We are are planing to replace our 3rd floor porch and I have a question about the orientation of the boards. What is the purpose of the board that is parallel to the siding and perpendicular to all the other boards (marked in yellow on the picture). Is to ensure a proper seal to the siding? Is it required? I am mainly asking because it complicates construction.

enter image description here

Picture from below enter image description here

  • 3
    It's probably a design element, but it's hard to say from this narrow view. What's underneath. What's overhead? Siding doesn't "seal". It drains. – isherwood Feb 25 at 14:59
  • Thanks. Just added a picture from below. The porch is covered but the roof is 10'-8'' above the porch flooring so there is some protection but still plenty of rain and snow. – user2503795 Feb 25 at 15:12

That's a "breadboard end", and it's simply a design element.

There is no requirement for it that I'm aware of. If you do an internet search for deck images, you'll see a wide variety of decks with and without this type of breadboard edging, and the ones with it will have it in varying widths. It's purely aesthetic.

The most important thing is to have metal flashing that runs up under the last piece of siding above the deck and across the top of that tripled ledger board. The metal will help shunt water off the top of the ledger instead of letting it sit there and rot it out.

  • I believe the third ledger board is there just to accommodate this pretty deck layout. – jay613 Feb 25 at 18:14
  • Quite likely correct, @jay613 – FreeMan Feb 25 at 18:22
  • Shouldn’t this be closed as opinion based. Everyone is quick to vote to close on structural questions because they don’t understand structures and don’t feel comfortable in answering the question...but when everyone has an opinion on which way a deck board can be installed, then they contribute. (2-faced) – Lee Sam Feb 25 at 18:46
  • @LeeSam the question asks "what is the purpose" and "is it required". Both seem to be fairly straight forward and not opinion based. If, however, you believe it's opinion based, please feel free to VtC. You've provided many excellent responses on structural questions, places where I definitely keep my mouth shut, despite having VtC some of them. You're always free to vote to reopen structural questions if you believe it's appropriate - a comment indicating that you believe there's enough info to answer will likely carry much weight in reopening deliberations. – FreeMan Feb 25 at 18:55
  • My wife finds that it is easier to sweep if not parallel to the siding--but only if the outside edge is open and not obstructed. – peinal Feb 25 at 19:05

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.