Structural Design – 5 headings

94 Comments

1. I’m in the process of building a braairoom at my house – we’re about 2/3rds along the way – but a sticky point has now come to the fore between myself and the builder re some structural elements.

   We followed the correct procedure in getting plans drawn up, getting it approved by the local authorities etc. The builder then went ahead building strictly according to the plans.

   Unknowingly to me (I have no knowledge of the industry), the height of the ceiling specified on the plan (2.4m) does not allow for a minimum of 4 courses of brickwork above the sliding doors (3m). After the builder completed the brickwork and was about to start with the roof – a friend of mine (who is an architect) pointed out this structural issue when she saw photos of the “progress of the braairoom”.

   I pointed this out to the builder, who in turn dismissed the issue and decided to carry on – saying that his engineer will sign it off.

   Long story short – his engineer is now also not willing to sign it off; and the builder simply stands by his case that he “simply followed the approved plan”.

   My main question is: Is a builder not expected (by law) to follow the National Building Regulations above all else? Who is ultimately responsible for the problem I am now having?

   Your assistance would be greatly appreciated.

   Regards,

   Ruan

2. What is the distance between the fence and a storm water drain?

3. Greg, since your house was built (with approved plans – I presume) according to an engineer’s specification, unless this was part of the specification (which would, by law, have been included in the plans that were submitted to council), then your builder is correct. However, if you want some sort of protective “apron” around your house, that is your prerogative. In any event, if it was not specified in the approved plans, you can expect to be charged extra for the work and materials.

4. Hi all,

   I have just had a house built, on a gentle slope, clay soil, thick floating foundations. All to engineers specification. My question is, most houses have a concrete or tile apron around the house( a splash guard?) My foundations were backfilled, do i need one or does the law require one, as my builder says i do not, yet i feel that this is a pre requisite as severe highveld storms genersate a lot of water flow and i worry that this may erode under the foundations over time. Please help

   Greg

5. Hi Karin,
   There are no height restrictions regarding the window sill height above the floor. The only stipulation is that the glass below 500mm above floor level must be safety glass. Whoever designs a building does the design according to what the building is to be used for as well as the clients specifications.

6. Could you please tell me where I can find out what specific school building regulations entails? I need to know what the height of the windows should be drom the floor.

7. Thanks for your prompt response – I will try see if I can find an engineer who could help.

8. We are neither architects nor engineers Edward and the Building Regulations are not a design manual. They simply give very basic guidelines. Although the discussion of building with timber has been included in these latest building regulations, I am not aware of anything that deals with deck structures as such.
   We did a book on Decks & Patios some years ago, and one of the projects was a deck built on a slope next to a swimming pool. It was built by a professional who used 144 mm x 44 mm timber for beams and joists – and the span between posts was no more than 3 m. So if you are using less sturdy beams, you’ll have to reduce the span considerably. An engineer will be able to advise further.

9. How do I find out the recommended spans of timber for building a deck structure?
   e.ge what could a 38 x 114 span between posts?

10. Franco, the legislation (The National Building Regulations and Building Standards Act) defines minor building work – which does not require plans. Have a look at the link I have given you here. It doesn’t mention verandahs (these are usually part of the structure of the house), but “open-sided car, caravan or boat shelters or carports that do not exceed 40 square metres in size” are considered minor building work.
    The Act also says: “Any building control officer may in respect of the erection of a building defined in the national building regulations as a minor building work, in writing-
    (a) exempt the owner of such building from the obligation to submit a plan in terms of this Act to the local authority in question for approval;
    (b) grant authorization for the erection of such building in accordance with the conditions and directions specified in such authorization.”
    So you don’t need plans but you need “permission”.
    SANS 10400 is very clear that minor building work must comply with the NBR.
    There is commentary on minor building work in Part A of SANS 10400 (this has not been changed – so if you download the old SANS 10400 (1990) from our downloads page you can read all three paragraphs – pages 45-46). The first para says:
    “The term “minor building work” was intended to cover certain building work which, because of either its nature or magnitude (or both), was such that it would not be necessary to submit full plans or, in certain cases, where no plans or any other documents would be required. The implication is that where no plans are required, the building does not have to comply with the National Building Regulations since, without plans, there is no means of assessing an application. It is, however, necessary in all cases that an application be submitted to the local authority so that it is aware that the work is proposed and it can set conditions in those cases where it is considered necessary to invoke at least some of the National Building Regulations to control the proposed building work.”

11. Good day Penny, Thank you for your replies to my earlier questions. I read in one of your posts that plans for open sided structures, like carports and verandas, are not necessary, although permission from your local authority is still a prerequisite. Can you confirm this or did I understand you wrong?
    Regards

12. Henk, the National Building Regulations relate to all building in South Africa, but there are some specifications in terms of coastal structures versus those inland. Roofs are one area where there are differences. But there isn’t somewhere that you can refer to that details coastal versus inland. You will need to plough through the full Monty … or ask a “competent person” for advice.

13. Hi Sydney,
    You should contact the NHBRC, click this link >> “nhbrc.org” << They might be able to help you IF the developer and builder are registered, which they should be by law. It seems to me that you have more of a contract problem than a building one. It all depends what was in the contract when you agreed to the contract terms. I suggest you read through this first.

14. Hi Kryska,

    If the bedroom has direct access to the backyard, you will require a weatherstep in the order of 170mm. It may be less, if circumstances allow. You would then have to lower the yard level to suit.

    If the bedroom does not allow direct access to the backyard, the internal floor slab may be at the same level as the external yard (even lower), but there should be sound and proper waterproofing measures in place and the yard should be well drained in order to allow spontaneous storm water flows away from the structure. Best to contact a Professional Engineer to assist.

    Good luck

    Anton

15. Hi Kryska,
    It’s impossible to tell just by this description. Your first step is to check the plans to see if the building was constructed according to the plans. Your local authority should be able to help in this regard (go to the planning department). The levels should be shown on the plans and these should relate to exactly where foundations for each level should be built. It sounds as if this is a sloping property?

16. Hi, I would like to know if you could help me. We have moved into a
    new house but the addition to the house(4th bedroom) is not up to
    standard. It’s going to be corrected but there is a dispute about the
    floor level. The current floor level is on the same level as the
    backyard. Does it need to be raised or is it fine like that?

    Please help.

    Thank you Kryska

17. I bought a house from the developer, i gave the house plan but they
    didn’t build according to the approved plan, because the builder is
    not willing to solve the problem how can you help to solve this issue
    because am staying in the house that is not according to the approve
    plan . Please help.

18. Hi there,

    I was wondering, is there a differens between building a house on the
    sea edge and building somewhere in land? if so.. were can I find these
    regulations regarding to this matter? I am looking for what the
    differences are.

    Thank you,

    Kind regards,

    Henk

19. Johan I have updated the section on Roofs (https://sans10400.org.za/roofs/) – including the tables. I have also added a section on thatch roofs.

20. Johan there isn’t a section, as such, in the National Building Regulations that deals with thatch, but thatch is covered in Part L: Roofs. Specific sections that refer to thatch roofs include:
    The table for maximum truss spans for various rafter and tie-beam sizes (which you will see if you click on the link, above). Thatch is in the category Class B.
    The table for the number of connecting devices – also Class B. In addition, the regs state that the centre-to-centre spacing of trusses relevant to Class B covering should not exceed 760 mm.
    The table for maximum spans for rafters – again Class B.
    The table that gives minimum roof slopes and sheet end laps – which we haven’t included. Thatch with a thickness of 150 mm should have a MINIMUM slope of 45 degrees; and a thickness of 300 mm should have a slope of at least 35 degrees.
    Fire resistance and combustibility issues also apply. You will find these in Part T: Fire Protection of the NBR – a VERY lengthy document that was updated considerably in the recent amendments. e.g. If the thatched roof is bigger than 20 sq m the building must be located at least 4.5 m from the boundary (not the usual 2 m). Size also affects other elements including sprinkler systems. Municipalities also have regulations on thatched roofs – contact yours for their requirements.

21. WHERE CAN I FIND INFORMATION ON THE REGULATIONS ON THATCH ROOFS ?

22. This is out of the realm of building regulations, apart from which anything like this – if possible – would have to go through a number of legal processes. A lawyer will have to answer your question.

23. Greetings Penny,

    Is it possible to build three houses on one foundation slab and declare them free hold? Give individual title deeds for each “structure” ?

24. It sounds to me as if the responsibility lies fairly and squarely on the shoulders of the engineer.

25. I have been doing work in Lenasia, and was asked to erect a structure that was supplied to me. No soil tests were done but we were told to carry on. The client then brought an Engineer to site, as he didn’t know if the foundations we dug were right. The Engineer told us that he was satisfied with the dept and the width, but we have to put steel into the foundations. He then had another person there whom I don’t know, who said that in Lens they never put steel into the foundation. Then the steel were delivered. There are no drawings for the steel structure, although the supplier says that he can get an Engineer to give drawings. No drawings were submitted to the Local Government, and no approvals were obtained. We now have a problem with some of the structure and I need to speak to someone who can advise me what to do.