Armat Posted August 23, 2004 Report Share Posted August 23, 2004 My attic conversation has becoming a real problem. Most important handicapped issue is that the ceiling joints are made with 2x4.Enough to support a plaster ceiling and light storage but not strong enough for people to walk on. I did lot of reading on structural engineering lately and what this guys did on the middle rafters is horrible. Notice the rafter is nailed to 2x8 board but the board is supported by 2x4! Yeah I felt my stomach sink when I saw that. Needless to say I got to use maybe double up 2x6 since 2x8 or 2x10 will raise the floor to much and loose precious space. Another problem is attaching 2x6 to the rafters which seem already stressed from holding the roof and supporting the ceiling and adding floor weight seems plausible to me. I have to mention that there is a central wall under the ceiling, which joints rest half way so the load on the rafters is only half the ceiling. I could be wrong on the rafters but they are only 2x5.5 inch so not really strong staff. I am getting disheartened. Any inputs guys? Quote Link to comment Share on other sites More sharing options...
Armat Posted August 23, 2004 Author Report Share Posted August 23, 2004 (edited) Notice on this picture the 2x4 are directly attached to rafters.If you think they are crappy builders now you are wrong back in 1900 they were no codes.They did whatever was cheaper and fast at least now no house can be built without passing inspection and generally contractors follow the codes since they risk loosing their license. Edited August 23, 2004 by Armat Quote Link to comment Share on other sites More sharing options...
THOTH Posted August 23, 2004 Report Share Posted August 23, 2004 I don't know Armat - but once I helped a friend beef up (and straighten [level] up) his ceiling joists...and it caused the plaster to seperate from all his downstairs walls! What a disaster (and it was a rented house that he suddenly became responsible for fixing up) - quite a nightmare...so may be more trouble then it is worth. It may also be worth it to pay a structural engineer to figure out what those joists can hold and what you can easily do to improve your situation... Quote Link to comment Share on other sites More sharing options...
Maral Posted August 23, 2004 Report Share Posted August 23, 2004 Stop reading those books and find someone , a contractor , anyone and have them have a look at your attic and give you advice and then make them khoravadz to thank them Quote Link to comment Share on other sites More sharing options...
Armat Posted August 24, 2004 Author Report Share Posted August 24, 2004 Thanks for the advice.I think my attic is off limits for living space by the codes and any contractor would not touch it as is without totally replacing the roof structure which means $$$$$$ hmmm more like $xx$$$xx$$$ which I don't have.So I am thinking of cheating by doing it myself but I have to consult my friends,family,computer geeks,Sip,Vava and the rest. I am puzzled about this.someone has told me that nails and screws, no matter how many you put on a joist, do not weaken its strength. His logic is that nails and screws only part the wood fiber and do not break them. It sounds logical but I wonder if this has any scientific foundation... Quote Link to comment Share on other sites More sharing options...
Azat Posted August 24, 2004 Report Share Posted August 24, 2004 Armat jan, the best I can do is tell you hot to run a cat 5 wire up there. Sorry. Quote Link to comment Share on other sites More sharing options...
Armat Posted August 24, 2004 Author Report Share Posted August 24, 2004 By the way in retrospect my building inspector was a joke.I remember now he never looked at the roof structure among many other problems.I have learned to notice critical issues regarding buying a house.My next house if and when is going to be inspected by ME.If you need advice buying a house talk to me and I can direct you where to look for potential problems. Quote Link to comment Share on other sites More sharing options...
Armat Posted August 24, 2004 Author Report Share Posted August 24, 2004 Armat jan, the best I can do is tell you hot to run a cat 5 wire up there. Sorry. Azat jan thanks anyway Gevo ures du.You are the house framer.Talk to me about nailing.Any input? Quote Link to comment Share on other sites More sharing options...
gamavor Posted August 24, 2004 Report Share Posted August 24, 2004 Armat, short but valuable advice. How good is your insurance over the house? Quote Link to comment Share on other sites More sharing options...
Azat Posted August 24, 2004 Report Share Posted August 24, 2004 Azat jan thanks anyway Gevo ures du.You are the house framer.Talk to me about nailing.Any input? Armat jan, if you need info about nailing I am sure I can help too. Oh wait, I take it you are talking about real nailing Quote Link to comment Share on other sites More sharing options...
Accelerated Posted August 24, 2004 Report Share Posted August 24, 2004 someone has told me that nails and screws, no matter how many you put on a joist, do not weaken its strength. His logic is that nails and screws only part the wood fiber and do not break them. It sounds logical but I wonder if this has any scientific foundation... from my experience (son of a builder), that someone is wrong, as far as I have seen - nails and screws weaken the strength of any timber and increase the probability of it cracking.... Modern building codes (in Australia) specify that the attic must carry the load of person(s), but I dont know about 1900. Quote Link to comment Share on other sites More sharing options...
bellthecat Posted August 24, 2004 Report Share Posted August 24, 2004 from my experience (son of a builder), that someone is wrong, as far as I have seen - nails and screws weaken the strength of any timber and increase the probability of it cracking.... Modern building codes (in Australia) specify that the attic must carry the load of person(s), but I dont know about 1900. Yes totally correct - that's why builders often use glues to join separate lengths of timber, or use a sort of mesh-like plate with lots of short nails in it (I forget the technical name for it!). How are the ceiling joists connected to the rafters, Armat? And how big a span do they cover unsupported. Actually Armat, those 2by4 timbers are probably strong enough to support normal weights once a floor is put on top. They will all start to work together to support the load once they are structurally joined using the floorboards. But it depends on how much weight of furniture you are going to put on the new floor and what the space will be used for. Most people don't weigh that much. Quote Link to comment Share on other sites More sharing options...
Armat Posted August 24, 2004 Author Report Share Posted August 24, 2004 Yes totally correct - that's why builders often use glues to join separate lengths of timber, or use a sort of mesh-like plate with lots of short nails in it (I forget the technical name for it!). How are the ceiling joists connected to the rafters, Armat? And how big a span do they cover unsupported. Actually Armat, those 2by4 timbers are probably strong enough to support normal weights once a floor is put on top. They will all start to work together to support the load once they are structurally joined using the floorboards. But it depends on how much weight of furniture you are going to put on the new floor and what the space will be used for. Most people don't weigh that much. Steve good questions. The span for 2x4 is 10 feet resting on the middle wall and they are nailed huge nails to the rafters.When I made the the openning for stair to the attic I had to cut the plaster ceiling and I was amazed how heavy that thig was and it was just 2x5 feet.That knowledge made me think twice about stressing those 2x4 more since it seems 10 feet span is too long to withstand additional human wight.I am going to install 2x6 maybe double them up.I can't take chances but still the rafters streingh is still quetionable. Quote Link to comment Share on other sites More sharing options...
Armat Posted August 24, 2004 Author Report Share Posted August 24, 2004 here what I found from Engineering forum( yeahh I joined them ) Where the nails/screws are mostly installed in the top edge of the joist which is under compression loads. The bottom edge is under tension and is therefore more sensitive to fastener damage. Quote Link to comment Share on other sites More sharing options...
Armat Posted August 25, 2004 Author Report Share Posted August 25, 2004 Here is what one structual engineer said about my questions about nails.I am sharing this since I love you guys and some day it may be useful. A floor joist deflects under load because the wood cells on the top compress and the wood cells on the bottom stretch. Every time you pound in a nail, you may tear a bit of wood fiber but you also compress all of the wood cells surrounding the nail. If you insert enough nails you are basically pre-stressing the joist allowing for less compression of the top edge and therefore less deflection. Quote Link to comment Share on other sites More sharing options...
Accelerated Posted August 25, 2004 Report Share Posted August 25, 2004 A floor joist deflects under load because the wood cells on the top compress and the wood cells on the bottom stretch. Every time you pound in a nail, you may tear a bit of wood fiber but you also compress all of the wood cells surrounding the nail. If you insert enough nails you are basically pre-stressing the joist allowing for less compression of the top edge and therefore less deflection. Yeah, it sounds all well and good in theory - I should think it also depends on the quality of the timber being used.... Quote Link to comment Share on other sites More sharing options...
Armat Posted September 28, 2004 Author Report Share Posted September 28, 2004 Just finished the floor joints! I worked hard on my every spare time and decided to have 2x6 run next to 2x4 and bolted together. I still have lot of work to do but the worst is over. It was a real pain in the ass to reach under the rafters to drill holes for the bolts. Now I appreciate Michelangelo working years band over on Sistine Chapel I can't upload pictures What's up!I wanted to show the fruit of my labor Quote Link to comment Share on other sites More sharing options...
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