How long can trusses be exposed to rain?
When storing the trusses horizontally, blocking needs to be used on eight to ten foot centers, or as required, to minimize lateral bending and moisture gain. As far as how long trusses can be exposed to the elements, a ballpark number is about a month.
How far apart should roof trusses be South Africa?
When constructing a roof framework, the rule of thumb is that any purlin should have a minimum nominal depth and width of 76 mm or 50 mm, and max centre-to-centre spacing between the purlins ought to be 1,2 m.
What type of wood is used for roof trusses in South Africa?
South African Pine
“It is a fact that residential roof truss construction in South Africa is the single biggest user of locally produced structural timber which is mostly South African Pine.
How much do wooden trusses cost?
$35 to $400 per truss
The majority of roofs are wood trusses. Wood costs anywhere from $35 to $400 per truss, depending on the size of the roof. Mainly used in residential construction, wood trusses are about half the cost of steel, but they can be susceptible to warping and damage over time because of environmental factors.
How do you protect trusses from rain?
Trusses stored for more than one week shall be protected from the environment in a manner that provides adequate ventilation of the trusses. If tarpaulins or other protective covers are used, the ends shall be left open for ventilation. Tight fitting coverings are not recommended, since they can trap moisture.
How long does truss last?
Wood roof trusses can be expected to last as long as the home itself (100+ years), if they are maintained in a stable, resonably dry environment. Moisture from excessive humidity, condensation, or roof leaks, and termites are the things that can shorten roof truss life.
What grade of wood is used for roof trusses?
2, No. 3, MSR and MEL are all used in trusses.
How far can a wooden truss span?
A roof truss can span up to 80′ without support, however in any home that distance would be impractical and incredibly costly. Trusses are designed to span spaces without interior supports, and spans of up to 40′ are the most common in today’s homes.
How thick should roof trusses be?
We usually opt for the 35mm thickness in timber when designing standard timber roof trusses. This could be for Fink Trusses in a house construction or Queenpost trusses for a garage. Meanwhile, the 46mm thickness option is used for attic trusses due to fire regulation guidelines.
Can you leave trusses outside?
How long do wood trusses last?
How long can wood trusses span?
Trusses can be installed in buildings with wood, concrete or masonry walls, including those located in high seismic zones. While spans can extend over 100 feet, the most common long-span applications range between 60 and 100 feet.
Is it cheaper to build your own roof trusses?
Today, over 80% of new homes are built with trusses, rather than rafters. The main reason for this is cost. In raw material alone, trusses are 40% to 60% cheaper than making a roof using rafter or “stick” construction.