Rafters vs. Trusses: Which One Is Right for Your Roof?

Where rafters came from

Rafters are the original way to frame a roof. They've been used for centuries.

The simplest version is a ridge pole at the peak with rafters running up to it from each side wall. Many settlers framed their log cabins this way. Others used purlins, logs running from gable to gable with boards laid across them. Either way, every piece was cut and fit on site by the person building it.

The switch to trusses

Trusses have been used in barns and bridges for centuries. But they didn't take over home building until the 1950s, when metal connector plates made it practical to build them in a shop. The postwar housing boom needed houses built fast, and trusses cut down the labor needed on the job site.

That shift has continued every year since. Today, most houses call for trusses. They're engineered for the job and delivered ready to set.

Still, some areas and some builders prefer rafters. A well-framed rafter roof has a handcrafted look and feel that a prefab truss doesn't. You can see the skill that went into it.

When rafters make sense

That appeal matters less than it used to. But there are two places where rafters still make sense.

Usable attic space

If you want to turn your attic into living space, rafters can often claim more of it than trusses can. The webs inside a standard truss fill the attic. Attic trusses (also called room-in-attic trusses) are built for this and work well in a lot of houses. But if you want the most space possible out of your roof, rafters can do things trusses can't.

That space takes planning. The floor joists below need to be sized for living space. They usually also tie the rafters together so the roof doesn't push the walls out. If the design raises or removes those ties for headroom, the rafters need a structural ridge beam.

Exposed framing

On an open porch, or inside a home with a vaulted ceiling, some people want to see the rafters and the roof deck above them. If that's the look you want, rafters are the best way to get it. The same rule applies here: a vaulted rafter ceiling needs an engineered ridge beam, usually LVL or glulam, with posts to carry it. Without it, the roof pushes the walls apart.

When trusses make sense

For most roofs, trusses are the better choice. Here's why.

Cost

Trusses are more cost-effective and will save you money on a new house. Most of the work happens in our shop instead of on your job site.

Ease of use

Trusses show up prebuilt. Your crew sets them and moves on instead of cutting and fitting every piece on site.

Open floor plans

Trusses span from outside wall to outside wall. Rafter roofs often need interior bearing walls or beams to hold them up. If you want a wide-open floor plan, trusses make it easier.

Less to get wrong

Trusses still have plenty of technical details, but there's less your framer needs to know than on a rafter job. The engineering is done before the trusses leave our yard. But trusses must be installed and braced per the drawings, and they should never be cut or notched on site.

Fewer builders who know rafters

There are fewer builders every year who can frame a quality house with rafters. A rafter roof is only as good as the crew that builds it. If you can't find a crew with real experience, trusses are the safer bet.