Here are a couple of my first sketches of the Monitor barn I'll start on in the coming year.

The equipment shed looks great and the proposed barn looks very nice.

With respect to the foundation I would avoid the temptation to used blocks for the walls, especially in VT. Blocks are composed of very porous material that is capable of absorbing ground water. The blocks are typically placed and secured with mortar which is susceptible to water damage. As the block and mortar are exposed to moisture and repeated freeze thaw cycles the foundation system is prone to failure. Would be a shame to construct such a nice building on such a sub-standard foundation system. If you are going to do it yourself and you aren't worried about time I would get some kind of mixer and pour a foundation. You could use ICFs for forms or construct your own from plywood. I definetly would not use blocks in this climatic region

Kevin,

Nice looking work on the shed. And I love monitor barns, having grown up with one.

I'd be a little concerned about a couple of structural issues with the design of the barn, though if I were building it. There's nothing tying the plates of the central aisle together, so the top of the posts will want to bow out. If the shed rafters are connected to the lower plate in a way that they can pick up the outward pushing of the posts and the shed ties can handle the tension load and the posts are stiff enough to not bend overmuch due to the cantilevered loading this all is causing, then you should be fine. But I would look at doing away with the pseudo-hammer beam and going to a more traditional design using a tie beam that joins the posts a short distance under the plate (a dropped-tie) and make sure the connection there can handle the tension.

Thanks for posting the photos and the sketch -- it really makes the forum more interesting.

Gabel

I've recently started looking at the possibilities for a rubble trench foundation. Since it's a bank barn, I'll be backfilling on three sides, but the wall at the lower end of the slope will be exposed and therefore will be built from block or mortared stone. I haven't figured out how well that will integrate with the rubble trench on the other walls, though.

I'd hate to think about having to mix enough cement on site for full foundation walls. (No way to get a cement truck into the site.) I did look at some ICF options that would allow me to use less cement, but it still seemed way over-engineered for an unheated barn.

Gabel,

Thanks for the feedback. I'm trying to sort out where the forces would be coming from that might cause the tops of the posts to bow out. My assumption is that the roof trusses will be acting to prevent any spreading.

The reason I went with a hammer beam style was to gain some headroom in the loft (plus a little bit of interesting aesthetic in the space). The central bays are only 10' wide with just 6' 6" clearance under the hammer beams on the second floor. If I were to go with tie beams just below the plates I wouldn't be able to walk upright through the space. (part of the second story space will be used for a bunkhouse, so headroom was important)

If you're going to build concrete block foundation walls I highly recommend the method called Surface Bonded Block, or SBC. I read an article in Fine Home Building 25+ yrs ago and switched to that method for any and all block work we've done since then. It uses Quickwall, a glassfiber reinforced stucco coating on both sides of the wall of dry-stacked block (no mortar in joints). It's much stronger and very close to waterproof. Like any concrete structure it will absorb/hold some moisture. It's especially good if you're working by yourself 'cause you only mix a 50# bag of Quickwall when you've got your wall or a section of wall blocks stacked plumb & level, shimmed w galv brick ties as necessary. If it's gonna rain later you can mix and apply 1/2 a bag... you become a pretty quick stucco man, not a slow joint man (or slower stone mason). In addition to stronger and taking less time, you make a stucco wall with whatever texture or smoothness you like, rather than an uglier block jointed wall which holds dirt in its porosity and lets water thru w very little pressure or saturation.
You set your first course of block with mortar onto your footing to get it straight and level. Then dry stack (and shim) after that. Threaded rod is vertically imbedded at 10' oc as you place the concrete footing in the forms. use 3' lengths in the footings w a bend at bottom to lock it into the footing, then after you stack 3 or 4 courses of block use a rod threaded coupler to attach another 3' allthread. there are a few more details....
Maybe you can find the article in FHB, or similar in Journal of Light Construction.
These aren't all the details for fabrication. See http://www.quikrete.com/PDFs/SPEC_DATA-QUIKWALL.pdf for info and specs.
If you had lots of money you could construct a road for the big trucks and make steel reinforced poured concrete walls, or buy cut granite to fit and mortar into Better or Best.
Very important for whatever footings and foundation walls is DRAINAGE !!

And all this before the real fun of the Timber Frame work. I'll come up for your next raising. You did nice work w the hemlock.

Steve

Steve,

Thanks for that info. Until I started to dig into it (so to speak) I never knew there were so many foundation options. I was raised in a nineteenth century farmhouse with a dry laid stone foundation, but just assumed that most contemporary work was atop poured concrete or mortared block. I've been playing catch-up with all the modern variations (FPSF, ICF, etc) as well as new twists on old ideas (rubble trench, etc.)

I do have the advantage of good soils on a well-drained site and the ability to drain to daylight. With the exception of a root cellar under one bay, the rest of the area enclosed by the foundation will be an above grade crawlspace. (The central supports for the barn will be footed piers.) I'm assuming that I can just put down a layer of poly and a few inches of sand to keep any moisture from affecting the timbers in the floor.

Great looking equipment shed! Could you please provide some details about the dimensions of the structure: length, width, height, roof, and the post footing connections? Thanks.

Kevin,

Without a continuous tie at plate level (or really close to it) you don't have a roof truss. If you are counting on the collar beams tying the rafter pairs together and preventing spreading, then I'm not sure that's going to work. The tension would be pretty high on the joint between rafter/collar and also that would place a pretty big point load on the rafter. Also, the ridge doesn't seem to be doing anything since it isn't held up by either posts or trusses.

What's the height from the top of the loft floor to the top of the top plate?

Gabel,

I guess I'm getting my terminology mixed up. I'd assumed that a hammer beam configuration was a form of truss under the following definitions.

TRUSS. A network of timbers forming a rigid support structure; ideally, all members of the truss behave in either compression or tension, none in bending. Trusses are used to span distances impractical for solid members, or to support unusual loads.

HAMMER BEAM. A roof bracket consisting of an interrupted tie beam projecting from the top of a wall and supporting a roof truss. A complete hammer beam roof frame permits a large roof span made of relatively short timbers.

So the hammer beam, or "interrupted tie beam," is not capable of holding the tension?



6' 10"

The width of the span is 10'.

Thanks again for your feedback.

~Kevin