I would like to hear your opinions about pegging and wedging the king post/tie beam joint and pegging at other than 90 degrees? Thanks.

Other than ninety ? Need more information to provide useful feedback.

What are you building and what is the cause of the pegging issue ?

Other than ninety degrees to the face of the tie beam! I am building a king post truss, 28' span. Second floor loft. I am curious because have seen a few different examples of pegging and wedging at the king post/tie. thanks

Still not seeing it Trimber -

You can peg at 90...

And wedge in line with the tenon.

What are you asking after ?

28' is more than do-able, provided proper planning.

Trimber,

I can see at least one situation where you would not use pegs driven at a nominal 90 degrees from the face and that would be where lap joiney is employed. Oft times, especially with cruck framing two pegs will be driven at differing and equally opposite angles to help lock the lap faces together and prevent separation of the joint, but where a mortice and tenon is employed i.e. a fully enclosed joint then this would not be required. Tapered pegs driven into an offset (drilled) mortice and tenon joint do not pull up and sit at exactly 90 degrees but at a slight angle reflecting the degree of taper on the peg since tapered pegs pull up tight on one "face" of the peg only

Regards

Ken Hume

Sometimes I've seen these trusses made w/ the king post tenon running long, protruding past the bottom of the tie beam and then wedged... kind of like an anchor beam (tie beam) found in old dutch barns.

anchor beam pic here:
http://www.readingtontwp.org/mus-stickney6.jpg

My guess is 90-degree pegging is usually done because that's the easiest approach and facilitates draw-boring. It would be more difficult to draw-bore a joint w/ angled pegs.

I'm sorry?

Obviously there are helpful posts for this questions (see Ken Hume or ourbarns1). They responded with what they knew about the topic in as much as they felt was applicable. Then there is djswan?? Please refrain from your useless banter. "Nobody does it like me" is really old and obnoxious.

Trimbers

If the tie chord of the truss carries the load of the second floor loft, then the loading on the pegs could exceed the capacity of the pegs. Pegs that are in a constant pinch will suffer compression damage. Also the load on the rafter chords will increase with the addition of floor load on the truss system.

Trimber, Whats your thinking on pegging this arrangement as skewed angles?

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

Hi Jim,

Your reply has got me thinking and I might well have seen a tin ceiling a few years ago when visiting a delapidated house in Royalston, Mass. The parlour ceiling had a "pressed" pattern texture which looked a bit like moulded plaster and I am sure that someone mentioned that this was made out of tin sheet which I dismissed at the time because it was painted and looked like plaster to me. Maybe I have seen a tin ceiling after all !

Roger,

Yes I have heard the term chord used in bridge building - especially much used by Ed Levin and of course the trusses here are based on the use of geometric arcs and chords.

I don't think that it would be proper for me to say that one person's version of a term definition is more correct than another's. This is usually determined locally and by common use and hence acceptance of the validity of the definition.

I think that The Oxford Dictionary bases (includes and revises) the meaning of words based on the earliest recorded use of those words in published form e.g. newspaper, book, etc. and so your reference to Newlands would be a very early standard against which we could measure our use and hence acceptance of the meaning of the use of the word "primary" in respect of timber frame components.

Regards

Ken Hume

Ken, you wrote, "Yes I have heard the term chord used in bridge building - especially much used by Ed Levin and of course the trusses here are based on the use of geometric arcs and chords." I agree but I think about chords differently. In one sense chord and cord is the same word and truss can mean tie up, as with string or line. Also the carpenters of the past could both build and butcher, so I also think that chord could mean sinew and muscle.

Enjoy the snow. Roger

I would think the added metal could be over-kill for a 28' span. It sure wouldn't hurt though.

As for the tin ceiling, perhaps the church thought they had to keep up with the Jones'.

Did we loose the original poster?

Tim