Tag Info

5

The joists are almost certainly taking some tension load (keeping the walls from spreading) from the roof, at least, unless it's very strangely built. As is, given a quick look at load calculators and those inputs, probably not. even reducing live and dead loads to 20PSF (minimum live load for a "storage attic" and a pretty low storage load) and allowing ...

4

Balcony = Supported by hidden joists under its floor. Deck = Supported by joists or/and piers. Now if you have a balcony and given your question with lack of some information... You are capital letters CRAZY for installing a hot tub on a balcony. For something that heavy you would have to be assured metal joists or deep span (that might not be enough). ...

4

According to the table in the 2012 IRC code a exterior deck needs to handle a 60lb per sq ft (40 lb live + 20lb dead load). Most treated lumber that I am aware of is #2 southern yellow pine, using that criteria on the table in the code book, your joists can carry a 10'-9" span. The biggest failure in deck construction has not been the posts or the joists, ...

4

Any 'credible and/or official sources' will tell you to hire a Structural Engineer, which is what I'll say also. There are too many variables and unknowns for Internet advice to suffice. Prepare well to minimize costs, supplying all dimensions and drawings, and schedule a site visit. The Engineer may be able to give the details for a top truss run ...

3

First, your question how do I calculate what that new beam has to be given the existing joists and the desired post options? This is a bit long winded, but it is how we figure it out accurately. Figure out a design load per square foot (PSF), we typically use 40 PSF live load and 10 PSF dead load for floors and decks. In a simple span, the beam carries ...

3

Looking at the maximum joist span requirements for southern pine, 30 lbs/ft^2 live and 10 lbs/ft^2 dead load (the minimum values in my chart) I'm seeing a 2x8 at 24" spacing cap out between 12-13' (depending on wood grade, and this number will also vary by wood type). Best guess is that these joists were originally designed for an unfinished space where ...

2

A couple problems with the span calculation, IMHO (I am not a Licensed Professional Engineer): Select structural (the lumber grade) is frequently impossible to come by at an ordinary lumberyard, will cost the earth if it can be had, and is even less available (AFAIK) in pressure treated (though you should not need that, as per comments.) Number 2 is ...

2

You can use the Sagulator. Putting in some quick numbers for Ponderosa Pine, I found a single 2x6 on edge to be acceptable for an 11' span holding up to ~1000 pounds total. Laminating 2 or 3 together will be plenty acceptable, and may be overkill, depending on the wood you're using.

2

Yes, two 2x10's spanning 13'-6" will support 2,200 lbs. Grade of lumber can be No. 2 & better of typical framing lumber, like Hem.-Fir...it need not be Doug. Fir-Larch. In fact, each 2x10 will support 1,200 lbs. To be clear, spans are measured as "clear spans". That is to say, from face of support to face of support. Also, if your BBQ is located in the ...

2

A beam made up of multiple members with plywood spacers can be done, if the fasteners are up to code. However, that really isn't your question. You want to know if you can reduce the depth of your header while also increasing it's length. For any given condition (loading, length, beam size, material (wood or steel)), the two things that most affect the ...

1

You can do it with LVL. Grabbing the first LVL spec sheet I came across (Boise Cascade, from https://www.bc.com/versa-lam-lvl-span-size-chart/), I find a Versa-Lam LVL 2.1E 3100 has an allowable bending stress of 3100 psi. That will get you above the 2930 psi from your friend's calculations. So let's start there. That LVL comes in (among other sizes) 3.5&...

1

If it's an "open" roof system, then yes. If it's a "closed" (solid) roof system, then it must be able to withstand snow loads. (I know, where you live you don't get snow, but to meet Code, it needs to support a minimum of 20 lbs. per square foot of snow.) Therefore, with a closed roof system 2 - 2x6 Redwood joists can span about 12' -6" when supporting 4' ...

1

Wow, this is quite an effort, but I know how valuable space is in SF. I’ll make some assumptions and you let me know if I’m wrong. First, Loads are divided into Live Loads (storage boxes, books, Christmas decorations, etc.) plus Dead Loads (gypsum board ceiling, ceiling joists, 1/2” plywood subfloor, etc.) Generally we add about 3 psf for miscellaneous ...

1

It’s not clear the spacing of the 2x12’s nor how many 2x12’s you’d like to notch. However, I’ll make a few assumptions and you can let me know if I’m wrong. The Code requires a Live Load of 20 psf for uninhabited attics and 30 psf for habitable attics. (See ICC Table 1607.1) Normal living spaces are required to have 40 psf. I’ll assume 20 psf Live Load (...

1

I would be installing 4"x4" joist hangers between the rafters and set in pieces of 4x4 P.T. lumber. If you are hanging the bed with chains, I'd drill through the 4x4's at the appropriate spot and insert bolts with washers and nuts on top. Good luck.

1

You added below the top of the wall in the comments. So I would lag a rim joist to the studs and use joist hangers. Span will look like this: 2x10 @ 12oc for #2 2x8 @ 12oc or 2x10 @ 16oc for #1 2x8 @ 16oc for select span table

1

Loads are based on use...not all loads are the same. Floor loads are considered permanent loads (100%), while snow loads are considered short term loads (periodically loaded). Snow in some areas are rated very short term, less than 7 days (125% stress). Some snow loads are rated short term, less than 1 month (115% stress). What this means is that you’re ...

1

Yes, a 6 x 12 Douglas Fir-Larch (#2 and better) with a 12’ span will support 8,000 lbs. at mid-span. It’s deflection will be less than 1/3 inch when fully loaded. If the 6 x 12 is a Select Structural, then it will support 10,300 lbs. and deflect about 1/4”. BTW, I recommend the window (vinyl, wood, whatever) that you are going to install below this beam ...

1

One of the 1/2” rebar “you have access to” has enough “shear strength” to support my car full of groceries with me in it. However, you don’t want to use it for a horizontal support of grape vines, because it will rust and deposit so much rust in your vineyard that you’ll be labeled a hazardous waste site. Also, that rust will contaminate the taste and ...

1

I'd suggest a different approach. I have a 23 foot span with a 50 lb per square foot load capacity built entirely of 2x4 stock on 24" centers - the trick being, it's a properly engineered truss, that happens to be built from 2x4's You could get an engineering consult on how to turn your inadequate rafters (though in fact the collar tie makes them start to ...

1

I am guessing the big concern comes from the fact there are 2x4's that are 24" on center and that is either old construction or from something else. Depending on what will reside on that roof (shingles + snow etc..your loading will change) - the 24 inch centers seem to be fine .. now on to the real deal 2 x 4's vs 2 x 6's and the placement. Using 2 x 6's ...

1

You can do the math by hand or look for a beam calculator online, but it's easier if I just use engineering software I have to size this beam for you. Use 3 plies of 10' long 2x6 to support 400# located at the middle of the span. With 400# that will always be there, it will deflect 0.18", so less than a quarter of an inch. I sized SPF #2, so you'll be fine ...

1

Old I know but worth it: Lee Stan has the right idea but, To answer your question more directly - ****The joists should be AT LEAST 2x6 and can be mounted or hung lower than the rafters using joist hangers. Note the joist width is entirely dependent on your local codes for your span. California is different than others for example Also for 5/8 double layer ...

1

You’re dealing with “impact sound control “ not “airborne sound control “. Stacking 2 layers of 5/8” gypsum board on “hat channels “ is not the best way to control impact sound. First We control impact sound (walking in high heels, dropping objects, etc.) at the source by using soft materials to walk on, (carpet, cushioned vinyl flooring, etc.), and ...

1

you need to now live load and dead load required, soil conditions, local building code requirements, allowable sizes and spacing for the joists, hanger type used, if any, materials to be used, type of pier or foundation the posts sit on. that should be a good start. it might be time to call an architect. the deck you have if it were built here in southern ...

Only top voted, non community-wiki answers of a minimum length are eligible