Nov 122012

Planning House Extensions

Whether you are building a new home or planning house extensions to an existing home, you are going to need building approval from your local authority. Even if you are simply opening up a wall or partitioning a room by erecting a new internal wall, most councils will insist on working drawings.

house extension

A self contained flatlet has been added on over an existing double garage and a patio created on the flat concrete roof over the front entrance hall.

They won’t worry about issues like matching materials or style, but they will consider all the elements that relate to building codes and building standards.

Extension Options

There are various ways that you can extend an existing house. For instance you can go up and create a second storey or opt for a more straightforward lateral extension. If the pitch of your roof is sufficient, you might be able to convert this into an attic room. Alternatively you could add a separate freestanding structure with a link to your existing house.

Having said that your local authority isn’t going to be bothered with style, this is an element that is essential if the extension is going to look good. Materials should also match or look as though they have been chosen carefully. This means that if yours is a facebrick dwelling, the extension should be built using the same finish facebrick. If it is plastered and painted, it is best to match the paint colour. This isn’t always as easy as it might seem, since paint colors fade and from time to time manufacturers change their specifications.

Planning for a Building Extension

Sometimes, but not always, people do plan for future extensions. This makes it a lot easier when it comes to adding on a room or converting space. As an example, where a future door is planned, building in a lintel at this point, and enclosing the door area with straight joints will make it easier to knock out the brickwork at a later stage. The fact that the bricks aren’t bonded beneath the lintel won’t be an issue, because the lintel will support those above.

Even so, you will need to be sure that the extension is correctly executed, with the correct foundations (unless of course you are going up, in which case you will need to have existing foundations that can take the weight of the new building extension), and where brick or block walls meet, these will need to be bonded, or joined in such a way that cracking will not affect the structure.

Types of House Extensions

These include:

  • building a core house and then adding to it later according to existing plans
  • converting a garage into extra living space
  • converting an attic into habitable space
  • constructing rooms in a roof where there is no existing attic
  • adding or converting a cellar
  • adding a conservatory, sunroom or pool room, usually with glass
In all instances it is essential to ensure that your new house extension complies with building standards.

Develop a Core House

If you are building and you don’t have the means to build the size house you believe you need, an excellent solution is to build over a period of time. Thoughtfully designed, it will never look incomplete.

Below are three drawings that show how a core house (coloured yellow) may be added to over time.House extension 1

In the first drawing, you can see that it is a simple, compact two-bedroomed home. Both bedrooms share a bathroom and they are both the same size. Each room has built-in cupboards and there is a laundry cupboard in the passage outside the bathroom. The living area is open plan, with a bar counter “dividing” the living space.






House extension 2In the second drawing, the kitchen has been extended, in such a way that existing plumbing is used, even though the sink changes position. An exterior door is added, linking to a courtyard with a washing line, and to a double garage. One section of the garage incorporates a storeroom, adjacent to a loo with a basin, accessible from the courtyard.  The main bedroom is also included in this phase, although it could, of course, be built on later, since it is at the opposite side of the house. An en suite bathroom and more substantial cupboards are also included in the new plan.















In the third drawing, an open-plan lounge-dining room has been added (blue), along with a new entrance way and a guest loo. A swimming pool has also been included on the plan, though this could also be a separate phase.House extension 3

Convert a Garage

This can be a very convenient and reasonably easy way to extend a house, although local authorities are usually strict in terms of upgrading the existing finishes. For instance you may need to have a ceiling installed, and lighting and ventilation might need to be upgraded.

Add a Sunroom, Pool Room or Conservatory

There are companies that specialize in glazed structure (or one where a polycarbonate material is used) that fit this category, though you can also have something designed and custom built.

Go into the Roof

Many older homes were built with attics that were intended to be used for storage. You might need to add windows and insulate the walls and ceilings to make the space habitable.

If there isn’t an existing attic, and the roof is high pitched enough, you might consider building a room in the roof space. The basic concept is very similar to converting an attic, although structural alterations will be considerably more complex. If the pitch is not sufficient, you will have to extend the gable ends and increase the pitch of the roof.

In both instances you will probably have to add stairways that are easy to use.

In South Africa and other hot-climate countries, the roof space (and attic) in a house can become unbearably hot, so it is essential to pay attention to insulation.

Go Underground

Cellars are surprisingly uncommon in South Africa, but they are sometimes included in the design of a house, and may be added at a later stage providing the foundation walls are high enough. Generally it is easier to add a cellar where the house has been constructed on a slope.

Just remember that for a cellar to be converted into a habitable space (even if only as a playroom), it must be totally dry (there must be a damp-proof membrane between the brickwork and the soil beneath ground level) and have sufficient light and ventilation. Usually this will entail installing artificial ventilation and electric lighting.



  266 Responses to “Building Extensions”

Comments (266)
  1. A need to find and understand what the building regulations are
    regarding bolton structures.
    Not only Bay Windows, but extensions where the floor area has been
    enlarged by such bolton structures. Is the load that such a floor is
    able to support also 150kg/m2?

    • Hi Frik,
      I have contacted Simon from Beautiful Structures in Johannesburg (011 795 1827) and he confirms that most bolt-on structures are considered “Minor building work” and do not usually need plans. Where the floor area is increased the concrete must be mixed to the specifications that suits the load that the floor must carry, see our “concrete mixes” page. If you are concerned that the load is such that reinforcing might be needed then you should contact a structural engineer for advice.

  2. Hi,
    I need some advice, I currently have a second story covered patio
    (it’s part of my normal roof) it has 4 openings, front two governed by
    ballustrades and the side two have walls up to 1.5m can I enclose
    these holes i.e put 4 windows in without the need for new plans? Or is
    this more effort than I thought?


    • Hi Andrew,
      From the explanation of your situation it seems to me that you will not need any plans. You are only filling in openings and not compromising any structural elements of the building itself. Just make sure there is enough ventilation to meet the standards (SANS 10400: Part O Lighting and Ventilation). I would also send a letter to the Council Planning Department informing them of the alterations, this should cover you in the event of you selling your property at a later stage and the inspector seeing the changes and requesting plans and possibly delaying the sale.

  3. Hi Penny,

    we bought a house that was built in 1972. When houses only had one gargage. One of the previous owners converted the original Garage into a storage room/laundry. He added an Awning to the garage (this was not shown on any houseplans, when we bought the house in 2009) Since the floor of the awning are sunken, retaining walls of (700mm) was build on 2 facades, by means of red facebrick. DPC was installed and the walls are sound. I would now like to enclose the awning and convert it to a bedroom.

    The original garage as well as the awning were built well over the building line, and actually ends on the boundary between us and the neigbours.

    Who should I approach to have this approved?

    Since the retaining walls are sound I thought about building up to the roof with Shiplack board, insulation and drywall. Would this be allowed?

    Thank you very much for your book. It has helped a lot.

    Kind regards,


    • I am a little puzzled by your question Hannerie, because an awning is an overhead structure. Do you mean the floor or patio below the awning? Or do you mean a carport? No matter; whatever it is, you will need to have plans drawn up to be able to build on a bedroom. And you will undoubtedly have to get permission from your neighbors before the municipality will approve the plans. The materials you mention will probably be acceptable, but as I say you need approved plans before you can start building. Since the building regulations were amended in 2008, it is now mandatory for you to use a competent person to draw plans. You can read more about competency HERE. The legislation is also very informative regarding what is required – including when it is an extension. You can download the amendment HERE. If you were to go ahead without plans, your neighbour could very easily objection to Council and you MIGHT then be required to demolish what you have built. So it really isn’t worth it. A friendly chat with your neighbour is probably the first step you should take.

  4. My parents would like to put a vibecrete fencing infront of their home. Do they need to have plans drawn for this or can they just put is up.

    • Glenda, the National Building Regulations state that “any freestanding wall built with masonry, concrete, steel, aluminum, or timber or any wire fence that does not exceed 1,8 m in height at any point above ground level and does not retain soil,” is a form of minor building work. And minor building work does not require plans – as you will see if you click on the link above. However, you do still need to notify the local authority of minor building work, and they may require certain documentation to be filled out, including a site plan. Furthermore, some local authorities DO require plans for ALL walls and fences. Your best bet is to check with your municipality what exactly they require. Presuming the vibracrete (precast concrete) wall is below the 1,8 m height specified in the regs, point out to them that you are aware the project falls under “minor building work” in terms of the NBR.

  5. Hi,

    I would like to know the law/regulations on converting my garage into a maids quarters, problem is that it makes up a boundary wall. Is there any law/regulation that will stop me from converting the garage to a living quarter?
    The other problem is that the main waste drainage runs directly under the garage, is there a law/regulation stopping me from building on top of that pipe? The garage only has paving, no slab.


    • The National Building Regulations are very clear in terms of purpose for which any structure will be used. Many people put a “name” on plans – e.g. a store room – and then use it for something else – e.g. a bedroom. You might get away with this for a while, but if someone files a complaint, or you decide to sell the property, you will face problems… and usually fines. A garage is for cars; to be able to convert this to living quarters requires plans and permission from your local authority.
      When it comes to plumbing, the regulations and SANS are even more stringent, largely for health reasons. There are LOTS of laws and regulations that you need to be aware of. Don’t even consider trying to do this conversion without professional help.

  6. Hi Penny
    We would like to convert our yard into a garage. Could you please advise what the regulation is on car parking size area, as well as the lowering of council drain within our property. Thanks!

    • There is no specific regulation relating to car parking areas. If you want to build a garage in your yard you will need plans to be drawn by a competent person [click here for more info on competency]. In terms of council drains – you cannot lower this. You will have to ask them to do it for you.

  7. I currently have boundary walls that I would like to make higher. How high can I go without getting a structural engineers certificate?

    • Local authorities have their own requirements, some stricter than others.
      Generally though all walls need to be designed by a competent person who might be an architect or an engineer; both would know their own competency – i.e. the architect would know the parameters in which he can work – including the height of a boundary wall. Click here to find out more about competent persons.
      Having said this, your local authority will advise whether you can extend the walls upwards without additional plans. This will probably hinge on the existing foundations.

  8. Hi Penny

    Good work with the site!

    We live on a plot and we are planning to build an extension of our house. The thing is; we want to have it seperate from the existing house. Is it possible to be building an “extension”, without the builings being connected at all?

    • I don’t see why not Peter. Your only “problem” might be if the council sees the “extension” as a separate dwelling, in which case it will depend on the bylaws. I suggest you check the bylaws before going ahead with plans. In many cases the “label” you put on a building makes all the difference. For instance you may be allowed to build a workshop with a bathroom incorporated, but not a granny flat.

  9. Hi Penny

    We have a house with my mom and she wants to do the following, is the following allowed without proper plans and building permission:

    1: The back patio – she wants to close it totally with wall and sliding door. There is already a roof. Do we need planning permission to close this and make it into a sunroom? The patio was added to the latest plans a few years ago as it was never there. Not sure if the plans of the patio is approved but say it was. Do we need planning permission to close this and make into an sunroom?

    2. At the back next to the garage under roof, she wants to close some of the area as a room/washing room do we need planning permission for this?They have to add two side walls to close this and a sliding door.

    Thanks a mill

    • Marguerite, In terms of 1. my educated guess is that this is minor building work, which means you won’t need plans, but your should notify your local authority that you will be doing the work.
      In terms of 2. since you are changing the function of the area, you probably do need plans.
      Your best bet is to check with the local authority because at the end of the day, they are the ones whose requirements you have to comply with.

  10. I want to build an extension – a double garage with a room above it on my property. I have looked all over the Internet but cannot figure out the rules regarding FAR etc. is there a website I can use to find out if I can build on my property in the first place? Please help.

    • Generally you will be able to do this as long as the extension is two metres from your boundary. However there may be preclusions in your title deed (i.e. relating specifically to the property) or your local authority may not permit this. In some developments there are also rules that determine the percentage of the land that may be built on. So check the title deed and visit your local authority and ask them what their requirements are. In terms of the building regulations, you will, in any case, require approved plans to build and extension of this nature.

  11. Hi Penny. I would like to convert my garage into a self-contained cottage. The existing structure has walls and a roof. However, I would like to extend it by, say, half a metre. What is the procedure? I now know that I need council approval first. Then what, how? Thanks for your time and reply.

    • You will probably need to put plans into council, unless they consider it minor building work. If you are going to include plumbing, you will need to hire the services of a qualified, registered plumber – the same applies to electrical work.

  12. I am planning to extend a backroom in my home to make it a bathroom & recording studio. The back room had already been utilized an additional bedroom with the necessary electrical work. I used it as my small home recording studio/bedroom but due to constant overnight recording, I want to add a bathroom to it. Do I need to have an approved house plan for this or simply consult a builder and provide him with my requirements? What other regulations, if any, do I need to consider before starting the project?

    • If you are not changing external or load-bearing walls, you may not need plans. But it would be a good idea to ask your local authority as it might make a difference if and when you decide to sell the property. The building regulations and other SANS are pretty stringent, so you will, in any case need to hire a qualified plumber.

  13. In 2004 my parents objected to the City of Cape Town over a double story that used the set off on the boundary wall as a recreational area. Is this permitted? Building went ahead and I dont believe there was public notice for the last minute changed plans from single to double story structures on the boundary wall.

    The City of Cape Town has said diagonally opposite properties do not need to be consulted and the rule only recently changed. Is this true?

    The structures recreational area also sits next to telephone pole. Is this allowed?

    • There are two issues here. 1) the building regs and 2) the council by-laws. As long as the council is operating in terms of the NBR they can add requirements. i.e. They can ask for additional steps to be taken. They can’t negate requirements of the NBR.
      Consultation is one area that is governed by the local authority.
      In terms of the telephone pole, that also isn’t something that is regulated in the NBR. e.g. We have a telephone pole in our garden that supports lines to neighboring properties and not ours!
      But back to the beginning, I am not sure what the original objection was, viz to use “the set off on the boundary wall as a recreational area”. Can you elaborate? It sounds almost as though the boundary wall is in fact a retaining wall and that there is building above the wall? If your parents’ boundary wall forms part of a structure of any kind, and this wall is either on their property or built by them on the boundary, then they need to give the council permission. But as I say, I really am finding it difficult to visualize what you are describing.

  14. I used Graham from Build Solution to do Extensions and renovations at my house to the value of R256, 000. This all started in April 2011. I am still waiting for my COC, and he build my Kitchen over my main water pipe which caused a leak and cost me over R20,000 in water bills and repairs. I refused to pay and claim he did extra work for me without pay. The list is endless of all the mistakes and do I still have to fix them myself as I go along. What do I do to get my money back for the water leak? He is registered in a trust and is it difficult to take him to court.

    • Wiets, if Build Solutions Contractors & Consultant in Gauteng are the people that you used, they enrolled one build with the NHBRC and their registration has expired. If he was registered, you might have some recourse via that organization.
      It isn’t clear whether you have paid him in full, or withheld some of the money – but in any case, I think you really do need to go to a lawyer. There may be something in the Consumer Protection Act that you can use to take legal action against him personally.
      Also, don’t forget – that’s a good way of letting other people know that he should be avoided!

  15. What about when a private person who owns a residential property, who bought the property with a garden flat already built. What about the rules and dimensions. eg. how far from the fence must the building be? But what if the already built flat is built against the neighbours wall?

    • This is something that all purchasers should check when they buy a property. If you are concerned, then get a copy of the approved plans from council and see whether the flat is an approved structure. If it isn’t, you have two options:
      1. Submit plans for the flat.
      2. Continue in supposed ignorance.
      One would assume (even though it is never safe to assume anything) that the neighbours would have complained to council if the structure was illegal.

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