I need to jack up a section of a floor to replace a rotted beam. The wall
above sagged down a little over an inch once the beam had rotted. I have
full access in the basement, and the wall above doesn't support anything.
We're gutting and remodeling the bathroom above, so I'm not worried about
I have a basic plan of attack in mind, but I'd like to hear from other's
who have done this. What size jack did you use, how did you set it up, etc.
I'm an experienced do-it-yourselfer, and my wife and I even built our own
house, but this will be the first time I've needed to jack up an old floor.
There are hydraulic and screw jacks that will do the job. I'd use a jack
post, about $35 at the home center.
Careful lifting though, I'd do it in small increments over a day or two to
avoid stressing things around it. If you have a concrete floor, just put it
in place securely and get started.
Just would ad one thing, I was told to put down a plate(maybe with no
scratching surface) to distribute weight evenly. I 've heard of
stories of floors(under temp post) being damaged. Just a guess...
tom @ www.Mesothelioma-Poll.com
More like you can punch right through a badly-done basement slab with the
6x6 bottom foot of a screw post. Older houses, especially if basement floor
was originally dirt, often have less than ideal floors. Any post being
placed for permanent use should really have a hole punched and a footer
added. If that isn't in the budget or skill set, 2nd choice would be at
least a 1-foot square of thick steel plate, preferably tack welded to bottom
of pole. For a temporary pole to hold up a temporary beam, while you poke
the new beam in from outside the house, just setting the pole on the steel
By the way- with the home center screw poles- even with greasing them well
and using a cheater bar and/or BFH, I find you often need to use a helper
pole and bottle jack next to them, to unload them before you can raise
anything. Not a lot of mechanical advantage or contact area in that little
screw thread. It does let you avoid buying more than 2 hydraulic jacks,
though. Just keep moving the real jacks around, extend the screw poles tight
next to them, then release the hydraulics. Same principle as using real jack
stands on a truck. Even though you are only lifting an inch or two, all this
gets old, real fast. Hence my recomendation to OP to at least get a ballpark
estimate from a floor leveling company. Like a house moving company, they
have all the gear on the truck, they do it every day, and they will make it
relatively painless. (Especially the extracting and replacing of the beam,
which is a multi-strong-man job, not a husband and wife thing.)
Yep, sounds like the basement floor in my in-laws house. I don't know if
the floor was ever dirt, but the concrete floor is really rough and uneven.
I can't say I've ever seen the screw poles at the home centers. Where are
they typically located in the store?
In my case, the 6x6 beam is only eight feet long, half of which has already
rotted and been cut away. I'll probably cut out the remainder in chunks I
can get out easily.
As for the replacement, I'm planning to install built-up beams made of four
2x8's. Easy to lift into place, and all access is clear from inside the
basement. The original 6x6 beam has a 2x6 on top which makes the total
height exactly 7.5". The 2x8's should be a perfect replacement.
Price buying or renting the jacks, plates, etc, and then price having a
floor leveling company do the swapout. Horsing main beams around with few
ways to use any assistace other than maybe a come-along, is hard frigging
work. Those things are HEAVY. Good time to look at whatever holds up the
beam, and upgrade that as needed. Nothing special about the work, other than
making sure the beam and posts are the correct specs. Steel plates on floor,
cribbing or screw columns up to ceiling level, and parallel temporary beams
to catch the load of the floor. (If the lap joints of the floor joists sit
above the beam, you will need to support both sides.) Oh, yeah, got a make a
road to get old beam out and new beam in. (That can get hard if the beam is
longer than the space to the house next door.)
Several of the This Old House projects over the years included beam swaps.
Perhaps their web site has pictures showing a step-by-step.
If this is the centerline beam than runs the full length of house, my
preference would be to replace with steel, sitting on steel columns on
oversize footers puched through the basement slab. Yes, expensive, but it
will Never Sag Again.
I'll be watching this with interest. I happen to have a jack supporting a
post beam in my crawlspace that the previous owner left in place. I don't
have any idea what I'm gonna do there, the beam used to sit right at the
location where the french drain he installed now sits. I'll try not to
hijack your thread.
I have a jack post holding up my I-Beam. Seems big enough to hold
itself up, but I guess the builder didn't think so. ....unless he just
forgot to take it out??? There are 4 tabs at the top that are meant
to be bent around the I-beam, but no one bent them.
There is a small square pillar at the bottom of the stairs that I
think encloses another jack post.
If the OP does it himself and use jackposts, does he have to grease
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.