Moving Basement post – help needed.
Bencrx91
| Posted in Construction Techniques on
Good day all, I am starting redoing my basement.
The house was built in 1973 and basement will be redone on my spare time.
(1 storey house.)
Mainfloor is supported by one I beam about 45ft long which is also supported by 2 metal post.
I need to move 1 post 3 ft to one side in order to remove a portion of one basement wall (this wall is 24″oc).
My question is :
Will it create a problem if I move the post 3ft off ?
(it will still be supporting the I beam, but a bit off)
Do I have to set the new post in a “footing of some sort” or can it rest directly on the basement concrete floor?
Any other ideas/comments, experience, best practice ?
Thanks,
Ben
Replies
Will it cause a problem to move the post? Maybe.
Must the post be on a footing? Yes.
The post are evenly spaced. So there is about 15ft apart each "section".
The left section would be the same.
The middle section would be smaler (12ft)
The right section would be longer (18 ft) - IF i don't put a 3rd support.
I need to that to "open" an area at the bottom of the stair to the basement.If 1 put a 3rd support it would create 4 sections of :
15 ft / 12 ft / 8t / 10ft
How deep and what size the footing must be ?What steps must be used to install them ?I never did that before :O)
Thanks again for your help,
Ben
You should be ok to install a 4th support so long as there are no point loads coming down where the post is that you are moving. What is the structure above that post?
Is there any beam ending there from the roof or floor loads from above? If not, you will likely be ok, but repeating what someone else said, getting an engineer to sign off absolves you of any liability and will confirm it to be ok.
Re. footing, typically, a 24"x24" pier pad between 12" and 15" thick centered under the new pier posts is sufficient, but it depends upon the soil bearing capacity of the soils in your area.
The Pad should be set below the existing floor level and the new floor patch installed around the pad to keep the pad secure at the bottom. (typically the pad is 4-5" below floor level but find out what your local supplier stocks in post lengths and set your pier height accordingly)
Yeah, you'd be safe if you put in the third post -- provided:-- There's not currently a joint in the beam above or near the post to be moved.-- There are no unusual "point" loads (masonry fireplace, load-bearing wall from 2nd floor, supersized tub, etc) on the beam near the post to be moved.-- Proper footings are installed and the new/moved posts are properly connected to the beam.If you want to do the research you can probably figure yourself whether the beam is adequate without the 3rd post. Would require finding the tables for that size beam, finding the formulas for estimating the load on the beam, etc. Or pay an engineer. (You might be able to cut your costs considerably by doing accurate measurements/drawings for him, so he doesn't need to visit the site.) I'd guess there's at least a 50/50 chance that the beam is adequate without the 3rd post, so the investment may be worth it.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
your basement ceiling will now be your basement floor
Like others have said - Someone needs to look at your situation first hand. There are too many things we don't know, like:What the beam is. How much it supports. Your local codes. If there's any roof load on the beam..All those things are critical to beam design, and must be considered before you get a solution. Most beams I see are pretty well maxed out, so I kinda doubt you'll e able to easily do what you want to do. But there also may be other options you haven't thought of. Which again makes a case for having someone look at the thing...
I don't mind coming to work, but that eight hour wait to go home is a pain
In most urban locations, this kind of work requires a permit, and to get a permit you'll have to submit wet stamped engineering drawings. Here in LA, it's common for the engineer to pull the permit for you. I'd guess that the odds are about 9 out of 10 that the third post idea will work, and be the most cost effective solution.
-- J.S.
that pole is holding up gravity, remove the pole and gravity takes over
Um, OK -- So you put in the two new ones before you take out the one old one. Gravity will probably be happy with that, but only your engineer knows for sure.
-- J.S.
Edited 7/24/2007 2:56 pm ET by JohnSprungX
and the guy standing under them
You have a 45' beam, supported at each end and twice in the middle. Are the posts evenly spaced? That would give you three spaces of 15' each. If you move it 3', what will he new spacing be?
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Any other ideas/comments, experience, best practice ?
You need to spend a couple of hundred on an engineer for this one. If the beam was sized for 15' max spans, then you need some other options. A couple of hours of engineering can get you some. Good luck.
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I've never met a man that was owed as much as he thought he was.
Nobody here can safely and accurately answer your question because you have only provided about a forth of the necessary information.
Somebody could play twenty qurstions with you and still miss something critical.
You need an engineer to see what the loads and load paths are now. it is pssible you could move it, do away with it entoirely or even discover that it is inadequate as is and in need of a couple more posts
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in need of a couple more posts
there's been 14 posts in this thread already and they've all said basically the same thing...........
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I've never met a man that was owed as much as he thought he was.
there's been 14 posts in this thread already and they've all said basically the same thing...........
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And your point would be?A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
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I will probably go and see an engineer to ensure that everything is ok.
I found the original house plan. There are post, I beam and footing description on it.
My original dimensions/length are off a bit.
I have attached the picture to this post.
On picture :
Star #1 = the first additional post
Star #2 = the second additional post
The "original" post on the right - is the one to be removed.
Thanks
Ben
Is the steel beam continuous, or is it spliced somewhere?
During the Middle Ages, probably one of the biggest mistakes was not putting on your armor because you were "just going down to the corner"
Have an engineer look at it.
On your drawing, you'll notice that the posts are evenly spaced at 11'10". That would tell me that there are no splices in the beam and the even spacing is designed to resist "uplift". A uniform load remains flat, eccentric loading can cause problems if not engineered correctly. Three posts seems fine, but an engineer may require the beam to be cut ontop of a post.If you didn't have time to do it right the first time, how come you've got time to do it over again?
Allright, thanks again to all.A last question, were is the best place to look for an engineer ?Are they specialized office or they usually work with architects / contractors ?
Thanks again,Ben
It used to be you just kept your eye out for a guy with a pocket protector and a sliderule. A lot harder now.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Architects and contractors usually have an engineer that they work with regularly. If you know either, they could make a recomendation. It should be one that works on houses, not, for example, one that builds bridges.
Its a fairly straight forward problem, so cost should be minimal.If you didn't have time to do it right the first time, how come you've got time to do it over again?
The plan says " 7" I-beam" which does not say much. an I beam is specified as a W1855 or some such, which would mean aprox 18" tall and 55# per foot with a certain I-type configuration. or an H or with a different wall thickness making it heavier or lighter....So the engineer has to determine what it is you have now from a site visit.The posts supporting are only part of the survey he needs to make and examine. As Karp pointed out, uneven - or 'eccentric' loading from above can result according to how the rest of the upper house was build and loads transferred through the beam, which affects results...
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I think it weighs 17.3 #/lf."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Why do you thjink that? Nothing in the plans indicated it
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Call your building department.
They will recommend an engineer that they have worked with.
This will make things go very smoothly.[email protected]
On his print, just above and to the left of *1. A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
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I know Cal. That is where I quoted 7" I beam from.But 7" does not specify whether it is a 7x15, a 7x20, or a 7x26...Nor whether it is a S, H, or W configuration....So it really doesn't mean a thing.It could just as well say " 12" wood beam". What would that mean? Could be a 12" Doug fir, or it could be 4 or 4 or 5 or six LVLs or dimension lumber laminated together, or a 12" glulam....
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Even if a W7xwhatever I-beam is specified, it doesn't mean that's what is actually THERE. So once again, I think a site visit is warranted.
If things get any worse, I'll have to ask you to stop helping me.
Excellent, I'll keep you posted.
Thanks,
Ben
If the OP can measure it very carefully, he may be able to look in the tables and figure out what "w" series beam he has.
-- J.S.