Is It Illegal To Convert Loft Without Building Regulations

by | Oct 18, 2023 | Loft Conversion | 0 comments

Move Or Improve? Is It Illegal To Convert Loft Without Building Regulations

Are you facing the dilemma of choosing between buying a bigger house or converting the present one’s loft? Well, we all have been there once in our lives, and it truly is frustrating. On the one hand, getting a new home may seem a better option, but with a tight budget, we are left with one option: Loft Conversion!

A loft conversion is a great idea to add extra space to your home, but it does require a lot of work in hindsight. There will be numerous questions surfacing in your mind when you plan to choose this option. Do you need planning permission for a loft conversion? Is it illegal to convert loft without building regulations? Where should I start? How to get permission? So on and so forth!

While you are fighting and struggling to find a way to get your work started, you will need accurate information. But where can you find a comprehensive guide on building regulations and loft conversion? Let me tell you with a cliched statement: You’ve landed in the right place! In this guide, we will walk you through each step of the process that you need to know.

What is an illegal loft conversion?

The first thing you need to understand before actually starting conversion is the concept of illegal conversion. Any conversion that does not comply with government rules falls under illegal loft conversion.

When a loft conversion is done without following building regulations or obtaining planning permission, it becomes a serious issue. But how? The converted space might be unsafe or suitable for living, putting anyone in the house at risk. Therefore, to ensure everyone’s safety and comfort, addressing and rectifying this situation as soon as possible is important.

When is a loft conversion permitted development?

If you know if converting loft without building regulations is illegal, you might be looking for an answer to “When is a loft conversion permitted development?”

Typically, a loft conversion falls under permitted development, provided it conforms to specific limitations and conditions as stipulated in Schedule 2, Part 1, Class B of The Town and Country Planning (General Permitted Development) (England) Order 2015.

It is advisable to seek professional guidance from an architect or a reputable construction firm, such as Powerpillar, to determine the necessity of planning permission. These experts can provide crucial insight and ensure compliance with the regulations, avoiding any legal complications or issues in the future.

Why are building regulations necessary?

Before coming directly to understand whether Is it illegal to convert a loft without building regulations, make yourself aware of the significance of building regulations.

You need building regulations to safeguard the well-being of individuals residing near a property. While you adhere to these regulations, you may have the guarantee of the secure and conscientious execution of your loft conversion. However, neglecting to comply could jeopardise the safety of yourself and your dear ones and subject you to legal consequences.

Therefore, if you are contemplating a loft conversion, initiating contact with your local building authority is highly recommended, ensuring that your project aligns with the requisite standards.

Although this initial step may demand extra time and effort, the ultimate benefits in terms of safety and compliance far outweigh the inconvenience.

What are the loft conversion building regulations?

The fulfilment of building regulations, often presented as building regulations drawings, is a crucial requirement. So, to understand if is it illegal to convert loft without building regulations, you’ll need to know the building regulations.

While building regulations are typically more intricate than planning regulations, they follow a fairly standardised format. Once again, your architect or designer can assist you in ensuring compliance with these regulations.

Creating a Storage Space

If you want to turn your loft into a storage space, you may need approval for a building permit. The timber joists that serve as the “floor” of your loft (as well as the ceiling of the rooms below) are not typically designed to support significant weight. Overloading these joists may exceed their design capacity, requiring approval from building officials to ensure safety.


For those intending to use the loft for lightweight storage, you can typically board the floor without requiring Building Regulation approval. This exception applies to storing items of relatively low weight. Most loft floors are engineered to support loads of up to 25kg/m2. Building Regulations approval and additional support are necessary for heavier loads or when converting the loft into a habitable space.

Floor Joists and Beams

Converting the loft into a habitable space, such as an additional bedroom, usually necessitates additional floor joists alongside the existing ones to support the increased load.
Here are some key guidelines to keep in mind when considering your loft flooring:

  • If you choose to install 47 x 145mm joists, they should span up to 2.89 metres.
  • For 47 x 170mm joists, the span should reach up to 3.38 metres.
  • When opting for 47 x 195mm floor joists spaced at 400mm, they need to span up to 3.87 metres.
  • For 72 x 145mm joists, the span should be up to 3.33 metres.
  • In the case of 72 x 170mm joists, they should span up to 3.89 metres.
  • Finally, if you choose 72 x 195mm joists, they must be able to span up to 4.44 metres.

Load-Bearing Walls

When it comes to walls and roofing in your loft conversion, there are two critical considerations:

Head Height: Ensure that your loft conversion provides a minimum head height of 2.2 metres. Sufficient headroom is essential to create a comfortable and functional living space in your loft.

Loft Insulation

Your walls and ceiling must deliver adequate insulation to the loft space. Proper insulation helps maintain a comfortable temperature, conserves energy, and enhances the habitability of the converted area.

When your roof space lacks insulation, it’s crucial to address this by introducing thermal insulation to achieve a U-value of at least 0.16W/m2K. A practical solution is to add a layer of 250 mm mineral wool insulation.

If your loft space already has insulation, it’s advisable to aim for a U-value better than 0.35W/m2K according to the standards set by your building control officer. If your current U-value falls below this benchmark, it’s worth considering the inclusion of extra insulation in your renovation plans. This improves energy efficiency and enhances the overall comfort of your living space.

Sound Insulation

Sound insulation is crucial between habitable rooms and, in terraced and semi-detached houses, possibly between your loft and your neighbours’ lofts. This might involve upgrading the existing party wall with soundproofing materials.

In noise control, recommended sound resistance levels are expressed in decibels (dB). These levels are essential to mitigate everyday sources of disturbance, including footfall, conversations, and audio from TVs and music systems. Here are the recommended levels:

Between Homes

Walls: 45dB

Floors: 62dB

Within a Home

Walls: 45dB

Floors: 62dB

Fire Safety

Building regs for loft conversion in case of fire regulations necessitate additional fire protection, including a floor with a minimum REI 30 fire resistance, smoke alarms in stairways at each level, and escape windows at least 45cm wide. New fire-resisting doors or partitions (FD 20 or 30) may be required to protect the stairway and establish a safe escape route in corridors.


A permanent staircase is required to serve as a fire escape for a habitable loft conversion. It should have a centre headroom of 2m (1.9m for pitched roofs) and a pitch no steeper than 42°. Space-saving staircases with steps not exceeding 220mm in height may be a solution for limited space.

Loft ladders are typically not accepted for habitable spaces but are suitable for roof access or maintenance. Spiral staircases follow specific regulations based on the number of rooms in your loft conversion.

Single Room Loft Conversion:

Spiral staircase width: 600mm

Maximum riser height: 220mm

Maximum centre going: 145mm

Two or More Rooms Loft Conversion

Spiral staircase width: 800mm (900mm in Scotland)

Maximum rise: 220mm

Maximum centre going: 190mm

Can a loft be converted into a habitable bedroom without getting a building control sign-off and informing the local authority?

Absolutely, it’s technically possible to transform your loft into a bedroom without seeking building control approval or notifying the local authorities. However, I want to emphasise that it’s not a safe or advisable route. This approach could potentially put you and your family at risk.

If you’re considering turning your loft into a comfortable bedroom, I strongly recommend contacting your local building department first. Yes, it might require a little more time and effort initially, but it’s a responsible and worthwhile step to ensure that your project is done safely and in compliance with the necessary regulations. Your family’s safety and peace of mind are certainly worth it.

Building a Loft Conversion Without Planning Permission

It’s no secret that renovation projects require planning permission. However, homeowners often embark on these projects without obtaining the necessary permission. Much like building regulations, choosing to proceed without planning permission can lead to actions taken by your local authority.

So, what is the time limit for retrospective planning permission? If you’ve already completed the work without planning permission, now is a great time to consider applying for retrospective planning permission. While this does involve an approval process, it serves as a safeguard against potential future legal actions.

What is illegal loft conversion insurance?

Once we have understood the necessities of building regulations and have gotten the answer to “Is it illegal to convert loft without building regulations?”, it is now time to move to an important aspect. If you have decided to move forward in the loft conversion process without considering loft conversion regulations 2023 UK, this section is for you!

When people add a loft conversion without adhering to building regulations, it’s often a choice influenced by cost-cutting or trying to save money. This is where insurance policies can play a crucial role by shielding homeowners from potential legal actions initiated by local authorities.

You might have heard of it as “indemnity insurance.” Essentially, it’s a policy that, if purchased before the conversion and without any ill intent, can help you avoid the financial burdens associated with legal enforcement actions from your local authority. So, if you find yourself wondering, “Can I get indemnity insurance for a loft conversion?” The answer is often yes.

However, it’s important to note that while insurance can provide a safety net, it’s far more advisable to begin by following building regulations in the first place. This ensures that your loft conversion is legally compliant and a safe and sound addition to your home. It’s an investment in peace of mind and the well-being of everyone involved.

Building Regulations Indemnity Insurance

Building regulations indemnity insurance is designed to protect the purchaser of a property and any mortgage lender in case enforcement action is taken due to unapproved building work.
Here’s what you should be aware of:

Coverage and Premium

The premium, typically paid by the seller, is a one-time payment based on the property’s market value, typically ranging from £180 to £500.

Lender Requirements

Lenders may require buyers to obtain this insurance, especially if there’s an unapproved loft conversion, to protect against financial losses if the local building authority enforces actions like a Section 36 Notice or an injunction, reducing the property’s value.

Important Considerations

  • The insurance does not cover structural failures or collapses of the unauthorised loft conversion.
  • Typically, you can only secure this insurance after a year has passed (or four years for new builds) since the local building authority has a limited time to serve an enforcement Section 36 Notice.
  • The insurance may also cover homeowners if the local building authority seeks an injunction to address potential safety concerns.
  • A survey, often conducted by a Structural Engineer or RICS surveyor, is a requirement for insurance approval. If they find the work is unsafe, the insurance might not be granted. The survey cost may initially be the buyer’s responsibility, with a chance of reimbursement by the seller.
  • If the local building control authority previously rejected the unapproved work, you may not be eligible for this insurance.
  • The property must have been residential for at least one year before you can apply for this insurance.
  • Typically, these policies require confidentiality; revealing the insurance to third parties can invalidate the policy.
  • You’ll need the insurer’s consent if you plan to undertake further building works, as this may lead to the local building authority discovering the unapproved loft conversion. Consent may not always be granted.
  • You won’t be covered if you’ve already made inquiries with the local building authority regarding retrospective building control approval for the unauthorised loft conversion.

How much does a loft conversion cost?

The question of whether Is it illegal to convert loft without building regulations is always crucial in the process of loft conversion. When considering a loft conversion, one of the first practical steps is considering your budget.It’s a crucial part of the journey. The good news is you have various loft conversion options to choose from, and the average prices generally range between £20,000 and £80,000. This gives you the flexibility to match your project to your personal style and budget.

But if you’re keen on adding some extra features or special touches to your loft space, that can nudge the cost a bit higher. So, before you jump into your conversion project headfirst, it’s a smart move to take a moment to plan and budget thoughtfully.

By doing this, you can ensure your loft conversion fulfils your vision and stays within your financial comfort zone. This approach makes the entire journey more enjoyable and satisfying.

Final Word

When considering a loft conversion, navigating the complexities of building regulations and permissions is essential. An illegal loft conversion that doesn’t adhere to these regulations can pose serious safety and legal risks. While permitted development might apply to some loft conversions, seeking professional guidance is advisable to ensure compliance.

While it’s technically possible to convert a loft without proper approvals, it’s risky. Seeking building control approval and notifying local authorities is a responsible choice, ensuring your project is carried out safely and within the law. Consider hiring Powerpillar, your go-to construction and renovation team!

Emmanuel Nwaebo

Emmanuel Nwaebo is the Managing Director at Powerpillar Ltd and has more than 25 years experience in building construction and renovations. He has a bachelor’s in Electronics and Electrical Engineering with certification in Construction Health and Safety Technician (CHST). With an experience in managing construction and renovation services for years, he is extremely passionate about property management and loves helping people find their dream property.

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