Types of roof truss
Roof trusses carry the roof and push loads down to the walls. The right choice depends on span, roof pitch, internal layout, and the need for open space under the rafters. Most homes use factory made trusses for speed and consistency. Site built frames still suit small jobs and heritage work. The goal is simple: keep the roof stiff, control movement, and give the room below the shape it needs.
Short spans suit simple trusses. Long spans need stronger webs.
Think about access, services, and loft use before you pick a type. A little
planning saves time later and avoids costly changes once the roof is up.
Below are the trusses you will see most often with plain notes on when they work best
and what to watch for on site.
King post truss
This is the classic choice for short spans. One central post ties the ridge to the tie
beam with simple struts to the rafters. It is quick to set out and easy to read on site.
Use it for small rooms or porches where clean lines matter. Keep connections tight and
protect end grain from moisture at the wall plate.
Queen post truss
Two posts instead of one give a wider clear center. It bridges longer spans than a king
post and can frame a neat ceiling feature.
Good for rooms that need a central walkway or a roof light. Watch deflection at mid span
and brace the rafters well during install.
Fink truss
The most common house truss. The W shaped web spreads load with good material economy
which keeps weight down and cost under control.
Ideal for standard roofs with no room-in-the-roof. Leave clear routes for cables and
pipes at the eaves and never cut webs to make space.
Raised tie and scissor truss
These lift the ceiling line. A raised tie opens the room edge to edge while a scissor
gives a vaulted effect with opposing rafters.
Great for light airy rooms. Check thrust at the wall line and confirm fixings for
ceiling finishes that follow the rake.