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#34706 - 08/19/19 01:48 AM guidance for attaching frame to sill
MarkWill Offline
Member

Registered: 08/10/19
Posts: 3
Loc: Winston-Salem, NC
Hi all-

I'm a newbie; been interested in this for years but never had a place of my own upon which to build. well, that's all changed and I am working on building a workshop- a smithy really- in the timber frame style. I have the foundation wall sitting on nice sized footers, and then crusher run base covered with a brick paver floor in place. I plan to attach a pressure treated sill to the foundation wall, but then I plan to lay the timber base on top of the pressure treated sill in order to be able to use stub tenons on the posts. any guidance for attaching the timber base to the sill would be greatly appreciated.
THanks in advance for any advice and so glad to have found this group-
Mark Williams
Winston-Salem, NC

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#34708 - 08/20/19 01:13 AM Re: guidance for attaching frame to sill [Re: MarkWill]
Roger Nair Offline
Member

Registered: 10/20/99
Posts: 463
Loc: Bakerton, WV, USA
Has the foundation wall been built? How it is constructed will influence the choices. If not constructed then a design can be worked out from the start. Your choices will centered on foundation bolts or strap anchors that are secured to the foundation wall and the wall to the footings. Other considerations are site specific ie soils, wind storm risk and local code regulation.

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#34711 - 08/20/19 11:10 PM Re: guidance for attaching frame to sill [Re: MarkWill]
Jay White Cloud Offline
Member

Registered: 11/07/08
Posts: 557
Loc: Albany County New York
Hi Mark,

Welcome to the Guild Forum...

First feel free to send me an email if you would like.

It reads to me that you have already gone the route of a modern concrete foundation, with a brick floor to facilitate it being a "Smithy Shop" so my normal recommendation of just a traditional stone foundation is moot. The only foundation we place most of our timber frames on is a traditional stone one in almost all project both commercial/public and private/domestic...just as it always has been.

Anyway, what you are planing sounds just fine as I am reading it? There typically is no need to "attache" the timber frame to the concrete at all unless you wish it to be that way. Historically (and still today in most instances of traditionally built frames) they just "sit" on there foundations without any issue at all.

I can expand on any of this more if you so desire, or have other questions...

Regards and again Welcome!

j
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#34714 - 08/21/19 08:47 PM Re: guidance for attaching frame to sill [Re: MarkWill]
MarkWill Offline
Member

Registered: 08/10/19
Posts: 3
Loc: Winston-Salem, NC
thanks so much for the replies, Roger and Jay. Yes, the foundation has been completed, minus filling in gaps with concrete or anchor bolts. I think my only real reason for wanting to secure the timber to the sill plate is to pass whatever code the inspector decides to use once they come back (I think it's up for debate, as there are very few timber frame structures in this area with the exception of Old Salem). I have seen straps used in pictures, put in place in the gaps of the concrete block and then anchored with concrete. I thought that might be an option, but I would like for it to look 'prettier' than that. THank you, gents. I may be emailing you with some questions as I move forward. Best regards-
Mark

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#34793 - 08/24/19 09:13 PM Re: guidance for attaching frame to sill [Re: MarkWill]
Jay White Cloud Offline
Member

Registered: 11/07/08
Posts: 557
Loc: Albany County New York
Originally Posted By: MarkWill
...thanks so much for the replies..


Hello Mark,

You are most welcome! Thank you for coming to the TFG forum for your advice...

Originally Posted By: MarkWill
...Yes, the foundation has been completed, minus filling in gaps with concrete or anchor bolts. I think my only real reason for wanting to secure the timber to the sill plate is to pass whatever code the inspector decides to use once they come back (I think it's up for debate, as there are very few timber frame structures in this area with the exception of Old Salem)...


North Carolina can be a "funny" state when it comes to timber frames and how municipality officials "want" (or think?) they need to consider them. I was stationed there for a number of years (on and off) while in the Marines. I've been a part of and/or affiliated with several timber frame projects within the state. Vintage frames have gotten more leeway than modern built frames in a number on ways including foundation modality. With modern frames (especially if there is no PE involved in the project which is always recommended...or...an experienced Timberwright) the building department for a given municipality will often follow the path of least resistance and either not allow a timber frame at all...(less common today...thank goodness!!!)...or subject the project to "hoops and hurdles" that are not necessary...It all depends? I can state, that for both commercial and domestic, it is getting better each years as the general public learns more about the nature of the craft.

A dear friend (former student) lives in Asheville and has been operating a Tree Service ("Smart Fellers") for over a decade now. He has done a number of timber frames and is a resource if you wish to contact him.

Originally Posted By: MarkWill
...I have seen straps used in pictures, put in place in the gaps of the concrete block and then anchored with concrete. I thought that might be an option, but I would like for it to look 'prettier' than that. THank you, gents. I may be emailing you with some questions as I move forward. ...


I too find aesthetics (and authenticity) very important so understand the desire not to employ strapping. I can say there is no reason you need to in your build as I read it?

Hidden bolts or even (perhaps?) structural polyurethane adhesive (e.g. PL Premium) alone would more than surface to fix the PT board sill and the timber frame sill plate to the concrete well enough to meet local interpretation of IBC. If going with PT wood I would recommend (and I will only use) a thin copper shroud over the PT. I personally won't allow PT products on projects typically.

If a OPC foundation is spec'd for a project (as you have in your - again I don't use PT wood sill boards at all) and only the thin copper flashing. If a "tie down" system is demanded by local building departments the following is the format employed in such projects as yours:

1. I invoke our PE and traditional proven standards for the project. This usually (95% of the time plus) puts such issues to rest and no tie down is used and only a simple stone plinth foundation with perhaps drift pins...

2. If a PE is not part of the project and/or the effort to "push back" on the building department is not desired, then the copper flashing is laid over the OPC foundation wall with a 15 mm lip overhang. 20 mm by width of sill by 50mm White Oak, Locust, Catalpa, or related "draft spacers" are set on the copper every 2' and doubled at point loads, then the timber frame sill itself rests on these. After the sill is positioned and the "corners pulled" to square, the frame is raised upon its sill beam. At this juncture, at the corners and centers of each bay (or building department require spacing requirements?) 1/2" holes are drilled through the sill. Then, with a proper masonry carbide bit, the OPC foundation wall is drilled for a given spec'd epoxy anchor bolt system (several applicable types to choose from) and the frame is thus tied to the foundation.

Good luck and look forward to picture if you will share them. More questions are welcome too of course...!!!

j
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http://about.me/tosatomo

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#34892 - 08/30/19 03:08 AM Re: guidance for attaching frame to sill [Re: MarkWill]
MarkWill Offline
Member

Registered: 08/10/19
Posts: 3
Loc: Winston-Salem, NC
Ah! Now I like that idea- get rid of the pressure treated sill, place copper shroud, add spacers, drill and add wedge anchors secured with epoxy. This is great stuff- thank you!

out of curiosity and inexperience, what purpose does the copper shroud serve? Thanks very much and best regards-

Mark

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#34894 - 09/01/19 02:03 PM Re: guidance for attaching frame to sill [Re: MarkWill]
Jay White Cloud Offline
Member

Registered: 11/07/08
Posts: 557
Loc: Albany County New York
Hi Mark,

I thought you would appreciate that solution...

It has always appeased building officials in my experience that are not familiar with traditional timber architecture, while still allowing for a traditional project to be facilitated without to much encumbrance from modernity...

Great choice!!!...Drilled and wedge anchor systems are an excellent choice and a "first choice" for any project such as yours. Wedged systems in general are superior as they are typically not only inspectable (which PE just love!!!) but they also allow for adjust-ability and more importantly in Historic Restoration work, they are "reversible" from a conservation perspective while sill serving the function of making a (perhaps?) compromised foundational system more secure...

Originally Posted By: MarkWill
...out of curiosity and inexperience, what purpose does the copper shroud serve?...


As to "copper" in general...

It is historically and traditional virtually a "magical material" in many ways from the context of architecture and the built structures of purpose by humans. There are too many to list here from the perspective of multiple traditional crafts that have literally been employed for over 7000 years in the building arts. From ship hulls, to the suppression of decay in eave timber assemblies where rafter plate, torching mortars and related timber assemblies (like stitch beams) meet. Copper flashing and subsequent related materials retard the migration of moisture, or at minimum (as condensation WILL!!! happen at times) the copper is noxious to most mold, fungi, and related "wee-beasties" that plague architecture at certain structural local...LIKE...sill beam assemblies...

Additional, there is more "not understood" completely why copper does what it does than is fully understood. Much of the building art's traditional practices, like the application uses of copper, are yet to be fully explored within the modern context of understanding (or even written down in applied modality within tome) that will take the next generation of tradtional practitioners to explore and "re-learn" fully what our forbears new and understood better...

I can say, in all its application forms that I have witnessed and practiced, that whenever the extra time and expense of the use of copper has been employed within proper context, that the results have never ceased to unparalleled in means and method when compared to any modern material or method...

Hope the project is going well for you...Look forward to updates!

J
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http://about.me/tosatomo

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#34900 - 09/10/19 07:24 PM Re: guidance for attaching frame to sill [Re: MarkWill]
timberwrestler Online   content
Member

Registered: 11/07/05
Posts: 288
Loc: Becket, MA
Almost all PT wood these days is treated with copper. So I don't see the need for the copper above or below.

In your situation, I'd probably do something like concrete, capillary break (sill seal or something like it), PT bolted down (assuming there are bolts), timber sills screwed down to PT. If the bolts aren't there and you want to go through both sills, you could use longer expansion bolts but they're pricey.
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