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Joinery Design and Designer Problems

Started by kettleviewtimber, August 16, 2007, 06:52:36 AM

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kettleviewtimber

Help,

What are my options?  I have problems with a design and designer.  RidgeTop design (**** *****) designed the below joint. I have two purlins and one top cord coming together and the tenons interfere with one another.

RidgeTop was paid $50.00 per hour to design our home.  I have redrawn the entire frame.  There where other problems just like this one.  **** ****** has broken off all contact.

1.  What are my options for this joint?

2.  What are my options with this designer?

The material is Northern White Pine.  Tenons 1 1/2" , (Right)Purlin 6 x 10, Post 8 x 8, Top Cord 8 x 10, (Left)Purlin 6 x 8

beenthere

Welcome to the forum.
Not sure just what your specific problem is, but on the surface, seems you are in a pickle or two.

Are we looking at your re-draw or what you started with that caused a re-draw? 
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Jeff

kettleviewtimber, Welcome to the forestry forum.   I have edited out the name of the designer in your post as its not relevant to your question. Feel free to use the Forestry forum for any questions and research, but please limit the finger pointing unless you are prepared to deal with the potential consequences as you are ultimately responsible for the content of your posts.
Just call me the midget doctor.
Forestry Forum Founder and Chief Cook and Bottle Washer.

Commercial circle sawmill sawyer in a past life for 25yrs.
Ezekiel 22:30

kettleviewtimber

This is one of many problems with joints that caused a redraw.  I took all the component drawings from RidgeTop design and assembled them into a final assembly to do a sanity check, and these are the problems that I'm encountering.  The top picture is showing the problem; I have hidden the post to show the interference of the tenons.

Jim_Rogers

Having a three way joint can be an issue.
One easy solution is to make the two purlins join each other with a through spline.
I can draw it for you, but this should be checked by an engineer if there is a lot of load on it.

If you have a contract with this designer then you may have some recourse to go after the amounts you've paid him.
Do you have a contract?

Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

Jim_Rogers

One of the first thing a designer decided on is called the "general frame rules"
These frame rules tell the timber framer what the tenons and mortises are going to be, in size and layout.
For example on simple garden sheds like Jack Sobon's from his book the general frame rules are that the tenons and mortises are offset from the layout face 2" and then the tenons and mortises are 2" thick/wide.
This frame rule works as most of the timbers in this frame are 8" wide.
A standard timber framing rule is that tenons should be 1/4 the width. So 2" is 1/4 of 8".
For 6x6's then 1 1/2" tenons work.

To solve one of your issues at the three way joint you'd move the tenons from the purlins to the outer side of the post, and lay them out 2" off the outside face and maybe make them 2" wide. It really depends on all the size of all the timbers.

This moving of the tenon, or through spline that I have mentioned, will give the tenon from the rafter/top cord more space to join with the post.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

kettleviewtimber

Every tenon and mortise in this frame is 1 1/2" regardless of size of timber.  Most of them are 3 1/4" from the layout face. 

Is it an option to notch the tenons on the purlins where they intersect the rafter/top cord tenon? I have completed the post in this bent where the 3 way joint comes together.

I have completed 5 of the 7 bents with the one below being the first completed and assembled.

I do have a contract with the designer (RidgeTop design).




Jim_Rogers

Quote from: kettleviewtimber on August 16, 2007, 01:25:05 PMEvery tenon and mortise in this frame is 1 1/2" regardless of size of timber.

What type of wood is it? I see by your first post it's white pine......

It would appear from your/the drawings, that these timbers are really plates that are holding up other rafters. Is this true?

One reason I ask is to help you understand that each timber is given a name based on it's location, and it's location will tell us it's use.
Plates hold up other rafters, and therefore quite a roof load.
It appears from the drawing that these "plates" are housed into the sides of the post.
This housing will have a needed bearing surface to hold up the plates, but the tenon will also need to bear on the bottom of the mortise to insure you have enough bearing surface for the roof load.
So, my point is that you can't notch the bottom of the tenon at all.
I can't really say whether or not you can notch these tenon based on these pictures.
If you could show a picture of the tenons notched maybe I could tell you.
If you were to abandon the tenon idea, and create a hardwood spline that passes through the post and is pegged into each plate on either side of the post then this hardwood spline will be stronger and may help you.
You may need to add steel to this joint to make it safe.

If you go to my gallery and look at some of the pictures there, especially the ones about the raising in VT you'll see what I mean by splines and how they used them in creating three way and four way joints. I can help you understand how to create these new splines to solve your issues with the three way joint you have.
There are also other alternatives to holding the two plates to the post. The reason I mention this is if you notch the tenons, some, you may weaken them and then there won't be enough relish to hold the plate to the post. You may have to put another piece of lumber over the outside of this joint where it won't show and lag bolt it together. But I don't know for sure without complete understanding what's what....

We really shouldn't discuss contract on an open forum, but I sent you a personal message through the FF system tell you, you can call me or email me directly for further help.....

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

kettleviewtimber

Jim,

Thanks for all your info.

The wood is White Pine.  The purlin on the right is a plate that is supporting two rafters.  The purlin on the left ties bent 2 and bent 3 together. The notch will be on the top of the tenon not on the bearing surface.  Here is a picture I hope this helps. 




Jim_Rogers

If that rafter has a good shoulder on it where it rests on the inside surface of the post on a housing, you should be ok.
I don't know how you're going to peg all that together, as there won't be much wood left there......

Look at this:



With the rafter tenon a little shorter, and the plates joined with a through spline this works......

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

kettleviewtimber

Jim,

I started the redesign but I soon realized that I have a tenon that is below the joint in which the spline would interfere with.

The tenon is from a plate that is at a right angle from the plate on the right.  That plate supports rafters for a front entrace bay.

The picture will describe it better than I can.

 

Jim_Rogers

I see, look at my gallery for a short brace that fits in the corner between a post and beam as a solution to holding up timbers.

Here it is:


this may help you....

Jim

PS. nice talking with you this morning....

Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

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