The ceiling /floor joists in between the ground floor and the second floor are sagging (it’s over a hundred years old house). I want to build masonry/concrete columns on the ground floor (or use so called “lolly”columns) and run a steel “I” beam on top (cross direction with the joists).
My question is: how should I jack up the “I” beam together with the ceiling joists?
What kind of jack should I use?
I’m thinking of using 2 hydraulic jacks that are 9 to 18 inches height with a 4×4 on top (ceiling height is little under 8′).
Is there an easier/safer way of cranking it up?
Thanks for your expertise
Edited 12/19/2003 12:45:14 PM ET by Darius
Replies
D.
How long is the span (cross the joists)?
How long are the joists (span)?
How deep is the sag?
What is above the sagging joists? any walls, furniture, floor finish, etc.
What is under the spot where the jacks are going to be?
Better to use screw jacks.
A 4x4 isn't going to work. you need to use a header, 3 2x12s on edge maybe.
SamT
I'd use screw jacks rather than hydraulic. Its better to raise things very slowly over a few days rather than all at once. You may have a lot of things crack otherwise. You need to support the beam for a good while when you build the posts underneath and hydraulic jacks can creep. Adjustable steel columns are cheap. I'd use a pair of those. They'll adjust around 4 inches. Put them close to where the final columns will go and make sure there is cribbing or other support under the floor all the way down to basement floor. Are the new columns going on top of an existing bearing wall in the basement or new piers? It's not a bad idea to talk to an engineer about this kind of thing. Since the building exists and is not falling down, this may be more cosmetic than structural, but the footings in the basement that ultimately bear the load are of some concern. Now you're putting point loads on things that were not designed for that purpose. Also, solid blocking under your first-floor columns and how you attach the steel beam to the posts.
Darious, you will not be able to straighten the joists. The sag has been their for many years and the joists have taken a permanent set. I would suggest that you remove the flooring, if I guess right you have a finish floor and no subfloor.After removing flooring you can sister in new joists, probably deeper than your original joists. You will lose some headroom but you will have a straight floor. Consult a building inspector or architect for sizing joists.
mike
I have quite a jack collection. I cannot resist them at yardsales and such. Hydraulic, automotive, scissors, ratchet, screw- you name it, I got it... Strange thing to collect, I know...
I'll just make a quick plug for these simple Ellis post jacks, which are my new favorites for construction applications.
http://www.ellisok.com/products.htm
They have a 4x4 and a 6x6 model. Relatively cheap ($30/$45). Made in China with sort of rough welds and finish, but still quite beefy with a nice big acme screw. Anyone who has used standard screw or hydraulic jacks with a wood post will recognize the advantages of this design.
One of those products that you look at and say "duh, what took them so long", or "why didn't I patent that". You can even use them for pulling things together! Put one on each end, and double the range. More versitile and easier to adjust than those adjustable metal 'floor jacks'. Jacking plate end can be screwed in place for lateral bracing, or to ease any non-vertical work.
This company has generally marketed their stuff to rescue personnel for temporary propping of unstable buildings, but some of their stuff is great for construction.
Got mine at http://www.gearshop.com/acb/showprod.cfm?&DID=21&CATID=22&ObjectGroup_ID=149
That is the only 'click here to buy' store I am aware of, though Masco (masco.net) carries them too.
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I've had screws from China and pliers from China, both of which snapped under load. I'd be very skeptical about made in China metal items in any kind of jacking application.
-- J.S.
"I've had screws from China and pliers from China, both of which snapped under load."
I understand your concern. However, steel plate is steel plate to some extent. These only have to be as strong as the wood post they support. These acme screws are much more substantial than the ones in the metal post floor jacks sold everywhere (and where are they made?). Where are 90% of hydraulic jacks made?
I do not expect these to be as strong as some of the nice old Simplex screw jacks I own, but they are rated to lift my entire house at once, which I will not be attempting.
> Where are 90% of hydraulic jacks made?
I use Norco bottle jacks, which are made in Japan. I've also had a couple made in China hydraulics, a floor jack and a port-power set, both junk. (I still have the porta-power, anybody want it?)
Steel is not just steel. There are a vast number of different alloys, and a much vaster number of ways to screw up making them. There's no way to tell just by looking at them which one will be safe and which one will snap in an instant under load.
-- J.S.
Thank you to everybody for the response to my questions and for the link to Ellis products.
Mike, I did sister in new joists 4 years ago and installed a 3/4" subfloor and maple flooring, though the floor sagged again.. That's why I think I will be able to crank it up to where it was 4 years ago.
I'm going to remove all old flooring and pour a new footings for the columns on the ground floor.
Csnow, do you think those ellis jacks with 6x6 can be left permanently (I could wrap it with finished wood or drywall)?
thanks
darius
"Csnow, do you think those ellis jacks with 6x6 can be left permanently (I could wrap it with finished wood or drywall)?"
I would say no. Codes frown on this sort of thing. Fire performance is one factor.