provisions put in place.
  9. Obtain completion certificate from building control body on completion of works.

06 Conclusions and Recommendations

It would be advised as stated previously that a site visit is made to the property to ascertain the main issues explained in the report that are not conclusive. With the current evidence provided the following recommendations would be instructed:

  1. Stop works immediately – any continuation of work may lead to unnecessary costs in the event of planning enforcement.
  2. Make the area safe, wind and watertight. This will protect the building whilst working through the process of making your conversion compliant. Even at this early stage a structural assessment would be recommended as immediate alterations may be required to ensure structural safety is retained.
  3. Appoint competent individuals. The likes of an architect and structural engineer will take you through the process of achieving statutory compliance. Planning approval in your case will be required as well as a building warrant.
  4. Follow recommendations set out in section 2 of this report which covers many other issues relating to this project. This covers party wall issues, asbestos, insurance and other health and safety related matters.
  5. Further professional services can be offered; schedule works / quantities for tendering purposes / CDM Coordination / project management / contract administration etc if required.

Thinking of Cancelling the Project?

As a general guide, please see some indicative costs for a bungalow loft conversion, incorporating balcony windows, lounge area, bedroom area and bathroom. This is for general guidance only and is not a reflection of the exact cost you may need to pay. These costs may be out with the budget that you initially had in mind.

Building work                                                                                      £42,000.00 (Incl VAT)

Architectural fees (including site supervision)                             £6,000.00

Structural engineer fees                                                                    £1,200.00

Building warrant fee                                                                          £689.00

Planning Permission fee                                                                    £202.00

Certificate of Lawfulness                                                                   £101.00

Total                                                                                                       £50,192.00

After reviewing the costs, it may be the case that it is not feasible for you to proceed with this project. If this is the case you will still need a structural engineer to provide advice on how to take the structure back to its original condition and organise a contractor to complete these works.

This is why it is very important to get the right advice at an early stage to ensure you do not accidentally create a costly and unsafe alteration which may need to be dismantled and removed.

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