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Rot on Tie Beam

Started by SleepyDog, August 30, 2022, 07:03:23 PM

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SleepyDog

My uncle cut down a poplar tree on his property and we took it to the local amish mill. No take backsies. 

Some pieces are better than others but unfortunately I only was able to get two pieces for the tie beams and one of them has rot on the end. 

This is for a very small structure: 8' x 10' garden shed that will have a green roof. the tie beam will be spanning the shorter leg, about 82" before the tenons enter the 8x8 posts.

I plan on cutting out the rotten section, gluing and pegging a fresh board to it. Then make the necessary cuts for the tenons. The mortise will not be in the affected location

Is this sound (enough)?

Thanks in advance!

Matt



 

 ?

Jim_Rogers

When we have a situation like that, sometimes we put in a "free tenon".
Like this:


 
Each one has to be designed and installed per the exact size, location and need.

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

Don P

Alas, when that happens I go back to the "store". It gets down to what do you actually need structurally, does that remain. I run into those decisions in old work, I don't like making them on new. Mindful of what the wood handbook says about decay, it significantly reduces strength before it can be visually detected. I would rip that down a size for something else myself and order another.

kantuckid

Gluing green wood is illogical. Drying a beam that size is also a tough notion. 
The "Jim idea" is the 2nd best one by far IMO-after the "get another one" by Don P which makes the best plan IMO. 
A piece of wood has disappointed me several times before.  :D 
Kan=Kansas;tuck=Kentucky;kid=what I'm not

SleepyDog

How about the use of epoxies? I've seen some videos of people restoring old beams using it. 

Don P

This is why I have real mixed feelings about asking for exemption from grading. I doubt this meets any grade. All the design work based on some assumed strength goes out the window if you make a bad grading call.

I really don't know how deep the rot goes. I saw that off till I'm comfortable with what I'm seeing. I'm also surprised that it is straight.

Epoxy, I'd save the money, it has compressive strength, the bond to rot is just going to shear if called upon though. Tensile strength of resin itself is low unless you wrap the beam in fiberglass (tensile strength) and epoxy which brings us back to the correct decision. They are growing on trees  :).

SleepyDog

 

 

 

I believe I've cut out all the rotten section of the tie beam but I am still hesitant. 

1. Can the tie beam's tenon, not be centered? At least on one side. 

2. I have another piece that is just not as long. Does the tie beam need to go through both posts? (This is originally designed to be thru-tenon)

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