As the part of the home that does the most work sheltering us and our belongings from the wind and weather, proper setup of your home’s roof is one of the most important things to deal with.
Although there are general standards that have to be followed in compliance with local and/or national building codes, roof trusses can be set up in a variety of ways to meet certain needs.
What are these possible setups? What standards and building codes should I be looking out for? And how much would all of this cost?
Learn all of that and more about setting up your roof truss in this quick guide.
What Is a Roof Truss?
At its most fundamental form, a truss is a structure made up of straight pieces of material to form triangles that together allow the entire thing to sustain heavy loads. A roof truss, following this logic, is the use of this same structure to bear the weight of roofing material over a house.
Depending on the needs of the home or building to be made, the roof truss can be made with various materials and have different designs and configurations. In most modern homes, they are typically made of either wood or metal, and can either be bought in prefabricated form or can be custom-built on site.
How Far Apart Should Roof Trusses Be
One of the primary considerations for roof trusses in homes is their spacing, which dictates how well the overall support structure is able to carry and hold the roof and its other components (insulation, solar installations, etc).
Proper spacing between roof trusses is very important if you want to ensure that the entire roof area is properly supported with no weak points.
In the case of the more common wood trusses, 24 inches is generally used as the standard spacing between truss units. This happens to be the case in both prefabricated and custom-built structures.
To ensure the structural integrity of this and other spacing lengths, the roof truss itself must be built to a certain standard as well. For trusses with a spacing of 24 inches, three to four lumber pieces is typically used for the best results.
Now, does this mean your roof trusses need to be at this spacing? Of course not—you can have your spacing set further or closer than that based on your needs.
For instance, wider spacing can reduce the number of truss units you will need on your roof, reducing its overall cost. Of course, this may compromise the load-bearing ability of your roofing, so do keep this in mind and talk to your building contractor to get the best advice for your home.
What’s Standard Roof Truss Spacing For Metal Roofing?
Although wood is still the most popular choice for most homes, metal has become more and more popular in recent years. Thanks to its strength and resistance to things like termites and mold, builders and designers have been recommending metal more often for new home designs.
When metal roofs are concerned, the same 24 inches of spacing is still used as the standard for the same reasons as they are on shingle and tile roofs—a generally good balance between cost and structural integrity.
While you can get away with wider truss spacing, the generally lighter weight of metal roofing can make it a bit more vulnerable to severe weather without enough roof support keeping it together.
As for metal trusses (which are most common in commercial structures but can also be used in homes), their increased strength will give you the extra overhead to use fewer trusses and reduce cost that way. However, you will also need to account for the highest cost of the metal trusses themselves, among other concerns.
Roof Truss Spacing For Pole Barn
The different design of pole barn roofing makes it such that there is no one answer to the question of how far apart the spacing should be.
Trusses for pole barn roofing are often placed anywhere from four feet to even twelve or sixteen feet apart depending on what material you use for your roofing alongside the other considerations we have mentioned previously like cost.
How Many Roof Trusses Do You Need?
Another important point of consideration is the number of roof trusses that will need to be installed on your roof. If you follow the standard spacing rules for roof trusses, the exact number you will need for your roofing solution is mainly dependent on the length of your home.
As we mentioned previously, however, many roofing solutions do allow you to deviate a bit from this standard spacing, which is useful if you want to, for instance, extend the attic space in your home or want a bit more load capacity for heavy roof installations like solar panels.
How to Calculate Roof Truss Spacing
Roof truss spacing is typically measured from the midpoint of one roof truss to the next—following the standard lengths, it is this measurement point that should work out to 24 inches or whatever spacing length you choose.
To calculate the number of trusses you will need for your home given the spacing, you will need to get the length of your home, divide it by the spacing length of your roof trusses, and add 1 more truss to account for the truss unit that will be mounted on one of the edge walls of your home.
For an example home that is 30 feet long, the number of trusses you will need with 24 inch spacing is (30*12)/24 = 15, plus the 1 extra to make 16 roof trusses in total.
Roof Truss Spacing Costs Guide
Last but definitely not least on your considerations when selecting roof truss configurations for your home is the cost.
We’ve previously touched on the number of trusses being a significant contributor to the cost of your roof support solution, but it’s important to remember that there are other things you need to look out for as well, not least of which is the type and grade of the material to be used.
To compute the full cost of your roof truss solution, you will need to account for the length of the truss and the cost per foot of the material of your choice, then multiply that by the number of trusses you will need. We’ll use the previous example of 16 trusses for our example below.
So, say you want to use mahogany as the material for your roof truss, which a supplier has priced at $5 per foot. For a truss that is 25 feet long, the cost per truss works out to $5*25 = $125 per truss. Multiply that by the 16 trusses we need for our home and the roof support structure will cost us $2,000.