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JamesEric 12-12-2007 07:16 AM

Sagging flooring???
My house was built in 1900. The floor joist are actual 2x11-1/2 with a 12' span. The foundation is very solid and the old joist in great shape for 107 year old wood. The floor is not springy. I can access the bottom of the kitchen from the basement ceiling below. The kitchen floor is sagging 1/2" - 3/4" and I want to install 18"x18" Travertine tile. A contractor friend suggested that I just use a leveling compound and lay the tile. However a flooring company has suggested that they cut away the old floor and sub-floor so they could sister new 2x10's to the old joists. The 2x10's would span the entire length of the old joist just short of resting the foundation. The new joist would be screwed and glued to the old joist 16" on center with 3 screws every 16". They are not planning on jacking up the old joist. What would you do and why?



redline 12-12-2007 07:37 AM

Can you post a photo of the underside of the floor joists?

where they meet the foundation and where the sag is.

Are there any cracks in the floor joists?

How far are each joist spaced? (12,14,16,20,24...) inches on center

JamesEric 12-12-2007 08:22 AM

I don't see any crack in the joist so far but I have not opened the entire basement ceiling yet. I just moved into the house last week. I took the picture but I can't find my card reader so I can't get them form the camera to my PC. The joist are placed 16" oc. The sag is mainly in the center of the kitchen floor where the old owners had an island.

redline 12-12-2007 10:46 AM

I would suspect that the joist has a crack right where it meets/sits on the foundation. Older houses usually had the joist notched right in this area and over time the notch would crack. Today joist hangers are used so as not to compromise the thickness of the joist.

Zero Punch 12-12-2007 01:05 PM

You have two different issues to contend with here. First is the floor sag. If the floor is structurally sound Self Leveling Cement could do the job as your contractor friend has suggested. Second is deflection which your flooring contractor is concerned with, that is a requirement for the flooring product you desire to have installed. The requirements are much higher for a natural stone product than for ceramic and the larger the unit size is the more critical following accepted practices becomes. I would go along with your flooring contractor on this one he's watching out for both you and himself.

JamesEric 12-12-2007 03:35 PM


Originally Posted by redline (Post 80042)
I would suspect that the joist has a crack right where it meets/sits on the foundation. Older houses usually had the joist notched right in this area and over time the notch would crack. Today joist hangers are used so as not to compromise the thickness of the joist.

I opened a 2'x5' section and the full joist are just setting on the block foundation. Some time over the next few days I plan to remove the entire drywall ceiling in the basement so that i can get a full picture of what is going on. I do not feel any deflection in the floor unless I jump pretty hard on it. The 2x12's feel nice and solid. The reason that I am leaning toward sistering the joists has to do with the 18x18 tiles and I know that are not forgiving.

JamesEric 12-12-2007 04:36 PM

I checked things again. I looked at 5 of 12 joist and they all lookk to be in great shape. The are sitting nicely on the masonry foundation. The only problem is the center sagging. I also took more measurements and the joists are 1-7/8"x11-1/2". The spacing is 18" not 16" and the open span is 11'-6".

redline 12-13-2007 12:06 PM

You said that there was an island.
Did this island have a sink?

Is there any cuts in the joist for plumbing for this island or any other cuts in the joists for heating...?

JamesEric 12-13-2007 03:57 PM

The island did not have a sink and the joist are not cut.

redline 12-13-2007 04:05 PM

If the joists are all in good shape then you maybe be able to jack up the one that is sagging and then put shims where it meets the foundation.

JamesEric 12-13-2007 05:55 PM

It is sagging in the between the span over a room in the basement so I don't have room for a post. I am also afraid of cracking plaster and the joist since they are so old. The more I think about it the more I like the idea of sistering because. That way, I will be sure that the joists will not continue to sag under the weight of the tile and appliances.

redline 12-14-2007 08:56 AM

Does this room in the basement have wall(s) that support the sagging joists?

JamesEric 12-14-2007 09:22 AM

One side is on the foundation and the other has a masonry wall support.

jogr 12-14-2007 11:04 AM

Go with the sistered 2x10. It will level your floor and make the floor plenty solid for the 18" tile.

Your current floor actually may be stiff enough. I suspect the sag is an accumulation of 100 years of weight and not a weakness issue. But you've got to level the floor anyway and sistering in the 2x10 accomplishes both the leveling and gives you some good insurance that the floor will be stiff enough.

redline 12-14-2007 05:32 PM

It sounds like sistering is the best way to go.

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