iDRY Vacuum Kilns

Sponsors:

Multi-Purpose TF or Post and Beam Structure

Started by Rango, April 12, 2021, 01:16:49 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Rango

Hello FF,

After a number of weeks searching through Google and Youtube for information to design and build a building, I finally stumbled upon Forestry Forum.  I am calling the structure I want to build multi-purpose because it will be part pavilion, part outdoor kitchen/bar and part storage building.  My lot is small and I will also be putting in an inground pool that will sit next to this building.  The area I am thinking for this structure is 18x20' or 20x20' with half being a pavilion overhang for the kitchen/bar area near the pool and the back half enclosed with four walls for a poolhouse/storage area.  3 Bents 10' OC?

The floor will be a concrete monolithic pad or footings and stem wall if needed.  I live in Michigan and frost depth here is 36" and the snow load is 35psf.  The building code says the building can only be 14' at the ridge so I think I will only be able to go 6/12 on a gable roof pitch.  I have access to EWP, Red Pine, White Oak and Red Oak for timbers but the EWP is probably the easiest for me to work with.  I have a friend with a new sawmill that is willing to cut the timbers with some help from me.

I really like the look of a traditional King Post Bent especially for the pool side open pavilion area but maybe a hybrid would work better for the walled area?  I am very familiar with stick framing and I'm sure that would be easier for me to build but I would love to incorporate at least the look of a TF structure.

The questions I have first off are 1. How do I figure out what I need material wise for this project?  2. Should I go full TF/Post and Beam with no experience or go Hybrid and just add some TF elements?   3. Will I need to get my timbers certified to pass inspection?  If so, how does that work?

I have downloaded a lot of examples of what I would like to build from the internet but I'm not sure what the upload policy is yet.  I did see Jim's pavilion in another post and that is close to the look I want without the closed in area.  I am learning Sketchup so I am going to try and draw a rough plan to help visualize what I want.  I will try to upload something like that soon.

I know I don't have all my ducks in a row yet but any help to get me started will be appreciated.

Thanks

*I re-read the building code and I can go 18' max to the building peak so the roof pitch is not as much of an issue as I originally thought.  Also, I don't need to span the entire 18' on the gable end.  I am ok with putting a post at 9' to break up that long span.  In the enclosed area, it would be nice to have some loft space for additional light storage so maybe a Queen Post would be a better option?  Any thoughts on that?


everythingwood

I would recommend picking up a few books on timber framing to get yourself started.  Learning to Timber Frame by Will Beemer has a basic  12x16 plan with options for expanding to 16x20 all based on white pine timbers.  As you start designing something check out the "toolbox" under "extras" in the menu at the top of the page.  It has basic design calculators for posts and beams.  

If you look a couple posts down you will see my timber frame woodshed post... I'm just starting a 24 x 36 outbuilding that I guess you would call a timber frame/stick frame hybrid.  Luckily, I don't have to go through the whole inspection process... in our township it only has to be inspected if its a habitable structure.  We may cross that threshold when I do my home addition.


Don P

20' is not an excessive span for a kingpost truss. There is equally nothing wrong with building it with a midpost and structural ridgebeam that spans 10' back to the center wall. The enclosed area solves the bracing problems inherent in a fully open pavilion, good plan. A hybrid would be simpler to build. Based on what I'm hearing the open gable would be the only bent exposed to common public view. It comes down to whether the goal is the destination or the journey  :).

Rango

Thanks everythingwood,

I will look for the Beemer book.  I don't see many plans in the 18-20' range for some reason.  Must be a "multiplier" thing for 12' and 16' I guess.  I have played around with the calculators but I don't understand all of the inputs yet.  More reading to do! ;D  

I do have a call into the township to educate me in what an "accessory" building is and what it's going to need as far as stamped plans and inspections.  Zoning Administrator is off for spring break and no one else can or will comment.  Maybe I'll luck out and be exempt too.  I am required to file a building permit so I'm not holding my breath.

Rango

Thanks @Don P 

A lot will depend on what my township will require.  If I will need engineered prints and stamps on my timbers I will probably have to go the Hybrid route.  I don't know if I will have the time or the resources if I need to jump through those hoops.  

But, where there is a will - right?

Can anyone tell me what engineering or grading might cost for a small project like this?  

mudfarmer

Quote from: Rango on April 12, 2021, 08:18:09 PMI have played around with the calculators but I don't understand all of the inputs yet.  More reading to do! ;D  
If you look back through this TF section of the forum there are a lot of beam sizing posts and Don especially is very helpful walking through the thought/design process. You can put the pieces together to become either very dangerous or very well prepared, you pick ;D

Brad_bb

Not sure what your proposed building will look like/what you are thinking?  Post a pic. (you upload to your forestry forum photo gallery by clicking add a photo and then click the link in your album to post the picture in the post your in the middle of).  

Any timbers that are exposed to the elements I prefer to use White oak, osage or black locust as these are all rot resistant.  When using White oak, try not to have any sapwood on the timbers as the sapwood is not similarly rot resistant.

Hopefully in your area you'll have more flexible building inspectors.  In my area the inspector was not familiar with timberframing, but once he saw the working going on, and the quality of our timbers, he basically deferred to us being the experts.  Good thing as I don't think grading is logistically easy.  

18' height restriction?  Why? Seems quite short.  

You could do a queen post or a king to span 20'.  King post will have tension joinery but will look cool.  Queen often more in compression.  I have a 32' queen post as one section of my work shop.
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

Rango

Quote from: Brad_bb on April 13, 2021, 10:08:04 PM
Not sure what your proposed building will look like/what you are thinking?  Post a pic. (you upload to your forestry forum photo gallery by clicking add a photo and then click the link in your album to post the picture in the post your in the middle of).  

Any timbers that are exposed to the elements I prefer to use White oak, osage or black locust as these are all rot resistant.  When using White oak, try not to have any sapwood on the timbers as the sapwood is not similarly rot resistant.

Hopefully in your area you'll have more flexible building inspectors.  In my area the inspector was not familiar with timberframing, but once he saw the working going on, and the quality of our timbers, he basically deferred to us being the experts.  Good thing as I don't think grading is logistically easy.  

18' height restriction?  Why? Seems quite short.  

You could do a queen post or a king to span 20'.  King post will have tension joinery but will look cool.  Queen often more in compression.  I have a 32' queen post as one section of my work shop.
Thanks @Brad_bb ,
Here is the basic idea but I would like it more timber frame.  This picture seems to be more facade than true timber frame but the half open/half enclosed look is there.  I would two bents showing and the third within the enclosed area.  I would like to have windows in the peaks on both sides of the enclosed gable ends so I might have to go with queen post?


  
I do have some White Oak but not sure I would have enough for the whole project.  I have a lot of White Pine and I am ok with protecting the exposed wood every couple of years.  What are your thoughts on mixing species in a structure?
I finally got ahold of my inspector and he said the structural timbers will need to be certificate graded or signed off by an engineer.  Hopefully there is a NeLMA inspector near my friends sawmill.
18' is the highest I can go on 1 acre or less lot.  I am on .67 acres.  I was hoping to go at least 21' but not going to happen.

Rango

 




~ It's not to scale but here is my first try at drawing.  Snow load is 35 psf and no seismic issues to worry about.  We do get a fair amount of wind once in a while.  ~10x20 will be enclosed with board and batten siding with the rest open pavilion.  I am planning on a dark metal roof to help with the snow melt.  

For joinery, I'm considering Timberlinx connectors so I can tighten the joints as the members shrink.  Does anyone have experience with these connectors

Rango

Don P

Is that bent supporting a ridgebeam and common rafters, or purlins? The rigidity of the joinery determines whether it is acting as a truss with the kingpost in tension or if the tie is acting as a beam supporting the king in compression. I've worked on a job where those connectors were used. It's been awhile, I do remember kind of fussy installation but I believe they had pretty high capacity, would need to read the specs.

Rango

Quote from: Don P on April 27, 2021, 06:49:02 AM
Is that bent supporting a ridgebeam and common rafters, or purlins? The rigidity of the joinery determines whether it is acting as a truss with the kingpost in tension or if the tie is acting as a beam supporting the king in compression. I've worked on a job where those connectors were used. It's been awhile, I do remember kind of fussy installation but I believe they had pretty high capacity, would need to read the specs.
Sorry, I didn't add that detail but yes purlins on those rafters with probably a 12" overhang.  If needed I could also put (2) 2x8 or 2x10 ridge boards connecting the king posts of each bent.

Here is a link to the Timberlinx technical data page.  timberlinx.com/tech

Don P

I would check the 6x10x19' tie and make it to take the load , check the 6x8's with the purlins loading them.

Rango

Quote from: Don P on April 27, 2021, 08:37:49 PM
I would check the 6x10x19' tie and make it to take the load , check the 6x8's with the purlins loading them.
I think I am in the right calculator but I'm not sure what the total load or dead load is.  I searched for Total Load and Dead Load in search but haven't found how to get to those numbers.  Is there a post that details these inputs?


 


Maybe this post starting at #7?  Beam span and general structure information for post and beam pavilion

Is there a way to link single post to another post or put links in the signature line?  That would be very helpful for newbie's

Rango

Here is what I have gathered from the topic I listed above.



 


 

My snow load is 35psf + 10psf for Dead Load = 45psf Total Design Load

Tributary Area is 9.5' wide x 10' deep = 95sf 

45psf x 95sf = 4275 lbs Live Load on beam?
10psf x 95sf = 950 lbs Dead Load on beam?

Span is 19' x 12" = 228"



 


 

8"x14"x10' Ridge Beams between my bents and 8"x14"x19' for each of my Tie Beams?  Is this correct?

Jim_Rogers

In the above picture you have entered 288 in stead of 228. You may need to redo that calculation.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

Rango

Quote from: Jim_Rogers on April 30, 2021, 09:11:05 AM
In the above picture you have entered 288 in stead of 228. You may need to redo that calculation.

Jim Rogers
Wow.  Thank you Jim.  Rookie mistake.  Measure twice cut once  :D

Don P

You've used the uniform calc, if that tie is supporting a ridge support post at midspan use the midspan point load calc, doubles the max moment.

Edit; Drawings work better than word pics. Assuming we are talking about the front gable. Recheck the trib area. The 9.5' would be correct for half the 19.5' tie span. Depth would be the front overhang + halfway to the midwall.

Rango

Quote from: Don P on April 30, 2021, 10:15:41 AM
You've used the uniform calc, if that tie is supporting a ridge support post at midspan use the midspan point load calc, doubles the max moment.

Edit; Drawings work better than word pics. Assuming we are talking about the front gable. Recheck the trib area. The 9.5' would be correct for half the 19.5' tie span. Depth would be the front overhang + halfway to the midwall.
Hope this helps.


 

Don P

Yes, if the middle bent is TF you have done the trib area correctly. Then use the center point load truss calc if the king is supporting the rafters rather than hanging from them.

Thank You Sponsors!