What does /diy/ think of my 12’ by 12’ deck design? Any suggestions? The joists (in yellow) are 16” apart starting from the top down.
Yup, looks like a deck...
>>2788872Is the middle post necessary?
>>2788863Looks good for basic framing layout, any further suggestions would depend on planking materials and how you plan to fasten them. One general tip would be to add a self sealing rubber membrane flashing to the tops of all joists and carry it down onto any areas where there might be an applied trim or fascia underneath the plank overhang...no matter how much you gap the planks, decks will let dirt and debris get down into areas like that and that shit will stay wet and evrntually rot wood joists.If you can afford it and have access, under deck fastening systems that use a flange applied to the joists like picrel are pretty nice, especially in stainless steel...the ones that use a hidden "claw" or other part applied on top of the joist that space and lock each plank into each other suck both for alignment and if you ever need to replace a plank, avoid them like the plague.
>>2788863what retard measures like this? should be centerline to centerline
>>2788878That was bugging me too.
>>2788878I started from the headers top left down, I figured I would start from a corner so it seemed right. And offset for the thickness of the headers. And yes sometimes I’m a little retarded.
>>2788877I’ll keep this in mind. It’s my first time so any suggestions are welcome.
>>2788878I’m curious now, could you go into more detail on measuring like this?
>>2788888NTA but construction and other structural framing is based on center-to-center measurements because that's how engineering of safe spans between elements like minimal sized posts and joists are determined, and it allows things like posts and beams to be easily up-sized or multiplied without the need to completely re-draw things.It also has to do with laying out for fastening standard material sizes to have seams and joints naturally fall on a framing member or if you go smaller than the specified max. OC measurement you can still always cut a board or sheet goods down to fit so it fastens that way. If you go bigger like 17" OC and you end up an inch or two shy and have to tack on a nailer and patch in gaps it makes for a weaker structure, where framing 15" OC makes more cutting/fitting work but the finished structure will be stronger, all else being equal.
>>2788906Alright alright, so everything should be centered whenever possible. So instead of measuring my joists from the top down I should measure my joists from the center out?
>>2788877Also this, My layout has the headers joined to the posts and the joists attached to the headers. It’s all on one plane. Is it really necessary to raise the joists like that? I’ve seen decks like this and appreciate the look but I’m trying to keep this as low to the ground as possible to avoid having to make a set of stairs/having to attach railings. I believe that the code in my area is “if it’s more than 9.5 inches tall it will need stairs”.
>>2788939Top image is correct. bottom 2 are not allowed. The theory is, is that with all the weight the deck stability shouldnt be placed on the shear strength of the fastener, but instead should be loaded onto the top of the post. Check your code first. If its allowed then u do u.
Notched deck post
>>2788944>placed on the shear strength of the fastener,luckily thats not how fasteners work
you dont really want to or need to put posts all around the perimiter. it's better to set them in a foot or twoactually your entire design looks wrong as fuck.
>>2789026nice worthless comment asscrack. can you elaborate as to why the image is wrong, and how fasteners work?
>>2788947You can notch a 6x6 but not a 4x4.
>>2790289>image is wrongnever said image was wrong.bottom two are clearly some kind of screw/bolt.the strength of a screwed or bolted joint should come from the friction between the two surfaces held together by the fastener under tension.the friction prevents shear forces on the fastener.
>>2790292that's what I thought you were referring to. In my experience wood shrinks depending on the moisture content during assembly, so I'd wonder how much tension there is in 5 or 10 years, or even more. Decks are expected to last a long time when made of treated lumber, and eventually I'd say much of the load is carried in pure shear on the fasteners. Are you a mechanical engineer? Your reasoning is more appropriate for things made of metal.
>>2788915It means measure from the center of the joist/pole to the center of the next joist/pole.>>2788939>>2788944Knows stuff and is right in practice>>2789026>>2790292Knows stuff in theory, but it’s irrelevant here. Wood cups, bends, swells, expands, twists etc especially outdoor. You have exactly zero control over the friction force between boards joined this way. If you stand on a joist, it should rest on its support, not be attached to it.
this is how I would frame it. the skirt is never supposed to be structural, but in this case it helps that weird corner. all posts should be notched like >>2788947bolts should be used in all corners to tie the skirt together, and on the legs to tie them to the main beamseverything is 2x12, dont use any less or you will meed a ton more ground posts
>>2790385oh I should say you can go without posts and just put it directly on the concrete at those specific points. just follow of the rule no more than 2ft from center of post to edge of beam, no more than 4ft center of post to center of post. going higher than 2ft with the posts also needs cross bracing. you wont really avoid being 2.5ft off the ground with this design but that shouldnt be a problem unless you live in a trailer house or something
>>2788863Where is the shed?
