Bracing, bracing, bracing

Bracing is one of the most overlooked aspects of roofing. With this in mind, SA Roofing takes an in-depth look at this important facet of the roof system – with the help of expert engineer, Errol Hobden of International Truss Systems.

In the real estate world the estate agents have a mantra, “Location, location, location.” We have all certainly heard this phrase many times. You may wonder why the word location is repeated three times. The reason is to emphasize the importance of the location of the property when purchasing real estate. If you purchase a property in a good location, the property is most likely to increase in value over time, giving you a good return on your investment. Location is the number one rule in real estate, and it’s often the most overlooked rule.

In the roof truss industry, this phrase can be translated as, “Bracing, bracing, bracing.” Bracing is one of the most important, integral parts of a roof structure, and it is also one of the most overlooked parts. Many contractors don’t realize that most roof failures are a result of inadequate bracing. A roof structure can be perfectly designed and manufactured, but if it is not correctly erected and braced, you will end up with an unsafe roof that will in all likelihood wind up costing you a considerable sum of money in the future.



The ITC Certificate of Competence

How do you know if your truss fabricator is qualified?

The ITC Certificate is to install a consistent, professional approach into the prefabricated timber roof truss industry through a set of standards governing:
1. The design procedures employed;
2. The presentation of quotations;
3. The competence of key personnel;
4. The quality of manufacture;
5. The erection instructions provided to the site.

Select the download link to view The ITC Competence for Truss Fabricators Document.



Interesting LCP Roofing Facts:

Every node on a truss is TWO plates but ONE pressing point. The average pressing points the factory can produce on a normal shift is 900. A very complicated roof will produce less roof area than a simple roof. It is therefore wise to check the pressing points before estimating the time it will take to fabricate the roof trusses.

Category "A" roof structures MUST be checked by our System - International Truss Systems before fabrication. LCP Roofing is an ITC-SA category "A" fabricator

The erectors can erect on average 175m2 per day per team. This is dependent on access control to sites, site conditions and complexity of the roof structure

The average roof tile and fitting weighs 5kg
An Infraset Sunset tiles weighs 4.8kg and Marley Modern 5.4kg. Therefore, changing the tile specification after quote is done will affect the loadings and possibly a different design and may also influence the costs.
A shorter tile overhang may not necessarily result in a cheaper quotation or final overall cost due to the changes in loadings on the chords

Minimum pitches for Roof Sheeting is:
Corrugated - 10 degrees
IBR - 5 degrees
SAFLOCK - 3 degrees
Roof sheeting is fixed with class 3 roof screws except concealed fix roofing where we use a class 2 screw as the screws are covered by the sheeting

Our tri-axle trailer can load 6 000 tiles
Our Volvo Roof 07 can load 2 700 tiles on the trailer and 2600 tiles on the rigid
The Superlink can load 7300 tiles
The Hino can load 800 tiles
The DAF can load 2000 tiles
The truss trailer can load 52 trusses upright
The highest a vehicle may be according to the National Road traffic act is 4.3m. The minimum clearance of our roof trusses on the roof truss trailer ROOF 16GP is 350mm. Therefore the highest truss form apex to the BOTTOM of the sprocket that we may transport is 3.95m. Anything higher will require the truss to be split (piggy-backed)
Tiles can be load a maximum of 7.50m from the Centreline of the truck. A Truck is on average 2.40m wide. Thus the farthest tiles may be offloaded from where a truck may safely park is approximately 6.0 to 6.3 metres.
The average transport rates are R 18.00/km for the larger trucks. Remember to work on the total return trip unless a return load can be secured.


Warranties and Defects


The NHBRC’s Warranty Scheme provides warranty cover on all new mortgageable housing units, built / facilitated by a registered NHBRC Home Builder and enrolled with the NHBRC.

This Home Building Manual is for structures, which comprise four storeys or less (inclusive of basements). Structures of greater than four storeys shall be submitted to the Technical Department of the NHBRC for consideration prior to enrolment. 


Building Regulations as they apply to roofs

General rules for the construction of roofs

As with most of the National Building Regulations, those that apply to roofs relate to SANS other that 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 MIST 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.