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AVB-AMG

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Posts posted by AVB-AMG

  1. Posted

    Like many of you I am shocked and saddened this evening by the news and images of the disastrous fire that has engulfed the famous Notre-Dame Cathedral in Paris.  It is a devastating loss, (hopefully just a bad wound....), not just to Parisians, and not just to Catholics, but to all Christians around the world who appreciate the enduring symbolism of these magnificent Cathedrals, that are cultural treasures, that have survived revolutions and world wars over many centuries.  Also mourning is anyone who appreciates French Gothic Architecture and the incredible effort it took to design and build Notre-Dame almost 900 years ago, as well as renovate it in the 19th Century.

    As you can see from @PeteF's amazing photos of the heavy wood timber structure that supported the main roof of the Cathedral over the nave and transept and the central spire's structure, it would make sense that once a fire begins and its rapidly rising heat is trapped inside under the roof, that a super heated ignition point could be reached very quickly.  Usually, heavy timber burns very slowly, but due to its old age and presumed extreme dryness, it probably ignited and burned much more quickly.  Since there was a renovation project underway at the Cathedral's roof, all enclosed with scaffolding, I will venture a wild guess that the fire started from some most unfortunate construction related accident.  We will know in coming days the real extent of the damage to the rest of the Cathedral, but I can imagine that there will be extensive damage due to a combination of variables of heat and smoke from the fire, in addition to the water pumped onto the roof to douse the fire, soaking many other areas. 

    I believe that the French will undoubtedly commit to rebuilding the destroyed parts of the Cathedral.  They really must, since it is such an important national architectural landmark, transcending its original religious purpose and beloved by the French for its recognizable symbolism, just below the level of the Eiffel Tower and Arc de Triomphe.  Since it is France, I would not be surprised that once the cathedral is ultimately restored where possible and reconstructed, using taxpayer money, that there may be calls for it to no longer serve  just as a Catholic church and that it should become a more ecumenical or non-denominational religious building open to all religions.....or even be turned into a museum, like the Turks did with Hagia Sophia in Istanbul.  Who knows....?    

    BTW, the company I have been associated with did the 2014-2015 renovation of St. Patrick's Cathedral in New York City and as part of that renovation, working closely with the FDNY, the project team and all trade contractors working inside and outside the Cathedral adhered to very strict fire prevention precautions.  As part of the renovation a sprinkler system was installed in certain parts of the structure and building code required fire-resistant materials were installed wherever possible, including the roof.  Here is a link to more information on that project:
    https://saintpatrickscathedral.org/restore-st-patricks-cathedral

    AVB-AMG

    • Like 1

  2. Posted

    @deerpark

    For your peace of mind, it could not hurt for you to have a consultation with an Attorney versed in liability issues, about what, if any exposure you may have.  While you may not at first, appear to be legally at fault, your "friend" could possibly come after you if you have liability insurance, as one approach to pay for repairing the damage, which could start to snowball. (see below).  In today's litigious society, anything is possible.

    BTW, I would advise your friend to do the following:
    Call his insurance agent, then an approved plumber with this type of experience and then an attorney.
    For proof of the event and resulting damage, I would suggest that he take as many photographs of the flooded basement now, before his plumber starts to pump out the water.  Also, take photos during that process and of all the water damaged items before he startsto move them.  He should ask his insurance agent what else they may need from him.  Finally, he should not be too quick to accept the Insurance Company's check for repair work and replacement of damaged goods.  He needs to make sure as much as possible that he has accounted for ALL repair and replacement costs for the damaged plumbing pipes and electrical wiring, wall and insulation materials, as well as ALL items adversely affected by the flooding.  One of the biggest issues that arise post flooded homes is the growth of mold.  If it is not addressed then the entire house could be affected, causing respiratory health issues for him and his family.   
    BTW, I am NOT an attorney and am not giving any professional advice, just some thoughtful suggestions and ideas to ponder....
    Good luck.

    AVB-AMG

  5. Posted

    @Sniper:

    Well you are the self-proclaimed expert on all of this.....  I hope you are satisfied with yourself, always wanting to have the last word on any topic.  It is quite obvious to me and others that you stubbornly refuse to learn anything from what others bring up and suggest, since you know it all.  What you fail to understand and accept is that any licensed Architect or Structural Engineer, when designing the structure for any building, has to take in multiple variable factors to determine the worse case scenario.  That includes a conservative safety factor.  You may think that is over-design but that is part of the reason we have building codes and we have to be licensed, to ensure the life safety aspects of a building.  I think the O.P. has heard and observed enough of your diatribes, as well as my suggestions, to be able to figure out what he should do now.

    From what I can gather, I believe that a key difference between you and me is that while I am also self-confident and think I know quite a bit, I also have humility and understand that there is much more that I do not know and can learn.  I want to learn.... Apparently, you do not.

    Also, you seem intent on just cutting and pasting things you find on the internet to supposedly prove your point, without taking other variables into account.  If structural design were that easy then nobody would need an Architect or Structural Engineer to design a building.  Suit yourself and do it your way.....  I certainly would not want to occupy, let alone live or work in any building or structure that you were involved with the planning, design and/or construction, since I would not feel reliably safe, nor would anyone else. 

    Your constant attitude that you know it all, that you are right and everyone else is wrong, is not just irritating, but makes me realize just how insecure you must be, for whatever reason.  I do feel sorry for you.  Your linear thinking, stubborn repetition of incorrect assertions, combined with your refusal to acknowledge anyone's ideas or suggestions as having any validity or merit is why I cannot and do not take you seriously and do not respect you.

    AVB-AMG

    • Like 1

  6. Posted

    2 minutes ago, Handyman said:

    Hell if I know. I've got more crap up there that you could fit in a C-130.

    When the ceiling sags I just brace it with a 4x4 and a bottle jack from Harbour Freight.

    @Handyman:

    FYI - it is my professional opinion that your solution to your sagging ceiling is a viable solution....   Good job!
    Let me guess.....  originally, you also probably only planned to store your Christmas ornaments up in your attic.... right?

    AVB-AMG

    • Like 1

  7. Posted

    @Sniper:

    Let me try to explain this clearly to you.  The design solution of the O.P.’s issue cannot be considered in a vacuum, which you seem to be doing.  The original horizontal 2x6 ceiling joists are 20 ft. 6 in. long and were adequate to serve their original purpose of connecting to and forming bracing of the roof rafters, to address roof dead load as well as the possible live loads, including snow, ice and wind.

    Now, the O.P. wants to use some of the space in the attic for storage space.  So the existing horizontal 2x6 joists need to be augmented to provide additional stiffness and load bearing capacity. 

    You left out an important result of using that American Wood Council calculator, which is the following information of the 2x6 joist:

    The Maximum Horizontal Span is: 
    10 ft. 0 in.
    with a minimum bearing length of 0.53 in. 
    required at each end of the member.

    Property Value
    Species Spruce-Pine-Fir (South)
    Grade Select Structural
    Size 2x6
    Modulus of Elasticity (E) 1300000 psi
    Bending Strength (Fb) 1943.5 psi
    Bearing Strength (Fcp) 335 psi
    Shear Strength (Fv) 135 psi

    So according to this online calculator, the actual clear span of the O.P's existing 2x6 ceiling joists are just over (exceeding), their recommended span, which should be of concern.  Also, this online calculator does not address wind load or seismic load that needs to also be taken into consideration.  As a licensed Architect, I also read and realize the limitation of these rather simplistic calculators and highlight their disclaimer below:

    "While every effort has been made to insure the accuracy of the information presented, and special effort has been made to assure that the information reflects the state-of-the-art, neither the American Wood Council nor its members assume any responsibility for any particular design 
    using this Online Span Calculator assume all liability from its use"
     
     prepared from this Online Span Calculator. Those

    Keep in mind that different building codes vary in what they require for various types of spaces.  Basically, a design load is a combination of both dead load and live load.  Design loads will be significantly less than the load that will cause the 2x6 wood joists to bend, deflect or ultimately crack and fail.  The O.P. has expressed that he does not want his bedroom ceiling below to bend and he would also like to consider the option to use additional insulation between those joists to gain a higher R-Value.

    U.S. building codes specify a uniform live load of 40 pounds per square foot (psf) for most residential floor designs. This load is intended to account for the large number of loads that can occur in a residence. In reality, these loads do not typically take the form of uniform loads. They generally consist of furniture, appliances and a myriad of other furnishings that actually induce individual point loads.  According to the International Building Code for residential construction (2009), they indicate that design live loads will vary based on a number of factors, but at a minimum, 10 psf live load for attics without storage, 20 psf live load with limited storage, and 30 psf for habitable attics or attics for significant storage, served with fixed stairs.  I am more conservative and when I take into consideration the other original purpose of those 2x6 joists and bracking, I would design the augmented/sistered 2x6 joists to accommodate a 40 psf live load and specify a minimum of ½ inch thick plywood, preferably 5/8 inch for added diaphragm stiffness. 

    As I said before, who knows what a future homeowner of that house will decide to store up in that attic and I would want to error on the side of caution to allow for a much heavier live load in that scenario.  I would also ensure that high quality wood products and screw fasteners are used and that the installation is properly framed, set, blocked, anchored and braced to ensure the the result has all of the necessary strength and rigidity, not just for the added live load but also to address the possible lateral loads that may be imposed on it.

    Some people, (you), might consider this over design, but I do not.  The cost is not that much more and the peace of mind one will have, is worth it in my opinion.

    AVB-AMG

    • Like 1

  8. Posted

    On 4/12/2019 at 1:37 AM, Sniper said:

    I even went and searched in all types of construction forums and web sites to see if I could find a single example, nope, not a single one. In every case of sistered 2x6's, they were placed directly next to each other at the same height, basically to make a 4x6, not a offset higher joist.

    I challenge you to post examples where this was done in residential construction.

    While there are different ways to sister existing joists, the majority all use the same size joist and join them on the same plane, not offset 2".

    Now, I wait for you to provide some verifiable links or details showing that offsetting 2x6 joists 2" is the correct way to sister them.

    @Sniper:

    I admit and agree that the most common form of sistering any floor joist is to use the same sized member and attaching it to the existing joist without an offset.  In addition to providing added stiffness and load supporting capacity, the suggested option of the 2" offset allows for the installation of additional deeper insulation material, something that the O.P. was contemplating.  I never said that the offset sistered joists is the only way to accomplish his goal, but just one idea.  I have seen this method used on one residential renovation project a number of years ago that one of my associates was working on.  Its configuration was calculated and verified by the project's Structural Engineer and used successfully.  Unfortunately, I do not have any photos of that framing before it was enclosed.

    As far as your assertion that I believe that I "am smarter and far superior than everyone here", you are welcome to your feelings and opinion.  I will disagree with that, but it does not really matter what I think.  Unlike you, I know what I know and also know what I don’t know and do not pretend to be knowledgeable, let alone an expert on everything, like you come across doing in so many of your posts. You apparently have a bug up your ass regarding professional Architects and Structural Engineers, which is your problem, not mine.  My original criticism of your posts in this thread remain valid.  If your claimed construction experience is true, it unfortunately does not seem to have taught you about how structural loads are transferred to bearing walls in either balloon or platform wood residential construction.  Keep in mind, we do not know what the age is or construction type is of the O.P.'s house.

    I agree that multiple actual experiences of taking a project all the way through the programming, design, documentation, bidding and construction phases is the best way to learn the practical realities of materials and how they are joined together.  IMHO, it probably takes 10-15+ years of this sort of experience before one feels truly comfortable with what they have learned, both in a formal academic classroom AND from real life experience, working with experienced tradesmen on site.  I consider that entire process to be a collaborative one with a team, not just of the design professionals, but with the G.C., trade contractors, consultants, suppliers and fabricators.  I have no problem listening to suggestions of alternative approaches and/or beneficial substitutions, if they will result in a better project outcome, preferably saving the Owner time and/or money.  I have offered one approach here for the O.P. to consider and have never said it is the only solution to meet his goal.  More importantly, I have also strongly suggested that he consult with a local registered Architect or Structural Engineer who are actively involved in and experienced with structural wood construction in residential renovations, to come to his home and examine what exactly the existing conditions are and determine what the various feasible options are for him to consider.  IMHO, that is the most responsible approach to take.

    AVB-AMG 

  10. Posted

    1 hour ago, Zeke said:

    @Ray Ray stop with the luan lunacy. Jeebus 

    @Zeke:  I have to admit that you have a wonderful way with words......

    1 hour ago, Ray Ray said:

    Yes, really.  How many attics have you been in?  How many construction jobs have you done?  I speak from experience.   If you use quality plywood, screwed down correctly and on the beams then 1/4 will suffice.  You're not gonna be storing lead weights up there.  It's gonna be Christmas decorations, old clothes and toys.  

    @Ray Ray:

    Granted, you certainly know your firearms, but on this topic you are on thin ice (plywood?).....

    Just because you have been lucky enough to not have punctured your foot through a 1/4 inch thick plywood floor in an attic, does not mean that is what one should use when designing and constructing a new storage space in one's house.  Who knows, maybe the O.P. collects antique lead toy soldiers that weigh a "ton"....   The point is, once that attic storage space is completed and available, from my experience with my wife, all sorts of things get stashed up in the attic, without much thought as to how much all of that accumulated stuff weighs.

    FYI – the American Plywood Association (APA), recommends using their rated sheathing for floors.  Specifically, their APA Rated Sturd-I-Floor product.  It is intended to be used as a single-layer flooring material or as a subfloor/underlayment for padding and carpeting.  The panel surface has extra resistance to punch-through damage.  It is available in the following thicknesses (measured in inches):  19/32, 3/8, 7/16, 15/32, ½, 19/32, and 5/8.  That is the product I have specified on projects where there is a need for it.  The Structural Engineers that I have dealt with when designing wood frame construction, have always specified a minimum of one half inch (1/2”) plywood to be used as a subfloor over floor joists that are set 16” on center, that would receive only a light covering of padding and w2w carpeting.  It would be thicker if wood strip flooring, or a thin-set mortar bed with either ceramic tile, quarry tile or stone flooring would be installed on top of it.  Also, the National Wood Flooring Association (NWFA) recommends the use of a minimum 19/32” performance category wood structural panels (CDX plywood or OSB) as a subfloor material when the floor joists are spaced at 16 inches on center.

    As I said earlier, you are free to use whatever size (thickness) plywood as a subfloor in your home, but when it comes to someone else’s home, it is a very different matter for all the reasons I stated in earlier posts in this thread.  Good luck in your future exploration of attics and take a tape measure with you and see if you can determine what the thickness is of the plywood used for their flooring…..

    AVB-AMG

  11. Posted

    2 hours ago, siderman said:

    Take a look how the roof rafters align with the floor joists. Maybe you can just install some vertical 2x4's nailed to the rafters and joists for more support. Essentially combining the strength of both framing members. 

    @siderman:

    That could also be another option, but would be a second choice.  In order to determine if it is viable, one needs to know the size of the roof rafters, their span length and spacing.  The reason it is a second choice is that the roof rafters are sized for the dead weight of the roofing materials, as well as wind loading and live loads, (i.e. snow and ice).  One concern is that if the live load of the "stuff" stored in the new attic space is too great or concentrated then the roof rafters would deflect (bend) and possibly have their structural integrity compromised.  All of that can be figured out mathematically, once you know the variables noted above.

    AVB-AMG

  12. Posted

    5 hours ago, Sniper said:

    I see a couple of potential issues here. You're telling him to sister another 2x6, 2" up on the existing joist (by screwing it to the old joist) and to run it full length. Depending on his roof line, he might not have the clearance, as the top of the new joist can hit the underside of the roof sheathing on the exterior wall. Second, all the weight of these new joists are going to be carried by that 2" of existing joist resting on the load bearing walls, instead of increasing it by having BOTH joists rest on the load bearing walls.

    If he's going through this un-necessary exercise, he should rest the new joist on the existing exterior wall and center load bearing wall, just like the existing joist, NOT raise it 2 inches. This way, the weight of the attic floor is being supported by BOTH old joist and new joist, resting on the load bearing walls. Then, he can screw the new to the old to increase structural integrity, if he wishes.

    To raise the new joist 2 inches, and have to put in tons of screws to fasten it to the existing joist is overkill and a waste of time and effort.

    @Sniper:

    While what you are saying seems to make sense, to a lay person, it is not really necessary from a structural perspective, but is sometimes done by some Carpenters in some cases for stability and does not hurt.  I implied that approach in my earlier post, but realize now that I was not clear.  The obvious solution is to insert a small piece of wood under the raised portion of the staggered new wood joist to serve as a so-called "bearing plate" for the new sistered wood joist sitting 2" horizontally on each of the bearing walls, but it is not necessary.  Importantly, it is not necessary for the structural load transfer since the bearing portion of the original 2x6 is still sufficient to accommodate the added load of the attached new 2x6 and, more importantly, the live load of whatever will be stored in the new attic space.      Adding wood blocking between the new "double joists" at the bearing points might be one way to provide additional rigidity, but again, not really necessary.  Also, if the end of the new 2' raised wood joist needs to be chamfered cut at an angle at the top end to clear any sloped roof sheathing then that may be done without compromising the structural integrity of the sistered joist.  If you were knowledgeable about the the structural integrity of wood construction you would understand that what you suggested, while does not hurt, is not necessary to accomplish the structural solution.  But unfortunately, you do not.....  

    Your opinion that this is an "unnecessary exercise" and that this approach is "overkill and a waste of time and effort" is your opinion, which you are certainly entitled to have and seem intent on expressing.  But to continue to post your inaccurate and uneducated statements is not helpful to the O.P.  Why you insist on continuing to do that in this thread is most unfortunate and just comes across as belligerent and disagreeable based on your animosity towards me.  You do not have to like me and clearly do not, but don't use your personal hostility towards me to cause you to just act in a childish annoying and irritating manner.  Maybe your real intention of your continued posts in this thread, with your persistent and tiresome naive assumptions of structural engineering, that are either misunderstood or just plain wrong, are also just to provoke a needless silly debate.  Once again, I suggest that you stick to topics that you are more informed, educated and experienced with and not continue to do your "fly-by" ignorant assertions and incorrect statements.  

    AVB-AMG

  13. Posted

    4 hours ago, remixer said:

    We did alot of work for private builders. Mta (subway reconstruction and station) along with working with the school construction authority.  We got out of fabrication and erection business about 10 years ago when my dad retired and now only manufacture products for the steel industry. Ie manufacture corrugated structural steel deck. Steel Risers and threads. Base plates etc etc  

    another issue was fabricated steel coming in from Canada.

    @remixer:

    While most of our clients are private real estate developers or institutions, I can empathize with you and your father, having also worked on a number of publicly funded projects for the NYC School Construction Authority (SCA).  The challenge on those projects was that the client (SCA) would establish the project contractual "rules" but would also reserve the right and authority to change them mid-project....  very frustrating.   Also, the SCA would decide whether or not they wanted something to be designed and built, going way beyond what the NYC Building Code mandated, which added to the bottom line construction costs.  Plus, the new schools we did were contracted to General Contractors using the lump sum bid process.  Therefore, it was paramount that the estimators did not forget anything in the bids.  Otherwise, the Change Order process was a real battle and the GC's profit, already paper thin, was at risk.

    Growing up, my family spent a number of years outside of Philadelphia, in Chester County.  When I was in high school in the early 1970's, one of my best friend's father worked as an executive at Lukens Steel Company in Coatesville, PA, one of the oldest steel mills in the U.S.  He eventually took the job of President of Phoenix Steel, a specialty steel fabricator.  I remember taking a tour of one of their foundries in Ohio which was fascinating.  Around the same time, we also toured the Bethlehem Steel Corp. plant in Bethlehem, PA, (when it was still in operation), to see how steel was made and then formed into structural steel members, which was a truly amazing experience to watch.

    AVB-AMG

  14. Posted

    3 minutes ago, Ray Ray said:

    You are really overthinking this.  

    Really.....???   From the guy who recommends using 1/4 inch thick plywood as the new attic floor sheathing.....?  :unsure:

    I know that you, or anyone here, can do whatever they want in their home by just trusting their gut and throwing the dice in a "trail & error" approach.  But it is not all that difficult to do the math calculations and figure out what is needed, add a standard safety factor, just to be sure and ultimately, do it right the first time.  I am just making my suggestions based on my knowledge and experience as an Architect.  It is up to the O.P. to decide what he wants to do and how to do it.  As he said earlier, the bedroom that he and his wife sleeps in is directly underneath this potentially new attic storage area.  I think that they both would really like to sleep well and not worry as to whether or not he (they), made the best choice in resolving this issue....

    AVB-AMG

  15. Posted

    1 hour ago, EngineerJet said:

    Yes the interior wall is load bearing. So with a single 20.5 joist, do I need about 10.25 on each side? Do I need the full 10.25 or can I get away with shorter? (Such as 8.25 or whatever is acceptable) I ask for reasons of getting the wood up there. Manuevering up there would be easier around stairs.

    @EngineerJet:

    Good to hear that the central interior wall is load bearing.  
    Yes, you do need to use the full 10 ft. 3 in. long wood 2x6, attached to the existing 2x6 attic joist, in order to achieve the desired additional stiffness and load bearing capacity.  The new 2x6 needs to also sit on both the existing perimeter wall and interior load bearing wall by at least 2 inches.  I understand the possible added difficulties involved in carrying, maneuvering and setting into place the slightly longer wood members, but that is always part of the challenge of this sort of renovation construction work.  Sometimes, one easier way to access the attic interior is by "treading" the new materials through an attic vent opening in the gable end of the roof.  In that case, you temporarily remove the actual vent and hoisting up the wood members and slide them into your attic.  Just one idea....   Good luck!

    AVB-AMG

  16. Posted

    Just now, remixer said:

    Yes I know the details of that building. 

    My family has been in the structural steel fabrication and election biz since the 60’s 

    @remixer:

    That is a tough business for U.S. fabricators, especially over the past 15 years, with the competition of low-cost foreign (Chinese) structural steel flooding the market.  Also, having to deal with competition from the concrete industry, since poured-in-place concrete is primarily used for the vast majority of new high-rise residential buildings being constructed in the NYC metropolitan region.

    AVB-AMG

  17. Posted

    12 hours ago, EngineerJet said:

    all the joists run the full plan of 20.5'

    Ok, so are you sure that the interior wall that runs parallel to the two perimeter walls is also load bearing?
    Also, are there any perpendicular wood blocking 2x6's installed to stiffen those long-span 2x6 attic joists, to prevent any bending or twisting?  That is a very long span for a 2x6 joist and probably was only intended to serve the purpose that I explained in my original post in this thread.

    AVB-AMG

  18. Posted

    22 minutes ago, remixer said:

    Dam. That’s about 400per hour engineer work :)

    btw can’t open it 

    Hmmmm..   Would a friendly FFL possibly give me any sort of $$ credit at their retail store...???
    BTW, the attachment to my post is a PDF file.  You will need to have Adobe ACROBAT installed on your computer in order to be able to open and view PDF files.  (BTW, Adobe ACROBAT is offered free by Adobe and can be downloaded from their website).

    AVB-AMG

  19. Posted

    10 minutes ago, EngineerJet said:

    Appreciate the suggestion. Would the sistering joist need to run the entire span of the existing 20.6 feet? Or am I using smaller sections to sister on the existing joist? If I'm using smaller sections, how long should each section be? One section in the middle? two sections at every third? Itll be a huge hassle if i have to get another 20' member into the attic, lol.

    From what you have said earlier, the interior wood wall is a load bearing wall so the new, additional 2x6 wood joists would only have to be 10 ft. 3 in. in length and rest at either end on the vertical bearing walls by at least 2" for sufficient load transferring support.  But you would need to sister the new joists on both sides of the interior bearing wall, to each perimeter wall.   I assume that each of the existing attic joists are that length (10 ft. 3 in.).... Or are they all 20 ft. 6 in long?

    AVB-AMG

  20. Posted

    4 hours ago, remixer said:

    oh it happens from time to time..  there is a building in NYC (Citicorp) that was in danger of toppling over if wind conditions were just right. Repairs were done in the middle of the night to stiffen the joints. No one had a clue until may years later. Funny thing was the issue was found by an engineering student.

    It was a major issue and NYC was in decon one weeks before a hurricane was going to hit NYC

    link to the story

    http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_tower_design_flaw_that_could_have_wiped_out_the_skyscraper.html

    @remixer:

    I was studying architecture in Manhattan back in the mid-1970's, as part of my junior year "abroad" and remember watching the erection of the structural steel trusses for the Citicorp Center building on East 53rd St and Lexington Ave., since my apartment was just two blocks to the north.  It was really fascinating to see such a large building with the columns at its base, offset from the four corners.  The issue was that the steel members, ("V" trusses), were connected using bolts, instead of being welded, as a cost-savings decision.  The link you provided for the story about the structural deficiency for CitiCorp Center was just a cursory overview of what happened, leaving out some important details.  For those of you who may be interested, (you?), here is a link to a more thorough explanation of the problem and the executed solution.

    AVB-AMG

     http://www.engineersjournal.ie/2015/12/08/citicorp-centre-tower-failure-averted/

  21. Posted

    @EngineerJet:

    Ok, if I understand you correctly, what you have sketched above is a plan layout of the existing 2x6 attic joists, rendered in brown colored lines, that span perpendicularly from the exterior/perimeter house bearing walls to the load bearing interior wall.  In an earlier post, you mentioned that the total horizontal length from the two perimeter walls is 20 ft. 6in.  If that is the case then the actual clear span of the existing 2x6 attic joists from each perimeter wall to the central load bearing interior wall is 10 ft. 3 in.  That is at the maximum recommended span for that size wood joist to serve their original purpose. 

    Again, if I understand you correctly, your proposed 2x4 risers, rendered in blue colored lines, are just placed on top of the existing 2x6 attic joists, running perpendicular to them.  By doing that, you are not increasing the stiffness or load bearing capacity of the existing attic joists.  All that does is add additional weight (load) on the existing 2x6’s.  Then you would lay your plywood floor sheathing on top of the 2x4 risers.  I would not recommend that you do this layout, as you propose….

    Let me explain in more basic terms to try to avoid confusion.  To ensure that you can safely create an attic space for storage purposes, one sensible option would be what @Malsua had originally suggested and I further elaborated on.  That is to augment the existing 2x6 wood attic joists by fastening, (sistering), another 2x6 wood joist to each existing joists, running in the same direction.  When you do this you would offset them in the vertical cross-section by two inches (2”), as illustrated in my basic sketch attached here as a pdf file.  You would need to connect the two attic joists with a secure fastener that would be strong enough to ensure that the two “ganged” 2x6’s are now working in tandem structurally to create a stronger load bearing horizontal member (joist).  That is accomplished by using 3/8" x 2 1/2" stainless steel hex head screws that are installed in a staggered configuration at 16 on center (O.C.) to gain the desired stiffness and bearing properties that will allow you, as well as any future owner of your house, to store whatever you want within reason, up in your attic space.   This approach also will allow for the option to install added insulation between the augmented wood attic joists to achieve a much higher (better) insulating R-Value.

    I hope this clarifies what I am suggesting you consider doing.  But as I had recommended earlier, the best route to take is to have either a licensed Architect or a Structural Engineer to come to your home to see for themselves and to verify exactly what your existing conditions are and to then perform the necessary calculations to determine what your various options are.  That would not be too expensive and worth the gained peace of mind that whatever you ultimately decide to do will be adequate, as well as safe for your needs.

    AVB-AMG

    Section Sketch of two 2x6 joists sistered together.pdf

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  22. Posted

    1 hour ago, Ray Ray said:

    I still say 1/4 inch will do.

    @Ray Ray:

     You Sir, are now just being a provocatuer, (a.k.a. a wise ass.....) ;)

    AVB-AMG

    1 hour ago, remixer said:

    That being said I think AVB has this covered. 

    I got my own problems . Just got done using roundup on the mulch beds to kill the emerging weeds and when done my wife’s asks me if I noticed her tulips starting coming out.....   they looked like weeds to me and I just remained silent. 

    Damn......  If I did that, I would not bother coming inside for dinner....  and just sleep in the car....

    P.S. - Thanks.....

    AVB-AMG

  24. Posted

    On 4/10/2019 at 4:20 PM, Malsua said:

    The only thing I was going to add was that if it's spongy, sister some 2x6s in there.   Cross as much of the span as possible, add some glue, lag or better yet, bolt it tight.  If the joist is going to fail, it will fail in the middle 3rd all other things equal.

    @Malsua:

    That is a very sensible option.  If the O.P. is going to go to the trouble of augmenting the existing 2x6 wood joists in the attic, I agree that instead of using 2x4 members, to use 2x6 lumber, and then stagger them in section by two inches (2") which would add both stiffness and load bearing capacity to the joists.  When I have done this in the past I recommend using  3/8" x 2 1/2" stainless steel hex head screws staggered at 16 O.C. to gain the desired stiffness and bearing properties. 

    On 4/10/2019 at 12:34 PM, EngineerJet said:

    well that escalated quickly. Either way, thanks for the insight. I'll probably build a 2x4 riser spanning the storage area just so I have the options of adding insulation if i need it down the road. The fact that it will have a wall in the center will allow me to sleep at night.(Literally, since my bedroom will be directly under)

    @EngineerJet:  See my comment and suggestion above.....  Also, by doing it this way, you will be able to add more insulation to achieve a higher R-Value and can also add a vapor barrier as part of it, typically available with some fiberglass batt insulation blankets.  Keep in mind that when one compresses fiberglass batt insulation, the R-Value per inch goes up, but the overall R-Value goes down because you have less thickness of insulation.

    On 4/10/2019 at 12:52 PM, remixer said:

    Not sure why your Facepalming... you replied to him asking if he had at least 9" between joists when he said he has 16" center joists.

    @remixer:  I assume by now you understand that @PK90 was referring to a depth (thickness) of the fiberglass batt insulation of nine inches (9") and not the horizontal o.c. spacing of the rafters, hence the facepalm.  While I am often criticized here for my lengthy and wordy posts, one benefit is to hopefully reduce any ambiguity or confusion by not making certain assumptions.

    On 4/10/2019 at 12:54 PM, PK90 said:

    Still :facepalm: with a :icon_lol: added.

    @PK90:  At least you can find the humor in all of this...   It is rather comical...!

    On 4/10/2019 at 4:00 PM, 10X said:

    Yep.  Who'd have thought that a thread asking for an architect's opinion--right there in the thread title--would get so heated when an architect's opinion was provided.

    @10X:  Thank you for your overall perspective observation and backdoor compliment....    Some folks who post here seem to like to offer their opinions when they would be better off just reading and listening to others who are more informed than they are on the topic being discussed.  I have learned much about firearms from many posters on this forum, gaining an invaluable education and did not pretend to know more than I did at that time.  I am amazed that some people seem to be "know-it-all's" on just about every thread topic.  It says quite a bit about those people.....

    On 4/10/2019 at 4:12 PM, remixer said:

    Correct. As much as it bothers me avb is right.  If u can’t trust an architect and an ffl confiming his finding who can u trust

    @remixer:  While we do not agree on most of our politics, we do seem to be in sync on this topic, in our attempts to help the O.P.  Thank you for the :good:

    AVB-AMG

  25. Posted

    On 4/10/2019 at 12:58 AM, Sniper said:

    That is what I said, without writing a short novel. The open span is a bigger issue then the load, if the ceiling joist isn't being supported by a wall below. And the "live load" only uses a small portion of the total available support of the attic floor joists, in most cases, unless someone is storing a library of books or some other uncommon heavy items.

    Yes, an attic has "live load" with the stored items in it, but it doesn't compare to the "live load" on the main floor like I mentioned above. Not even close. The main floor is carrying the weight of all the walls/sheetrock, cabinets, flooring/tile, plumbing fixtures, doors, all types of heavy furniture, personal belongings, and finally people. Plus add in the weight of the attic and what's stored up there. There's a hell of a lot more "live load" on the main floor joists than the attic, and there's usually very few walls under that main floor to help support it.

    So, back to the OP, unless he has some really long open spans that the ceiling joists run across, 2x6's with 1/2" plywood would be fine for the average attic storage. The only weight on those joists now is the ceiling sheetrock on the bottom of the joists.16" OC is fine for that application.

    @Sniper:

    From what you have written in your post above, it is clear that you do not understand the basics of how residential balloon frame wood structural design works.  Not to worry, many people do not understand it and that is why they hire Architects, Structural Engineers and General Contractors to determine the best solution to safely meet their residential structural goals.  

    What is reckless and potentially dangerous is for you as a lay-person, who does not know how and where the variables of structural loads are determined, carried and dispersed, is stating to the O.P., with apparent absolute certainty, that you know that his existing situation will work for his intention.  Of course, who cares if you are wrong.....   you are just some guy giving his silly uneducated, as well as unlicensed opinion on something you know nothing about.  

    We Architects and Structural Engineers have studied theses issues and are tested and licensed by both state and national registration organizations for a reason.  Unlike you, we have an obligation to gain an education from both formal schooling, apprenticeship to other licensed professionals and from our work experience.  We must be knowledgeable of and to adhere to accepted means of design and construction in order to, at the very least, meet the minimal established standards for safety and durability, as well as adhering to all applicable building codes.

    You may be knowledgeable about many things, but this topic is clearly not one of them.

    AVB-AMG

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