first post and a couple of questions

[billy_wizz]

Hi there
    i found this site looking for information on timber frame building! Unfortunately as its near my birthday i'm on a book embargo but have two on my list! I'm planning a small wood shed to start with 8'wide 10' deep the shed will be 8' x 8' with a 2' covered porch! It will be built with softwood. My options at the minute are European larch and pine i believe it is radiata or scotts but will have to check! Doug fir/spruce and western red ceder(not sure if its the same as the one you refer to but grows quite fast in the uk) may be available at other times! I was thinking of 6"x 6" for the sils posts and beams using 4 corner posts!
I have access to a box operated stenner vertical bandmill to mill the timbers! sorry for the ramble now for the questions

1, How accurate does the box heart cut need to be, does the heart center need to run perfectly down the center of the beam and if not how much off center can it be before it causes real problems?

2, Of the timbers i have and will have which are the best to use and are there any that shouldn't be used?       

3, If the stub tenon locates the post to the sill how is it fixed to the sill as the stub tenon doesn't look long enough for a good peg hold?

many thanks peter

[Jim_Rogers]

Welcome to the Forestry forum timber framing section.

1) Within an 1 on a 6x6 would be ok. If you get way off center the timber may flex to one side.

2)Not sure about these types as they don't grow in my area. Check with carpenters fellowship members they should be able to tell you more.

3) gravity. Some people run metal straps down the outside of the post past the sill to the concrete foundation to get a secure hold down.


Keep asking questions.

Jim Rogers

[Magicman]

Welcome to the Forestry Forum, billy_wizz.   

Just curious, do you have any relatives with the name "Poston"?

[billy_wizz]

magicman i don't have have relatives by that name that i know to!

jim just to clarify if the cut runs from heart plum center one end to heart off by 1" the other end is that still ok as well?

[Jim_Rogers]

jim just to clarify if the cut runs from heart plum center one end to heart off by 1" the other end is that still ok as well?

Yes, hearts can wander off center some, but not a lot.

Jim Rogers

[Chilterns]

Hi Billy,

You don't say where you are located in England but if your check out the Timber Framing section and the Timber Felling & Conversion section on the Oxfordshire Woodland Group web forum this will provide you with some ideas about what you can do with Oak, Doug Fir, European Larch & Western Red Cedar - all of which are good useable timber.

The North American practice of using stub tenons on post bottom is rarely seen in England with a 4 inch long pegged tenon being more normal practice.

Chilterns

[Dave Shepard]

Would those buildings have no floor systems? Like you said, over here we use stub tenons almost exclusively. In fact, I don't recall a pegged post bottom tenon in any old building that I've looked at.

[Chilterns]

Hi Dave,
Please check out some recent photographs taken by Jeremey Hunter on the "Timber-Framing from Scratch" course run by Joe Thompson at The Weald & Downland Open Air Museum.

On the second from last photo you will clearly see the correct cross sill to long sill and long sill to post pegged connections and configuration. Temporary tapered metal pegs have been used instead of wooden pegs and this makes it easier to see the location of the pegs. The tenons are nominally 4" long and the mortices between the sill to sill and post to sill are interconnected faciliating this joint to self drain of any rainwater ingress. The long sills are left with 4" horns that act as relish for the cross sill mortices.

Chilterns   

[Heartwood]

Stub tenons should only be used on a closed-in frame and if there is some other means of holding the frame down, such as sheathing or straps tying the posts to the sills and/or foundation. In an open building, such as a pavilion or woodshed, pegged tenons should be used as a minimum hold-down. If a big wind comes up on an open-building roof, gravity can't be relied upon to hold the frame down.