A loft conversion is an excellent way to add valuable living space to your Reading home, but not every loft is suitable for conversion. Before you get too excited about transforming your attic into a stunning bedroom, home office, or playroom, it’s important to understand the practical limitations. At Blenheim Constructions, we’ve worked on countless loft conversions across Reading, and we know exactly what makes a loft conversion viable—or impossible.
In this blog, we’ll explore the key factors that determine whether your loft can be converted and what types of lofts typically cannot be transformed into usable living space.
Key Factors That Affect Loft Conversion Feasibility
Several technical and structural factors determine whether a loft conversion is possible. Let’s break down the most important considerations:
1. Insufficient Head Height
Minimum Requirement: 2.2 metres (7 feet 2 inches)
One of the most common reasons a loft conversion is not feasible is insufficient head height. Building Regulations in the UK require at least 2.2 metres of clear headroom in at least 50% of the usable floor area.
If your loft has less than 2.2 metres of headroom from the floor joists to the highest point of the roof, you have a few options:
- Lower the ceiling of the floor below (often expensive and disruptive)
- Raise the roof (significantly more expensive and may require planning permission)
- Consider a dormer extension to increase internal height
Pro Tip: To measure your loft’s head height accurately, measure from the top of the floor joists (not the ceiling of the room below) to the underside of the ridge beam at the roof’s highest point. If you’re unsure, Blenheim Constructions offers free site surveys to assess feasibility.
2. Roof Structure Issues
Trussed Roofs vs. Traditional Roofs
The type of roof structure your home has plays a major role in determining whether a loft conversion is feasible.
Trussed Roofs (Prefabricated Trusses)
Many modern homes built from the 1960s onwards use prefabricated roof trusses. These trusses are engineered as a single unit with diagonal and vertical supports (W-shaped or fink trusses) that create obstacles in the loft space.
Can trussed roofs be converted? Yes, but it’s more complex and expensive. The existing trusses must be removed and replaced with a traditional roof structure using steel beams and supporting columns. This adds significant cost—typically an extra £5,000 to £15,000.
Traditional Roofs (Cut Roofs)
Older properties, especially those built before the 1960s, typically have traditional cut roofs with rafters, joists, and a ridge beam. These roofs are much easier and more cost-effective to convert because the loft space is relatively open and unobstructed.
3. Inadequate Floor Joist Strength
The existing floor joists in your loft were designed to support the ceiling below—not the weight of people, furniture, and additional building materials. To convert a loft into habitable space, the floor joists must be strengthened or replaced to meet Building Regulations.
What if the joists are too weak?
If your existing joists are insufficient, we can either:
- Install new, stronger joists alongside the existing ones
- Add steel beams to distribute the load effectively
However, in rare cases where the existing structure cannot support reinforcement without excessive cost or disruption, a loft conversion may not be viable.
4. Lack of Space for a Compliant Staircase
Building Regulations require a proper staircase (not a ladder) to access a habitable loft. The staircase must meet specific criteria:
- Minimum width of 800mm
- Maximum pitch of 42 degrees
- Consistent rise and tread dimensions
- Adequate headroom (2 metres minimum)
If there’s insufficient space on the floor below to install a compliant staircase, a loft conversion may not be possible. This is particularly common in smaller homes or properties with complex layouts.
Solution: In some cases, we can reconfigure the layout of the floor below (such as relocating a bathroom or closet) to create the necessary space. However, this adds to the overall cost and complexity.
5. Planning Permission Restrictions
While many loft conversions fall under Permitted Development Rights, certain properties face planning restrictions that make loft conversions difficult or impossible:
Listed Buildings
If your property is listed, you’ll need Listed Building Consent in addition to planning permission. The local authority may reject proposals that alter the character or historical integrity of the building.
Conservation Areas
Properties in conservation areas often have stricter planning rules. Dormer windows or roof alterations visible from the street may be prohibited.
Removed Permitted Development Rights
Some properties have had their Permitted Development Rights removed through an Article 4 Direction. This means planning permission is required for loft conversions, even if they meet standard criteria.
Important: At Blenheim Constructions, we conduct thorough planning checks before starting any project. If your property is subject to restrictions, we’ll advise on the best course of action.
6. Roof Pitch Too Shallow
A shallow roof pitch (below 30 degrees) can make loft conversions impractical. Shallow roofs don’t provide enough internal height, even with dormers, making it difficult to create comfortable, usable space.
Solution: In some cases, raising the roof or installing a mansard extension can overcome this issue, but these options are expensive and require planning permission.
7. Properties with Flat Roofs
Homes with flat roofs generally lack the vertical space needed for a traditional loft conversion. While it’s technically possible to add a new storey above a flat roof, this is considered a full extension rather than a loft conversion and requires planning permission, significant structural work, and a much higher budget.
8. Shared Roof Spaces (Terraced or Semi-Detached Homes)
If you live in a terraced or semi-detached property and share a party wall or roof structure with your neighbours, there are additional considerations:
- You may need to serve a Party Wall Notice to your neighbour(s)
- Structural changes to shared walls must be carefully managed
- Sound insulation must meet Building Regulations to prevent noise transfer
While these factors don’t make loft conversions impossible, they add complexity and cost. At Blenheim Constructions, we handle all Party Wall procedures and ensure compliance with acoustic insulation standards.
How to Determine if Your Loft Can Be Converted
The best way to find out if your loft is suitable for conversion is to have a professional assessment. At Blenheim Constructions, we offer free, no-obligation site surveys where we:
- Measure head height and roof pitch
- Assess the roof structure (trussed or traditional)
- Evaluate floor joist strength and reinforcement needs
- Determine staircase placement and compliance
- Check planning restrictions and Building Regulations requirements
- Provide an honest assessment of feasibility and cost
We’ll let you know if your loft conversion is viable and, if so, what options are available to maximise space and value.
What If Your Loft Cannot Be Converted?
If your loft isn’t suitable for conversion, don’t worry—there are alternative ways to add space to your Reading home:
- Single-storey extensions (rear or side)
- Two-storey extensions
- Garage conversions
- Basement conversions
Blenheim Constructions offers a full range of home extension services, so we can help you explore all your options.
Trust Blenheim Constructions for Expert Loft Conversion Advice in Reading
Not every loft is suitable for conversion, but with the right expertise and planning, many challenges can be overcome. At Blenheim Constructions, we’ve successfully converted lofts of all shapes, sizes, and complexities across Reading. Our team will assess your property honestly, provide transparent advice, and deliver a loft conversion that meets your needs and budget.
Whether you’re dealing with a trussed roof, limited headroom, or planning restrictions, we have the experience and knowledge to find solutions.
Contact Blenheim Constructions for a Free Loft Conversion Survey in Reading
Ready to find out if your loft can be converted? Get in touch with Blenheim Constructions today for a free, professional assessment. Visit
https://blenheimconstructions.co.uk/ or call us to book your survey.