Need lots of help lol.....

[yankeeredneck]

I have thought about that. I would think that a 2x8 16 on center and leave an area to go to either side (maybe with a door or 2) would be sufficient. Still would have to do something on either side of the center girder but a double 2x8 like the center girder should be enough to hold up 7 1/2ft of single 2x8 floor joists. And have a post every 10ft.

MAny option.....all depends on what the wife wants to do. I will update as I can on this as you guys have given me many thoughts on this.

[yankeeredneck]

I think I have been shocked ....lol Wife approved the wall set up. She liked the idea of sectioning the basement so she can have an area for canning and I can have a place for my computer servers ( I work in IT ). About blew me away lol.


I'm thinking about doing a 2x8 wall 16 on center and a structure block in between them with a opening right in from of the stairs....its only about a 3ft section. And then do the double 2x12s for the left and right girders with a post at the 10ft mark on each of those. Sounds like I have a plan in place.

[yankeeredneck]

Here is what I am planning:



Where there are the two areas that look like they open up to each side would be correct. Where the stairs are, I do plan on doing a wall as well. Those are 4x4 posts set every 2 feet. I know I am over thinking and over doing the structuring, but I think it should work.

What do you guys think

[Don_P]

Under the center girder, building a wall with a treated 2x4 bottom plate, running 2x4 studs on 16" centers and sheathing the wall preferably with 1/2" osb or ply would be quite sufficient and would make a better wall than 4x4's on 2' centers. For your other posts, a 4x4x8' is good for around 4000 lbs, a 6x6x8' is good for around 14,000 lbs, however, the steel BOCA posts have an adjustable screw jack and are plenty strong enough for these loads. I believe any of these are going to be stronger than your nail laminated columns and probably cheaper. I'm not understanding where the I beam figures in but if it is an attempt at stiffening the joists it probably won't have sufficient shear connection to do much there.

[yankeeredneck]

Don

I see where you are going with the design. Basically your standard 2x4 wall with 16 on center (PT of course for anything touching the concrete) will be better. And the 4x4 posts will be just for holding up the stairs. So a standard 2x4 wall and at the openings for each pass through just make sure I do the correct header is what you are saying?

The BOCA posts will be what I would be using for the left and right girders any way.

[Don_P]

There ya go. One problem I've seen, and felt, is the framers will build a 2x4 load bearing wall in the basement and then it doesn't get sheathed. Then under load the 2x's bend sideways under load. It doesn't really take much to hold them in line to kill that bowing and vibration, then as a stiff wall it is more than adequate.

[yankeeredneck]

Well, hopefully today I do the wall with my brother-n-law and nephew. Hopefully pics to come of the work in progress and completed.

[yankeeredneck]

Had a small set back but should have things done this week. I do have one other question.

Do I still have to have the left and right girders done? I figured a double 2x12 with the posts every 10ft but wanted to make sure if the center girder wall will basically carry the structure correctly.

[akwoodchuck]

I'd say you do need those beams....you're way over what I would consider acceptable span for rough cut 2x8s and diagonal sheathing....but I really hate bouncy floors...

[yankeeredneck]

I'd say you do need those beams....you're way over what I would consider acceptable span for rough cut 2x8s and diagonal sheathing....but I really hate bouncy floors...

I hate bouncy floors as well. My plan is to cut in the double 2x12s and add hangers for the 2x8 to the double 2x12s. And of course the posts every 10 ft.

[Don_P]

Hmm, lets do some math. You would be supporting about 7' of width... halfway towards the exterior wall and halfway towards the center girder x 10' between posts x (40+10psf)= 3500lbs

http://www.timbertoolbox.com/Calcs/ddsimplebeam.html
Back out and put in these inputs;
3500 lbs
120" span
4.5 wide
7.25" deep
#1 SYP 8" wide
10 year
3 members
2x8
No
No

That is one way, you need to break over each post. If you can drop to 8' post spacing then 16' lumber can be "woven" over the posts making for a stronger better beam and 2 @2x8 should work. You can playe with other depths and combinations, point being it probably doesn't have to be 12" deep, nothing wrong with that just more options available. Cutting the gap is not fun!

One more, double up the existing joists, no additional girders, deflection barely fails but is improved by 50%. Tipping up joists, especially in a deflected floor is not fun either. This is the least stiff option but avoids additional girders and posts.

[yankeeredneck]

One more, double up the existing joists, no additional girders, deflection barely fails but is improved by 50%. Tipping up joists, especially in a deflected floor is not fun either. This is the least stiff option but avoids additional girders and posts.

About that Don

I wondering about that. It had been suggested that I add a 2x12 to the current 2x8 and I should be able to not have the additional girders. What's your opinion on it?

[Don_P]

2x10's would be plenty but you do run into an issue at the ends. They need to notch back down to 2x8 at the bearings. Although a 1/4 depth square notch is permissible that causes a stress concentration at the re-entrant corner, the inside corner, of the notch. In plain speaking it tends to cause a split to form from the notch. Can't tell you how many times I've seen that in old work. It is better to drop down from the notch at a shallower angle or an arc than to have a sharp cornered notch.  If you build some forked long levers out of 2x lumber bolted or heavily screwed together it helps when tipping up the new joists. I have both sistered alongside the existing joists and also simply run centered between the existing and blocked the new ones in there rigidly. I think sistering with plenty of nails is probably better but can be a real pain to get them up tight without breaking the new joists. A bottle jack on its side with pump down can help but takes several hands, and watch what you are doing to the joist you are pushing against. It is all patient work, if frustration rises its time to go split some firewood  .

[yankeeredneck]

If you build some forked long levers out of 2x lumber bolted or heavily screwed together it helps when tipping up the new joists. I have both sistered alongside the existing joists and also simply run centered between the existing and blocked the new ones in there rigidly. I think sistering with plenty of nails is probably better but can be a real pain to get them up tight without breaking the new joists.

Any way you can show me what your talking about here? I think I understand it but want to make sure what I am thinking is what you are describing.  (lol) Would I still need the left and right girders if I did it this way?


And yes....busting wood the old fashion way is a nice way of relieving stress lol

[Don_P]

You would not need the additional girders doing it this way. The floor is now actually strong enough with the reinforced center girder, it lacks stiffness which is a serviceability issue rather than a strength problem. So what you are now doing is stiffening the floor until you find it acceptable. I would start by doing every other joist, see how it feels and then deciding whether to do every joist.

Here is what we call the tweaker, pretty simple, make it out of scrap, the handle is about 6' long, make 2 and have a man towards each end twisting the joist upright. Inspect the floor above you for protruding nails etc. Typically put the top of the joist as near as possible to where you want it and twist the bottom under it.

[yankeeredneck]

Don

So you are saying put one of these under the ends of the joist after adding the sister joist?


Note: Never mind---- did a quick Google search and answered my own question on that

[Don_P]

Now I'm not sure what google told you 
That is simply a tool to give you leverage to twist the joists into place, it will not remain in the finished project in any way.

Let's back up and explain the options here. Since this is a performance enhancement there are several levels of performance you can get to. The stiffest floor would be to install the additional rows of girders. If you prefer a very solid floor or intend to install tile at some point, that would be the way to go. At the least stiff end of that spectrum would be to double up the joists with 2x8's. Deeper joists are considerably stiffer than shallow ones, so each time you step up to a deeper joist the stiffness improves. Because of your 2x8 end bearing depth I suggested a compromise of using 2x10's. This stays within the notching rules which are about horizontal shear, the splitting I mentioned above, and gives what I believe will be sufficient stiffness to be satisfactory but it will not be concrete stiff. Hope that clarifies your options better.

[yankeeredneck]

Don

Yes it does and yes the tweaker is what I thought it was. Although I will be doing the joist sistering later on....like in a month or two... my plan is to stiffen the floors up. By doing the 2x12 route with the notched end not only round at the "corner" but I also planned on 2x4 wall under the ends against the concrete walls of the basement. And sense I had planned on sheathing the center girder wall anyway.... I will notch the 2x12 to fit the wall and new wall and use hangers there. and stagger 2x8s in between the joists to make the joists connect. I know this might be over kill but not worried about that. I just want it so that way when my kids jump....it does shake the whole house lol

[NathanS]

Yankee, just curious... you're thinking about adding joists because you don't want the additional posts in the basement?

I am just reiterating what has been said... you will have a better floor if you add the girders and leave the joists alone.

Adding those joists is going to be back breaking, knuckle busting, lots of cursing pain. From the pics it looks like you may have to move wiring too... hopefully no plumbing or duct work is in the way.

[yankeeredneck]

NathanS

That would be correct. I really don't "want" to add them but if I must, I must. As for the wiring and plumbing....that's all getting redone so it won't matter to me on that. I still have cast piping in the house for the septic. And cloth wrapped 60's wiring in the house for a good chunk of the house. The HVAC just got put in.

If I must add the left and right girders....then so be it. A double 2x10 with a post every 10ft passes the tests per the timbertoolbox site.

[yankeeredneck]

Wall has been started. Should be finished tomorrow. Pics to come .... stay tuned

[yankeeredneck]

https://imgur.com/guv5mld
https://imgur.com/bnPXLRh
https://imgur.com/9RG5SBj
https://imgur.com/7EuTNtu
https://imgur.com/R2Be5id
https://imgur.com/5np65Ew
https://imgur.com/P4gBsFN
https://imgur.com/L0egShU
https://imgur.com/kojUKjf
https://imgur.com/m7hWeYC
https://imgur.com/c98CIB9
https://imgur.com/qJA9bx4


Have the wall done except for the sheathing. There was only a few dollars difference between 1/2 inch OSB and 3/4 T&G Flooring OSB.....so I went with the  3/4 inch. Sheathing will go on later this week.

Don....Thank you for all your help in this. You too NathanS. Everyone here on the forum.... excellent advise and knowledge.

[yankeeredneck]

Finished Project:

https://imgur.com/lZbQJDk
https://imgur.com/gisBW9N
https://imgur.com/rHgpN7d

[Don_P]

Looks good, did it improve the flatness? How does the floor feel at this point?

[yankeeredneck]

It did improve the flatness. After doing a lot of measuring, the floor whole length of the girder went like this : ^   ^   ^   ^  ^ at every 8ft; which is where the posts were. So we basically left those peak areas loose in the wall and it has actually settled back down just about perfect. Now everything is within 1/8 of an inch or closer. Not bad!

The stiffness is much better. It still shakes the house when the kids jump but is not as bad. Once I get the left and right girders done and add some blocking in between; I'd say that will stiffen the floor right up.

When I do those I will make a new post. Right now  I have to concentrate on the farm. Hopefully in a month or so I can get back onto the house.