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  1. #1
    Join Date
    Jan 2012
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    Colorado
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    3

    Post Leveling floor due to sagging joists?

    I am wondering about my options for leveling an attic floor in my 1.5 story house from 1874. My husband and I live in the foothills of Colorado at 7500 feet elevation. The foundation is in fine shape (thanks to being owned by Masons over the years) which includes a good-sized basement, but placing additional supports underneath the attic is not an option as it is situated above the main living areas of the house. We plan on replacing the current flooring and so have no problem ripping that out to access the joists.

    Our home inspector guessed that the sagging has simply occurred over time due to the large distance the joists are spanning, which is ~25 feet. The joists are original 2x8's and in good shape. The sagging occurs gradually across the length of the room (28 feet) at no more than 2.5 inches at its maximum. However, it dips twice since the floor rises back up where the chimney is situated in the middle then dips again and rises again on the far side of the house.

    Our goal is to gradually change the attic into both a full bathroom and another bedroom. I have had a general contractor take an initial look, and he did not seem to see anything that would prevent such a remodel. I'm assuming we should start with the floor and would like to do as much of the work ourselves as is sensible. The general contractor plans to use some combination of architect and/or engineer.

    I'm I in way over my head here? Is leveling in this situation even possible? Or should I get used to the sloping floors and learn to live with them?

    (I don't know if it matters, but someone noted with interest that the floor joists on the 1st floor run perpendicular to the joists on the 2nd floor. I have no idea if this is normal.)

  2. #2
    Join Date
    Jul 2010
    Location
    SoCal
    Posts
    5,434

    Default Re: Leveling floor due to sagging joists?

    2-1/2" dips are major. 25' span is big. 2x8 joists may be the wrong size.

    Your contractor may be a bit too eager to get started, so talk to an engineer for possible solutions first, and don't think that you have to get used to this situation or learn to live with it.

  3. #3
    Join Date
    Mar 2009
    Posts
    1,387

    Default Re: Leveling floor due to sagging joists?

    Howdy. Installing a girder, beam, in the center of the span to carry the load and the additional loading of using the attic for living space would be a far less expensive improvement. The beam is made of either wood or steel depending on the loading and headroom available. Beam exposed or covered with finish materials allow for your interior design. 2by8s 25' span are way to light for the attic floor without any loading. First inquire what the regional building department will require for permitting,building code requirements. A structural enginers plan will allow you to not only properly build but also address other load issues & improvement you may need= possibly save you $$$$ and headaches.
    Any an all of my comments are just my opinion and not to be confused with facts.

  4. #4
    Join Date
    Dec 2010
    Location
    Houston Texas
    Posts
    2,501

    Default Re: Leveling floor due to sagging joists?

    The joist size, span and spacing are well undersized to support a living space above. You'll need to install beams as suggested above or trusses for new joist.

    There is nothing that skill and an unlimited budget can't overcome.

  5. #5
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: Leveling floor due to sagging joists?

    Quote Originally Posted by jillw252 View Post
    I am wondering about my options for leveling an attic floor in my 1.5 story house from 1874. My husband and I live in the foothills of Colorado at 7500 feet elevation. The foundation is in fine shape (thanks to being owned by Masons over the years) which includes a good-sized basement, but placing additional supports underneath the attic is not an option as it is situated above the main living areas of the house. We plan on replacing the current flooring and so have no problem ripping that out to access the joists.

    Our home inspector guessed that the sagging has simply occurred over time due to the large distance the joists are spanning, which is ~25 feet. The joists are original 2x8's and in good shape. The sagging occurs gradually across the length of the room (28 feet) at no more than 2.5 inches at its maximum. However, it dips twice since the floor rises back up where the chimney is situated in the middle then dips again and rises again on the far side of the house.

    Our goal is to gradually change the attic into both a full bathroom and another bedroom. I have had a general contractor take an initial look, and he did not seem to see anything that would prevent such a remodel. I'm assuming we should start with the floor and would like to do as much of the work ourselves as is sensible. The general contractor plans to use some combination of architect and/or engineer.

    I'm I in way over my head here? Is leveling in this situation even possible? Or should I get used to the sloping floors and learn to live with them?

    (I don't know if it matters, but someone noted with interest that the floor joists on the 1st floor run perpendicular to the joists on the 2nd floor. I have no idea if this is normal.)
    It's difficult for anyone to say sight unseen over the internet.
    You mentioned the chimney is centrally located, perhaps the celing/floor joists are not running the full span of 25 or 28 feet. It would depend if there is a support structure built around the chimney and if there are central walls located on the lower level and might explain the change of direction of the upper joists. In fact you may find some of the upper joists running both parallel and perpendicular to the lower floor joists.
    Another issue would be the spacing between joists. Chances are they are spaced further than 16 inches apart which will contribute to sagging.

    Personally , if you are going to renovate the upper level I would wait until the engineered drawings are available before doing anything. The drawings will detail what will be required to bring the current floor structure up to the needed requirement. It would be pointless to do anything now if you have to take it all out and redo it it later.

    There is a possibility that the floor can be worked on from above without the need to tear out the ceiling below -- depends on how things are currently structured. However, when it comes time to build out the future bath and other rooms you will have the lower ceiling opened at some point --- especially for plumbing , heating and electrical additions into that space.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  6. #6
    Join Date
    Jan 2008
    Posts
    1,321

    Default Re: Leveling floor due to sagging joists?

    Based on the OP, it seems the central chimney might have been used as a structural element. It may or may not be sufficient for that usage when turning a ceiling into a regular floor- especially considering the proposed bath if that includes the weight of a water-filled tub. Regardless of that even for ceiling joists you've got an undersize or overspan condition now- hence the sagging- so you are in for some work to convert this space. The best bet would be to sister in the existing joists with lumber adequate for this flooring span, pulling the existing joists into plane as you go. Finding lumber that long will be a bugger these days, and costly in comparison to standard lengths.

    You say the joists run opposite from the floor underneath. Probably there are two 8" beams perpendicular to these joists carrying the joist tails in the middle, attached to the chimney or it's walls and also the outer wall. If so you've really got your work cut out for you as these aren't so easily sistered; you now have to shorten the joists for the new lumber. Plus the beam will be higher than the needed sister joists since it has to carry more load and thus must be wider (taller).

    You may not like the idea but I like beamed ceilings and considering the age of your home they won't be out of place. By adding beams underneath you may be able to save a lot of work on top, though 2X8 joists at half your width is still overspan for a floor so you'd still have to sister those, but at least you'd not have a high beam in the middle of the floor with support now being given from underneath. Another advantage here is that you wouldn't need those new beams for full load support; you have some of that already in place so the ceiling beams could be smaller as long as they are adequately tied together with the existing ones.

    You're in an unusual situation and you really need someone with great structural knowledge to solve this problem. A good contractor can do that, you don't necessarily need an engineer. What I've mentioned are not all the possible options and based on other elements you may need more than this. Foundation structure comes into play here, as does wall construction- especially at door and window headers which will now carry more load than before. Sill beam support will have to be adequate for the added load.

    This job may be relatively easy or it may not and without knowing all the unknowns the best we can do here is to offer you what we see as options based on what you've told us. Whoever handles this will need to see what's under the attic floorboards so if you're really eager to get started go ahead and remove them since you were going to do that anyway so they can have a really good look at things. That's where the biggest questions are in this equation.

    Phil

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