Flat Roof Replacement Cost

Want to know how much flat roof replacement costs?

On average, you'll pay between £1,000 to £5,000 for a new flat roof, depending on the size needed and the type of flat roof you choose.

So, what else can this guide help you with?

In this complete guide, we look at the flat roof cost per m², garage roof replacement costs, including the cost of materials and labour, timeframes and any additional costs that need to be considered.

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How Much Does a New Flat Roof Cost?

Looking for flat roof replacement costs?

The average cost of a flat roof is anywhere from £1,000 to £5,000. This seems like a rather wide range, but this is due to all the factors that affect the price.

For example, depending on the type of flat roof you opt for, the price could either be reduced or increased. However, flat roofs will always be cheaper than the cost of a new pitched roof.

There are other factors to consider, including the size of the house, the labourer’s expertise, and the ease of access to the roof. This is all in addition to other considerations like scaffolding and so on.

The material used on the roof is one other factor to consider. There are four materials most commonly used in flat roof construction:

• Felt
• Rubber
• Fibreglass
• Lead

For a flat felt roof, you can expect to spend between £40 to £70 per m².

It's worth noting that replacing a flat roof can fluctuate in cost as it's affected by several factors, which we'll discuss in more detail. The most crucial factor is the size of the house, and what section you want the flat roof placed in.

For example, a flat roof for a one-bedroom apartment is between £1,500 to £3,000, assuming the flat roof will act as the main roof.

If you're on a budget, you could use the flat roof for a section of the house like the garage. Garage roof costs range from £700 to £1,000, making it the cheapest option if you're looking for a garage roof replacement.

The price of labour is vital when considering flat roof costs. Different companies will have their own quotes, so be sure to compare them to get a great deal.

One other factor that affects the price is the materials used for construction. For instance, a metal roof generally costs more than one made out of rubber.

Replacing a flat roof can be expensive, but you may qualify for a new roof grant.

Replacement Flat Roof Prices

To put flat roof replacement costs into context, check out our table below for a brief rundown on the prices:

When you have your flat roof repaired or replaced, you might want to add on other maintenance to your drains and gutters or fix up other areas on your roof to make the most of your roof specialist.

The table below sets out the costs of roof maintenance and other repairs:

Flat Roof Replacement Costs (Supply Only)

Considering fitting the flat roof yourself?

Labour takes up a significant chunk of any amount budgeted for flat roof costs, so it is a good idea to get a sense of how much the project will cost without additional labour fees. This gives you an idea of how much the labourers charge when they present a quote.

So, how much does a flat roof cost per m² in the UK?

Typically, this depends on the material. Check out the image below for the details of the different materials and the prices they go for:

Additional Flat Roof Replacement Costs

There are a few other costs to consider when dealing with a new flat roof. In this section, we’ll consider some of the other jobs that might need to be carried out before you lay a flat roof.

Scaffolding Costs

By law, scaffolding is necessary for any job that requires height. Since replacing a flat roof requires the labourer to climb to the roof, some scaffolding might be necessary.

There are situations where a ladder could do the job, but this isn’t the case with flat roofs as they take a considerable amount of time.

So, what is the cost of hiring scaffolding when repairing a flat roof? The average price should be about £900 to £1,000, but this figure can fluctuate depending on the size of your house and the amount of scaffolding required.

Gutter Cleaning Costs

The term "flat roof" is slightly disingenuous as the roof isn’t really flat, but slanted somewhat to ensure that water and debris don’t pool together and cause damage over time.

That said, even with the water sliding off the roof, debris, leaves, and so on can still cause a problem if they are left unattended. Not only do they damage the roof, but they can also clog up the gutters and drainage system. In this case, you’ll need to have your gutters regularly cleaned.

If you are worried about the cost of gutter cleaning, then you can rest easy as this is a straightforward DIY job. But, if you'd prefer to have a professional take care of it for you, you can expect costs of around £200.

Roof Repair Costs

Before work can commence on your flat roof, most contractors will inspect it to ensure that there are no persisting problems. Depending on the type of roofing issue, the cost of roof repairs can range from £250 to £300 per beam if you need to repair your roof joists, to £10,000 and above for a full roof replacement in extreme cases.

How Much Does a Flat Roofer Cost?

As alluded to earlier, the cost to fit a new flat roof is shared between the necessary materials and labour.

Therefore, if you are hiring professionals to handle the job, you’ll need to get hold of a good roofer with adequate experience. They will usually charge between £25 to £50 per hour.

It is also essential to consider that the job of fitting a new flat roof could take up to two days. In addition, most roofers require an extra hand to carry out their jobs effectively. Therefore, you will likely be paying two people for the job.

Most contractors will include their prices with the overall cost to replace the flat roof. So, pay attention to the quote to ensure you aren’t charged arbitrarily. Generally, a flat roof replacement should cost somewhere between £200 to £500 in labour fees.

However, the price and timescale for the job could change in some circumstances. For instance, the material used could impact the time necessary to carry out the job, as some materials are easier to work with than others.

Also, ease of access is vital. The job will take a longer time if the labourers don’t have an easy way to get to the roof. For this reason, a scaffold might be necessary. This not only ensures the safety of the worker but also saves time.

What Impacts Flat Roof Replacement Costs?

Presenting accurate prices for flat roofs is tricky as so many factors affect the price, from the size of the house to the expertise of the labourer. In this section, we’ll examine some vital factors that affect the cost of replacing a flat roof.

Type of Flat Roof

There are four commonly used materials in the construction of flat roofs. They include felt, rubber, fibreglass, and lead. These four materials all have different properties and drawbacks. In terms of price, felt is perhaps the most affordable, while lead could cost a pretty penny.

Not only the price, but materials can also affect the amount of time needed for the job as some materials are easier to work with than others. On top of that, some contractors might increase their price, depending on the complexity of the job.

Location of the Property

The cost of living in large cosmopolitan cities is pretty expensive. This usually has a knock-on effect on other things, including food, and, in this case, labour costs. Therefore, if you live in a big city, a new flat roof cost could be higher than initially expected.

This is also true in rural areas as the availability of competent tradespeople might be hampered due to the location which could lead to an increase in the price.

Also, if your home is distant from the company or tradesperson coming over to embark on the project, this could increase. This is due to the common practice of contractors billing clients from the moment they leave their offices or workshops. Therefore, a long commute could end up costing you a lot of money.

Ease of Access

There are a lot of things that could affect the time and effort required to install a flat roof. One of the most important is the ease of access to the roof. Each project comes with its own set of challenges. This will include existing problems on the roof or the need for additional materials.

For instance, if the roof is for a three-storey building, scaffolding will be required. This will obviously come with additional costs. Also, if the roof is in poor condition and there are clogged gutters, and so on, this will reduce accessibility and hike up costs.

Size of the Flat Roof

Size matters. This is not only because of the material but also the amount of labour required and the time needed to finish the project. As mentioned earlier, a felt roof could cost somewhere £40 to £70 per m² and this means the total cost of the roof will depend on how large it is.

For instance, the price of installing a flat roof on the entire house would be significantly more than just doing the porch roof. Apart from materials, since larger roofs take more time, the labourers are likely to cost more money.

Scaffolding Hire

Scaffolding is a necessity for most height-related jobs in the UK, which means you might want to add scaffolding costs to the budget. Obviously, a flat roof requires some height, and more often than not, a scaffold will need to be erected.

Earlier, we already determined the costs of hiring scaffolding. Be sure to check your quote so as not to end up paying more than necessary.

Waste Removal

Flat roof repairs could get pretty messy, depending on the situation. This is because dealing with waste could be a real problem. Thankfully, most companies deal with waste and add it into their quotes, meaning you don’t have to think about it. However, if you do the job yourself, it might be necessary to pay for the disposal of waste.

What's Involved in Replacing a Flat Roof

Since different materials are used to construct flat roofs, they have slightly different methods for replacing or repairing.

Therefore, in this section, we’ll examine how repairing and replacing might be carried out by professionals and point out how things might differ. This way, you’ll be able to follow up with your contractor to ensure that the right steps are being implemented.

1. Inspecting the Roof

The first step to replacing a flat roof is to inspect the existing one to see if there are any deficiencies and if anything will need changing or repairs. During this stage, the contractor might notice several things, from a sagging roof to blocked gutters.

2. Removing the Old Roof

Once the inspection is done, work can commence. The first thing any contractor would do is remove the old roof before a new one is installed. This varies from material to material as the tools needed might differ.

3. Measuring the Space

Once the old roofing material is gone, the next step is to measure the space. This is important as it informs the contractor how much material is needed for the job. It is usually advised to order more material than necessary; as it’s always better to have a surplus than a deficit.

4. Installing the New Roof

The final stage is the installation. Depending on the material, this can go in different ways. For instance, with felt, the material is laid in place and secured with nails or drills. Meanwhile, with rubber, the best means of securing the material is with a strong adhesive.

Can I Replace a Flat Roof Myself?

DIY roof repairs or replacements are tricky. Although they look easy enough on the surface, there are usually several unseen complexities lurking underneath. The easy answer to the question of replacing a flat roof by yourself is yes.

That said, there is a real case to be made for getting a professional to have a look at the roof, especially as they are trained to notice the little issues in the roof that you might typically identify.

Typically, the first indication of a damaged roof is if there are leaks, but it is possible that this isn’t caused by damage, but rather blocked drainage or guttering.

If you insist on going the DIY route, ensure you have the right tools. This includes a shovel, crowbar, nail gun, hammer, heat gun, and so on. Also, we advise only going down the DIY route if the repairs are small as this saves more money than engaging a professional.

As noted earlier, small repairs are usually problematic as they can cause further damage, and it is best to replace the roof if there are any problems.

While repairing the roof yourself is possible and much cheaper, a poor job could lead to structural issues which will only come back to haunt you in the future. More so, it could even become a safety hazard if left unchecked.

Building Regulations for a Flat Roof

The British building regulations are the prevailing legislation when it comes to dealing with a flat roof. Since the work usually carried out is less complicated, there aren’t any particular rules to live by.

As with most other roofs, the regulations stipulate that the roof must be at a slope of 1:80. In addition, it is also necessary to have a competent drainage system. Also, ensure that the roof is strong enough to walk on and is insulated if cold.

Apart from that, any other necessary regulations will be pointed out by a contractor.

Planning Permission for a Flat Roof

There’s generally no need for any planning permission to carry out work on an existing roof. However, there are some exceptions, including if the new roof will work differently from the previously installed one.

Also, if there are to be any structural alterations, then permission might be necessary. Again, just like with building regulations, your contractor should bring this information to your notice.

Choosing a Flat Roof

Flat roofs are commonly defined by the materials used in their construction. It can be tricky determining the best flat roof material, so this section will focus on the different materials and their advantages and disadvantages to help you decide.

Felt Roof Cost

Felt roofs are made with a felt material. They are also made to be light and easy to install. They are also one of the more affordable flat roof variants.

Pros

• ✔ They are affordable and save money
• ✔ Maintenance is a lot easier and cheaper than other types
• ✔ They are a lot easier to work with

Cons

• ✖ Due to the quality of the material, they typically do not last long
• ✖ Depending on the weather conditions, they can get damaged quite easily
• ✖ Once repairs are carried out, they don’t look very aesthetically pleasing

Rubber Roof Cost

Rubber roofing, as the name implies, makes use of rubber in its creation. It is generally easy to work with, and replacing it will require the contractor to cut up the existing rubber with a knife to dispose of it.

Pros

• ✔ It is much more eco-friendly
• ✔ The installation process isn’t difficult
• ✔ The material is resistant to thermal shock

Cons

• ✖ The colour fades over time, and it doesn’t look nice
• ✖ Rubber isn’t a great material for DIY enthusiasts to work with
• ✖ It can be scarce and difficult to find

Fibreglass Roof Cost

This is usually made with layers of fibreglass, which is reinforced to protect the roof further. Fibreglass roofs cost between £190 to £250 per m², and the material is popular since it tends to last longer than a lot of the other variants available.

Pros

• ✔ Since it is such a versatile material, fibreglass is the go-to material for many homeowners, and its beautiful aesthetic doesn’t hurt
• ✔ It is pretty lightweight
• ✔ The material is easy to access and exists in abundance in the market

Cons

• ✖ It comes pre-cut which means additional work might be necessary to get the required shape and size
• ✖ Maintenance isn’t easy and requires the attention of a professional
• ✖ Fibreglass needs to be handled with care, which makes it less suitable for DIYers

Lead Roof Cost

Lead roofs are typically the most durable due to the materials involved in the creation. This means they last really long since they are water and corrosion-resistant. Also, they require a slightly different method for maintenance, which is called ‘flashing’.

Pros

• ✔ Lead is highly flexible which makes it really convenient to work with
• ✔ It is incredibly durable and stays in good condition for a while
• ✔ Lead roofs are recyclable which also makes them eco-friendly

Cons

• ✖ Lead is in low supply and is difficult to come by
• ✖ It is a toxic substance, so if it affects the water in a home, it could be potentially harmful
• ✖ It is a pretty heavy material, which means that if the underlying timber isn’t strong enough, it could cause sagging

What Flat Roof Alternatives Are There?

While flat roofs are great, there are other alternatives available to homeowners that they might find more attractive. In this section, we’ll consider some of the more common ones.

Roll-on Roofs Cost

These are very decent alternatives to traditional roofs and are incredibly easy to install. They simply need to be rolled in place and nailed.

Pros

• ✔ They are easy to install
• ✔ They are cheap and affordable

Cons

• ✖ They don’t last very long

Sheet Metal Roofing Cost

Sheet metal is incredibly durable and is used for a lot of structures. Not only does it last long, but it doesn’t rust or corrode, which means it tends to look really nice. Therefore, this is an excellent option for shed roof replacements, barns and other outbuildings.

Pros

• ✔ It is a durable material to work with
• ✔ It doesn’t rust or corrode

Cons

• ✖ It is heavy which could lead to sagging

Asphalt Roofs Cost

Asphalt roofs used to be really popular, but this is changing. That said, it is quite affordable as it is similar to felt material. It is usually the best option if you are renovating on a budget.

Pros

• ✔ It is very affordable
• ✔ It is easy to work with

Cons

• ✖ It has a short lifespan, meaning you might need to change it only a few years after initially installing it

Do I Need to Replace My Flat Roof?

Unsure if your flat roof needs replacing? While flat roof repair is usually frowned upon, there are situations where they might become necessary.

In this section, we’ll discuss some of the reasons to replace your roof and the signs you might notice.

Leaking

This is one of the most common signs of a roof in need of repairs or replacement. Roofs are made to keep water out and protect the home from the weather.

Therefore, if there is water seeping into the house, this is a sure sign that there might be a problem with the roof.

Algae stains

Airborne algae might settle on your roof and, over time, could start to discolour it. While it might not necessarily affect the shingles, it doesn’t make for pretty viewing. If you’ve had your roof for a while, this could be a good opportunity to replace it.

Moss

Moss tends to grow between little spaces in the roof, especially in colder climates. Also, while they might not be a great danger, they generally don’t look right. Removing moss isn’t difficult, but you need to be careful to ensure that you don’t damage other parts of the roof in the process.

Cost of Flat Roof Removal

Removing a flat roof is usually done when it is about to be repaired or a new one installed and is therefore usually added to the flat roof repair cost. That said, there are situations where removing the roof might be part of another project, such as converting the roof.

In this case, a professional will likely charge between £80 to £100 per m². Once the removal is complete, disposal is the next problem, and while most companies will add it to the initial bill, some contractors will bill between £100 to £150 to get rid of the waste for you.

Checklist: Hiring a Roofer to Replace Your Flat Roof

Before you hire a professional to work on your flat roof, consider the following:

• What qualifications are needed: A good example is a Level 3 (NVQ) Diploma in Roofing Occupations.
• What experience do they have? Two years plus experience might be a good start, depending on your budget.
• What’s their previous work like? A good portfolio will give you an idea of what to expect.
• Have their previous customers rated them highly? Check for online reviews/feedback on their work.
• Are they part of any accreditation? The more proof they offer of their skillset, the more confidence you will have in their ability.

FAQs