As my first TF project, I'm building a small shed (12X8) in my backyard for storage and would appreciate a little help. I live in Toronto, so we don't see a lot of timber framing around here!

1) What size timbers should I be using for this size shed?

2) Can I just float the floor on patio stones on each corner and under each post?

3) What kind of time commitment will it take to prepare the timbers?

Thanks in advance!

1. 6x6 with 1.5" M&T
2. No. The bottom of the frame must be held together either by sill plate or foundation.
3. That depends on your skill level and tools you have. 1 or 2 weeks perhaps.

Thane

Hello,
Can you explain point No. 2 a bit more? Must a frame, in general, include a sill plate or be anchored - which is what I assume you mean - to a foundation? I am thinking, for one thing, of Japanese frames standing on stones, or the framing members of the Dutch barns I know of standing on short masonry pillars or footings.

Don Wagstaff

There is an old barn directly behind my house, the oldest part of which is 30x45 with 15' bent spacing. There is no sill plate at all, but the posts are all anchored directly atop very large rocks that are buried in the ground. This is in Indiana, and the barn was built some time around 1900 -in more modern times concrete has been poured around the base of some of the posts, which has actually caused them to begin rotting.

However, I would recommend a sill plate, because without it you run into the problem (which this barn has) that the bottoms of the posts begin to spread out and eventually this causes joints elsewhere up overhead to fail (in this particular case, the canted purlin posts have in some cases pulled free of the purlins, shearing the pegs on their tenons that joined them to the purlins)

That said, it is perfectly reasonable to have foundation support under the sills only at the major load points, i.e. where posts join the sill. This is a technique that has been used all over the world for thousands of years. The stave churches of Norway are so built, and to this day the massively huge Bauernhäuser of Switzerland and south Germany have such foundations. This is also similar to how log cabins were traditionally supported, having in many cases stone buried only under the corners of the structure

But as for patio stones, I would go with something a little larger than that, especially if your ground freezes during the winter. If the ground freezes (and usually even if it doesn't) than it heaves substantially, meaning your square and level foundation will soon be pushed out of alignment, which will cause many structural problems. The solution to that is to have your foundation posts go down below the frost line (well below, because I can guarantee that the frost will on occasion go below the normal line for your area) I imagine in Toronto the frost line is much deeper than ours here.

I built a three bent structure with no sills. There is a girt connecting the post about 2' up from the bottom of the post, holding the post together. If this can be at the top of the post why not the bottom? All the post are different length as well, sitting on tires with cement in them, poured from the extra waste at a previous job. These tires sit on foam sip window cut out, in a very wet area. It will actually flood to the tires at times. I have seen little to no movement in the frame. But I have not checked it with any accurate devise other than my eye on passing. The Stall door inside did need adjusting through the winter to latch properly, though.

Tim

Thanks for the info! I intend on having sills, just wondering if I need to add a stone under the posts (on the 12 foot side) in addition to the 4 corners?

If the sill is plenty beefy you could get away with out additional foundation. A 12' span is not really pushing the limits of a normal sized timber. If you do have frost issues omitting the 3rd point may make things easier.

Tim

Thanks for the advice again! Would a 6X6 sill be considered "plenty beefy" for this size shed?

What are the plans for a joist system? If they mortice into the 6x6, no. Then comes the list of questions to solve for the size, species, intended use, loads - live and dead, what part of the country do you live in, joinery decisions and more.

Beefy would be in the 8-10 inch range.

Tim