LVL question on porch

[jpcjguy]

Hey all,
Doing a screen porch using 6x6s - question on LVLs vs 2x10 specifically.... (porch thread: https://www.garagejournal.com/forum/threads/screen-porch-project-begins.550944/#post-11376959
Here is the long side and the placement of the 6x6 posts and the rough spacing between in red. The inspector said the following that I can use:
"2 ply-9.25” LVL @ 9’ spacing- (works will up to 11’ span)"
He is also going to do some calculations if doubled up 2x10s would work (save some money). The plan is to stagger any joints also


So I believe cost wise, 2x10 with staggered joints would be the most economical but would staying with LVLs be worth it? 2x10x10 is $13 at Lowes vs 2x10 LVL is $53.....

 

[PCustoms]

I would NOT vary your spacing, that is going to stick out IMHO.

What's your question?

 

[mike93lx]

If the span fits within what you can do with sawn lumber, I would just do that.

I this case, the lvl probably doesnt really add anything (increased span, flatter surface, and shorter height)

 

[kwb]

Inspector is doing calculations?
So much for checks and balances.

 

[NORDFORD]

Having worked with both, I’ll take the LVL’s every.single.time. By the time you sandwich plywood, what are you saving? What’s your time worth?

No hunting for good boards with same dimensions. Stronger, flatter, straighter.

 

[PCustoms]

Having worked with both, I’ll take the LVL’s every.single.time. By the time you sandwich plywood, what are you saving? What’s your time worth?

Who said anything about plywood?

 

[Hank11]

Having worked with both, I’ll take the LVL’s every.single.time. By the time you sandwich plywood, what are you saving? What’s your time worth?

No hunting for good boards with same dimensions. Stronger, flatter, straighter.

This ^^^^^^^

and if you can get it delivered, I would try to get one long LVL. Nearly complete freedom to put whatever you want wherever you want underneath.

 

[mike93lx]

Having worked with both, I’ll take the LVL’s every.single.time. By the time you sandwich plywood, what are you saving? What’s your time worth?

No hunting for good boards with same dimensions. Stronger, flatter, straighter.

Plywood is only used to make a header match wall width. It does nothing for strength and wouldn't be used in this application.

 

[NORDFORD]

Who said anything about plywood?

Well, nobody. Depending on the rest of the plan, it may not be used in this situation, but it is plenty of other applications where lvl’s are still the better choice.

 

[loganb]

My personal thoughts....I would be using sawn lumber not LVL's here as the cost increase to me doesn't give me much benefit.

It's low load....roof load only on something not that deep. Span isn't very long and doesn't look like there is a space constraint on the height forcing an LVL vs a taller 2x. 6x6 posts make it easy to land triple 2x on there if you want. For 4x the money in this application I just don't think the benefit is worth it

And I love LVL's and specify them a lot in my day job....but for this application...2x10 or 2x12's

 

[larry4406]

I dug thru some older plans from prior houses, and the only thing close, is a covered deck that used trusses, was 24' wide, and was 12' deep. Not sure of your patio depth (dimension perpendicular to rear of home, but looks larger than 12'. This would mean you would have more roof load than I did).

The 6x6 PT posts were spaced 7'-8" on center and used 2-ply 2x10's as the beam, not LVL's.




Progress pic of the covered porch (work incomplete)

 

[ddurrett896]

I did something kinda similar and spanned 22' with double 16" LVLs. I'd minimized the number of posts so you have better line of sight to the backyard from inside the house, plus in the porch area.

If the door placement isn't changing, I'd put a post on each corner and each side of the door (4 total).

 

[mike93lx]

I did something kinda similar and spanned 22' with double 16" LVLs. I'd minimized the number of posts so you have better line of sight to the backyard from inside the house, plus in the porch area.

If the door placement isn't changing, I'd put a post on each corner and each side of the door (4 total).

If it was an open porch, I'd absolutely go this way. But screens will require some form of divider/support anyway, so the posts are less of an issue. At least with how I look at it

 

[jar944]

What's the rafter span?

 

[jpcjguy]

Hey all
Thanks for all the replies. The depth of the porch is 18' 6", with the plan to use 2x12s from the house to the outside wall. This will be screened in, so the extra 6x6 makes the screen sections manageable.

 

[CraigStu]

I agree LVLs are a waste of $ for this plan. If you wanted just a porch roof then yeah, LVLs w/ less posts would make sense. But to screen it in you need posts anyway so why spend the $. Also, if this is a diy, single 2x10s are easier to lift up onto the posts so you can screw and glue them together in position. Also I agree w/ PCustoms, make the spaces between posts all equal.

 

[mike93lx]

I'd look at 2x10's longer than 10 footers. Longer will generally be nicer quality

 

[PCustoms]

Hey all
Thanks for all the replies. The depth of the porch is 18' 6", with the plan to use 2x12s from the house to the outside wall. This will be screened in, so the extra 6x6 makes the screen sections manageable.

Has anyone done the calcs on that?

At the roof pitch, is a 20' 2x12 long enough?

What about the rafter tails?

 

[jpcjguy]

Has anyone done the calcs on that?

At the roof pitch, is a 20' 2x12 long enough?

What about the rafter tails?

going with a 2:12 pitch to keep the sight lines as high as possible. (asphalt with ice and water shield over the entire roof)
based on some online calculators, the rafter length is 225" (based on 2:12 pitch and 222 inches (18' 6" run)) - so a 20ft rafter *should* work - will be close....

 

[mike93lx]

going with a 2:12 pitch to keep the sight lines as high as possible. (asphalt with ice and water shield over the entire roof)
based on some online calculators, the rafter length is 225" (based on 2:12 pitch and 222 inches (18' 6" run)) - so a 20ft rafter *should* work - will be close....

Planning to scab on tails?

Is this within the rated capacity of a 2x12?

 

[PCustoms]

TGI feels like it would be a lot less headache, and backache, then 2x12

 

[jpcjguy]

TGI feels like it would be a lot less headache, and backache, then 2x12

Definitely an option!

 

[jpcjguy]

Planning to scab on tails?

Is this within the rated capacity of a 2x12?

might have to scab tails - once the final math is done.....
inspector actually said 2x10 for the rafter!
I think a 2x10 or 2x12 would work looking at these charts for rafters (https://www.weyerhaeuser.com/application/files/3215/4223/2335/LB-4026.pdf)- and will err on the stronger side.

 

[jpcjguy]

As for the spacing of the columns, if you look at the porch straight on, the house back door is slightly off center and I am following that "walkway" - I think it will look ok because either side of the screen door going out to the yard defines different spaces.
Here is a quick mock up of the layout and the green "walkways". So either the house door and the screen door line up or the screen sections across the back are equally spaced...guess I have to pick one...

 

[PCustoms]

As for the spacing of the columns, if you look at the porch straight on, the house back door is slightly off center and I am following that "walkway" - I think it will look ok because either side of the screen door going out to the yard defines different spaces.
Here is a quick mock up of the layout and the green "walkways". So either the house door and the screen door line up or the screen sections across the back are equally spaced...guess I have to pick one...

At close 20' away I'd be inclined to offset the door.

Your eyes are going to see the wonky post pattern from across the yard, but not that the house door is offset

 

[mike93lx]

I agree. Even spacing on posts then add a door to the side of one in the best spot.

 

[Hank11]

Double doors for the win!

 

[CraigStu]

Typically w/ screens you would need to be pretty close to the outside wall to see the inside door through it. So I would even the posts.

 

[Joemctag]

If the span fits within what you can do with sawn lumber, I would just do that.

I this case, the lvl probably doesnt really add anything (increased span, flatter surface, and shorter height)

Plus, pretty sure that lvls shouldn’t be exposed to wet, sunlight, or even all the temperature and moisture fluctuations.

 

[mike93lx]

Plus, pretty sure that lvls shouldn’t be exposed to wet, sunlight, or even all the temperature and moisture fluctuations.

You can get treated lvl's