Frequently Asked Questions
YOUR QUESTIONS, ANSWERED
Whether you’re planning a house extension, garden room or granny annexe, our FAQs cover everything from pricing and planning permission to build methods and timelines — helping you make the right decision with confidence.
At Modexa, we say ‘Love where you live’. We understand that often, people love the area where they live, and don’t want to move. The location, proximity to friends and family, not to mention the cost of moving these days. All of these things are important. However, sometimes their houses don’t give them the lifestyle they’d like. Extending your house is a brilliant way of getting best of both worlds. It will also add value to your property. Modular builds reduce time, stress, cost and complexity. Our modular builds include house extensions, annexes, conservatory upgrades and garden rooms. So, if you want to love where you live just that little bit more, ask about modular extensions from Modexa Build
Modexa build are a team of experience builders who specialise in modular builds. The business is owned by Tom and Dean, both of whom have many years in the trade, and have overseen countless projects.
A modular extension differs from a traditional build. Modular extensions are made to order and fabricated offsite to current building regulation standards. They are transported to the site on the day they are needed. A modular build consists of a number of pre-fabricated walls and ceiling panels complete with insulation, membranes and finish of the customers choice rather than brick or stone.
Just like traditional builds, modular extension also need foundations. Modexa build allow for a standard foundation detail, which will always be inspected by our engineer and/or the local building inspector. Where traditional foundations are not practical Modexa offer a ground screw system so whatever the conditions we will be able to offer a solution.
Both types of construction are essentially pre-fabricated in factory conditions. However, where ‘prefab’ would usually refer to temporary structures, ‘modular’ are very much permanent. They have all the properties of traditional extensions including durability, insulation and aesthetic. People often use “modular” and “prefab” like they mean the same thing, but technically modular is a type of prefab. The difference is mostly about how much of the building is made in the factory and how it’s assembled on site. Components can be PREFABricated off site such as roof trusses, stud walls etc Modular construction is a more advanced form of prefab where finishes can be applied in the factory massively reducing the time on site that impacts the client
Modular builds are quicker, cleaner and often cheaper than traditional builds. They minimise disruption on site, and help to avoid delays caused by weather conditions. Modular extensions are versatile, precision-built and cost-efficient. Structurally they are often stronger than traditional because they are designed with transportation and installation in mind
The cost of a modular extension is largely governed by how big it is. The bigger the extension, the more expensive it will be. TAKE A LOOK AT OUR GUIDE TO MODULAR EXTENSION COSTS HERE
Yes, you can get a mortgage on a house with a modular extension. Modern modular buildings are built to comply with UK Building Regulations, just like traditional homes, so structurally they’re designed for long-term residential use. – lifespan of a 100+ years allows for at least 4 mortgage cycles
Extensions cannot exceed 50% of the total area around the original house. Known as ‘the 50% rule’, this is a planning constraint used by planning officials to help decide whether a project can go ahead or not.
It really depends on the size of extension that you want, but it is unlikely that £30k will cover the cost of the build. TAKE A LOOK AT OUR GUIDE TO MODULAR EXTENSION COSTS HERE
With today’s high quality manufacturing standards, there are no significant disadvantages to a modular extension. They are built to last, and governed by strict compliance regulations.
It really depends on what you want from your extension. A 3m x 3m extension is perfect, for example, for an additional sitting area facing the garden. A smaller extension like this will cost less, and be cheaper to heat, too
No, if it’s a straightforward 4 m extension at the rear of your house. Your existing house and plot size may change the requirement for planning.
Garden Rooms are hugely popular, as they offer a great way to utilise space in your garden, whilst adding value to your property too. Garden rooms are usually stand alone rooms built in a garden that offer light and airy multi-use rooms
It’s up to you! Garden rooms range from smaller, study-size rooms to larger, multi-purpose rooms that can house sofas, chairs…even pool tables!
Although it really depends what you want from your garden room, they will typically be between 9m2 and 24m2. If you are considering a gym for your garden room, assume this should be at the larger end of this range.
The cost of a garden room is largely linked to its size…the larger the garden room, the more expensive it is likely to be. TAKE A LOOK AT OUR GUIDE TO MODULAR EXGTENSION COSTS HERE
Almost certainly! Garden rooms are increasingly sought-after options, as they offer great versatility to an existing garden space. For garden lovers, they offer an unrivalled opportunity to be ‘in’ the garden for enjoyment and relaxation.
Garden rooms can be heated; Modexa work with specialist teams to ensure power and utilities can be brought into a garden room.
Modular is a great way for you to get the garden room of your dreams. Modular garden rooms are bespoke built, quick to install and extremely durable.
Think of a Granny Annex as being a fully contained extension in which someone can live, with everything they need. A granny annex will be a larger extension, fully equipped with a kitchen, bathroom, bedroom and living space.
Because a Grany Annex is effectively a self-contained unit, they tend to be larger in size. It would be safe to assume that a granny annex would be between 40 and 70 metres squared.
A Granny Annex is a larger extension, so will be one of the more expensive extension options. TAKE A LOOK AT OUR GUIDE TO MODULAR EXTENSION COSTS HERE
It is very likely that a Granny Annex would increase the value of your house, although it may limit the market in terms of whether the buyer needs the annex or not. However, since Granny Annexes can also be perfect for larger families or guests, they should be viewed as highly purposable.
Yes. Every Granny Annex will have all the main utilities shared by the primary house – heating, water, Wi-Fi etc.
Modular builds are perfect for a Granny Annex, being so flexible, and manufactured bespoke for each project.
Conservatories were extremely popular in the 1980s and 1990s, where the UK saw a huge growth in their popularity. As a result, many older generation conservatories are showing their age. Modexa Build are experts in taking an older conservatory and bringing it up to date with a new roof, new walls, new layouts and much better insulation properties.
Subject to a foundation survey, a conservatory conversion will generally use the existing conservatory as its base, so will usually be the same size.
The cost of a conservatory conversion will largely depend on what needs converting. For example, a replacement roof will inevitably be cheaper than if the roof and walls need replacing. Also make allowance for improvements to insulation, too
Yes, updating an older, inefficient conservatory will add value to your property. In fact, older and unsightly conservatories can often not add value to a property if they are deemed to be of little benefit to a purchaser.
Traditionally, older conservatories would suffer from being too cold in the winter and too hot in the summer. With innovations in thermal retention and glazing, a converted conservatory can get over these issues and be a wonderful space to use all year round.
A modular approach is ideal for conservatory conversions; they are built off-site and assembled on site, reducing the amount of time a conservatory will be open to the elements during build.
Yes – modular technology means that one and two storey extensions can be built.
Modexa can offer a full turn key service should it be required inclkuding traditional builds
All of the construction elements are included in a modular build’s price – walls, ceilings, plaster etc. Take a look at OUR GUIDE for a full breakdown of what is and isn’t included in our modular extension price.
No, not necessarily. Modexa Build are able to design and build your extension from our own drawings and measurements. This can greatly reduce the cost of your project. However, if you are contemplating a more complex build, you may want to consult an architect.
Yes. We will work to current building control standards and provide all our clients with a compliance certificate
We offer a full range of interior and exterior finishes, depending on whether you want your extension to blend in with your existing property, or stand out and make a statement! Options include timber, zinc, aluminium and brick slips
Modular extensions are manufactured offsite and assembled onsite. This means that they can be brought into relatively small spaces, unloaded and taken to the point of assembly.
We would be able to build a 20m2 modular extension for around £55,000. Prices vary only slightly for how this is configured. Take a look at OUR GUIDE for a full breakdown of price by size.
The basics of a modular extension are the same regardless of what the extension becomes. However, a kitchen will be more expensive due to the need for the kitchen itself, and the likely need for additional plumbing.
Modexa Build work on Joint Ventures (‘JV’s) where another business may own land for development, and are looking for a construction expert to help in the development which can then be sold for a profit. The JV can offset some of the cost of the build against profits further down the line.
We work with, for example, land owners or property owners in a JV. Take a look at OUR JOINT VENTURE page for more information.
As well as modular extensions, Modexa Build have worked on numerous traditional builds, too. These have included, for example, apartment conversions, penthouse apartments and luxury multiple apartment buildings. TAKE A LOOK AT OUR CASE STUDIES for further details.
The directors of Modexa Build have been in construction sector for many years, with decades of combined experience. Over these years we have overseen the construction of many different project types.
In the context of modular building, ‘‘Superstructure’ refers to all of the components that are manufactured offsite – walls, roof cassettes and where necessary floor construction.
Yes. We offer a shell-only structure for those customers who would prefer to complete the fit out of their extension themselves.
Yes – we work in close partnership with a bespoke kitchen manufacturer, as well as with more mainstream suppliers.
A brick slip is a brick façade, usually around 20mm think and cut from real brick. They are a flexible and low cost way of adding character to the outside of buildings
Yes, since a Granny Annexe is a completely self-contained unit
A modular extension is a great solution for someone with mobility limitations or that may be vulnerable. Accessibility can be built-in to a modular extension, rather than being an afterthought. Also, the time taken to build is greatly reduced, meaning that there is much less in the way of disruption for the person who will be living in the space.
Whereas an accessible bathroom may have features that are useful for someone with a physical impairment, a purpose-designed wet room will have completely level floors, non-slip surfaces throughout, and fully adjustable walk-in showers or baths.
Yes, subject to application, there is help towards the cost of accessible living extensions available from the government. Take a look at our guide here:
Absolutely, modular build is perfect for assisted living accommodation and will be designed in line with the approved part M document in the building regulations