Changing Flat Roof To Pitched Roof Cost

A roof is one of the main parts of a house. If you want to convert your flat roof to pitched roof, check out our guide to help you understand what to expect in terms of cost and other related details.

Changing flat roof to pitched roof

Flat roof to pitched roof cost

If you have a flat, or low-pitched, roof that is leaking and you don’t want to replace it entirely, you may be interested in converting it to a pitched roof over the top of your existing one to reduce the risk of further leaks.

The cost of converting a flat roof to a pitched roof is typically between £3,000-£4,500, depending on the building materials used and whether or not scaffolding will be required. In most cases, this type of conversion takes just two days at the most. 

Generally, converting a flat roof to a pitched roof is normally cheaper than installing a brand new roof, as the materials and labour are cheaper.

On the other hand, roof tiles that are most popularly used are concrete tiles which can range between £0.75 to £3 per tile, the clay tiles would range between £1 to £5 per tile while the slate tiles between £1 to £12 per tile.

The prices can vary depending on the size of the tiles. For instance, the larger roofing tiles will be priced more but would not need as many tiles.

Cost to convert flat roof to pitched roof

In this section, you will find details on the different prices involved in converting flat roof to pitched roof. This can also depend on the type of roofing you need.

Roof TypeAverage CostDuration
Small Roof With An Open Gable£3,000-£3,6003-5 days
Roof With A Box Gable£3,500-£4,2004-7 days
Large Roof With Gable With Scaffolding£4,000-£4,5006-1

Cost of roof materials

This is the primary cost component when changing a flat roof to a pitched roof. The main determinant is the type of material that you choose to use. The table below has a cost breakdown of the same.

Clay£1 to £5 per tile
Concrete£0.75 to £3 per tile
Slate£1 to £12 per slate
Thatch£75 to £100 per m2
Insulation£5 to £15 per m2
New Guttering£450 to £720
Soffits£100 to 260 per m2
Roof Battens£3 to £5 per batten
Trusses£25 to £35 per square m2

Labour Cost

Converting a roof from flat to pitched roofing is a big job that requires several professionals to handle it for you. The usual rate is around £150 to £250 a day and can take between 2 to 3 days – depending on the size of the roof.

You’ll need to pay for the design of your roof before work commences. This can cost around £50 to £90 depending on which consult you choose and how long it takes them to do the job. They both last about two to three weeks.

Other miscellaneous costs

In addition to the main structure, other jobs can be done as part of your pitched roof replacement, such as adding extra features like dormer windows, creating new angles, choosing more complex trusses or even a new loft conversion. However, these customisations will, of course, come at a cost and need to be approved at the planning stage.

You should also be aware that more work is probably needed. For example, you might have to replace damaged ceiling joists or replace the roof. You may need the chimney, heating vents and pipes extended.

Other costs you may need to consider include crane hire, which can cost up to £380 on a typical day. The crane is required to be operated by a qualified tradesman, though you might want to opt for a contract lift that includes the services of a certified crane operative and could cost up to £700 a day.

The cost of a conversion will vary depending on the size of the roof and your local area, but you can expect to pay around £40 to £150 a day for scaffolding hire.

Process of changing flat roof to pitched roof

Before making the switch from a flat roof to a pitched roof, consider the various options available. Since you need to completely change your roof, it is best to work with a structural engineer or architect who will help you decide on the best option for you. There are various options, such as building a shallow pitched roof over a flat one or building a new floor and putting an additional pitched roof above it or installing a trussed roof.

Broadly, the process would follow these 5 steps:

  1. The first thing that you need is to remove the roof, including all tiles and coverings. At this point, an expert will examine the situation and come up with a plan to fix it before installing a new one.
  2. The roofers will then check the joist spacing to ensure it can accommodate a pitched roof installation. They’ll place trusses over every second joist and connect them to the wall structure. 
  3. Once the framing is in place, the trusses will be measured to figure out how much plywood is needed to cover them. The plywood will then be pulled over the entire roof and hammered onto the trusses to form a different shape.
  4. A tarpaper will then be used as a temporary measure of roofing until more permanent repairs can be made. It’s typically rolled along the length of the roof and up towards the peak. This will then be nailed in place and the tiles and ridge boards will then be installed.
  5. The final step would be to cover the gable end seams with the roof coverings and siding fire safety matting. This will remain in place under the roofing material, which you can then secure over the plywood.

What factors affect the flat roof to pitched roof cost?

When choosing a roofing contractor, you will want to consider the cost of your chosen provider. The expense of the project is one of the most important points for you to review before you start your work. Before beginning any work, you must have all existing materials removed to ensure that the remaining roof will be properly assessed. In most instances, this roof is damaged during removal, and this should be repaired before continuing with any other steps in the process.

Depending on the type of roof you choose, you will have to decide whether to let your budget or your imagination be your guide. A mono-pitch roof may cost less than £40 per square metre, which is perfect for those looking to save a buck. King post truss roofs typically cost around £1100 to 2250 just for the trusses, which are ideal if you’re planning on creating a large roof that offers lots of joist support.

It’s also worth considering how complex the pitch roof is, as a shallow pitch roof over your flat roof will be much less complicated and will therefore result in reduced labour costs. It’s better to install a new floor before building a roof over it, leading to less problematic construction and therefore taking up more time.

The materials you use to construct your pitched roof will also have an impact on the overall roof conversion cost. For example, roof insulation options include spray foam insulation, which costs about £20 to £50 per square metre, or roof insulation panels, which typically cost about £25 per square metre.

Additionally, it is important to factor in the pitch of your roof correctly, because the higher it is, the more pressure it puts on your walls, and this creates a greater risk that your plans will be denied. Ideally, you would want to avoid drawing up and submitting plans repeatedly as you would have to incur an additional cost due to delays.

Flat roof and pitched roof comparison

Flat roof

A flat roof is the ideal choice for a new home. With no need for ridge ventilation or gutters, this design option takes the stress out of keeping your property in good condition. It’s comparatively easy to install, cheaper and has a more contemporary design choice. However, it does have a shorter life span and can be prone to leaks as well.

Pitched roof

A pitched roof is one of the best options available today. For the homeowner, there are many benefits and drawbacks to a pitched roof. Some of them revolve around costs, style, and energy efficiency. It has a more traditional design, quite easy to maintain and has a longer lifespan with better drainage abilities. However, it can be more costly and may require a complex construction.

Why convert from flat roof to pitched roof

Converting your flat roof to a pitched roof offers many benefits. Pitched roofs offer a more traditional, classic style that may appeal to you or any potential buyers. Pitched roofs are also known to last much longer, on average around 50 years. They are much more durable and can withstand the elements in any climate, while flat roofs may only last 25 years. This is because pitched roofs do not gather water but disperse it, so they rarely ever leak.

People looking for a roof conversion to pitched roofs often do so because their flat roof is failing in some capacity. If this is the case, then there are many benefits of installing a pitched roof. They offer more space and better ventilation as well as super-easy insulation.

Planning permission to convert flat roof to pitched roof

Flat roofs are an architectural statement and are unique to a property. However if you’re looking to change the look and make it more desirable then you will be required to pay for planning permission which costs around £210 for UK residents.

If your project is going to knock more than 150mm off the height of your existing roof and it will be higher than the highest point of the present one, you will need to apply for planning permission even if it does not extend beyond the boundaries of your property. And if the volume of your new roof exceeds 40 cubic metres for a terraced house and 50 cubic metres for a semi-detached house you’re also going to need planning permission as well.

You can find more information here.

Reducing pitched roof costs

One of the best ways to save money when you’re planning to replace your flat roof with a pitched roof is to get started properly, because if you do this, it will be a lot easier on your wallet. This way, you won’t have any unexpected costs pop up as you go along with your project and some other things might start seeming more expensive than they are.

Re-using your old tiles is a great way to lower your costs. However, it’s important to ensure they are in good condition before recycling them. It’s also worth noting that using high quality tiles, such as slate or concrete might be worth investing in since they can last 100 years and will save you lots of money over time.

Cost to remove pitched roofs

When a pitched roof has been around for a long time and you start to notice leaks or significant damage has occurred then you may want to have it replaced. For professional removal, you should expect to pay between £80 and £115 per square metre although this will vary depending on the pitch of the roof and the materials used.

Looking to change your flat roof to pitched roof?

Our expert roofers at SPS Roofing can work with you to convert your existing flat roof to a pitched roof. Our main working location is Exeter, but we cover most areas within Devon. Do get in touch with us for a no obligation quotation and we will be happy to assist.

Looking For A Qualified Roofing Company?

SPS Roofing Ltd is a highly rated roofing company based in Exeter operating across Devon and South West England including Somerset, Cornwall, Wiltshire, Gloucestershire and Dorset.