Estimate for single storey extension: House Extension Cost | Project Estimates

How Much Does an Extension Cost in Scotland in 2023? – Learn – Coldwells Build

Our comprehensive guide contains up-to-date figures to help calculate your extension project, plus variables to consider when working out cost in 2023.

If you’re craving extra space in your home, but don’t want the hassle and expense of moving, then a building extension could be the answer.

But how much does an extension cost? Unfortunately, that’s a bit like asking how much a car costs – there is no simple answer. A Ford and a Ferrari will both get you from A to B, but one is priced much higher than the other. The same principle applies to building an extension. There are so many variables which impact price, that it’s impossible to create a blueprint which will apply to every project.

However, you can estimate the average price of your extension, using cost per square metre (£/m²). If you don’t yet have construction drawings, the cost per square metre build rate is a rough guide of what you can expect to pay. We’ll take a closer look at cost per square metre later on. Firstly, let’s consider the major factors which influence an extension’s price.

Size, Shape, Height & Extension Type

There are many different types of extension to add space to your original house, including:

  • Single storey extension
  • Multi-storey extension
  • Semi-detached extension
  • Kitchen extension
  • Bathroom extension
  • Garage conversion
  • Conservatory extension
  • Loft conversion
  • Basement extension

The biggest impact on price is how the space will be used. For example, a kitchen or bathroom extension will cost more than a small office or playroom extension. Typically, the larger you go with size, shape and storey height, the more you can expect to pay.


Finishes and Specification

The quality of materials you finish your extension with (the specification) will also play into your final cost.

Think of this as you would the star rating of a hotel. A standard-spec finish (3 stars) with off-the-shelf laminate flooring, basic quality MDF skirting boards and windowsills, and standard lighting fixtures are cost effective options.

High-spec luxurious finishes (5 stars), such as solid wooden flooring, natural stone tiles and custom-built cabinetry and internal doors will add a unique look to your home, but also increase the cost.


Type of Construction

The construction method will also influence cost. A simple timber frame extension will be more economical than a complex steel frame addition. Similarly, the type of building materials used in the external finish – timber cladding, glass, metal, stonework – will all vary in price. Changes to steelwork or walls in your original home will see extra costs.


Windows and Doors

If you choose triple glazing, window seats or bifold doors, then you’ll have to budget more than standard, off-the-shelf windows and doors. The type of materials will also affect price. For example, uPVC is more affordable than aluminium or timber.


Kitchen and Bathrooms

For a bathroom, allow an additional £5000. But remember, this price will vary widely depending on the sanitaryware you choose. For kitchens, £10,000 will get you a low to mid-range suite. Bespoke kitchens will cost more.


Demolition and Waste Removal

Will an existing extension or structure need to be demolished before your new extension can be built? This will need to be factored into the cost, along with skip hire and removing waste from the site. If asbestos is present, a specialist contractor will be required to remove this safely. Another important factor to consider is the ease of access to the site. This can add to the costs of transportation of materials, tools and equipment in and out of your property.



Preparing the site, digging foundations and underpinning (strengthening the foundation of an original building) are important works which ensure the structural integrity of your new extension. If your site has sloping ground, expect prices to be higher than if you were building on existing flat terrain. There can also be additional costs depending on whether you’re moving drainage, gas meters, pipework or trees.

House Extension Cost Per Square Metre

Building cost per square metre (£/m²) is a useful method to calculate a ballpark price of an extension, with m² being the total internal floor area of your proposed living space.

Whilst we consider these rates below, we would always advise consulting a professional builder and investing in the initial plans for your extension to ensure it’s designed at a price that’s affordable for you.

Based on our own recent domestic projects in Scotland, we know that in 2023 the construction cost of extending and refurbishing a home falls between the range of: £2500 – £3000 per metre square + VAT.

What Does This Cost Include?

This cost is for building the shell of the extension only and excludes fitted joinery, kitchens and sanitaryware, as these all vary widely in price.

As every building project is unique, this price range should be used as a guide only. Coldwells Build cannot provide an accurate quote without detailed plans from your architect.

Other Costs to Consider

  • Surveyor fees: necessary if a survey of the existing house is required
  • Design team fees, ie – architectural technician
  • Structural engineer fees
  • Quantity surveyor
  • Planning application fee to local authority: planning permission is required, if your extension doesn’t fall within permitted development rights
  • Building warrant fee to local authority: this fee varies based on estimated construction cost
  • Landscaping
  • VAT at 20% of the labour, materials and services
  • Temporary accommodation: you may need to move out of your home for part of the build
  • Storage for goods and furniture
  • Insurance: check with your home insurance provider there are no additional costs for insuring your home for a construction project

How to Make the Most of Your Extension Budget

Opportunities to save money include:

  • Re-using and recycling existing materials
  • Use off-the-shelf products rather than designing bespoke items
  • If possible, time your extension for good weather. Bad weather can mean delayed schedules and if you’re renting while you extend, increased rental costs, too.
  • Be economical with cladding or render, but spend well on the main structure of the extension, including walls, roof, windows and insulation. Whether you’re building a glass extension or a double storey extension, cutting costs with poor materials will only cause more problems down the line.
  • If there’s something specific you want to include in your extension, but your budget won’t stretch, speak to your builder. They can utilise their experience and existing connections to investigate suitable alternatives.

Budget Advice From Professionals

As we’ve learned, there are many factors which influence the cost of an extension, so it’s crucial to establish your budget upfront and stick to it.

To achieve this, we recommend you work with an architect who has a track record of collaborating with builders in the design stage to provide cost visibility from the start.

This simple but fundamental difference saves money and time by transforming the relationship between builders and architects into an alliance which fosters not only creative collaboration, but most importantly, budget control.

The architect manages the creative design, and the builder and architect work together on construction science and costs. When construction costs are monitored and tracked in the design phase, the risk of budget blowouts decreases.

It’s also an opportunity to identify any construction related challenges early on. With practical input from the builder, potential issues can be ‘designed out’ before leaving the architect’s desk, saving time on rework at a later (and more costly) stage.

We always recommend you discuss your budget with your builder, as they can guide you on what type, size and spec of extension it will allow for.

Final Thoughts

Extensions can be complex projects, but with careful planning, they’re the most rewarding home improvements you can make.  

If you’re in the process of planning your house extension and could benefit from some real-world professional advice about budget, logistics, timing or any other elements, then please get in touch to schedule a complimentary planning session.

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The Cost Of A House Extension In Cornwall

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Assuming you would like an introduction to an article discussing the cost of house extensions in Cornwall: The cost of a house extension can vary greatly depending on the size and scope of the project. However, in general, a house extension in Cornwall will cost between £2,000 and £3,000 per square metre. This means that a typical single-storey extension of 20 square metres will cost between £40,000 and £60,000. There are a number of factors that will affect the final cost of a house extension, including the type of extension, the materials used, the builders chosen and the location of the property. For example, a loft conversion will usually be more expensive than a conservatory, and a house in a remote rural area will usually cost more to extend than a house in a town or city. To get an accurate estimate of the cost of your house extension, it is advisable to get a number of quotes from different builders. It is also important to remember that the cheapest quote is not necessarily the best – it is important to choose a builder who has a good reputation and who you feel you can trust.

House extensions on a single storey are an excellent way to increase the value and size of your home. There is no better way to add a single story extension than with a single story house. The construction of a single-story home extension on less than one-third the size of a house requires no planning permission. In Cornwall, a single-story house extension is typically worth £29,000. Costs can vary depending on the materials used and the firm chosen. A single storey extension will set you back around 1,000-2,000/m2. The upper price range can be as high as £34800.

It is located on England’s southeast tip and has a population of more than 500,000 people. It is estimated that Cornwall had the most residents of any second home. If you want to improve your property’s value and appeal, make certain that the work is done by reputable businesses in Cornwall. On April 20, the house extensions on Single Storey St. Ives – TR26 were completed. A month and a day ago, a customer made an inquiry on Quotatis for single-story house extension, and the builder responded, indicating that they would like quotes. I’m interested in prices for both supply-only self-build and included in the installation and foundation suggestions for a self-build home. House Extensions are available for a house on Single Storey Street, Austell, PL25.

Mark W.’s Start Date: Less than a month from now. Currently, a customer is in the process of obtaining quotes for the construction of a single-story extension to their property. The property owner is the owner of the property. The property belongs to the owner. This property is a detached property. S is a good choice. You can get free, no-obligation quotes from four verified contractors in Cornwall.

The best value for money comes from comparing customer reviews, services, and prices. A kitchen diner extension, on average, will cost between £25,000 and $45,500. If you live in London, you can expect much higher costs. When it comes to the total cost of your kitchen diner project, it will almost always be dependent on the size as well as the quality of the finishes. The cost of a small additional item can range between $14,000 and $17,000. The cost of installing a large wrap around the extension with glass on both sides will most likely range from £80,000 to 120,00. A single-story house extension is estimated to cost between £34,000 and £37,000, with a small single-story extension typically taking about three months to complete. The first step in the process is the preparation of the site, which can take up to two weeks. The duration is determined by the size of the project as well as whether or not you intend to live in the house while it is being completed.

How Much Does It Cost To Build An Extension Uk 2021?


Building an extension is a great way to add extra space to your home. The cost of building an extension will vary depending on a number of factors, including the size of the extension, the materials used, the location of the extension, and the amount of work required. Generally, the cost of building an extension will start at around £5,000.

The cost of constructing an additional 2,000 square feet of internal space ranges between £900 and £2,250 per square foot. If you want to sell your house, you must consider whether you will add more value than the extension will cost. If you have expanded the size of your home, it may result in a higher council tax rate. A 30m2 kitchen extension could cost between £40,500 and £67,500, plus 20% VAT. This could easily be between £1,700 and £2,500/m2 in some parts of the South and high-value areas of the United Kingdom. An 8x4m kitchen extension would cost between £43,000 and £80,000 to complete. Side extensions typically cost between £75,000 and £300,000 to construct on average.

A lean-to uPVC structure is the most affordable option when it comes to conservatories. A 20m2 oak frame would cost £2,500 + VAT. You can’t look at your new extension the same way every time you open it, so pay attention to the way it looks from the outside as well as the light you’re bringing inside. Modern construction methods may be more expensive to begin with, but they may also be more cost-effective if less time is required on the construction site. The timber frame can be used as an alternative construction method. A contractor’s estimate is usually what they will charge you for your extension. When working on a larger extension project, it is really beneficial to engage in a quantity surveyor.

It is recommended that written builders’ quotes include information on the scope of the work, a breakdown of costs, and a clear indication of whether VAT is included. Most extensions will be subject to VAT at the standard rate of 20%, especially if you use a contractor to complete the work. One of the most common extension projects that qualify for VAT relief is the following. To claim VAT relief under this category, you must use a VAT-registered builder – you cannot reclaim the VAT on your own.

To ensure you get the best price on a new extension, research and get a few quotes from reputable contractors. Extension costs can vary greatly depending on where you live, so get at least three quotes to ensure you are getting the best deal.

How Much Does It Cost To Put An Extension On A House Uk?

The cost of a 15-meter-by-15-meter rear extension to a single-family house is expected to be between £15,000 and £20,000. In general, the cost of a 25-metre by 25-metre rear house extension is between $30,000 and £40,000. A large (50m2) rear house extension can cost up to £60,000, depending on the size.

How Long Does An Extension Take To Build?

Because the size, complexity, and location of the extension, as well as the experience and skills of the builders involved, do not provide an exact answer. The average time for an extension is between 6-8 weeks for a single-story extension, or 10-12 weeks for a two-story extension, according to a rough estimate.

What Is The Average Price Of A House Extension?


House and room additions range in price from $86 to $208 per square foot on average, with the most expensive costs ranging from $22,500 to $74,000 for homeowners. In comparison, adding a 20×20 family room costs around $48,000 on average, while adding a 12×12 bedroom costs around $17,300. A bathroom can cost up to $18,000 to build.

A house extension is one of the most exciting building projects to complete. The cost of an extension can range from £7,500 for a garage conversion to £160,000 for a basement addition. If you add the extension, it could boost the value of your home by up to 20%. The cost of building in London and the South East of the United Kingdom typically rises above that of other parts of the country. Your contractor may provide you with more or less than the market rate depending on how the project is built, the materials used, the complexity of the build, and the skills he or she possesses. If a project is to be extended, it must first be completed in a very long time. A lot of work is required when trees and shrubbery are removed, as well as when patio and awning removal is performed.

It is recommended that you use an architect or architectural technician to draw up plans for your dream home. The exterior of the shell-only extension is made up of only walls, brick, or block, and a roof. Shell extensions for 2 square meters (m2) cost between £750 and £1,500. It can cost up to £5,500, 000 to upgrade 20m2 of space. Once the work is completed, your living space will have been fully extended. The cost of a two-story house extension with 60m2 of floor space ranges between £106,000 and £150,000. The possibility of legislation speeding up the process of obtaining an extension is one option.

Adding side extensions to an existing room is an excellent way to increase the size of it. Because kitchens are more specialized than bathrooms, the cost of your kitchen extension will be higher. If you want a quicker and less expensive way to add value to your home, consider converting an existing garage. A 15m2 garage conversion can cost between £7,500 and £20,000, depending on the materials and labor used. Despite their high price, basement extensions are becoming increasingly popular. The cost of a rear house extension is determined by the size and complexity of the design. A typical basement extension takes 40m2 of space, which equates to around £100,000-£160,000 in cost.

Costs are affected in addition to quantity and quality of materials used and the rates of individual tradespersons. You can reduce the cost of your house extension without compromising on the vision you want to achieve. Most builders will provide you with an estimate of how long you will need to consult with a specialist or overwatch using standard construction methods. If you require a specialist, equipment, or additional considerations, your costs will rise. A square or rectangular footprint is the least expensive. Straight-forward pitched roofs have historically been the least expensive to construct. You will be able to save money if you can manage some of the work yourself or if you manage it from start to finish.

Although you may be able to save money by installing a better extension, you will be required to spend far more. Planning permission for residential and minor home improvements is usually granted within eight weeks. You have the option of leaving, too; however, if you do not have one, tradespeople can work on your behalf. It will be easier for the project to move forward if you leave because builders will no longer have to check in with you before performing certain tasks.

Adding A Room To Your Home Is Cheaper Than Building A New Home

A home that includes an addition is typically less expensive than a home that includes an addition but is only slightly larger. To put it another way, the cost of closing your old house and purchasing the new one would nearly certainly push this option over the top.
How much does it cost to build a bathroom and add a room in a house? A primary bedroom and bathroom typically range in price from $35,000 to $84,000, depending on the size, features, and material used.

Patricia Smith

My name is Patricia Smith and I‘m an amateur historian with a passion for medieval affairs. I‘ve been studying this period of history since I was a child, and I‘m always looking for ways to learn more. I‘ve traveled extensively throughout Europe and the Middle East to visit various sites and monuments related to the Middle Ages. Through my travels I‘ve come to appreciate the diverse cultural, political and economic developments that defined this era. I‘m particularly interested in exploring the various social and religious beliefs of the period, and the ways in which these shaped our modern world. I‘m a regular contributor to various history forums, and I‘m currently working on a book about the medieval period.

Ready-made projects of one-story houses at affordable prices

  • Project 112

    Total area: 255 m 2

    Cost: 10950000 rubles.

  • Project 111

    Total area: 298 m 2

    Cost: 13300000 rubles.

  • Project 104

    Total area: 142 m 2

    Cost: 4,800,000 rubles.

  • Project 115

    Total area: 78 m 2

    Cost: 3,040,000 rubles.

  • Project 103

    Total area: 118 m 2

    Cost: 3565000 rubles.

  • Project 105

    Total area: 82 m 2

    Cost: 3165000 rubles.

  • Project 100

    Total area: 80 m 2

    Cost: 3570000 rubles.

  • Project 110

    Total area: 227 m 2

    Cost: 9780000 rubles.

  • Project 117

    Total area: 60 m 2

    Cost: 2510000 rubles.

  • Project 113

    Total area: 90 m 2

    Cost: 3670000 rubles.

  • Project 119

    Total area: 73 m 2

    Cost: 3430000 rubles.

  • Project 114

    Total area: 124 m 2

    Cost: 4830000 rubles.

  • Project 120

    Total area: 108 m 2

    Cost: 3,750,000 rubles.

  • Project 118

    Total area: 73 m 2

    Cost: 2620000 rubles.

  • Project 107

    Total area: 154 m 2

    Cost: 6870000 rubles.

  • Project 108

    Total area: 134 m 2

    Cost: 6630000 rubles.

  • Project 109

    Total area: 127 m 2

    Cost: 54


  • Project 101

    Total area: 111 m 2

    Cost: 4,800,000 rubles.

  • Project 106

    Total area: 134 m 2

    Cost: 6,020,000 rubles.

Above are one-story houses: projects and prices for them. Focusing on the options presented, it will be easier for you to set the vector to your own desires.

What height the building will be is one of the important decisions made by the customer. Today, customers are increasingly choosing ready-made projects of one-story houses. Reasons for the popularity of horizontal buildings:

  1. Saving. Compared to tall cottages, less equipment and materials are required. No need to rent a crane for a long time, the cost of strengthening the foundation is lower.
  2. Possibility of expansion. Some projects of houses on one floor provide for the possibility of adding rooms in the future.
  3. Safety. When there are no high balconies and stairs, the risks for children, pensioners and the disabled are much less. In case of emergency, evacuation proceeds quickly.
  4. No barriers. In many projects in Voronezh, houses and the surrounding area are a single harmonious space. From the premises, the owners quickly get to the garage, to the barbecue area and also easily return.

ASG “Everest” offers the construction of one-story houses according to ready-made projects. Construction work can begin immediately after the conclusion of the contract. The cost of construction will not come as a surprise, along with the project, the customer receives an estimate, which already takes into account the main items of expenditure.

Projects of one-storey turnkey houses: purpose

The construction of the cottage involves several stages:

  1. Selection of a plot of land and its geodetic survey.
  2. Discussion of projects for the construction of houses in Voronezh, the choice of one option.
  3. Making adjustments to the drawings (if necessary).
  4. Project approval. The customer puts his signatures on the documents.
  1. Construction of houses: construction of the foundation and load-bearing walls, arrangement of the roof;
  2. Connecting the building to communications, wiring pipes and wires inside the premises;
  3. A cycle of finishing works on the facade and inside the building, beautification of the territory.

The success of the entire construction of a house depends on a competent planning process, and therefore the choice of a finished project or designing your own determines the nuances that may arise at any of the stages in advance.

One-storey houses: projects and prices

The budget is one of the most important issues for the customer. Various factors influence the price of projects and construction of one-story houses in Voronezh. The main ones are the area of ​​\u200b\u200bthe house, the price of work, the materials and equipment used.

For those who are not indifferent to how much the construction will cost, we offer ready-made projects of one-story houses and budgeting services. The budget will include costs for:

  1. excavation;
  2. construction works;
  3. installation of engineering networks;
  4. internal sanitary works;
  5. external and internal finishing;
  6. installation of automation, low-voltage devices, equipment and furniture;
  7. site beautification.

Preliminary calculations are especially important if the construction is carried out with borrowed funds or the budget is strictly limited. The prices and terms approved in the estimate of one-story houses are not subject to change. Transparency of settlements contributes to a trusting relationship between the customer and the contractor.

Please note that the site contains basic prices and projects of one-story houses. A complete picture of the cost gives an estimate, compiled taking into account the characteristics of a particular object.

Experience ASG “Everest” – more than 20 years. We have ready-made projects of turnkey one-story houses for plots of any size and configuration. For details, please call or visit our office in person.

Order an estimate for the reconstruction of the building – turnkey price

Before starting work on changing the appearance or characteristics of the building, the customer must know the price of the work performed and the cost of building materials. The answer to this question is given by the estimate of the reconstruction of the building. The document indicates the cost of each operation, and also calculates the total budget. Thanks to him, you can plan costs in advance and avoid stopping work due to lack of funding.

Estimates can only be prepared by qualified engineers who have the necessary education and experience to prepare such documents. In this case, you can be sure that all calculations are made correctly, during the reconstruction process there will be no unforeseen cost overruns.

Why do I need an estimate for reconstruction?

Estimate documentation is compiled during project preparation. It is necessary for the following purposes:

  1. Determination of the total cost of construction and costs for each stage of the reconstruction of the object;
  2. Distribution of financing by types of construction operations, by stages of work;
  3. Control over the spending of funds by the contractor, reporting to the customer, investor, regulatory authorities;
  4. Reconstruction contractor selection based on the amount of costs that they indicate in the calculations.

Thanks to this document, it is possible to plan the construction and its financing, ensure the continuity of processes, and evenly distribute the attracted resources.

Stages of drawing up an estimate for the reconstruction of a building

Costs for construction work depend on the characteristics of the object, volume, as well as the complexity of installation, deadlines, location of the building, and other factors. Also, the cost is affected by the price of materials, logistics, the use of special and construction equipment.

Cost estimators determine the cost of reconstruction, acting according to the approved scheme.

Study of the reconstruction project

The main document for the preparation of estimates is project documentation. The costs of the customer depend on what work is planned at the facility. These include:

  • changing the configuration of rooms or ceiling heights;
  • dismantling or replacement of bearing elements;
  • strength increase;
  • strengthening of the base of the building;
  • extension of additional rooms or floors;
  • facade change;
  • replacement or modernization of engineering structures.

Reconstruction can be complete. It is carried out to improve the technical characteristics of the object, increase the living or usable area. Small provides for redevelopment inside without replacing load-bearing elements. The type of work and their cost depend on the option chosen.

Scope of work and material required

The next step after studying the project is to calculate the amount of construction work (in man-hours) and materials that are used during the reconstruction.

Specialized software and regulatory documents are used for this. The estimators transfer the construction operations provided for by the project to the application programs and calculate the costs. They include:

  • work of builders;
  • services of special equipment;
  • use of tools and fixtures.

The amount of materials is calculated according to standard technological maps.

Determining the cost of materials and work

The basic index method is used to calculate the cost of purchased materials and work. It allows you to determine the costs at current prices, which simplifies further payment by the customer for the services of the contractor.

As a guide, unit prices are used, which are tied to the conditions of construction at a particular facility. Cost adjustments are made using conversion indexes. They are set by state authorities depending on the region and are revised over time.

An alternative would be the resource method, where costs are determined by cost item based on HPOS or design data.

Features of drawing up estimates for reconstruction

To increase the accuracy of calculations, estimators take into account special factors that affect the cost of reconstruction of an object. This approach simplifies financing and keeps costs under control during construction.

Breakdown of work into stages and accounting for seasonality

Complete reconstruction of the building is carried out gradually, which allows you to correctly plan the work depending on their priority. In addition, thanks to the stages, you can divide the payment into several parts in order to reduce the financial burden on the customer.

The number of stages and types of work in each of them depend on the building reconstruction project. The plan includes the following items:

  • preparation of the facility for construction;
  • dismantling of finishing and building structures;
  • strengthening of load-bearing elements;
  • erection of extensions and additional floors;
  • replacement or modernization of engineering networks;
  • decorative trim.

Each of the stages, depending on the complexity, can be divided into stages. The estimate indicates the costs for each of them, broken down by operation.

The second option for the distribution of work during reconstruction is seasonality. Depending on the air temperature and other factors, designers draw up a work plan with estimates for a specific time of the year. For example, in winter it is impractical to carry out outdoor construction work, but you can do interior decoration in heated rooms.

Consideration of specific requirements and regulations

Reconstruction costs may be higher than standard if workers need to take into account special industry requirements or government standards during construction.