What size floor joists are needed to span 28 feet?
This is too far of a span to make a clear span anything except steel bar joist. 28' is a long span. Plus you could not afford to put in floor trusses even if they could be built to span this length. Lots of suppliers will sell you anything, but the fact is - will they be strong enough to carry themselves, plus the sub-floor, plus the load you are going to be putting on them? The sensible and only cost effective solution is to install steel support columns at the mid-way point - you will need to cut your concrete floor and install a good concrete footing under each column. Then run a floor beam that rests on these columns, I suggest an LVL *laminated veneer lumber*. Then you will cut your floor joist span down to a reasonable 14' span. I would use a manufactured open web floor truss. If you take a scaled top view drawing into your local lumberyard they can price you the LVL's and also have the truss company engineer the load for both the LVL beams and the floor trusses.
What size header beam do I need for a 15.5' span?
I'm enclosing a 16' L x 6' W porch on the front of my single story house. I'd like to fully open the wall, currently the exterior load bearing wall, to create a large open room. The house is a single story rancher 30' long with attic space above. The wall opening span would be about 15'-15.5'. I'm thinking of using engineered lumber to reduce the depth of the header beam. This would make the beam less obtrusive. What size header can I use?
Header size for 10 foot span?
Drive some long screws down through the floor where your sides of the opening will be. Now mark this location underneath on the existing subfloor. Now install some cross blocking between your basement ceiling joist so the blocking is right under these 2 places. A 3' offset will hold this weight fine without adding sister joist. That can be a nightmare with all the wires/bracing running in the joists. 2 jack studs under each end is fine. 2 is the most I have ever seen - even on architectural / structural blueprints. The doubled 2" x 10"s with sandwich 1/2" filler is fine. Remember to install a temporary brace wall - just a few 2" x 4"s with a top/bottom plate. Do this on both sides of wall you are putting header in. Put a diagonal brace to keep this wall rigid. You can put a pc. of styrofoam under ceiling and on floor to keep from damaging those areas. You don't have to fasten these temporary top/bottom plates down - if you set this wall plumb it won't go anywhere as long as you don't knock it over. Cut studs so they fit nice and tight. Remember you are going to probably have some floor patching to do where you are removing this wall. Maybe some electrical is in that wall. Go to it. Shut off your furnace until you are done with demo or the return air will spread the dust in your furnace filter and probably blow it all over your house.
Header size for 16 foot span?
I have always used a solid 4x12 with 6 inch long cripples and then your double plate on top of that. It is important to make sure you crown your beam with the crown up. It will flatten when it gets installed. If you want you can use two 2x12's with a 1/2 plywood in between the 2 boards. Glue and screw the heck out of it. Again check your crowns and in this way you can crown one up and one down and then use the boards together to make them straight. Anything over 6 feet long span should be 4x12 up to 20 feet then you would go to a 4x14 up to 25 feet then you would go to a glue-lam beam I hope it all works out for you. Have fun. The honest truth is that you should be talking to your county inspector. or the building department.
Wood Beam Size for 22 foot span.?
You need to go to a local lumber yard that carries engineered wood beams (called micro-lams or LVL's). The lumber yards have pre-calculated charts that will help you determine the exact width and height of the beams. You will need to provide them with some detail as to what is being supported. Your best way would be to take pictures inside and outside to make sure enough info is at hand for the calculation. You also need to make sure you have adequate support under each end of the beam. Have this discussion with the lumber rep as well. No disrespect to the others, but DO NOT consider using any number of 2x12's (or smaller) for a 22' span. It will not hold without severe bowing. Your getting free advice from a professional. Please don't listen to amateurs when it comes to structural integrity.
What size of reinforced concrete beam do I need for a span of 5 meters?
To answer this question, you need to know the loads and location of the beam. Beam size also depends on how much reinforcement is provided. Anyways these are the designing part, from general practice I would suggest you to provide a 250x450 beam, with 6 nos 16mm dia steel; 3 at top & 3 at bottom and 8mm dia stirrups @150 c/c.
What is the purpose of a header above the door if it doesn't span beyond the doorjamb (see photo)?
Thanks for the A2A Ted. Technically, that is not a header. It is just a framing member placed there to frame the door opening and to provide a nailing surface to attach the exterior siding. A header is used to carry the load of the roof or wall, or anything above it, and it’s cladding, beyond the opening it is spanning. This 2x sitting on top of the door opening does neither. It is just a ‘nailer’. I have to agree with Pete Mayne about this looking like an outdoor shed of some kind, and that so called door looks rather like a window from what little is shown in the photo. Anyway, this photo is a great example of what ‘not to do’ when framing a load bearing header and should be inserted into any Framing 101 course. Framing like that should be limited to framing-in a medicine cabinet in a bathroom and very little else.The horizontally installed 2x is also a ‘no-no’ in correct framing, even if it had cripples or jack studs properly inserted at it’s ends, as it is subject to eventually sagging and creating a problem with the opening below. Horizontal single ply headers are frequently seen in fast track apartment and condo framing where every 2x4 saved is money in the framing contractors pocket. They are typically seen installed over bedroom doors and closets in non-load bearing walls. I never allowed them anywhere on any of my projects, and that meant looking at every opening. On a 240 to 400 unit project, that was a lot of openings, but any that were found were ripped out and replaced and after a while they got the message that the old son of a bitch running the show was not to be screwed with.
What size load bearing beam do I need for a 12 foot span? joists above are 16" apart.?
I suggest using an *LVL. This is a beam made up of (2) layers of laminated veneer lumber. These LVL's are 1+3/4" thick so when 2 are combined and glued together you have a 3+1/2" thickness on the total beam. Laminated Veneer Lumber is much stronger than regular dimensional lumber and it has no grain. Regular dimensional lumber has natural grain running with the long way length of the lumber and is subject to cracking/splitting along this grain. 12' span is not what I call *short for a load bearing wall. First you need to temporarily brace both sides of the ceiling about 2' back from the existing wall. Put x bracing on both sides of each temp. wall. Then remove your wall. Now the end studs of this new opening are going to be accepting the load from this new beam or header.Make sure they are double studs at each end and that they rest on solid blocking under them. Purchase 2 layers of LVL long enough to make your beam. You can install them one layer at a time - just use heavy duty liquid nails to glue them together. Use strong *C-Clamps to pull them together tight, or drill and use carriage bolts to suck them tight together. I suggest using a 14" tall LVL for this header. Lvl lumber is about $4-$5 per lineal foot, but it's well worth it. Be thinking of how you are going to patch the floor where the bottom of your old wall was. You may already have decided to put new flooring in the newly enlarged area. Have a shop vac ready and be prepared for some dust as you remove the wall, also plan on having a few electrical wires to relocate and possilby a plumbing/vent pipe or even a heating duct. Cover furniture/cabinets with plastic - turn off furnace so it does not suck dust in return air and blow it all over your house. Put box fan in a window or doorway to suck out dust quickly.
Will a 4x12 douglas header work for a 14.5 foot span?
I'm opening up a wall on a one story addition to the house and putting in a folding glass wall. The room is 15x20 with 2x6 joists at 16" on center supporting a slanted roof covered with Mineral Guard rolled roofing material over plywood. There is already a 4x12 spanning the length of the room supporting the joists halfway, so this wall is really only supporting the lower half of the roof. I've looked over tables and forums online and found different answers. Anyone have an engineering table with a supported answer?
Will double 2x12s spanning 16 feet through the center of a 16x20' room be strong enough to support the floor attached to them without sagging? If not, what is the maximum allowed span?
Wow, 4 inches is a LOT to jack up a 100+ year old beam. You may be creating a lot more problems than you solve by doing this unless you are stripping the entire house down to it's structure. If that isn't the plan then, assuming adequate ceiling heights, you might be better off reinforcing the beam in place and then levelling a new subfloor over the top of the old one. All of that being said the answer to the original question is "it depends". Two 2X12s are inadequate for that combination of span and supported joist length. Therefore whether or not your solution would work depends on the integrity of the original 6X6. Personally, I wouldn't count on it. My approach to this type of job is that I don't want to have to do it twice. I'm also not a fan of layering new over old. If I were doing this job I would put in a temporary beam on each side of the original beam using jack posts. I would remove the old beam and replace it entirely. For a 10 foot supported joist length (which is what you have - supported joist length = 1/2 the sum of the joist spans on either side of the beam) then a beam constructed of quadrupled 2X12s in SPF will give you an allowable span of 16'4" (I'm assuming there is just 1 floor above the joist) according to my local code - yours may vary. I would probably put in 5, I prefer to err on the side of overbuilding. Glue and screw the hell out of it. You might want to look into an engineered beam, like a glu-lam. It'll probably end up being smaller and stronger. Definitely joist hangers. As I mentioned at the start of my answer, you're going to want to put a lot of thought into what else is going to move when you straighten that beam. This could be a big can of worms.Also this is not a job to undertake without competent help if you don't know what you're doing. This is a dangerous job when done wrong. Possible consequences to screw-ups include structural collapse, it would be entirely feasible to kill yourself here. Be careful