Rafters or Trusses

Specific Inspection Topics Structural Inspections
1

Are these considered Rafters or Trusses?

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2

Rafters
http://activerain.trulia.com/blogsview/2135174/trusses--rafters----what-the-heck-is-the-difference-

3

Truss but very old.

4

Truss.

5

Home built in 1950

6

Looks looks a bolted W truss design.

7

Site built trusses, not engineered.

8

Truss, but old. Not engineered

9

You took the words right outa my mouth.

10

No point in giving it a single name. It’s:
“… a roof framing system not designed by a structural engineer but not showing signs of failure after approximately 60 years in place, indicating that it is structurally adequate. A more accurate evaluation would require the services of a structural engineer.”

11

Very nice verbiage.

12

Excellent.

13

Actually we have no way of knowing who designed it, and what their qualifications were. I would change the narrative to “may not have been designed by an engineer”

14

Actually, it’s the “roof-ceiling frame construction” and not “roof framing” as is a integral system used to support both aspects of the structure. Second, how do you know it wasn’t an engineered design? Third, stating that they are “structurally adequate” is the professional opinion of an engineer, unless you have that designation?

I have reviewed blueprints for structures from the 30’s with detailed drawings for the truss/rafter system.

15

thumbs up!

16

I would classify them as trusses. If there were no apparent structural issues and a history of performing as intended for 50+ years, I don’t think there would be a need to make any comments.

Over the past 20 years less than 5% of the houses I have inspected had serious structural problems (decks excluded). I would say 95% of the structural issues in those 5% occurred within the first 10 years.

An occasional broken truss web or cracked rafter does not warrant calling a structural engineer IMO. The redundancy of multiple trusses or rafters will minimize the effects of one damaged member. Adjacent trusses or rafters will pick up the load. Most good contractors can do the repair.

IMO inward bowing of basement walls, although rare, is the most serious and expensive structural problem I find. Differential foundation settlement is more common, but still expensive to repair. Bowing and settlement take years to develop, expensive but not usually life threatening.

By far the #1 structural problem and potentially the most dangerous structural issue is poorly designed, maintained and constructed decks. Deck failures are sudden events and 99% of the time occur with people on them.

In general I would rank the frequency of structural problems and who to call in this order:

  1. Decks - Probability of life threatening defect (HIGH), Call for contractor to repair, call for structural engineer only in unusual cases.

  2. Foundation settlement - Probability of life threatening defect (LOW). Call for contractor to repair in minor to moderate cases, call for structural engineer in severe cases.

  3. Roof framing problems - Probability of life threatening defect (LOW), Call for contractor to repair, call for structural engineer only in unusual cases.

  4. Bowing Foundations - Probability of life threatening defect (LOW), Call for structural engineer. Engineer will likely call for contractor repair once design issues have been resolved.

17

Good point. I’m changing that narrative.

18

…spread the knowledge my friend. The only reason I know it is becuase I learned it from someone else…