Domestic roofs always come in a variety of shapes, sizes and materials. Whatever the variations are, however, they all have certain features in common that have been developed over many thousands of years to keep the interiors dry and warm. Because the style of roof, its construction principles and types of roofing materials can vary, the cost of a roof replacement can also vary, sometimes significantly. Luckily, If the repair and maintenance work involves removing the tiles or slates, these can often be safely stored and reused with only a few breakages.
A large proportion of the roof repair and replacement costs are taken up by providing access, a safe working area and labour costs rather than materials. Because working on a roof always involves an element of risk, you will find that most roofers work either with another roofer or a labourer so that lifting and carrying can be done safely.
Main Topics
Types of Roof
- A Flat Roof is a basic roof, comprised of a flat surface with just enough slope (or pitch) to allow rain to run off.
- A Shed Roof is a steeper version of a flat roof and gets its pitch by having two parallel walls at different heights.
- A Gable Roof is the roof type commonly found in temperate climates and good at shedding rain or snow. Furthermore, it is the simplest of ‘proper roofs’. This style was made popular by the Ancient Romans who made all of their structures with this roof. It consists of two pitched surfaces raised and joined in the centre at a ridge board and sloping away to the eaves. The slope can be steep or shallow depending on the purpose.
- A Hip Roof has four slopes of the same pitch joined in the middle by a ridge board. At least two of the opposite slopes are triangles, the joining edges of adjacent slopes being called ‘Hips’.
- A Gambrel Roof is also called a Dutch roof and is a version of a Gable Roof but with two different pitches on each roof slope, the upper pitch being shallower than the lower pitch.
- A Mansard Roof is a type of Gambrel Roof but with four surfaces like a Hip Roof. Similarly like a Gambrel Roof, each surface has two different pitches.
You can probably see the difficulties with constructing some of these roof profiles. Firstly, if the roof has a steep pitch and a high ridge it will be more difficult to access so will be more expensive. Similarly, a complicated construction like a Hip, Gambrel and Mansard will need more skill to build than a simple Gable or Flat roof and so be more expensive.
Finally, as if that wasn’t all, there are also two ways to build a roof:
- A Cut Roof is where the roof rafters, joists and other components are cut to size from individual timber pieces on-site and fitted one at a time. Often oversized timber components are used to ensure each component is strong enough.
- A Roof Truss is where each ‘A’ frame is built in a factory, transported to site and assembled into a roof. Because each truss is designed and assembled beforehand, the timber components are only as large as they need to be.
Types of Roof Material
The purpose of a roof is to protect the house interior and its residents from all the forces of the outside world. Furthermore, the style and building material will vary depending on its location in the world and the local climate. Because of this, a roof in one country may be there to protect the interior from rain or cold, while in another country its purpose may be to give protection from heat or predators. Traditionally the roofing material would have been the most easily accessible waterproof material available from the area. It is probably obvious that clay tiles were the materials in areas where rivers were common, thatch in agricultural areas, and slate in areas where this type of rock was mined or quarried.
Nowadays we do not have this limitation as most materials are available nationwide through a network of Building Supply Merchants. Additionally, you may find that local Planning Laws restrict the types of roofing materials you can use to those that are in keeping with the area. Always check with your Planning Department before starting work and changing anything, as altering the roof type (or profile) or roofing materials will always affect the average roof cost if changed part-way through the project.
General Roofing Costs
You can see the approximate costs for a gable roof of about 55m2 from the following tables.
| Item | Average Roof Repair Cost | Extras | Notes |
|---|---|---|---|
| Roof repair | £50 per hour | Materials extra | Slipped & broken slates and tiles |
| £150 to £200 per half day | More extensive repairs | ||
| £300 per day | Larger jobs including roof flashing repair etc. |
You can also see an itemised breakdown of the average cost for a new roof.
| Item | Cost |
|---|---|
| Complete tile replacement | £4000 |
| Roof Battens | £100 |
| Lead Flashing | £100 |
| Lead Valley | £100 |
| Roofing felt/breather membrane | £100 |
| Fixings | £20 |
| Roof Tiles | £750 |
| Scaffolding | £700 |
| Ridge Tiles | £100 |
| Labour (1 week, 2 people) | £2000 |
The Cost of Roof Tiles
You can probably see that tile and slate roof costings will vary depending on the chosen material and profile.
| Item | Cost per m2 |
|---|---|
| Concrete Tiles | £12 to £25 |
| Clay Tiles | £25 to £40 |
| Slate Tiles | Up to £70 |
Components of a Roof
In order for you to fully understand how a roof is built and the difference in labour costs, you must have an understanding of what each piece is called together with its function.
- A Ridge is the highest level where two opposing pitched surfaces meet. Rafter pairs always push against a ridge board.
- A Valley occurs when two surfaces meet on the downward slope, the resulting ‘V’ profile is called a Valley.
- A Hip is formed when two surfaces meet on the upward slope.
- Flashing is the term given to a waterproof seal between the roof and the building structure. It is usually made from lead but can be copper or synthetic plastic-based materials.
- A Verge on a gable roof is where the roof edge is exposed.
- An Eave is formed where the bottom edge of the roof overhangs the building walls.
- A Rafter is a length of timber that forms the pitch of the roof and is supported between the top of the building’s walls and the ridge board.
- A Joist is a horizontal timber component that spans the building on top of the walls, tying together opposite rafters.
- Roofing felt is a continuous flexible layer made from a waterproof material that prevents moisture from entering the roof space. It is tacked directly to the rafters.
- Roofing Battens are lengths of timber with a small cross-section, nailed to the rafters on top of the felt onto which tiles are fixed.
What can cause a leak?
Leaks are the main reason why you will need to have roof repairs or replacements. But what causes a roof leak?
- Damaged or cracked roof tiles.
- Damaged or cracked lead flashing.
- Damaged roof valley.
- Blocked valley.
- Cracked ridge tiles.
- Loose mortar of verge tiles.
All these are caused by weathering from frost, snow, wind and rain. Some are even caused by pests such as birds and insects.
How long can you expect a new roof to last?
This depends on what the roof materials are, whether it has been fitted by a qualified roofer and the quality of the roofing battens.
| Roof covering | Expected average lifespan |
|---|---|
| Welsh & Cornish slate | 150 to 200 years |
| American slate | 75 to 125 years |
| Canadian slate | More than 100 years |
| Spanish slate | 40 to 50 years |
| Chinese slate | 60 years |
| Composition slate | 10 years |
| Clay Tiles | 60 years |
| Concrete Tiles | More than 60 years |
FAQ
Are there any roof replacement grants available in the UK?
There are grants available from your local council to help with the cost of repairing and replacing faulty roofs, however, the actual details vary depending on the council so you must check if you are eligible. Factors affecting this include:
- Whether your annual income is under a certain amount.
- Perhaps your roof does not meet the required standard.
- Maybe, you have a specified disability.
- Perhaps you intend to renovate a previously empty property.
There are other requirements and eligibility standards that may apply. You should contact your local council for full information on the grants available in your area.
What is the cost of replacing roofing felt under the tiles?
This depends on the extent of the damage to the existing roofing felt and how easy it is to access the roof. Unfortunately repairing or replacing roofing felt always involves removing and replacing roof tiles, while sometimes the flashing will need replacing as well as the felt. These are all skilled and difficult jobs to do properly so always get a professional to carry out this kind of work.
| Repair small section | Cost |
|---|---|
| Labour (2 people) | £300 |
| Access scaffold tower hire | £150 to £200 |
| Materials (new breather membrane, battens & mortar) | £50 |
| Repair felt around eaves | Cost |
|---|---|
| Labour (2 people) 2 days | £550 |
| Access scaffold tower | £150 to £200 |
| Materials (membrane, battens, replacements for damaged tiles) | £150 |
For a complete refelting job, you must remove all the tiles, store and replace them afterwards. For a typical 100m2 detached house, the following costs apply.
| Item | Cost |
|---|---|
| Roofing/breather felt, battens, replace broken tiles, flashing | £600 |
| Labour | £3,500 |
| Access scaffolding | £1,000 |
Are There Any Permits and Planning Required?
There are a few points that you need to be aware of regarding UK Building Regulations.
- If you are replacing more than 50% of the existing roof covering, you must upgrade the roof insulation to current standards.
- If you repair or recover less than 25% of an existing roof, you don’t usually have to submit a Building Regulations application.
- You will need approval if you want to carry out structural alterations or the new covering is of a different fireproofing standard.
- You will need to comply with Building Regulations if the roof covering is different and will affect structural stability (eg changing the covering from slates to concrete tiles considerably increases the weight of the roof which will, in turn, require stronger rafters and additional braces).
- Depending on the appearance of the new roof you may have to submit a planning application.
If you are in doubt, always contact your Planning Department and Building Control office to check if you have to comply with any regulations or apply for any permits.
Your roof is an important part of your house and as such it must be built and repaired properly to maintain its structural integrity and its weatherproofing. Although your roofer may not need any special registrations or qualifications, it is always a good idea to make sure they do. Most councils run a ‘Competent Roofer Scheme’, so that skilled roofers can self certify their own work for a nominal fee. If your roofer is not registered he will have to pay a larger fee because a Building Control officer will have to inspect the roof on completion.
Still Looking For A Roofer?
Although the average cost to replace a roof always seems like a large expense and one that could be avoided by doing the work yourself, it is always better in the long term to employ a professional.
- Professional roofers are aware of the dangers involved in working at height.
- Professionals appreciate how each component of a roof works together to provide a completely stable and waterproof unit.
- They understand how to fix and remove each component in the best possible way.
- Trained roofers are aware of the requirements of the UK Building Regulations.
- They understand the properties of different roof coverings.
Furthermore, the cost of scaffolding is always a large proportion of the total house roof replacement cost so you should always consider getting any other roofing work done while the access is available. Tasks that may probably need doing include repointing the chimney; cleaning, repairing and adjusting guttering; fitting and adjusting rooftop television antenna; painting and repairing fascia boards; cleaning moss from the roof surface. If you leave this extra work until a later time, it will involve erecting the scaffolding again and probably incur extra costs.
There can be a lot of work involved to keep your roof in good repair using regular maintenance. However, if you look after your roof, you can be sure that your home will remain warm and dry for many years to come.