If you’re planning to build a new house or adding an addition to your existing residence one of the main issues you’ll need to decide is how you will keep the roof in place? If your plans do not require flat roofs that is, you must decide between trusses or rafters.
A trip to the attic of nearly every older house will reveal the fact that rafters were an most popular choice to construct homes in past. Nowadays, however, around four-in-five new houses constructed within the U.S. utilize truss construction. It is evident that things have changed. However each method has its own advantages that could favor one method over the other. Moreover, new construction that utilizes either or both methods — is in progress each day.
What is what is a Rafter?
The technique of using rafter for roof construction is commonly referred to in the general sense as “stick framing.” The rafters are long planks typically 2-x-10s or 12s, that are angled downwards towards the central beam located at the top of the roof. They then intersect with the walls of the outside. These planks of long length help support the roof sheathing and roofing.
Ceiling joists that extend horizontally across the attic space that is between the exterior walls hold the walls and, together with the rafters on top create a cohesive ceiling and attic construction.
What is an Truss?
A truss is a constructed wooden structure made of wood that combines the triangular weave of structural components to help support the roof, while also tying the exterior walls of the home together. Long sloping beams that extend up to above the level of the truss as well as one that is horizontally across the bottom are referred to as chords. The ties and beams which form the triangular interior webbing of trusses are made to spread the roof’s weight across the entire space.
A typical house roof comprises a number of trusses that are evenly spaced over an area that extends from one side of the building to the other end. Contrary to stick-built rafter construction, which is built on site, the majority of trusses are built in a factory before being shipped to the construction site, ready to be installed.
Which one do you have?
If you’re purchasing an existing home, then the decision between rafters and the truss structure has been designed for you. As mentioned above scenario, if the house is an older property, it’s almost certain to include rafters , while modern homes are more likely to use Trusses. If the house is brand new in a brand new development Truss construction could be considered to be a Slam-dunk. However, some brand new custom-designed homes may employ rafters as a parts or in the entire structure.
What is the Difference Between Them?
Rafter Pros
More Attic Space
If you are thinking you may be interested in converting your attic into a space, or require lots of open space for storage, the rafter construction leaves the attic space wide to be used in this manner.
Ceiling Options
If you’re planning to incorporate specific ceiling designs such as a vaulted cathedral ceiling, rafters will leave space in the attic to accommodate the required structure. Trusses can be customized to allow for vaulted ceilings, however it’s basically an unusual procedure that needs specific considerations.
Attic Insulation
Installation of attic insulation as well as other measures that improve efficiency like radiant barriers are generally easier and faster in the open space left by the rafter construction.
Less Time to Lead
Because trusses are made in a factory, precise plans with precise dimensions have to be prepared well in advance of the exact date they will be needed. Since rafters are constructed on site in the event of a need so less planning in advance is required.
Rafter Cons
More time-consuming and costlier
Construction site can be slower and requires much longer to build and is more time-consuming for the people. A huge residential rafter roof can take up to a week for construction. Depending on the labor costs in your area which can increase the price of construction significantly.
Highly skilled, experienced workers are required.
When the truss method of construction is becoming the norm for residential construction those with the abilities to construct rafters quickly and precisely are becoming harder to come by. In many instances the craftsmen who are skilled in this field are getting older, and in the process, they may be quit by now.
Truss Pros
Factory Quality Control
Because they are produced in an indoor facility and often using CNC-controlled saws and fabrication equipment the quality control is constant. Trusses can also be checked and certified by a third party organization.
Just-in-Time Delivery
The building project could be planned by the truss manufacturer to ensure that the finished trusses will be delivered at the exact time they are needed. The storage on site is therefore not necessary and trusses are not exposed to weather conditions.
Faster Construction
If trusses aren’t large enough to be lifted manually by two or three people — as is often the case with residential construction projects, the entire roof can be trussed within two or three days.
Greater Strength
The ties and beams which form the triangular interior webbing of trusses are made to efficiently disperse the roof’s weight over a greater area. Additionally, the triangular structure allows for greater use of shorter and more affordable pieces of timber.
Reduced Costs of Cumulative
A study conducted by The National Association of Home Builders examined two similar homes. The house constructed using the trusses had a 16 percent reduction in the amount of the cost of materials and labor compared to the house built with traditional rafters.
Truss Cons
Reduced Attic Space
The triangular webbing composed of evenly spaced trusses creates a divide in the attic space, making conversion to a space difficult and reduces space to store boxes and other objects.
Costs that are higher up-front
The initial cost for factory making trusses is more expensive than the price of raw lumber used to construct rafters. (Less the time required for installation generally makes up for it.)
Installation and Delivery Questions
Trusses with a finished design are large and the quantity required to build a big home will require an 18-wheeler to transport. Thus, the location is required to be accessible to a vehicle that is big. Additionally, trusses constructed to accommodate larger square footage typically cannot be handled manually by only a few employees. In these instances, cranes will be needed at the site to raise the trusses to their proper position.
Very little flexibility for design changes
After the plans and dimensions are provided to the manufacturer and the Trusses are constructed and fabricated, any re-thoughts on the design will be difficult. The last-minute roof design or attic modifications are either not achievable or will require high costs.
Future Changes
Truss systems are interdependent structure. When it is constructed and put in place, subsequent modifications could cause problems and cause dangers due to a weaker structural integrity. This can include actions such as drilling holes in truss components to allow cables that pass across the attic. Thus, an examination and an informed opinion from an experienced contractor is recommended before making minor changes to the trusses.
