Considering a flat roof to pitched roof conversion for your home or commercial property? Pitched roofs offer numerous advantages over flat roofs, such as reduced maintenance needs and a longer lifespan. However, there are careful considerations to make before switching from a flat roof to a pitched roof.
Today, we’ll assess the benefits of converting from a flat to a pitched roof, how much this costs, the conversion process, and common challenges you may face. If you’re interested in the idea of converting to a pitched roof and want an accurate estimate of the costs for your home, give us a call today at 01993 259226!
The Benefits of Converting a Flat to a Pitched Roof
There are plenty of advantages of pitched roofs, such as:
- Reduced Maintenance Needs: A pitched design minimises water pooling, lowering the risk of leaks and reducing repair frequency.
- Increased Natural Water Run-Off: Steeper slopes enable efficient drainage, ultimately preventing water damage and mould.
- Longer Lifespan: The improved structural support allows some pitched roofs to last over 100+ years with proper care, such as those featuring Welsh slate.
- More Visually Appealing: The traditional look of pitched roofs is more desirable for many property owners, improving property value in many cases.
- Allows for Loft Conversions: The additional space beneath a pitched roof offers the potential for extra living areas or storage.
What Should You Consider Before a Flat-to-Pitched Conversion?
Before you get started, there are a few factors that you need to consider:
Existing Building Structure
- Structural Assessment: Arrange for a qualified structural engineer to assess your property, who will check that the walls, roof supports, and foundations are capable of handling the additional weight of a pitched roof.
- Load Bearing Analysis: Identify whether existing beams and joists are sufficient for the pitched roof, or if reinforcement is needed. Based on the assessment, you may need to install additional supports.
Materials Suitable for Pitched Roofs
- Choosing a Material: There are many materials to choose from when building pitched roofs. Three of the most popular include:
- Concrete Tiles: The cheapest option, with various colours available.
- Clay Tiles: The traditional choice, suitable for most, if not all, pitched roofs.
- Slate Tiles: The strongest option, slate roofs can last a lifetime.
- Compatibility with Insulation: Ensure the chosen roofing material works well with additional insulation and ventilation systems. This helps you to maximise the energy efficiency of your property.
Required Permits and Building Regulations
- Planning Permission: Converting a flat roof to a pitched roof is usually classed as a significant structural change, so you’ll need to apply for planning permission in most cases. As of 2025, this will cost you £210 in England, or £190 in Wales.
- Building Regulations Compliance: Ensure that the pitched roof design meets current building regulations; this includes fire safety and proper insulation, which is particularly important if a habitable space is being created within the pitched roof. Contact a professional architect to prepare a compliant design for you.
How Much Does a Flat Roof to Pitched Roof Conversion Cost?
To give you an idea of how much your pitched roof conversion may cost, here is a rough estimate:
| Type of Pitched Roof | Average Cost of Conversion |
|---|---|
| Small Roof With Open Gable | Between £3,000 to £3,600 |
| Small Roof With Box Gable | Between £3,500 to £4,200 |
| Large Roof With Gable and Scaffolding | Between £4,000 to £4,500 |
Cost of Pitched Roof Materials
The material you choose for your roof covering will also impact the price - here’s how much they typically cost:
| Type of Material | Average Cost (per m²) |
|---|---|
| Concrete Tiles | Between £15 to £25 |
| Synthetic Slate Tiles | Between £20 to £40 |
| Clay Tiles | Between £35 to £40 |
| Plastic Tiles | Between £40 to £45 |
| Mid-Range Slate Tiles (Such as Spanish) | From £75+ |
| Premium Slate Tiles (Such as Welsh) | From £180+ |
Structural Extras
There are other structural elements which you’ll need to factor into your budget, including:
| Type of Structural Element | Cost |
|---|---|
| New Guttering | Between £450 to £720 |
| Insulation | £5 to £15 per m² |
| Roof Battens | £3 to £5 per Batten |
| Soffits | £100 to £260 per m² |
| Trusses | £25 to £35 per m² |
To get the best estimate of costs for a flat roof to pitched roof conversion, we strongly suggest getting in touch with one or more local roofing companies. Here at Empire Roofing, we offer a free, no-obligation quote that will give you a more accurate idea of how much your conversion will cost. So, if you’re in the Oxfordshire area or surrounding counties, get in touch here to see if we can help.
The Conversion Process From a Flat to Pitched Roof
During the conversion of a flat roof to a pitched roof, unexpected factors may arise, such as the requirement for additional structural reinforcement for your new roof. Generally, the conversion process will follow:
1. Initial Planning & Design
Start by consulting a structural engineer to assess the current roof and an architect to develop the new pitched design. Establish your budget, choose a roof style (such as gabled or hipped), and secure the necessary permits while ensuring the design meets building regulations.
2. Preparing and Removing the Flat Roof
Your chosen roofing contractor will prepare the site with the necessary scaffolding and safety measures and then remove the existing flat roof. The underlying structure will be inspected for any damage, and repairs or reinforcements will be made as necessary.
3. Installing the Pitched Roof Support
The roofers will reinforce the structure by installing or modifying trusses and rafters to achieve the desired pitch and support the new roofing material. The trusses will be measured to determine the amount of plywood required, and the plywood will be laid across the roof and firmly nailed to the trusses, creating a new roof shape.
4. Installing the Tiles/Slates
New decking (often known as sheathing) will be laid, and a waterproof membrane will be applied, such as tarpaper, to protect the roof from leaks. Your chosen roofing material will then be installed onto the decking.
5. Applying Finishing Touches
The project will be completed once all relevant flashing, guttering, and ridge boards have been fastened. A final inspection will be conducted to verify compliance with safety and regulatory standards, such as assessing whether all fire-safety matting has been installed.
What Are the Challenges of Converting a Flat Roof to a Pitched Roof?
Although converting a flat roof to a pitched roof is a popular choice, it’s not without its challenges. Here are some potential issues to be aware of:
- Unforeseen Issues: During the removal of your flat roof, unexpected problems such as structural damage may be noticed.
- Cost Overruns: To prevent budget surprises, you should allocate a contingency fund (approximately 10 to 15% of your budget), secure multiple quotes from local roofers, and maintain clear communication with your contractor throughout the project.
- Permit Requirements: It’s important to consult with local authorities and experienced architects early on so that you can be confident all legal requirements have been met. Otherwise, you may face significant delays to your project.
- Tiled Roof Weight: Pitched roofs typically weigh more than a flat roof. To accommodate the extra weight of a pitched tile/slate roof, you may need to pay for extra support to be put in place.
FAQs
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Can I change my garage's flat roof to a pitched roof?
Yes, this is a popular project which follows a very similar process to a standard flat-to-pitched roof conversion. Similarly, house extensions with flat roofs can also be converted.
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Will a pitched roof help with my home’s energy efficiency?
A pitched roof will contribute to better energy efficiency, as long as it has been combined with proper insulation. Pitched roofs are more energy-efficient as they offer more space for insulation, and facilitate better ventilation; retaining heat in the winter, and keeping your house cool in the summer.
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How long will it take to convert my flat roof into a pitched roof?
This depends on the size of the roof, the complexity of the project, and the type of material you choose. A standard, simple roof conversion takes between 2 to 3 days, but in many cases, it will take longer.
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Do I need planning permission to convert to a pitched roof?
Yes, you'll generally need planning permission for a roof conversion, costing £210 per application for properties in England, or £190 for those in Wales. This is because it’s usually classed as a significant structural change - where the conversion will make the property higher than the previous highest point.
Our Reputable Roofers Will Get the Conversion Job Done
If you’re looking for a team to convert your flat roof into a pitched one, look no further than Empire Roofing. Our Oxfordshire-based roofers are skilled in handling roof conversions of all sizes, ensuring compliance each and every time.
To get started with us, please give us a call at 01993 259226 or contact us online, and we’ll arrange a no-obligation consultation to discuss your project ideas and how we can help.
