I have seen pegs angled on other king post truss frames and wondered if it was correct.

Hi Trimber,

I think that we need to see a digi pic of these king post / tie beam angled pegs. I have not seen this arrangment before.

Roger,

Is a tie chord the same as a tie beam and a rafter chord the same as a principal rafter ?

Regards

Ken Hume

Ken

I use the term chord as a indication that the element is a major piece in a truss system. The terms tie beams and principal rafters do not, to me, imply use in a truss. Ken, can this use of "chord" be limited to the USA?

Hi Roger,

I seem remember from my school days that the term chord relates to a line intersecting with a circle and just maybe if a truss is laid out using a string line making a circle then there might well be a logical connection with the use of the term chord to describe timber frame components. The term chord is not in common use in England to describe the components under discussion here but I just checked out the TFG Glossary and this does indeed include a reference connecting both terms.

You are quite correct that a tie beam need not necessarily be included within a truss but more oft than not is however a principal rafter is nearly always a primary component of a truss.

Regards

Ken Hume

Ken, you wrote "however a principal rafter is nearly always a primary component of a truss." In my way of thinking, a principal rafter is a major supporting member of a common purlin roof and to me a roof truss does not imply the use of common purlins. So I guess that we differ on the common situation of employment or just the regimen of terms.

28 foot span is doable, but what load do you expect the loft to carry? Is it addressed in the engineering? From what I've seen so far, it would seem that a kingpost truss spanning that distance usually cannot carry a full 2nd floor live load in combination with the roof snow load. I have seen lofts done though for some storage space. Anyone with experience, please jump in too.

There was an old church here in Machiasport, which was dismantled. It was a king post truss roof system. The ants had turned the tenons on the rafter feet to swiss cheese, you could crumble them in your hands. Not all of them, perhaps three out of 12, that was enough. The interesting part was the brick chimney, it sat on two round logs set across the tie beams. What does 16' of brick chimney weight? Add to that lath and plaster and a tin ceiling with additional joist material. The span was at least 36' maybe 40', I don't recall exactly.

28' is a short span. If there is a question on how to peg the king, I would seek direct person to person expert help with what the joint comprises.

A picture of this "toe peg" would be interesting.

Tim

Hi Tim,

- Tin Ceiling ? what's that all about ?

Mo's post about Independence Hall contains close up details of how to make that kingpost to tie beam joint. A metal reinforced joint is probably the most common solution to this design problem.

Regards

Ken Hume

Ken:
A tin ceiling is the type of ceiling tile made out of tin, or basically really thin steel alloy.
I did a google search and selected images and got this site that shows lots of tile types:
http://www.oldhouseweb.com/product-showc...es-stores.shtml
There is also lots of descriptions about how they can be used.
Very decorative......

Jim Rogers

Ken, I checked Newlands "The Carpenters Assistant" and the term chord turned up in the glossary and was used extensively in the section on bridges. Newlands also uses "principal" for the entire truss and the various truss componants. I am rethinking.

All the best, Roger