I need input from the pros out there, especially the framers. I plan on hiring out the rough framing of a front porch addition to my house. I’m doing the design work and drawings myself. Two story 1920 Dutch colonial. Bottom story is brick, second is frame. Foundation is good ole Ohio limestone. My question is when it comes to designing the attachment of the porch deck to the house what would be the pros and cons of these two approaches. Ledger board through bolted to the rim joist or free standing posts close to the house with cantilevered beams. With a ledger the difficulties I see are boring through the brick and rim joist in order to place lag bolts. The protruding foundation stones would also require that the ledger somehow be “stood off” of the brick walls with spacers of some sort. The post approach would require footings being dug pretty close to the existing foundation. I’m also not sure whether a “free standing” deck would be less stout. Your thoughts please.
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Rip, my preferred method is the ledger ; you say the foundation is limestone how far does it stand proud of the brick. if not much (1-2") limestone is fairly easy to work just chip back the stone where it's needed. Or maybe a dbl ledger say a 2x6 or 2x8 with 2x10 or what you need for your joists. then I usually put a post within 4-5' of ledger so the ledger keeps the deck to the house and the post carries most of the weight.Or maybe you could post a pic or diagram. Just my 2-cents worth. Bill D. Quality Woodchips So. MD. On the Bay.
Bill and Tim,
Thanks for the response. I suspected the ledger was the way to go with the main hurdle being the protruding limestone. One solution I thought of which is actually a method of ledger attachment that I think I have seen in order to allow the ledger board to dry out if need be would be to place some short spacers along the brick portion which would receive the ledger and then attach the ledger thru bolted as you said thru the spacers. That way the ledger itself would stand proud of the of the actual wall plane. Would this be a reasonable approach without compromising the structural integrity of the ledger board ?
The post approach would require footings being dug pretty close to the existing foundation.
These footings need to go to virgin soil. If you have a basement and these new footers are in the 3' (approximate) overdig, then that means existing basement footer depth.
The ledger should be through bolted to the rim not lagged. Drilling through the brick is no big deal with a rotary hammer drill. Shimming the ledger straight isn't that bad either.
carpenter in transition
How much does the stone foundation protrude? Enough for the porch to bear on?
Is this going to be just a porch with a roof? No rooms above? How high is the porch above grade?
My inclination would be to dig new footings for the porch and make it free-standing. Your fill has been there since the 1920's and should be well settled and compacted by now. If in doubt, make the footings bigger.
Al Mollitor, Sharon MA
The porch can't bear on the foundation. It only protrudes enough due to the fact that it is a "rubble" foundation such that you don't have a continuous vertical smooth plane from the brick to the limestone. The ledger in order to be sized properly will have to extend down beyond the margin of the brick and the limestone hence the dilemma with getting the ledger to hang plumb if you were to simply attach it directly to the masonry.