# Main beam sagging 1/2 inch?



## AllGoNoShow (Aug 3, 2006)

Let me start out. While I am part-time employed by a contractor (the easy windows-roofing-siding type)- I am not a contractor but was hoping some of you guys (and girls!) could provide assistance. At this point i have no idea who to call-an enginneer (what type?), framing contractor, etc? Here is my problem.

I have a 2-story 1700 sq feet colonial built in 1930. I am replacing the hardwoods-started tearing up the old ones and have realized the main beam of the house (which appears to be like 4 or 5 2X4s nailed/glued together) is sagging 1/2 of an inch to 5/8th of an inch. There are 3 metal support posts that extend to the concrete floor in the basement up to the main beam-it appears 2 of them were at one time shimed up (as much as 4-6 inches) with pieces of wood in between the top of the metal post and the main beam. The 3rd one is not shimed at all-extends directly from the floor to the main beam(this post is at one of the sides) and appears it was not original-like someone added it years ago. Interestingly enough, where this 3rd unshimed post is the floor doesn't sag as much (the joists are under 1/4 inch out of level).

Now, how do i fix this? Who do i even call? Is this normal for such an old house? The two rooms that i am putting 3/4 solid hardwoods in are on opposite sides of the main beam-with an archway meeting in between where the main beam is underneath. Obviously in current form I can't hardwood the floor without a huge wave-and it would be a hell of a job to level the subfloor by feathering out progressively thinner plywood 12 feet from the main beam to the outer walls.

My contractor boss admits this is over his head and was not sure on who to contact. Any assistance you can provide would be appreciated. I just bought this house a month ago and am hoping this is not going to be an expensive problem.

Nick


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## Bradracer18 (Dec 14, 2005)

Sounds like you might need to install a new beam(I'd use a couple mircolambs nailed together)......and then use the same posts....put this in before taking out the old one(have to get some more posts for temporary).....and then crank on the posts until it becomes level..???.....


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## Joasis (Mar 28, 2006)

If the "main beam" is in decent condition, then simply jack the beam at the low point, and shim accordingly. It is possible the steel supports with shims now may not have been long enough, so they spaced it. The one that is allowing the sag isn't spaced, and the house has settled to it, or the floor has settled, but anyway, jack it up carefully, making sure you don't crack walls over head, and use a 1X to shim with...may fix you right up for zero cost.


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## JMG1959 (Aug 26, 2006)

I would pull a string line and jack it up to plumb. It's hard for me to visualize. But it sounds like you might want to put in some temp beams. Then the spots that you want to put the permanent beams beef that area up with footings or a pier. Place steel in the hole and poor a heavy duty pad. Replace the floors with 1 1/8 in. sturdy board, screw it in and use construction adhesive.


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## thill (Oct 2, 2006)

I do a lot of this type of work, and the real answer is hard to tell without seeing the job. But here are some thoughts.

Adding full-height lally columns is the easiest option. Put them in the low spots, and over a period of a couple of weeks, crank them up to level everything out. The extended time period helps prevent some cracking, but probably not all. You want to replace all of the shimmed existing columns, and add new ones where the sagging spots are.

The second option, if more columns is not an option, is to go with a microlam beam. Using a jack, lift the floor to the proper height, and build temp. support walls on either side of the beam, 1 stud at a time, directly under each joist. Make sure to put your new beam under the old BEFORE building the 2nd temp wall. Once the house is supported, tear out the old beam and install the new.

Be sure to oversize the microlam a little, to avoid problems and deflection. You really need to assess the load and spans before sizing the beam. What is on top of this beam, and how far are the spans? Most beam suppliers will do the calculations for you for free, if you buy from them. 

Good luck with the project.

-TH


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## AllGoNoShow (Aug 3, 2006)

thill said:


> I do a lot of this type of work, and the real answer is hard to tell without seeing the job. But here are some thoughts.
> 
> Adding full-height lally columns is the easiest option. Put them in the low spots, and over a period of a couple of weeks, crank them up to level everything out. The extended time period helps prevent some cracking, but probably not all. You want to replace all of the shimmed existing columns, and add new ones where the sagging spots are.
> 
> ...


Thanks for the tips. I think replacing the existing shimmed coloumns with extended lally coloumns is the best idea. The shims are what is causing the problems-you can see the wood used to shim has compressed and is cracking/starting to push out on the sides. The main beam only extends like 18 feet (if that) and has 3 coloumns already so i don't think additional coloumns are required. After a little more research I have developed this gameplan: 

get 3 15 ton jacks and use them to jack up the main beam slowly over a week or so to level(using different sized Pressure Treated pieces of lumber under them to help distribute the load on the floor)-knock out the 2 shimed coloumns using a chisel and hammer on the floor (whoever put them in did not incase the bases in concrete-just sort of put some concrete on the sides-wouldn't be surprised if a hammer would knock them out after the load is off of them actually)- measure and cut (or get the adjustable) lolly coloumns and put them in-get new concrete to fit small hole which needed to be made to remove old coloumns-and then lower main beam back down to the new lolly coloumns 

The more I look in the basement the more i realize how terribly supported these old homes are. The 2X8 joists don't sit on the main beam completely-they are notched at the ends that meet the main beam-only about 4 inches of each joist sits on the actuall top of the main beam (and only about 2-3 inches "deep" on it). Stupid old house!

Nick


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## PipeGuy (Oct 8, 2004)

If you haven't already, you might consider using lumber to spread the load of each jack over an area of at least 3 feet square. If it were me, as long as I had the columns out I'd probably want to determine if the footer sections at each were sufficient and if not replace/enlarge them.


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## Project53 (Oct 4, 2006)

Just a thought, and this is with out seeing this of course. But you might save time, money and cracking walls. If you just get 3 adjustable Lollys. Place them right next to the existing. Slowly crank them up. The center one you could knock out almost right away.


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## karma_carpentry (Aug 7, 2005)

I'm with joasis - seems like the sensible and simplest solution.

If there's any sign of serious deformation - cracking or sinking - of the slab where the columns sit, then I'd add PipeGuy's advice and spread out the weight a little more. Even cut off a little of a column if you need ot get more room to make some sort of pad, but it sounds like with the existing 4 to 6 inch spacer you'd have enough room.


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## AllGoNoShow (Aug 3, 2006)

I may try the shimming first as you guys reccomend. The shim will have to be 4 inches tall. Is that too big of a wood shim? What kind of wood should i get so it does not compress in the future? oak? I did some exact measuring-one column needs to go up 1 inch and the other has to go up 1/2 inch.

Also, i just realized the jacks i got were not 15 ton-they are 8-ton. I am using 4 of them (one on each side of the column shims i am replacing). Are these adequate or should i return them and get higher ton rated ones? (the house is a 2-story colonial and about 1100 sq ft is on the main beam {the other 600 sq ft is an addition))

Thanks! 

Nick


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## AustinDB (Sep 11, 2006)

I have a 35' beam running the distance of my 75yr old house holding up a 13' floor span which is held up by metal columns. The base of one column rusted allowing considerable sag in the floor. Point being if you are in a location where a damp basement is possible, try separating the base of the column from the floor (I've used a brick w/ success or a thick piece of aluminum). 
try to avoid a 4" shim. How about a 4" concrete block (laid flat of course)? If you need a shim, try Corian 'scrap' . 

I read of a post from a person who does this for a living...recommending 20 ton jacks. You might find the 8 ton jacks just aren't stout enough to lift the weight (especially under a load bearing wall).


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