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Portico and Front Porch design help

Discussion in 'Off-Topic' started by crazymjb, Jun 4, 2019.

  1. silversquirrel

    silversquirrel NES Member

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    The tension tie prevents the outer ends of the beam from spreading. The house keeps the inner ends from spreading. If you push the rafter pair in middle, down with a given force, they will push the 2x8s outward.

    Think of it as a plank. Put a 2x8 on the flat, across 2 sawhorses 5 ft apart, and walk across it. It bends right? Now put 2 in a sandwich and block it in the center, and every 12" .. walk across it. Wont bend. Turn it 90 degrees, now You made a truss for sideways force.

    Science, bitch.
     

  2. djbradles

    djbradles NES Member

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    No doubt you are correct. But with this given build and such a small surface area with very little weight, even with snowpack, I highly doubt those beams would move outward at all. Put several overweight men plus snow on the peak and maybe there would be some flex? Provided his beams are well supported in though the siding and blocked between studs and supported beneath like mine are and with the roofing material further stabilizing do you think there really is a chance of compromise? Serious question. I am not an engineer, drafter, or contractor. I’ve just built many things with careful research over the years.


    ETA: Oh let me correct my statement as I just noticed in the beginning that those are not beams but only 1x6 or so nailed together. I would much rather have s4s Douglas fir for those at a very reasonable cost going in through the siding.
     
  3. crazymjb

    crazymjb

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    The tension tie at 4 feet would be adequate to control for bowing I would think.
     
  4. djbradles

    djbradles NES Member

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    It would
     
  5. crazymjb

    crazymjb

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    Here's the house more or less as it is now. This is from the sales listing 4.5 years ago, but the front is more or less unchanged. As you can see... low on the curb appeal. I'm thinking this will make a big difference, also going to go to black shutters and fix the window wrapping where necessary. Also doing something about the front door.

    [​IMG]
    That looks awesome. I love the real wood, but this house aint fancy enough for it.
     
  6. JJ4

    JJ4 NES Member

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    I also don't think you'll have a problem.

    Here's the roof framing of the shed I built just by looking at a few sheds. 2x6 24"oc witha 12 foot span. The joists on the lofts and the collar tie on the center keeps it from spreading. So theres 4 feet from the loft joist to the center truss with the tie, then another 4 feet to the loft on the other side. Then again its only been through 3 winters so far. No permits/inspection however.

    20190607_173644.jpg
     
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  7. crazymjb

    crazymjb

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    Design was approved and permit issued. Caveat is that the rafter supports need to be nailed together. I'll just build out the box with scrap (want it to be 8X8 for aesthetic reasons).
     
  8. crazymjb

    crazymjb

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    Got the 48" holes for the footings dug tonight.

    How much room do I have to play with where on the board the bolts are staggered? I know they have to be at least 2" from the end of the 2*8. If my math is right, I can be at 3" from the bottom and still be in the sill plate and not have to worry about the concrete block at all. I'm really not comfortable digging 2 more piers that close to the block foundation.

    The ledger board (if in same location of current concrete stoop) will sit somewhere between the sill plate and top row of foundation blocks. The underside of the front door is about 10.5" from the block foundation, and I want the ledger about 5-6" below that (since the deck boards are about 1" thick). Code says 1/2" lag, and given my dimensions, that's every 30" alternating top and bottom, and in this case only a 96" run. I also thought of bolting all the way through the block and putting a PT plate in the basement on the other side. The other idea was using a classic expansion anchor in the center of the block where it is solid concrete. I'm honestly more concerned with damaging the blocks than supporting the ledger. But it needs to be to code.

    If I can get away with keeping all lag bolts in the wood, that's what I'd like to do. If not, any guidance on attaching a ledger board to a hollow block foundation? Googling says that acrylic anchors work, but also that sleeve anchors will work. Any idea where I can get galv or other ACQ rated sleeve anchors? Should I just use traditional expansion anchors and do so in the center of the block where it is solid? Per the table, I only need one of 3 total anchors in the block instead of the house based off how the ledger will sit. I'll probably do a few more anchors just for good measure, though.
     
    Last edited: Jun 13, 2019 at 1:04 AM
  9. Manomet

    Manomet NES Member

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    The deck does not have to be anchored to the house.You will need two lateral support brackets if it is. Hang the ledger from large metal nail plates, anchoring into block is not effective nor code compliant.
     
  10. crazymjb

    crazymjb

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    Can you elaborate RE the lateral support brackets and nail plates?

    ETA: Talked to the inspector today when he came to look at the footing holes. He basically said they are just going to check to make sure the frame is secure to the house and they won't be unnecessarily nit-picky, and he doesn't want me risking cracking the concrete block. I'm thinking of using a 2x12 ledger board with the 2X8 joists and hangars flush with the bottom. That would give me room to do a staggered bolt pattern into the sill/band joist without messing with the concrete block, while still getting the deck height ~4-6" below the front entry door as the old stoop currently is. Keep in mind this thing has less than a 5 foot joist span, is 8" off the ground, and is a front entry way.
     
    Last edited: Jun 13, 2019 at 1:24 PM
  11. Manomet

    Manomet NES Member

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    If you take a large nail plate or strap hanger and nail 3 or 4 of them to the back side of your ledger, attached to the majority of the width of the ledger and leave 4" or more extending up you can hang the ledger from the sill and provide full support. An oversized ledger like the 2x12 suggested can split under load over time and drop. This is not suggested in the code but a better solution than lagging to the block. All decks and porches are required to use a minimum of two lateral support brackets which tie the new deck to framing inside the house. There are a variety of manufactured or home made types which can be used but the intent is to insure the ledger does not separate from the building. It sounds like you re working with a reasonable inspector who is more interested in safety than his domain.
     
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  12. silversquirrel

    silversquirrel NES Member

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    Yup. This recent addition to the code (ma anyway) is to prevent a big deck from pulling away from the house. Sometimes an overloaded deck can rip the rim joist right out. Think old triple decker, back deck patched together by a cheap landlord, with keg and 20 college kids.

    Your design is just fine.
     
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  13. crazymjb

    crazymjb

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    Here are some updated pics of the progress. Hoping to have the framing all done tomorrow so I can have it inspected and get it finished. We have a family party next Sunday, so hoping the house doesn't look like a sack of ass then. Just saw these comments right now... so I've attached the 2X12 to the house, should I throw some flat brackets on the front to prevent any possible splitting in the future? I might just do that anyway while I have access. Front side/back side shouldn't make a difference I would think.

    If you all see anything obviously f***ed up I need to fix, let me know. I didn't use joist hangers on the front side since the load is carried by the beam sitting on the footings (and the joists are tied in with hurricane ties).

    [​IMG]
    First official use of the Jeep winch. After I loosened up the roof, I figured best to stand back to avoid dropping the thing on myself.

    [​IMG]

    Sledge and elbow grease was effective in demoing the old cinderblock steps. My back is still killing me.

    [​IMG]

    Question on attaching the roof. It appears the original siding is board and batten (and fortunately there is zero rot). I was originally going to run a 2X8 ledger on which the 4X8 supports for the rafters would attach. The old roof was attached directly to that bottom board. So should I use a smaller ledger, or pry that board off and cut back the board and batten and attach directly to the sheathing? I'd rather attach directly to the board and batten as was done previously. My concern there is a 2X8 ledger will allow for pockets for moisture to collect that cannot drain. I know that the flashing along the roof should prevent moisture from making it's way to the ledger, but in the event it does, it seems having a 2X8 on top of that 2X6 with the space between the battens would be bad news for rot purposes. Is it cool to use a 2X6 and some blocking on the ends for the 2X8s supporting the rafters? This whole thing is overbuilt anyway. Let me know if you need me to clarify
     
  14. crazymjb

    crazymjb

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    Framing this up by myself was a huge pain in the ass. Hopefully the rain isn't too bad tomorrow and I can get the sheathing on the roof, get the step built, and have the inspector by to check out the framing so I can piss away some ungodly amount of money on PVC trim.

    [​IMG]
     
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  15. djbradles

    djbradles NES Member

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    My porch took me 9 months and one fall off the roof. I know your pain.
     
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