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Tag: Extension

Single storey house extension designed online
Common Questions, Regulations and Laws

Do I Need Planning Permission for an Extension?

House extensions are a hugely popular home renovation because of how they impact your house and your life while you’re inside it. They open all kinds of doors and have a massive uplift to quality of life, but a common question that is asked about it is how planning works when it comes to getting one, and more specifically, if you need planning permission for an extension, or if there are other routes available.

The short answer is that in all honesty, it depends on the size and the complexity of your house extension. House extensions do need planning permission if they will have a large impact on your neighbours or the local street scene, or if they are large in size. Smaller extensions however don’t need planning permission in many cases thanks to permitted development rights and prior notice. The answer depends entirely on what you’d like done.

Using Permitted Development Rights

In order to be able to build an extension without planning permission, and therefore using your Permitted Development rights, there are a few important criteria that you need to meet. The main characteristics to consider are based on the size of the proposed work, but there are a few specifics:

Less than 50% of land taken up

The proposed extension should not use more than 50% of the space available on the property. If that’s a rear extension, for example, it can’t use more than 50% of the garden. This is of course vastly different depending on the property, but it’s one of several limitations to consider.

Less than 3 metres extended from the original house (or less than 4m for detached houses)

From the rear wall of the property, the extension must not exceed 3 metres. That becomes four metres for detached houses. This may well cause a conflict between the point above, but it is whichever is the smaller size that is the limit when using permitted development.

Less than 4 metres high

The height of the extension is also important. For rear and side extensions (which are the typical permitted development candidates since the front is more difficult), the height cannot exceed the height of the original property. It also generally needs to be less than 4 metres, especially for side extensions.

Materials in Keeping

The materials used to build the extension need to be in keeping with the rest of the property. Anything vastly different would require planning permission, as it would have a negative impact on the property and the community as a whole.

Using Prior Approval

Another route to go down that is more of a middle ground between Permitted Development and Planning Permission that still prevents needing planning permission for an extension is the use of prior notice. This is where you submit a brief application to the council and pay a small fee, and they contact your neighbours and see if they have any objections. If not, you have up to 6 metres extended away from the property (or 8m for detached houses) to work with. The rest of the criteria for permitted development like material choices and height still apply.

Using Planning Permission

For an extension that doesn’t meet these requirements, or for anything else that you’d like, it’s usually going to be a job for a homeowner planning application instead. This means you’ll need planning drawings and to submit the application (or have an architect or designer do it for you) and receive approval before you can move forward with the build (as well as getting building regulations drawings in place).

The planning process generally takes around 16 weeks including drawing time. That includes every stage up until approval at which point, you’ll be able to move forward as planned with your extension. It is also worth noting that there are different types of planning application out there too. Special circumstances like living in a listing building or conservation area make things more intricate and have their own, for example. From a general level, however, it mostly comes down to the points above.

House extension being built from conservatory
Common Questions, Regulations and Laws

A Guide on Replacing a Conservatory with an Extension

Conservatories have been one of the most popular types of home renovation for years now, and they’re a feature of thousands of homes across the UK. The issue that comes along with them, however, is that as time goes on, people’s opinions on them tend to change. Structures with that little insulation and that much glass are extremely susceptible to temperature fluctuations, and as a result, a lot of people out there want to know about replacing a conservatory with an extension, instead. The problem there though is that it is not quite as easy as it sounds.

The main reason that replacing a conservatory with an extension causes issues is that technically, they’re very different things, and as a result, they tend to need an awful lot doing to them in order to be converted. They also need to meet specific criteria, or they may need removing altogether and have an extension built in their place. The good news though is that although it may not be straightforward to get a house extension specifically, there are a number of changes that can be made to make the conservatory much better suited for your needs.

So, Can I Replace my Conservatory with an Extension?

There’s a lot to consider when you’re working out what is and isn’t going to be possible for what you want to achieve with replacing a conservatory for an extension. Sometimes, it is possible, other times, it’s just not achievable. In either case, you’ll have a range of upgrades available to you, but the best thing to do first is to make a list of requirements and see if you meet them:

Footings & Foundations

Footing needs to be over 1m+ deep for the base of your conservatory to be eligible to be used as the base for an extension. To test this, you’ll likely need to dig in front of the conservatory, or dig a few holes around it and take measurements. If they’re not, then you’ll likely be better off starting from scratch anyway, since this is a little bit messy. Alternatively, you can utilise underpinning to make them more viable.

If they are deep enough, or if you aren’t sure the next step that is probably a good idea is to get a structural engineer to inspect it for you and confirm that this is the case and you’re in a position to carry out the replacement.

Permissions & Authorities

The next hurdle to face to convert or replace your conservatory with a house extension is the permissions and restrictions that are subject to as a homeowner. Planning permission for example is a good place to start. If the conservatory is the same size/footprint as the proposed house extension, then you may need to gain any further permissions. It is however still a good idea to get a certificate of lawfulness, as this proves that that is the case. That’s great when you’re trying to sell or insure should you need to.

The other side of the coin is building regulations. Building regulations are essential for any build, and they will be a problem with replacing a conservatory with an extension. That’s because they are classed as totally different things. Conservatories are classed as a temporary structure and are closed off from the main property. An extension would be opened up, like another room, and as a result, you’ll need to meet very different criteria (unless of course you remain technically a conservatory and don’t need to open it up to the house. We’ll talk more about this soon).

Option 1: Converting to an extension

Sticking with the notion that you’re looking for an extension above all else and a full conversion is the goal, there are a number of areas to keep in mind. That’s even after you have checked the foundations had building regulations drawings created, since specifically parts a and l of the building regulations will need to be adhered to in order to become an extension.

Assuming that the footings are adequate, the initial steps would be to insulate the floor, walls and roof. The use of glass generally needs to be reduced to 25% of the floor space as a rough guideline for it to be able to meet building regulations requirements. Swapping out window frames/glass walls with brick and blockwork or timber frames is the best way to go about this and will be unavoidable.

This does bring the attention back to the footings, however, as changing this much glass for masonry means there’s a lot more weight in the structure., The footings need to be able to handle this safely. This wouldn’t have been a requirement when they were first done, so it’s unlikely. Again, a structural engineer will be able to advise here.

The roof can be introduced after the walls and openings are altered/constructed. There is a range of options available to you, like pitched tiled or flat GRB roofing, and you can choose which is the best fit. Bare in mind planning constraints, however, as this could need to be pre-determined. Roofing in this case typically costs around £120 per square metre.

Once all this is done, you’re essentially finished. All that is left is carrying out any required checks. That’s before of course decorating as you see fit.

Option 2: Keeping Conservatory Status, but Improving

Although replacing your conservatory with an extension isn’t an easy thing to do, that doesn’t mean you’re stuck. The second option that you have available for you and your property is to simply improve your existing conservatory. You can convert and improve a conservatory to variable different levels to suit your budget and requirements providing you don’t need the conservatory opened up to the house and signed off as a proper room.

The first place many look to here is converting a polycarbonate roof to a glass or warm roof, usually referred to as an insulated roof with tile effect. Converting the roof like this typically costs around £100 per square metre, so would likely only cost around 3-4 thousand for the whole build.

Adding insulation to the walls may be difficult depending on your conservatory layout. Brickwork changes are usually limited for building regulation and foundation reasons but are still possible in most cases. Insulating walls can cut space internally, however, and it costs around £40 per square metre for 65 mils of insulation as is standard. A great alternative is replacing the level of glazing, like standard double glazing for triple glazing instead. A new glazing unit is typically around £150 each.

Risks of Replacing a Conservatory with an Extension

With a renovation that is trying to combine two separate types of structure like this, there are always going to be risks involved. In many cases, they can actually make the whole thing a waste of time and resources too, so plan your moves carefully.


The biggest risk from a project like this is that you’ll end up spending more than you would have done from simply starting fresh. Conservatories can be taken down and sold as second-hand. This can actually be a wise decision for some situations. You can then use that money to put towards a house extension that’s perfectly suited to what you want.

Poor aesthetic from the finish in many cases

If the transition does prove successful, there’s also the risk of having a very poor aesthetic as a result of your hard work. Conservatories don’t look incredible at the best of times, but if you’re incorporating an extension, you could end up with some kind of hybrid, bringing out the worst of both in terms of appearance.

We wouldn’t recommend spending more than 10-15k on doing this, as still will inherit awkward junctions, making the overall quality, tightness, ventilation etc questionable. It can lead to issues with the contract and warranty with the builder, and that can be a real minefield down the line should there be anything wrong with the build. If you can meet the targets of your project at that price, it’s worth doing for the practicality, but always do investigations first. It could be of poor quality and quickly become a money pit and a huge source of stress. Check foundations first for materials and quality, amount of glazing,

Builders working on a house extension project
Common Questions

The Best Time of Year to Build an Extension

Building a house extension in general can be a complex process, but finding the best time of year to build an extension can be even harder. It’s a very split topic, with a huge number of people suggesting it’s summer or nothing, and others saying that winter is easier, cheaper and more accessible. The hard truth is, in reality, they’re both right.

We’re here to break it down into the advantages and disadvantages of both, and ultimately, give our own opinion, which is that all in all, the best time to build a house extension probably is spring/summer/autumn for ease and comfort, but it’s never too difficult to do.

Building an Extension in Spring

Building an extension in Spring is often the best time to go ahead for many people. It has the best of both worlds in terms of the two arguments you’ll usually hear when it comes to building an extension in general.

The weather should be friendly, the builder should be slightly more available, especially if you’re booking well in advance, and you’re not missing out on accessing your garden etc when you want it. All in all, this is likely the best. Even if the extension has issues and lasts longer than expected, you shouldn’t run into any issues.

Building an Extension in Summer

Summer is the most popular tie of year to build an extension just because of how practical it is when it comes to having work done. There will be no cold spells in the house from walls or roofing being altered, and that’s the most important thing for most people who are on the fence about the build. The weather should also be ample to let building go full steam ahead without any delays. The issue is, the builder you want will likely be very fully booked if you’re hoping to get one within a few weeks or even months’ time.

Building an Extension in Autumn

Building an extension around the autumnal time of year is still common, but it does begin to pose just a couple of problems that might cause you issues with your extension build. Although the temperature might not be an issue when it comes to moving walls, the weather may begin to turn and cause problems in that sense. As long as you get started early, building an extension in autumn shouldn’t be a particularly bad time of the year, but if delays have to take place for whatever reason, it might lead into winter.

Building an extension in Winter

Winter is likely the hardest time of the year to build an extension, although that doesn’t have to be a bad thing all of the time. Winter of course brings with it shorter days, wet and cold weather, and some builders that are seasonal. All in all, that can result in you not being able to proceed with your extension exactly as you’d like, which is not great. On the other side of the coin, however, most competent builders will be happy to get it done non the less. It may occasionally be too cold to work with cement, but aside from that, the inconveniences from the cold can be handled, the builder will likely be very quickly available, and you’ll be finished in time for the better months coming. That’s a win-win.


All in all, the best time of the year to build an extension is generally whenever works best for you and your living situation. Providing your builder can make the booking work with you, the best time of the year to build is whenever you can justify losing access to that area of your property for a while. If it’s a double-storey extension, of course, that may be slightly more difficult, but it’s all a part of the process. When you want to be able to use it and the areas affected, and when you are comfortable with the work taking place. That’s really all there is to it!

Loft conversion vs house extension
Common Questions, Finance

Loft Conversion Vs House Extension: Which is the Better Fit

You’re not short on options when it comes to renovating your home, and one of the biggest decisions often comes down to whether a loft conversion vs house extension is going to be the better fit. They both have a whole world of potential to offer your home, and that’s putting it bluntly. They can both give your property an entirely new lease of life, but with both of them being so great, deciding which one’s right for you might be easier said than done.

We’ve broken it down into the six most influential factors on your decision to give you a better idea of what’s the best option. Of course, different things are important to different people, but these all have a big impact on your home.

Prices & Costing

The first place most homeowners look when debating if a house extension or loft conversion is going to be the best option is with the prices. They are often very different after all since they’re totally different structures. Typically, loft conversions are the cheaper of the two.

Loft conversion use space that you already have in your home since you are building upwards, not outwards, and that alone is a big money saver to start. You already have a roof and a foundation, and that brings conversion costs much lower than building from a new. They typically range from 10,000 to 30,000 depending on your property, location and the type and size of the conversion you want, but they can go all the way up to 70,000+ for very large conversions with dormers, or even a mansard.

Extensions on the other hand tend to be more expensive even with less area being built. Typically, extensions tend to cost around 2,000-3,000 per meter squared. That would make a mid-sized extension, say 4×5 metres 40,000-60,000 to be built to a high quality. It can of course be done cheaper if the extension is smaller or uses cheaper building materials/facilities, but these are rough representative figures.

Ease of Build

As well as what they will cost to have done, another big decision influencer when deciding on a house extension or loft conversion is the ease of implementation too. How easy they are to have designed and built can be a big player in the final choice and deciding what is the best choice.

Loft conversions, since you are usually converting space that you already have, typically can fall under your Permitted Development rights. That means there is no planning permission required. With house extensions, that only tends to be the case if you are taking up less than 50% of your garden and the extension is smaller than 3×3 metres, which might not always be the case and will more often require planning permission to be built. That makes things very slightly more expensive and time consuming. Lofts are not guaranteed Permitted Development either and still may need planning, but it’s uncommon.

The build of the renovations themselves is also very different. Loft conversions typically take 6 weeks to be designed and have all necessary approvals in place and then another 6-10 weeks to build. On top of that, most of this building takes place upstairs and in the roof, meaning there are not builders taking over your home. Extensions are of course much more complex, needing to move and add walls, changing facilities, and all in all, the process is slightly messier and takes a few weeks longer to complete, but they do provide much more accessible space, which we will come to shortly.

Variety & Options

Another key consideration for choosing a loft conversion or house extension is that there is a different level of variety on offer for your project. Lofts tend to be thought of as much more limited in what you’re able to build, but there is actually a range of different options, just like there are with extensions.

Loft conversions are typically either dormer loft conversions, or Velux or roof-light conversions, and they’re the most popular types in the UK. Even on top of these, however, there are also variations like mansard loft conversions, which solve the height restrictions many people face, as well as hip to gable loft conversions, which are ideal for end-terrace houses in particular.

Extensions however still do have a whole world of variety because of their very nature. Even on top of the placement, like with front, side or rear extensions, there is still the possibility to have them extremely uniquely built. There are options for open plan living situations, glass rooms, garden rooms, and everything in between, all working with the location they are built.

Space & Potetial

Looking to the point of space available in a loft conversion vs a house extension, it is a tricky one to debate. In most cases, it comes down entirely to budget and the space that you available to use, but there are still some important points to consider.

Generally speaking, loft conversions have the potential to have more floor space, since the loft likely spans the entirety of your home. That means there is a lot of space to be converted easily. The only real issue that comes from this is the space that would be available when it is converted once the insulation is added and any slants and staircases are factored in. you also then have to think about the type of loft you’d want to have, as dormers, hip to gable conversions and mansards will all provide even more room.

On the other hand, extensions are not one to forget about either. House extensions are of course a whole new room added to your property, or even multiple rooms with a larger extension or even a double storey. They don’t have the limitations that lofts do, but they do have some of their own. Getting planning permission for larger extensions for example may be more difficult. All in all, though, extensions do technically have more potential for more space. It is one to think about.

Property & Resale Value

Any type of renovation will likely have a very big impact on the value of your property. That much is a given. If it is going to benefit your living situation even just aesthetically, then it is going to help the value of your property. Because of how different a loft conversion is vs a house extension though, there is still a difference in what they have to offer. If you are looking to the long term, this may sway your decision.

Loft conversions can actually add up to 20% to your property’s value providing that it meets typical requirements of a bedroom and bathroom included, which is a huge chunk of equity likely worth more than you pay for the process. If it is not a bedroom, however, then this may be more like 5-10% simply for the added space. Either way, it is sizable.

Extensions, however, tend to be more consistent. That is providing that you’re not ruining a room to get one by blocking its light or making it unrealistically small. They usually result in forced modernisation of your home which goes in their favour, and all in all, they tend to add £1000-£2000 to your property value per square metre of usable space, and that is even more in more expensive to live areas.


Another useful area to consider when making the choice between the two is the uses that they can practically provide you, your home and your family. Of course, any extra space is diverse, and you have a wide range of options of what to do with it. Being more realistic, however, there are some better fitting purposes than others that can help you to mould your home into a space that really works.

Loft conversions because of their location are generally well suited to be bedrooms, potentially with ensuite, and that is one of the main reasons for their massive popularity alongside their lower building costs. On top of that, having a room that is on its own floor and out of the way of other rooms, it also opens a lot of doors for them to become recreational spaces, providing you can move past potential banging on the ceilings in rooms below depending on the quality of the conversion.

Extensions, however, have a lot more room in the practical sense. The day to day space that they can offer you is huge. They give you the option for living space, kitchens, downstairs bathrooms, downstairs bedrooms for those in need, sunrooms, playrooms, open plan kitchen diners, utility rooms… the list is endless. There is also the option to add a second storey to the extension to get both upstairs and downstairs benefits of an extension, but that is all down to budget and preference. There is more variety, but at a greater cost for that prime location in the property and not something tucked away.


Finally, the last point to look at before you are able to crown a winner from your decision is the implications that both renovations can have on your property. They are not small changes after all. Having any work done can be stressful, and that needs to be remembered.

The build for example is much easier for a loft conversion than it likely is for an extension. All of the work being done in the roof makes things much more out of the way than an extension might be. It is also likely much quicker, too. They also tend to be more applicable to use permitted development rights in their creation, where larger house extensions do not have that option.

All in all, it all comes down to the budget you have to work with, and more importantly, what you need to gain from the finished project. Renovations like a house extension or a loft conversion can change your life in a range of different ways. They really can be transformational to your home life and add a huge chunk of value to your property at the same time.

If you’re on the fence even after reading all of this information, the best people to speak to are always going to be architectural professionals like ourselves. Whether you are in the UK, we have teams on hand to help. Contact us today and we will do everything we can to point you in the right direction.