# Attaching Porch Column to a flush beam



## hick23 (Apr 11, 2012)

Hello, I'm building a wrap around porch. Due to ground clearance I have a flush beam (3 2X10) around the perimeter of the floor and then I have Joist (8 feet - 2X10 - 12 inch centers). I now need to get a roof on this thing. I'm going to install 8X8 columns for the look - not for the strength as it's not close to needed. I could use a 6 X 6 and trim out to the 8 inches or I could use a 8 inch post.

My problem is that I can't envision how to attach the post to the beam. It's a flush beam and it's 4.5 inches thick. I need about an inch or so for the decking to attach around the post (I'd have another inch of overhang beyond that for the decking) So all said and done I can get about 4 inches of column to land directly on top of the flush beam which attaches to a footing directly below.

So what would you all recommend in this situation. I was thinking of adding a few 2X8's and bolting through it to make the flush beam wider where the columns will sit but it would mean all the weight would be on the bolts. Any better solutions to this problem? Or thoughts on whether this would at least be acceptable?

Thanks

Hick


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## user1007 (Sep 23, 2009)

What about steel posts and plates. They would provide more than enough structure and support with a much smaller "footprint". I shouldn't think they would be that much more than sistering stuff together or using oversized wood posts just for the look. Trim them out with whatever post look you want? You can even buy elaborate round column trim and crown etc.


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## mae-ling (Dec 9, 2011)

I will tell you some thing you probably don't want to hear now but may help someone else reading this. Posts should have run to the ground/footing.

Your beam now, what does it sit on? Your posts should line up with whatever it sits on.


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## cortell (Nov 27, 2010)

Consider notching the post. Your 8x8 post is actually 7-1/4" x 7-1/4". 4" of the post will rest on the beam; 3-1/4" of it will dip below and be fastened to the beam with two carriage bolts. You'll want to make sure the post rests above a beam support (sonotube or whatever you're using); if it can't rest directly above it, it can rest up to 9-1/4" inches away (the actual depth of the 2X10 beam)


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## hick23 (Apr 11, 2012)

I created a video to explain better what I'm doing - forgive me for calling a joist a beam in one of my dumb comments  Appreciate you taking a look and giving me your thoughts.
http://youtu.be/2zPnOACkqGs

Maeling-you mentioned running the posts right to the ground. I don't think it's feasible to run a decorative column from footing to roof where deck isn't the same level as the footing unless I'm missing something. For a deck made of ceder or PT posts I can see doing that although you would then have all your load on the brackets attached to the side of the post. You would need big brackets to attach a triple 2X10 to the side of the posts as well. 

I guess I could just run 6X6 and then trim the post out instead of using prefab column as well. I could then notch the 6X6 like you said cortell.

Any other thoughts after watching my video 


Thanks,
Hick


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## cortell (Nov 27, 2010)

Hick, you deserve some sort of award for posting that video. You've basically brought us all to the work site to check out the situation. Brilliant. If only everyone who had a question did that! 

I'm sticking with notching the post--whether it's 6x6 or 8x8. It looks like with an 8x8, you'd need to move that one joist over to the right a bit. The 6x6, on the other hand, may just fit in between the joist and the carriage bolt that's to the left of it.


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## cortell (Nov 27, 2010)

Actually, I take that back. If structurally you need a min of 6x6 (not sure what sort of load you'll be holding up there), notching it would decrease the load point footprint. I'd go with an 8x8 in that case, and then frame an opening around so you can keep that right joist in the same location, but shortened--like framing for an opening in an attic floor.

Also, I'd probably use long lag screws instead of carriage bolts, simply because visually it will look funny given the surrounding carriage bolts.


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## hick23 (Apr 11, 2012)

Hey Cortell, ok, I understand what you mean - thanks. I'm thinking of possibly using these manufactured permacast or PVC posts as well. To use the them I would have to build up a base instead of nothing to fit the whole post on something. Have you ever seen something like that done or how these manufactured posts are attached to a flush beam?

Everywhere I look I only see details where they put them on flat surface or something.

I'm not concerned about what it will look like on the outside because I'm going to trim everything with Azek so it won't be visible.

Thanks,
Hick


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## cortell (Nov 27, 2010)

hick23 said:


> Hey Cortell, ok, I understand what you mean - thanks. I'm thinking of possibly using these manufactured permacast or PVC posts as well. To use the them I would have to build up a base instead of nothing to fit the whole post on something. Have you ever seen something like that done or how these manufactured posts are attached to a flush beam?
> 
> Everywhere I look I only see details where they put them on flat surface or something.
> 
> ...


Here's an idea. Cut two boards, same stock used in built-up beam, and lag screw them into the beam (I'd use four 1/2" hot-dip galvanized 8") and end-nail or screw them into the joists (four hot-dip galvanized 10d common or 3" deck screws). As long as a good amount of the post is sitting over the beam, I'd be comfortable with the rest of it sitting on these two boards. Again, only you know what sort of load we're talking about here, so use your judgement.


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## hick23 (Apr 11, 2012)

Cortell - you just took it a step above. Awesome - I appreciate your help here and grabbing the frame and making it clear. Awesome. Thanks!


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## cortell (Nov 27, 2010)

hick23 said:


> Cortell - you just took it a step above. Awesome - I appreciate your help here and grabbing the frame and making it clear. Awesome. Thanks!


You bet. Make sure to use washers with those lag screws. And please post some pics with the post attached if that ends up working for you. Good luck!


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## cortell (Nov 27, 2010)

cortell said:


> ....and end-nail or screw them into the joists (four hot-dip galvanized 10d common or 3" deck screws).


To clarify, four per side per block, not just the four seen in the image. Total of 16 nails or screws


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## mae-ling (Dec 9, 2011)

Man this should be awarded the best thread ever title, or at least the best explained


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## hick23 (Apr 11, 2012)

This was my first thread on this forum - I can't believe what a great place this is.


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## cjohnsonmn (Sep 25, 2012)

*Porch post footing alignment*

So how close do you have to be on the vertical alignment between the deck post on the frost footing and the porch post on the beam above? Do I have to dig a new adjacent footing if a porch post is not directly over the deck post? (My corner posts are right on but I need to fudge the two middle ones to get them evenly spaced. This came about because the porch roof was an afterthought --no cantilever of the deck at the corner. Its 9x21 ft with house ledger on two sides. Thanks.


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## cortell (Nov 27, 2010)

cjohnsonmn said:


> So how close do you have to be on the vertical alignment between the deck post on the frost footing and the porch post on the beam above? Do I have to dig a new adjacent footing if a porch post is not directly over the deck post? (My corner posts are right on but I need to fudge the two middle ones to get them evenly spaced. This came about because the porch roof was an afterthought --no cantilever of the deck at the corner. Its 9x21 ft with house ledger on two sides. Thanks.


Rule of thumb: the offset can be up to the depth of the beam. If you're using 2x8 beams, you can be off by 7-1/4".


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## ModernDayDarwin (May 18, 2013)

This thread may be old, but it helped me a ton. This is awesome.


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## jagans (Oct 21, 2012)

Great Video. Your deck appears to be designed to hold an Abrams tank or two. 

As far as the posts go, I would notch your posts so that 2/3rds sit on the girder, and one third continues down to the bottom of the girder, and gets lagged or through bolted to the girder. The bolts should have large flat washers under the head (And Nuts) which cut into the wood. Fastening the posts like this gives you the best of both worlds, good compressive strength, and good resistance to Moment (wind loads)

Your deck looks extremely well built. thanks for the video.


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## GBrackins (Apr 26, 2012)

J,

any other way to do it? even Abrams need out of the weather sometimes .....

gotta run get a powerball ticket, if you don't see me on here you'll know why!


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## jagans (Oct 21, 2012)

GBrackins said:


> J,
> 
> any other way to do it? even Abrams need out of the weather sometimes .....
> 
> gotta run get a powerball ticket, if you don't see me on here you'll know why!


Dont bother, I just bought 20 bucks worth, and Im gonna win. If I do, I might take a day off from posting!


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## jagans (Oct 21, 2012)

cjohnsonmn said:


> So how close do you have to be on the vertical alignment between the deck post on the frost footing and the porch post on the beam above? Do I have to dig a new adjacent footing if a porch post is not directly over the deck post? (My corner posts are right on but I need to fudge the two middle ones to get them evenly spaced. This came about because the porch roof was an afterthought --no cantilever of the deck at the corner. Its 9x21 ft with house ledger on two sides. Thanks.


Irrelevant if I understand the question. The deck substructure transfers the vertical loads to the footings. Where the posts are located on the perimeter of the deck is irrelevant.


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## MTN REMODEL LLC (Sep 11, 2010)

jagans said:


> Irrelevant if I understand the question. The deck substructure transfers the vertical loads to the footings. Where the posts are located on the perimeter of the deck is irrelevant.


Yes... Assumng your flush beam is adequetly sized for your post/pier spacing (and of course the expected imposed loads)


My question is how are you going to attach the posts to your flush beam.... considering shear issues.


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## GBrackins (Apr 26, 2012)

I myself would probably use a Simpson Strong-Tie ABU standoff post base with (2) lag screws


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## ModernDayDarwin (May 18, 2013)

GBrackins said:


> I myself would probably use a Simpson Strong-Tie ABU standoff post base with (2) lag screws


Most examples of those show them connected to a concrete post. Is there a reason they couldn't be used in a wood-to-wood connection.


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## cjohnsonmn (Sep 25, 2012)

jagans said:


> Irrelevant if I understand the question. The deck substructure transfers the vertical loads to the footings. Where the posts are located on the perimeter of the deck is irrelevant.


Just to clarify, I was asking about the allowable offset placement of load bearing porch roof posts. Snow loads on roofs can get pretty heavy in Minnesota, and I dont think you can just position the posts anywhere over your substructure beam and footings - much less along a cantilevered deck perimeter for example. But maybe I'm wrong?

This really is a great post thread - pun intended - I've learned a lot. My next question will be about tying a porch roof into the the existing roof lines and pitches.... (probably should start a new thread for that?)


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## ModernDayDarwin (May 18, 2013)

MTN REMODEL LLC said:


> Yes... Assumng your flush beam is adequetly sized for your post/pier spacing (and of course the expected imposed loads)
> 
> 
> My question is how are you going to attach the posts to your flush beam.... considering shear issues.


What about something like this? My gut says "no" simply because there's no connection between the column and anything, just gravity and the steel. 

http://i.imgur.com/neaI6Te.jpg

edit: removing the image hot link. Far too big to embed.


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## ModernDayDarwin (May 18, 2013)

cjohnsonmn said:


> Just to clarify, I was asking about the allowable offset placement of load bearing porch roof posts. Snow loads on roofs can get pretty heavy in Minnesota, and I dont think you can just position the posts anywhere over your substructure beam and footings - much less along a cantilevered deck perimeter for example. But maybe I'm wrong?
> 
> This really is a great post thread - pun intended - I've learned a lot. My next question will be about tying a porch roof into the the existing roof lines and pitches.... (probably should start a new thread for that?)


As a rule of thumb, roof support over cantilever is a big no-no unless. Now if you had a professional engineer involved to verify the design, you can do some crazy stuff. Google "largest cantilever in the world" and you'll see what i mean.


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## GBrackins (Apr 26, 2012)

ModernDayDarwin said:


> Most examples of those show them connected to a concrete post. Is there a reason they couldn't be used in a wood-to-wood connection.


there is no reason I know that they cannot be used with wood. Change over from anchor bolt to either through bolts or lag screws.


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## ModernDayDarwin (May 18, 2013)

GBrackins said:


> there is no reason I know that they cannot be used with wood. Change over from anchor bolt to either through bolts or lag screws.


Out of curiosity, what would the proper notching method be? I know that structural integrity is compromised if you notch more than 1/3 a piece of wood, but it seems like a column would need more surface area resting on a beam to transfer the load. Of course I think between the notch resting on the beam and bolts through the beam, it would hold. 

Something like this?


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## MTN REMODEL LLC (Sep 11, 2010)

ModernDayDarwin said:


> What about something like this? My gut says "no" simply because there's no connection between the column and anything, just gravity and the steel.
> 
> http://i.imgur.com/neaI6Te.jpg
> 
> edit: removing the image hot link. Far too big to embed.


Interesting.... I'm not an engineer and don't know.... certainly better than toe-nailing it though:thumbup:


Best

Peter


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## MTN REMODEL LLC (Sep 11, 2010)

ModernDayDarwin said:


> Out of curiosity, what would the proper notching method be? I know that structural integrity is compromised if you notch more than 1/3 a piece of wood, but it seems like a column would need more surface area resting on a beam to transfer the load. Of course I think between the notch resting on the beam and bolts through the beam, it would hold.
> 
> Something like this?


Those are interesting thoughts also.... I would suppose it would also depend on whether that beam was solid, or how well it was laminated to itself. Intuitively, it seems it ought to be sufficient... but if I had big snow loads, I'd want an engineer stamping it I guess.

Best
Peter


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