Roofing

Posted by Garden Route Contractors on

Roofing, what you need to know! 

Building Regulations as they apply to Roofs

In short, allot of information has been written about roofs and the safety elements which is important to take note off but we are going to try and summarize it here for you to understand. In general roofs must comply towards the following principles. 

  • Roofs are expected to be durable and waterproof.
  • Roofs are expected to withstand rainwater or any other surface water. 
  • Roofs must not be able to accumulate rainwater
  • Roofs must be anchored against wind

You can contact us for Free assistance to get into contact with a Professional Roofing Company. Press into this link https://bit.ly/3L5S2A4

Standards for Roofs as they apply in South Africa!

In 2011 Part L: Roofs was published by the SABS. Following this the guidelines are much more comprehensive and useful. However as you are the end consumer it is important to take note of this information. And for your convenience you may contact us for Free assistance to get into contact with a Professional Roofing Company. Press into this link https://bit.ly/3L5S2A4

Rules pertaining to the construction of Roofs!

As with most of the National Building Regulations, those that apply to roofs relate to SANS other than the one specific to that particular element. For instance, where any roof is to be supported on the wall of a building as described in the relevant section of Part K: Walls, the roof MUST be constructed in accordance with the rules laid out by the relevant SANS (in this case 10400). In addition, the new SANS remind designers and builders that other sections are also vitally important when it comes to roof design, including Part A: General principles and requirements; Part B: Structural design; Part C: Dimensions; Part R: Stormwater disposal; Part T: Fire protection; and Part V: Space heating.

Of course they are. Any qualified designer knows that every one of the SANS that form part of 10400 needs to be considered as a whole. It’s just because the different new sections were published over a period of years that has made it more of a challenge for many.

Since anybody building a house MUST either BE a “competent person” in terms of the regulations, or must EMPLOY a “competent person” to put in plans and oversee the building operation, either you or the person you employ should purchase the updated section of SANS 10400 Part L Roofs from the SABS to double-check details and specifications. Also be acutely aware that circumstances vary from site to site.

There are several South African National Standards (SANS) that relate to roof timbers, all of which must be complied with when roof trusses and other roofing elements are constructed. In addition there are standards that relate to roof coverings and other elements. They include:

  • SANS 542, Concrete roofing tiles
  • SANS 1288, Preservative-treated timber
  • SANS 1460, Laminated timber (gluglam)
  • SANS 1701-1, Sawn eucalyptus timber – Part 1: Proof-graded structural timber
  • SANS 1701-2, Sawn eucalyptus timber – Part 2: Brandering and battens
  • SANS 1783-2, Sawn softwood timber – Part 2: Stress-graded structural timber and timber for frame wall construction
  • SANS 1783-4, Sawn softwood timber – Part 4: Brandering and battens
  • SANS 2001-CT2, Construction works Part CT2: Structural timberwork (roofing)
  • SANS 10407, Thatched roof construction

It is therefore important that you as a Public member take note to use a Professional Roofing Company.  Press into this link https://bit.ly/3L5S2A4

The requirements you should take note of this!

Roof design depends on a number of factors including the type of covering you are going to use, and the span over which the roof structure is to be supported. More often than not, the roof structure is assembled from a series of roof trusses. These rest on wooden wall plates, and are designed to span the walls of the house. They will be either nailed or bolted together on site, or delivered to site on order by a specialist truss manufacturer.

Illustration courtesy The Complete Book of Owner Building in South Africa

The trusses themselves are made up of rafters, tie beams, posts and struts, all of which are assembled according to a specific design. The illustrations above shows some of the most usual configurations. The new regulations have simple line drawings for:

  • Four-bay Howe truss with a maximum clear span of 6 m (the same as centre right above)
  • Six-bay Howe truss with a maximum clear span of 8 m (called a King Post Truss above)
  • Two-bay mono pitched Howe truss with a maximum clear span of 3 m
  • Three-bay mono pitched Howe truss with a maximum clear span of 4 m

The regulations also state that no member of any truss should have a length that is greater than 60 times its smallest dimension.

The basic requirements shown in the table below, apply to Howe-type trusses as listed above. There are some additional tables that we can mention here below, however all these details can be obtained from the professionals. 

It is therefore important that you as a Public member take note to use a Professional Roofing Company.  Press into this link https://bit.ly/3L5S2A4

Protection from the Elements!

There are other factors that relate to fire resistance an combustibility, and waterproofing – which of course has to be discussed flashing and flat roofs!

  1. Fire resistance and combustibility relate to light fittings and any other components that penetrate the ceiling, as well as the non-combustibility of “such assemblies”. No part of any roof or ceiling that is made of wood or any other “combustible” material is permitted to pass through any separating element of a building.
  2. Waterproofing refers mainly to runoff water from the roof … and therefore relates directly to the slope of the roof. This, in turn, is totally reliant on the roof covering used. SANS 10400 has specs on minimum roof slopes and sheet end laps. 
  3. Flashing, which is used to stop leaks coming in from around chimneys and other “projections”.
  4. Flat roofs are an issue all on their own! For instance, flat roofs are not actually flat, they MUST have a fall of about 1:50.

Part L of the updated national building regulations (published in 2011) also include new sections on roof coverings and waterproofing systems for pitched roofs, and drainage and waterproofing of flat roofs.

It is therefore important that you as a Public member take note to use a Professional Roofing Company.  Press into this link https://bit.ly/3L5S2A4

Credit to https://www.sans10400.co.za/roofs-l/ 

 

 


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