Job Costs Roofing

Costs Involved in Flat Roof Replacement


If you have a flat roof on your home, garage, office, or work building, then you’ll understand that there comes a time when the roof needs to be replaced or repaired, just like pitched roofs often need to be repaired too.

In this article, you’ll find out just how much it costs to replace or repair a flat roof. We’ll also give you all the essential information to keep costs down and get a good job done.

Flat Roof Replacement – How Much Does it Cost?

Flat roof waterproofing

Of all the types of roofs that you can put onto a building, a flat roof is by far the least expensive. The low cost of attaching a flat roof to a home, as well as the cheapness of maintaining it, is one of the big reasons why people opt for this type of roof.

There is no expensive cost of tiles, and the labour time required for a professional to fit the flat roof is also dramatically reduced as opposed to a pitched roof.

You can put a flat roof on any building, but homeowners commonly have flat roofs on a single garage or double garage, as there’s no need for insulation in this room. It can also allow for more space within the single garage or double garage too.

There are, of course, some disadvantages that come with a flat roof as well. The biggest of these disadvantages is the life expectancy of a flat roof. Unlike tiles roofs, which can easily last 20 years without needing to be repaired or replaced, a flat roof will require regular maintenance, and you can expect its life expectancy to be much less than 20 years.

On average, a flat roof will need to be replaced every 5 to 10 years, or, if you are lucky, then it could last 15 years.

Two main types of flat roofs are fitted onto buildings. The difference between the two is the level of insulation. A ‘cold flat roof’ is a flat roof that doesn’t have any insulation. Cold flat roofs are typical in buildings that are used for functional reasons rather than where people live. It’s most likely that your garage roof is a cold roof rather than a warm roof.

Flat roofs that are used for homes, offices, and buildings where people live or work will require more insulation. This type of roof is referred to as a ‘warm flat roof.’ When it comes to flat roof cost, then a warm flat roof will cost more than a cold flat roof simply because of the insulation.

The main costs that you will incur – whether you want your flat roof replaced or repaired – are the cost of the materials and the cost of the labour. A professional roofer will always attempt to do the job as quickly as possible, but we recommend that you agree on the timeframe in advance.

Paying for the job, rather than for the hour, can also help to keep costs down, too. This website will provide you with excellent tradespeople who you can contact for an easy, quick quote for getting your flat room replaced or repaired.

The Average Prices of Replacing a Flat Roof

The price of replacing a flat roof will depend upon a few different variables.

The first consideration is the type of material that the flat roof will be used to construct it. Felt, rubber, fibreglass, and lead are all used for a flat roof. The cost of a flat roof will generally be determined in price per square metre. Of course, this means that the larger the area of the roof, then the more money you will need to spend on a new flat roof. You will also need to consider the amount of labour required for a replacement flat roof.

Let’s have a look at the average price per square metre for the different materials.

A felt roof is the cheapest available flat roof. For a felt roof, then you can expect to pay an average cost between £40 and £50 per sqm. This cost might go up again if the boards fitted beneath the felt also need to be replaced. This would work out for the average double garage at the cost of approximately £700.

You will need a roofing professional to do the felt roof for you. To fit a felt roof onto a double garage, then you can expect the job to be done within two working days. If it isn’t a garage roof from felt that you need doing, but a felt roof for an extension to your home, then the roof will require insulation too, and that means that the new roof will end up costing you a little more, with the materials costing closer to £800, and the labour cost coming in at £500. This job will also take a roofing expert two days to finish.

A rubber roof is also standard when people look for a flat roof replacement. New rubber roofs cost more than new felt roofs. To get a professional roofer to do this job for you, then you can expect to pay at a rate of £250 per day for them to do the job. The materials will cost about £80 per square metre.

Once again, if the boards that sit beneath the top layer of rubber are damaged in some way, then they might also need to be replaced, which will push up the costs of material, and may require the roofing company to spend more time doing the job.

Fibreglass is another common material that’s used for a flat roof. This roof covering material will cost you more than felt or rubber. There are two types of fibreglass roofs that people tend to get fitted on their homes. One is a simple flat roof, and this will cost you about £90 per sqm.

Whereas if you want to get a bay flat roof, then the average cost for the materials and labour will be a little higher, as it requires more labour time, and there are more intricate finishes that the roofing expert will need to do. For the materials and labour, you can expect to get a bill for £250 per sqm.

Lead is the most expensive of all the flat roofs materials. A lead roof is far more costly than a simple felt or rubber roof. It’s not possible to suggest an average price for a lead roof because the price of lead fluctuates as it’s a raw material.

Make sure that you check all your options before investing in a new lead roof, as this is not the most cost-effective form of flat roof on the market. It will, however, last much longer than a felt roof.

Key Information About Replacing and Repairing a Flat Roof

Flat roof repair

Although it’s possible to estimate the average prices of the cost of repairing or replacing a flat roof, you won’t know precisely what you will pay until you have had a visit from a professional roofer. This is simply because the roofer will need to inspect the roof carefully before they can estimate what work needs to be done.

Underneath the roof covering or felt, fibreglass, lead, or rubber, there are wooden boards. If your flat roof is leaking or it’s old, then there’s a chance that these wooden boards are damaged or even rotting. A roofer cannot know this until they start working on the roof or have, at the very least, inspected the flat roof.

If your roof just needs the felt replacing, then costs can be kept down, both on new materials and labour. But if you need new wooden boards, then the roof replacement job will take more time, and, of course, you’ll need to get new boards, which means more costs on materials.

Everyone will get a flat roof replacement for a different reason. And depending on why you’re getting a new flat roof put on your home, then you also may want to consider whether you need to increase the amount of insulation that the roof offers.

As we’ve learned, you can have a cold or a hot flat roof, with the former having no insulation and the latter being insulated. If you’re transforming a garage into a livable room or a workspace, then you may want to ask the roofer to insulate the roof at the same time. Of course, hot flat roofs will always cost you more than cold flat roofs.

It also isn’t always entirely the best idea to get a whole new flat roof. Cost can be kept down if you simply go for a repair job instead. Flat roof repair will always cost you a lot less than a replacement. Your roof might be leaking because the layer of felt at the top has become damaged.

This is due to weathering or because of another external circumstance. You can simply call a roofing company to come in and replace the felt or patch up the felt instead of getting a whole new roof put on.

It’s a little more complicated if rainwater is pooling on your flat roof. This can be down to several issues. Firstly, there may be a structural problem with the roof. Perhaps the previous owners of your home didn’t employ a reputable roofing company to do the job, and the roof is simply structurally unsound.

If this is the case, then repairing the roof might not be possible, and instead, you will need to get a replacement. Flat roofs shouldn’t actually be flat. If they are, then water will collect on them. There should always be a gradual incline, as this allows for drainage. A roofing expert will explain this to you.

Costs can rise if the structure of the roof needs to be altered during the job, but it won’t cost dramatically more, especially if you’re getting a replacement roof put in anyway. It won’t add much to the labour time, and it shouldn’t add too much to the cost of roofing materials too.

Are Professionals Required to Fix or Replace a Flat Roof?

In theory, a homeowner can purchase the materials to fix or replace a flat roof and to do the job themselves. But this isn’t recommended. It’s a difficult job that will have many negative consequences if it isn’t done right.

A poorly repaired roof or poorly made replacement flat roof will be more susceptible to leaks. It may look worse than a roof made my a professional. And it could also have drainage issues. On top of this, home insurers may raise the price of the policy if they discover the homeowner has repaired the roof. That is unless the homeowner is a professional roofer.

If you have an issue with your flat roof, then the best option is to contact a professional. They can visit your home, inspect the roof, and then provide you with their professional opinion on how to proceed. A pro will pick up on things that a homeowner will not notice.

For example, a homeowner may look at a crack in the roof and think that a new layer of bitumen will sort the flat roof out. A professional, however, may look at the same roof and realise that there are major structural issues that need correcting, or they may notice that the wooden boards under the top layer need to be replaced as they are rotting.

In the long-run, you’re better off with a professional, as it will actually cut costs down. A professionally made roof will last longer than any repaired roof that the homeowner does. Also, it’s much easier. A professional can choose the right materials, order them, and then do all the labour required for replacing the flat roof.

Yes, you may save a bit of cash on attempting to fix or replace the roof yourself, but you could get hit in the back pocket in the long run. This is especially true if you’re planning on selling your house, as a surveyor might observe that the repair to the roof hasn’t been done properly. This could knock some money off the price you can ask for you home, as the future owners will want to hire a professional to replace the roof.

Important Facts About Flat Roofs

Modern house with flat roof

A flat roof is the least expensive form of roof that you can put on your home. Flat roofs are also more susceptible to leaks, weathering, and other issues as opposed to pitched roofs. But that doesn’t mean that flat roofs aren’t a good option. They are ideal for certain uses. A garage or a single-floor extension to the home can be an optimal building for a flat roof.

There are a variety of materials that flat roofs can be made from. The materials that you choose to make your flat roof from will affect the cost of the job. The most cost-effective material for a flat roof is felt. Other materials that you can make a flat roof from include lead, rubber, and fibreglass. The style of roof that you choose, such as a bay roof, can cause costs to rise, but you also get a better-looking roof for the money.

Flat roofs have to be weatherproofed. Different materials can be used for the weatherproofing of a flat roof. But the most common material that roofers will use to proof the roof is a bituminous felt.

Flat roofs need to be inspected regularly by the homeowner. Without regular inspections, small cracks can turn into major crevices that cause leaks. This may damage the inside of the room that the roof is on top of, or it could cause damage to the wooden boards that are found underneath the roof’s primary material, such as felt, rubber, fibreglass, or lead. Rotting boards mean that the roof needs to be replaced entirely.

Regular inspections by the homeowner should be done every year. It’s also essential to get a professional roofing expert to visit your home every four or five years to check on the status of your flat roof. Even though your room might seem like it’s in perfect condition, a professional will pick up on things that you will not notice, and getting their opinion can save you in the long run.

It’s highly recommended that a pro roofer should do a flat roof repair or replacement job. If you employ a company that specializes in fixing or replacing flat roofs, then you will have a roof that will last much longer than if you attempt to do the job yourself.

You can expect a roof that’s been made by a professional to last at least fifteen years. Still, there’s even a possibility that it can last even longer. Especially if you maintain the roof properly, give it regular inspections, and have a pro roofer visit your home every four or five years to check that everything is okay with it.

Remember, working on a roof can be dangerous, and expert roofers do it all day, whereas you, as a homeowner, are not used to work of this sort. It’s safer to get an expert roofer to do the job.

Most Common Questions About Flat Roof Repair and Replacement

Does Water Collect on a Flat Roof?

Rainwater on flat roof

If a flat roof was entirely flat, then you would expect puddles of water to gather on the roof, which would then lead to stagnant water to sit on the roof for long periods or for the roof to sag and buckle under the weight of the water. But a flat roof isn’t exactly flat.

There’s a slight incline in a flat roof. And this allows water to drain off the roof and into the guttering naturally. If water is collecting on your roof – also known as pooling – then you’ve got a problem, and that means that you need to contact a professional roofer to discover if you need to get your roof replaced or repaired. No roof that’s in good condition will have an issue with pooling.

Do Flat Roofs Require Maintenance?

All roofs need maintenance. And flat roofs are no exception to this rule. It’s entirely up to you how often you choose to inspect the roof yourself, but it’s worth checking at least once a year. This step is more critical if you live somewhere that has extreme weather conditions.

There are lots of parts of the UK where a significant amount of rain can fall from autumn to spring. You may also live in a part of the country where snow and freezing temperatures are common. All these weather conditions can shorten the life of a flat roof, especially if you don’t inspect it properly.

The best time of year to do it is when the weather has improved. This will allow you to see what you’re dealing with. Hiring a professional roofing expert to do the job in the summer will be easier for everyone.

Are Flat Roofs Insulated?

Flat roof house

There are two types of flat roofs that you can choose from. One type has insulation, and another type doesn’t have insulation. It’s possible to insulate roofs that are made from rubber, felt, and fibreglass. The choice is up to you if you pay the extra cost of getting the roof insulated.

A warm roof – with insulation – is necessary for any room or building that will be occupied by people for long periods. A cold roof – without insulation – is excellent for storage rooms or as a garage roof. If you have a single garage that you keep a car in or you use the single garage as a workshop, then you can probably get away with a cold roof.

If you’re considering converting a garage into a workroom, office, or a habitable room in the future, then you may wish to get insulation put in now rather than needing to do it in a few years.

If a Flat Roof Leaks, Does it Need to be Replaced?

A flat roof will need to be replaced only if the general condition of it is poor. One leak doesn’t mean that you will need a new flat roof, especially if the roof is otherwise in good condition. As always, if you call in a flat roofing expert to inspect your roof, they will be able to tell you if you need a new roof put in or if a roof repair job will be sufficient.

Of course, cost needs to be considered too. If the roof isn’t in good condition, then patching up the top layer of felt, rubber, or fibreglass will only take you so far. Repeatedly paying repair costs can end up costing more than just getting a flat roof replacement.

Do Home Insurers Treat Flat Roofs as the Same as a Front Gable Roof or Other Roof Types?

Flat roof house

Whenever you make any structural changes to your home, then you must always make sure to contact your insurers to inform them of the changes. If you’re simply replacing one flat roof with another, then it’s unlikely that the insurer will dramatically change your policy based on it.

Of course, one flat roof material might be preferred to another, so if you’re downgrading from fibreglass to felt, for example, then perhaps your policy might become more expensive. Compared to a front gable roof, however, a flat roof is treated differently by an insurer.

That’s just because it’s got more of a chance of leaking. A flat roof – whether it’s felt, rubber, lead, or fibreglass – doesn’t offer the same stability and security of a front gable roof or other types of pitched roofs.

Do Flat Roofs Need to be Inspected?

Yes. They do. Firstly, they need to be inspected regularly by the homeowner. Catching any leaks or damages early is the best way of keeping costs down. Flat roofs are prone to leaks, so keeping an eye on them, especially after extreme weather conditions, is always a good idea.

It’s also important to get regular inspections done by flat roofing professionals too. This is an official job that should end with a certificate of approval from the professional flat roofing expert.

If they give your roof the all clear, then you can be guarded against any issues with your home insurance provider if, for example, you are forced to put a claim in for a leak or for a repair job. These inspections only need to be done approximately every 4 or 5 years.