Stone Plinth Piers and Other Basic Info

Hello All,

I just discovered this very useful site as I begin a small timber frame project, which will be my first. It is a shed roof canopy to protect our two back doors from Western Massachusetts snow and other weather. I've attached a plan.

I'm just a hand-tool woodworking hobbyist and a very amateur carpenter, so this is a daunting undertaking. But, one step at a time.

Step one was getting the timbers from my driveway to my garage without killing myself or my two young children. Wasn't easy. Step two, I believe, is creating the footings for the two 8x8 posts. I had assumed I would be digging a couple feet down and pouring concrete piers, but having clicked around here for a couple hours last night, particularly on Jay C. Whitecloud's very generous and informed posts, it seems as if stone plinths set in a bed of rocks, with the bottoms of the posts scribed to the stones, is an alternative. That's an appealing alternative, because who wants to pour concrete, and see it on their patio every day? And I have a friend with a lot of big stones on his land.

Is there a single resource -- a book, a web page, a posting -- that will methodically walk me through this option? That will tell me whether it is appropriate for my structure, and all the relevant details -- how deep to dig, how to choose the stones, how to scribe the posts to them, how to attach the posts to the stones, how to raise the frame onto them, etc?

In other words, can I do this? And how?

Thanks in advance, and thanks to Mr. Whitecloud and everyone else who has posted such great information here already.

Alex

Hey Alexander!!! Welcome to Permies.com

You are the reason I think Permies is so great and getting so much better. Folks willing to put some effort in, and actually build stuff they can use! Then post about it...

In time, there will be a huge collection of successful DIY projects on all manner of topic, that so many more can learn from. I am also very pleased that you found my post of value and they gave you some insights into alternative methods.

I will try to do a brief rundown of where I think I may be able to help you at this stage in your project...

I just discovered this very useful site as I begin a small timber frame project, which will be my first. It is a shed roof canopy to protect our two back doors from Western Massachusetts snow and other weather. I've attached a plan.

I like it!

I would suggest ridding yourself of those intrusive upper "knee braces" (unless you really like the looks of them..) Some folks like the aesthetic of "knee braces" and there is nothing wrong with that.

Nevertheless, they do get in the way often of good fenestration (doors and window placement)...They only work in compression, and do not "strengthen" a frame as most assume they do. Actually, when the really do their best work (or at there strongest) is when they are in a "horizontal configuration" at the floor, lintel, and roof levels, or at the base of posts acting as "buttress." They also work better when much longer than typically found in contemporary timber frames. Anything 3' and shorter is more a "fulcrum" stressing joints then a really effective strengthening...

I'm just a hand-tool woodworking hobbyist and a very amateur carpenter, so this is a daunting undertaking. But, one step at a time.

Oooohh...I like that...

Hand tools. It may be a bit slow going as you learn there secrets (they will teach you more than I or a book ever could) but the rewards from these tools in built muscle and labor made three dimensional is priceless...

Step one was getting the timbers from my driveway to my garage without killing myself or my two young children. Wasn't easy.

Good proprietary beam carts start at $450 and just aren't warranted for none professionals only needing to build 3 to 6 frames perhaps in there life. A large "two wheel" (not single wheel) 10 cubic foot wheelbarrow, will work as a decent "beam cart" for almost every DIY project out there. I have moved some pretty massive timbers with these and anything too big goes at ground level on 3" PVC pipes cut to 1 meter sections. The issue is actually sometimes getting them not to roll so fast...

Step two, I believe, is creating the footings for the two 8x8 posts. I had assumed I would be digging a couple feet down and pouring concrete piers, but having clicked around here for a couple hours last night, particularly on Jay C. Whitecloud's very generous and informed posts, it seems as if stone plinths set in a bed of rocks, with the bottoms of the posts scribed to the stones, is an alternative. That's an appealing alternative, because who wants to pour concrete, and see it on their patio every day? And I have a friend with a lot of big stones on his land.

This sounds wonderful, and I am sure we all would love to see pictures!!

Once I understand better the structure, you may not need 8"x8" posts?? If you have them already...no worries. They will just add "boldness" to the frame...

Is there a single resource -- a book, a web page, a posting -- that will methodically walk me through this option?

No...unfortunately...and I am trying really hard over the next 6 months to a year at creating just that. It is part of the reason I started writing on Permies. To improve my typing speed, broaden my writing styles (thanks Burra, Judith, and big thanks Dale!!)

I (et al) will be following your post here so there should be no issue with getting more advise than you may even want at times...

That will tell me whether it is appropriate for my structure, and all the relevant details -- how deep to dig, how to choose the stones, how to scribe the posts to them, how to attach the posts to the stones, how to raise the frame onto them, etc?

I will do my best to cover some of that right now...

Get us photos of the building site from all angles and down from the roof view too if possible.

You are in Massachusetts, so the soils there can freeze to almost 4 feet. This also being next to another structure, makes it an additional challenge of "match" movement. Old vintage architecture like Barns and Heritage age Homes are often not built on foundations that go below the "alleged frost depth" but they have also been built by very experienced House and/or Timberwrights that could "read soils" and new which one would move more than others. Also if a soil matrix is "uniform" it will move "up and down" in a realitively predictable manner, so the entire strucutre may only get, maybe, a 20 mm drop or twist in the floors of the length of the building in say...200 years?

Again, your home (probably??) being rather new, (unless it is vintage?) should have a foundation of gravel and stone that penetrates grade by at least 1.2 meters (~4') for your area.

If you having read through many of my posts, perhaps this would be a time to do so, much of what you have asked here I have covered in a number of them, as have other DIYers also. I'm in contact with a number of them here and "offline" fleshing out their projects which they come back here and share about regularly...

In other words, can I do this? And how?

Yes...and many different and wonderful ways...you just need to pick one!!!

Good luck and look forward to learning more about your project!!

j

Jay C.,

Thanks very much for the quick reply and the encouragement.

I'm still trying to pin down what the posts will sit on and how. So:

-Photos of the building site are attached. Let me know if I should take more and I will. One post will be just to the right of the grill (as you face the house), and the other will be just to the left of the stairs. Let me know if I should take more photos from different angles (though I'd rather not climb up on the roof because it's steeply pitched).

-I realize the frost line is 4 feet down here in Massachusetts, but do I really have to dig that deep? I've gotten the impression you can get away with less if you're not building, say, a house. I noticed your footings at the Sharon Academy project, which looks amazing, aren't that deep. But maybe you're saying that since this will be attached to the house -- which was built in 1940 and has a deep concrete foundation, and hence will not move -- the posts need to have a deep enough footing that they won't move either?

-You say there are lots of methods, and I should pick one. Say I pick the method you used at Sharon Academy, mainly because it looks simple and those pictures offer more specific information than I've seen anywhere else. I still feel like I wish they came with a manual. Other than how deep I really need to dig, I need to figure out:

How large an area should the hole be?
What kind of rocks do you fill it with?
Why are the rocks standing on end, and is there anything special about the method for doing that?
What is "watering in," and how do you do it?
Is there anything I need to know about choosing the stones for the plinths? Any particular kinds of stones? Anything crucial about their shape? Might I need to shape them in some way?
Is there a pin or something that is hammered into the stones and inserted in the bottoms of the posts to keep the posts in place on the stones over time?

A million specific questions, really. Help!!

(Also, thank you for the strategies for moving timbers. Will need those. And can I really just eliminate the knee braces? I thought they were important for preventing racking, but if I don't need them I certainly don't want to bother with them.)

Alex

The things we all want to know but were too shy to ask!

Keep going, Alex.

If I may throw in my two cents ... I would not stop the roof just left of the stairs. I'd match the roofline of what looks like a screened-in room or a screened porch. Simply extend the roof and create sort of an indoor-outdoor area while not adding a lot of material to your project. In my opinion, it would be a better aesthetic and increase your functionality of your outdoor living area while serving the seasonal protection function you desire.

Thank you Dan. That is the plan actually. If you look at the model in the first post you can see that the beam continues past the left-hand post, and will tie into that existing roof (somehow!). Thank you for the feedback though! (You too Mike.)

Hi Alexander...

First, I agree with Dan 100%...

Mixing "roof pitches" is typically a "design error" in aesthetics at best, and often just a pain in the tookus when they meet. Timber framers have many conversation (and there is even a technical article about (and titled)..."When roofs collide."

Your "million questions" (and everyone else's) are actually a big help to me in becoming a better facilitator of these traditional systems. I often just overlook things I understand, or don't think of as important, when they are important and not necessarily easy to understand.

Because you project does lend itself (in many ways...not all) to the project at Sharon Elementary School, I am going to address each of your query on that post (if you don' mind thanks) I am actually here now working and taking some photos...so I will get to this tonight and/or tomorrow for you...

Thanks much for the photos...they help a lot. I may ask for some measurements and/or for you to create a "google virtual drive" for folks (and me) to fetch your sketch up file from...Then I can "fiddle" with it to see the size and scope of everything...

Thanks again for sharing this with everyone, it is really a great service and help to everyone including me, to see where I can improve the "teaching side" of all this for the "learning side" perspective. After decades of teaching...every student still improves me as a better communicator...Folks watching you go through all this should be very inspiring, encouraging and helpful...

Cheers,

Alexander Layne wrote:Jay C.,
And can I really just eliminate the knee braces? I thought they were important for preventing racking, but if I don't need them I certainly don't want to bother with them.)

Alex

They ARE important for preventing racking. I believe what he's saying is that you can use them in other configurations.

Jay C. White Cloud wrote:
I would suggest ridding yourself of those intrusive upper "knee braces" (unless you really like the looks of them..) Some folks like the aesthetic of "knee braces" and there is nothing wrong with that.

Nevertheless, they do get in the way often of good fenestration (doors and window placement)...They only work in compression, and do not "strengthen" a frame as most assume they do. Actually, when the really do their best work (or at there strongest) is when they are in a "horizontal configuration" at the floor, lintel, and roof levels, or at the base of posts acting as "buttress." They also work better when much longer than typically found in contemporary timber frames. Anything 3' and shorter is more a "fulcrum" stressing joints then a really effective strengthening...

My take off of the above is this:

For the "buttress" configuration, think of turning the post/brace assembly in your drawing upside down while leaving the roof in place, such that the braces are coming out of the floor instead of the ceiling. This seems like an excellent idea for structures with walls. Put the braces under the windows where no one would think of putting large openings in the wall anyway. In this instance I think you'd trade knocking your head on them for tripping over them unless you built in some sort of railing.

The "horizontal" configuration I'm a bit fuzzier on. I THINK what's being described is this: Imagine lying on the ground looking up at the roof (or raised wooden floor) so that the structure looks like a rectangle. There would be a brace in each corner. This wouldn't be visible if you were standing outside the structure looking at it. This seems like it would keep the sills/plates from racking in relation to other timbers in the same horizontal plane, but I don't see how it would keep the roof from racking in relation to the floor. Seems to me that you would need to use this in combination with either the braces you have now, or the "buttress" type anyway, at least for a free standing structure.


And a question of my own:

Jay C.,
When you say "anything less than 3' acts more like a fulcrum" do you mean "the joint is 3' from the post center" or "the brace is 3' long?"

Thanks.

Will,

Let me just clarify that this structure has no walls or windows; it's just a canopy -- a shed roof to protect the two doors. I have attached a side view that may make that clearer.

There will be clear roofing, so as not to block light coming into that window, which is our kitchen.

Thanks Jay C., I will keep an eye on that other post!

Alexander Layne wrote:Will,

Let me just clarify that this structure has no walls or windows; it's just a canopy -- a shed roof to protect the two doors. I have attached a side view that may make that clearer.

There will be clear roofing, so as not to block light coming into that window, which is our kitchen.

I understood that, which is why I don't think I'd trade the "upper" braces for "buttress" braces in your case. My comments were more about the applicability of the bracing variants in general and less about your specific project. I would suggest adding a horizontal member from the post on the right (furthest from the enclosed porch) to the house wall. This will keep the weight of the roof and rafters from racking the posts/sill assembly inward toward the house. (The porch structure would probably be adequate for that purpose on the other side.)

Got it. Thanks much Will.

Hi Will and Alexander,

Jay C.,
When you say "anything less than 3' acts more like a fulcrum" do you mean "the joint is 3' from the post center" or "the brace is 3' long?"

When the oblique brace design is forming an 3' legs which are the "opposite and the adjacent" elements of a triangle, or this distance is less, the bracing actually starts to create stresses within the joinery during loading events that are counter productive. Braces are never measured or I should say "size labeled" by their "hypotenuse." Hope that made sense...I have edited this now 5 times and I think it is the best I can do at the moment...

There is also a list of issues with braces in general (particularly in modern timber framing) that steam from just "habits" and not applicable reasoning. Like the concept of "pegging braces" of which there is zero need to do so as they only work in compression and any wood taken out of their already small tenons is not "good practice," nor of complete historic merit. Many braces are just wedged in place or have very very small pegs, or are "let in" type braces...

Hope that clarifies things a little better...sorry about that...

I am still outside but came in to make some phone calls for my project out in Wisconsin...

To clarify...and this comes up a lot with many folks not familiar with all the forms of timber framing...IS THIS...

There is "zero"...nada...zip...zilch......and absolutely no need for ANY "oblique bracing" (aka knee bracing or buttress...though buttress are so much better of the two types) of any type in any timber frame...IF...a "horizontal bracing modality" is utilized instead...Which is still the oldest form of bracing employed in the world today. I think I went into some detail on this in the other post and several more related posts here on Permies. I will check the other post, and if not try to expand that explanation further...

This topic comes up very often with the uninitiated to what some call "advanced timber framing" which is a misnomer and only should read as perhaps "Western systems (obliques) compared to the Eastern systems," (horizontal) bracing systems.

The 140' x 30' Farmers Market Pavilion I am designing and building in Menomonie Wisconsin has the same confusion hovering around it currently, as all the many "eyes" reviewing it are desperately trying to put "braces in" because they are convinced it has to have them...Solid "moment connections" at the bottom of a post (aka how it is affixed to the stone plinth) is more of a concerning topic for most "timber frame PE" than are the lack of "oblique bracing."

Most of the "well informed" timber frame PE actually prefer the clean lines and flexible robust nature of "horizontal bracing" systems such as found in the Sharon Elementary Pavilion frame's upper and lower cord (aka double plating). The below quote from just today's multi page correspondence between our PE on the project and "other minds" in Wisconsin addresses this very issue...

...double plating is a magnificent way to brace a frame - and, in the "wall" direction of this frame, is substantially more efficient than standard knee braces. I'm so on-board that bus...

Once anyone actually starts tangibly working with this type of timber framing (Asian modality that is) much of the mystery is removed and the logic and simplistic brilliance of such things as Japanese houses and shrines make much more sense...with there openness, clean lines and simple aesthetic...

Hey Alexander,

I was just trying to download some pictures I took today that I want to post, and couldn't help revisit what I wrote above to try to make it read better. Which of course got me to thinking about your project and the goals for it.

I have seen this type of "timber frame" remodel many types on structures. Front and back, and it really does "enhance" not only the aesthetic and strength of the structure, it adds a fair amount of "curb appeal" along with its value if resale is ever a possibility. Just some food for thought that ties into the next question/request I have. If you do choose to create a "shared file" for folks to follow along with on the CAD model of your project, could you please get some relatively accurate dimensions of all the different elements on the back of the house? I.e. the door, window sizes and elevations as well as the layout and configuration (to scale) of the "bump out" addition you are mirroring with your new timber frame. I may have some suggestions from a "valuation perspective" I would feel remiss not sharing with you if you actually do go through the effort to create such a nice timber frame addition onto the house...

Hi Jay C.,

Yes, I will try to get those measurements tomorrow. I hope it does add value to the house, but who knows -- future buyers might think it's odd, if they don't know any better. Anyway, I'm really building it because I will enjoy doing so, and we'll enjoy living with it as long as we're here which will be a good while, we hope.

I may be able to create a shared file -- someone else drafted that model for me on Sketchup, so I will have to try to get that first.

Thanks for all the feedback and information, please keep it coming.

Alex

A Google virtual drive is easy to create, and if you get the file on there to share, or just email it to me, I can create a "project file" for you and put it in my "virtual drive" which busting at the seams with projects like this by DIYers. That is probably the easiest and I do it as part of my work anyway so it's not a bother at all...Takes only a minute or two at worst...and actually make tracking a DIY project I am helping on much easier for me...

Jay C. White Cloud wrote:
When the oblique brace design is forming an 3' legs which are the "opposite and the adjacent" elements of a triangle, or this distance is less, the bracing actually starts to create stresses within the joinery during loading events that are counter productive. Braces are never measured or I should say "size labeled" by their "hypotenuse." Hope that made sense...I have edited this now 5 times and I think it is the best I can do at the moment...

Think I got ya.



Distance X should be greater than 3 feet.

After quite a bit of research I think I'm ready to give up on avoiding concrete for the footings. Everywhere I read says you need concrete down to below the frost line to avoid heaving in the winter. Jay C., I'm guessing the gravel footings at your Sharon Elementary project will work perhaps because the frame will be able to tolerate heaving? I don't know, but I can't seem to find really good specific information about how to do footings without concrete. Scribing to plinth stones seems totally manageable, and there are several great posts on that, but it's all the other details -- how deep do you dig the footings, how exactly do they prevent frost heave, how do the posts attach to the stones, etc. -- that I can't seem to track down.

Hi Alexander,

I haven't forgotten about you, just really busy, and trying to finish this project while 3 more have already started...

I will try to address some of this about "frost heave."

Below quote is from Stone wall collapse (frost) -- New England -- smarter solutions?

Jay C. White Cloud wrote:"Frost Heave" is often a "misnomer" in many locations and not...necessarily...all that is going on. That is why the many stone walls around the world...not just New England do not move. Many of these stone walls sit on...or near...bedrock, and/or a "mineral soil," not a "clay soil." The clay soil is part of the revelation...clays are an expansive soil when they get wet...even without ice to exaggerate this expansion. Get a "bentonite" clay in a soil and you have way more to worry about than frost as this is an extremely expansive form of clay...yet has many positive uses as well.

So the real issue is clay and/or water...if neither are present you have little to worry about. So the goal of any design is finding the clays, and removing the standing water which can freeze and expand.

No water...No heave...No clay...no heave....

Could not recommend the gravel trench more!! Best foundation system yet devised and still used today on just about every continent.

I think I covered frost heave also in the "Raised Earth Foundation" post...

Being in Vermont, "frost heave" can and is very much an issue in some soil types. Sharon Vermont, where this frame is, typically has very well drained soils in most of the area near the river.

For a project like yours, whether one uses large stone or a big chunk of concrete (artificial stone) the depth and installation of both is directed by the soil type as much as it is "averages in frost depth." Assurance of drainage is the primary issue to focus on whether a structure sits on made made stone or real stone.

In your case the other issue is a pre-existing structure you plan on tying into (i.e the house.) I typically will do not recommend tying into pre existing architecture just because of the risk of uneven settling This can be sometimes seen on some decks and porches added later to structures and/or added in new construction yet the "backfill" that the deck porch foundation is dug into settles more than the primary foundation of the house.

There is a great deal of info out there about "concrete foundations" and "frost." Not all of it is accurate, much of it is "incomplete," nor addresses traditional foundations. Empirically, whether here in New England, or anywhere that ground may freeze, all one has to do is look at historical homes and how they are built...They do not sit on concrete...They do sit on stone, and drainage is the primary focus along with depth excavation, and soil types. I would further add, that even with or huge building efforts...the majority of human architecture built in the world in history and into today...sit on wood and stone...not concrete.

As one more "food for thought" item...Let's consider the Brooklyn Bridge's foundation, one of the finest bridges of its kind. It is over 150 years old and still in great service, while the "concrete and steel" modern bridges all around it are either falling apart, need to be replaced and/or have been "down graded" in load capacity because of "issues.

What is the Brooklyn Bridge sit on?

Stone...

Scribing to plinth stones seems totally manageable, and there are several great posts on that, but it's all the other details -- how deep do you dig the footings, how exactly do they prevent frost heave, how do the posts attach to the stones, etc. -- that I can't seem to track down.

I am sorry......I feel like I may have left you hanging on those points and will try to make it clearer now. Please do ask more questions if you have them...

As for "how deep," that does depend on the soil type in your area and how far the frost specifically penetrates for your given area. To select a "safe" generic number...1.2 to 1.5 metres is safe for most of New England, and I add a bit more if not sure or don't know the exact soil types.

For example the "turnkey" project I just took on has a "sand/gravel" soil...It just doesn't freeze or heave from speaking with locals. We will be testing this out as we are building an all stone (dry laid) root cellar under the timber frame house I am designing for the client. The rest of this house (about 30 minutes North of Sharon in Bethel, Vermont) will sit on the same "stone plinth" foundation stone system as the Sharon Pavilion...Very much like most of the 300 to 600 year old homes do in Northern Japan.

As for how this prevents frost heave...again...no water...no heave...

Attaching the "post to stone" is by gravity in the traditional context and sometimes with a small "drift pin" or stone tenon in the base of the post. Just being scribe fit is typically enough for most simple structures with solid wall systems. Many of the old Minka farm houses of Japan (just like our old farm houses and barns here in New England) just "sit" on their foundations. There weight and gravity is all the "glue" that is needed.

Now to make all my "PE Friends" happy, on commercial/public buildings (and for extra insurance) we use "moment connection" (fancy word for mechanical fasteners in post foundations.) In the case of the Sharon Pavilion (if you look close at some photos) you can see that there is funny looking mortise in the side of the post near the base. This is where a 20 mm steel shaft penetrates up through the base of the wood post and is "fixed" with a large washer, locking washer and nut. I have had entire (small structures) like this lifted by crane...stone plinth and all...!! This is how strong the attachment is between the stone and the post in this configuration. The steel shaft (aka thread rod) is structurally adhered to the stone by an epoxy and is embeded 300 mm into the stone at minimum.

I would add again, I would not recommend using the house as part of the "structural support" for your "Canopy" area. I would make this a "free standing" and self supporting frame independent of the structure. Then the "main house" can move (or not move) and your frame can do the same. This does add more material and work, but I have always felt the gain in strength is worth it. Another reason to do this......if someone really likes it, they can buy it from you....

Please do post more questions if you have them...I will do my best to stay on top of them...

Alexander Layne wrote:After quite a bit of research I think I'm ready to give up on avoiding concrete for the footings. Everywhere I read says you need concrete down to below the frost line to avoid heaving in the winter. Jay C., I'm guessing the gravel footings at your Sharon Elementary project will work perhaps because the frame will be able to tolerate heaving? I don't know, but I can't seem to find really good specific information about how to do footings without concrete. Scribing to plinth stones seems totally manageable, and there are several great posts on that, but it's all the other details -- how deep do you dig the footings, how exactly do they prevent frost heave, how do the posts attach to the stones, etc. -- that I can't seem to track down.

For one there are VERY good reasons international code requires frost protection and most of your research points to it I'll be going over in this thread if you wish to follow along. Feel free to ask questions, or make comments: https://permies.com/t/50666/timber/Timber-Frame-Structural-Home-Design.

http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_4_par020.htm

Jay C.,

Somehow I missed your recent comment until now, but thanks much. I decided to pull a permit for the project, just to avoid the possibility of having to tear it down later, and to do the right thing generally -- which meant I had to dig four feet down and pour concrete. So, considering that I had to do that anyway, I decided to forget about the stone plinths on this one. That avoided fussing with scribing and so forth as well. I figured I have enough to learn on this project without complicating things further. I did make a square form on top of the Sonotubes to make it a tad less ugly. I got Simpson concealed post ties (CPT88Z), and set the j-bolts in there for those.

Next project, I'll do stone plinths. By the way I learned after the fact that a company called Chester Granite in Blandford, MA, makes granite plinths for not too much money, and they are cut so they don't require scribing.

Anywho...I will keep reporting on this canopy project as I make progress if there's interest here on the forum.

Thank you Terry as well for your advice.

Does anyone out there have any ideas about what to do where the new roof -- which will be transparent plastic -- meets the existing roof? That's the shingle roof on the porch. I hope it's clear from the pictures, but the situation is that both will be in more or less the same plane, and at the same pitch. I'm not sure how to handle the transition between them -- that is, what sort of flashing or other transition pieces to use to provide a watertight, seamless joint.

Any suggestions would be great.

I finally finished this thing (more or less, ha), and thought I would post some pics.

As I look back I want to emphasize how nice it was for Jay C. Whitecloud and others to read my early posts before I started and spend time writing encouraging and enthusiastic responses. There was good information there. And never having done any sort of timber framing, what I really needed at that point was encouragement and the sense that it was doable for a novice. So thanks much.

If I had it to do over again I would do a million things differently, but whatever, I muddled through, and it was the most challenging and rewarding thing I've built (simple as it is!), so no need to dwell on the many mistakes.

Here are some pics:

more pics

The finished product.

Well done!

That's inspiring!

Beautiful work!
There is one comment I have to make, so someone else doesn't do it the same way: The scarf joint, very well executed, is upside down from the most secure direction. The right post may be well braced to the beam, but the roof loading is putting more downward stress on the right side of the joint and trying to open it up. In general, a scarf or other joint in a continuous beam is best located around 1/4 of the span from a support (you got this), and the section nearest the support should be below the section with the bigger clear span, so gravity tends to force the parts together instead of pulling them apart.

This question is for Jay C Whitecloud or anyone who knows the answer.  I have been reading your info on the stone plinths but not sure I'm totally picturing the foundation right.  Are you saying you make a rubble trench or gravel/stone trench all the way around the perimeter from the frost line and fill up to grade and then place the large stones on top and then connect the posts to the stone or are you saying that you are digging holes a certain size below each large stone and filling that hole only with gravel or stone from the frost line to grade?

Thanks.

Jay has not been around for a while, but I think I can give some guidance on this. Whatever a particular project involved, if you are building a continuously supported wall, you would use the rubble trench. You might want to use it for point supports if a french drain is needed, as the effort is pretty similar either way. For individual piers, I would dig down as far as is indicated by the design factors, and fill with stone as far as needed to firmly support the big plinth boulder with its top a bit above grade, maybe 6" or so depending on conditions. This will be a different base height for each boulder, so you need to kow how you are going to set them. It would be important for the bottom surface of the boulders to be either flattish or symmetrical beneath the post support point, so the post load does not tend to make the boulder want to roll to one side or another. Stones packed tightly around the boulder will be important to the stability of the system.

Thanks.  When you fill the hole with stone what sizes of stone would be used?  Does anyone actually have photos of the process?

Whatever you have would work, the larger the better within reason. A mix of sizes if that helps them fit and lock together best would be sensible. Large flat stones against the outsides of the hole will minimize dirt oozing in between stones and loosening of the pack.

Okay, so do I need to fill in any spaces with gravel or small stones or do I just fill up with stones of various sizes and leave spaces?  So this is more like a stacking stone method and not a gravel and pounding method trying to crush stone down?  

When I put the stones in am I trying to stack the stone horizontally or vertically (other than your comment about the ones on the outside walls) or are you just tossing them in and making them snug?

Do you know if there are any photos or videos online about this?  I was searching but wasn't finding anything.

Thanks so much!

I can't tell you about "standard" methods of stone packing, just my experience stabilizing posts and standing stones.

My native stone tends to cleave into flat rectangular slabs, which gives an advantage, but you can work with anything. I find that packing all the stones vertically allows the last stones to be "wedged" and driven into place, holding the post or whatever tightly from the start. Laying stones horizontally here requires careful selection to fit them tightly in the space, and if there is not a flat stone on the outside of the hole, the stone ends can generally poke into the soil easily and not give much resistance to lateral movement. I would fill big gaps with gravel or small stones, but allowing plenty of free drainage space will keep the immediate vicinity from holding water and heaving from frost.

What type of tool and bit does one use to drill a 3/4" hole in stone about a foot down?  I searched for diamond bits but they say they only go up to 2" down.  What type of tool can I use that will do it on a faster scale or at least go down a foot?  Any suggestions?

Thanks.

Is placing a 3/4" threaded rod a foot deep into the stone good enough?

What brand or type of epoxy is used for the threaded rod in the stone?  Is there a non-toxic one I can use?  Does concrete or silicone not work to hold the rod and to keep water out?

Also, does anyone know where stainless steel threaded rods can be purchased at about 2 -2.5 feet long?  Can basalt rebar be used instead of metal threaded rods?

Thanks.