I can't find an existing question that completely addresses my question, so here goes.

My outside deck was recently rebuilt by contractors selected by my HOA. The deck is effectively on the second level, one story above grade level. When the new deck was put in, there was no sheathing or house wrap between the bandboard (I'm not entirely sure if that's the correct term, my apologies if not) and the wall stud 2x4's. Is this normal, or should there have been sheathing / wrap put back first? There are existing problems with the sheathing - a chunk is missing that's allowing water to get inside my walls when it rains, so the contractor is already coming back to fix that, but I'd like to know if I should push to have the deck taken down entirely and rebuilt against sheathing, and if so, how hard to push.


I am not really sure they attached this to your house right at all. I would need to see a picture.

The board that is against your house is the ledger. This runs parallel to your house you should see it bolted in. This would be load bearing (along with your posts) and is bolted into floor joists - which are not 2x4s.

Now you can run joists that attach to your house perpendicular to 2x4s. Meaning that You would have a couple of simple attachments that space/attach the deck to your house but this is not usually load bearing - load sits on the concrete posts. I don't think this is what you are talking about.

Back to the ledger... There should be flashing over the ledger (and under above siding) to prevent water from entering your house. Also your siding should be tight to deck and caulked. See the flashing picture below.

enter image description here

They can pull the interior deck boards and add the flashing - make sure they do the edges too because taking down the railings on each side will be some work for them. I am not really sure about the quality of the install if they missed this though. I am not a "deck" expert and this is just common sense. Also you saying the ledger is attached to 2x4s makes me wonder. Not saying that your deck was installed wrong other than the flashing but pictures and more info would help.

Edit - There is a way to add flashing when you forgot. See picture below for an example.

enter image description here

You see how this has to be notched into the joists. Because the flashing is usually under the joists. Personally I would call the city and make sure this doesn't pass inspection. Usually there is flashing completely under the ledger, above the ledger, under the joists attached to the ledger... At first I was thinking about retrofitting flashing but thinking about it more makes me think this is a tear down. You paid for this deck to be done right and no matter what - unless they pretty much take everything down minus posts - it isn't really right.

  • I'm relatively sure already that the flashing isn't there. I didn't see it get put in, and in looking at it over lunch I saw something that was trying to act like flashing, but was in the way wrong place. In your picture, the sheathing goes between the rim joist and the ledger board (which is what I called the band board, so I did get the vocab wrong), on my townhome, that sheathing isn't there.
    – John
    May 21 '13 at 17:38
  • @john see my edit. You should have a flashing board under your ledger that goes over the first piece of siding under deck and you should have a piece that sits like the first diagram. The diagram does not show this well but the flashing should be in between the ledger and the perpendicular joists/joist hangers, if that makes sense.
    – DMoore
    May 21 '13 at 18:16
  • Unfortunately, I don't have the "I paid for this" leverage, since it was paid for by my HOA. True, they paid for it via my monthly assessments/dues, but I'm still at one remove. I'm having an inspector from the Town come out tomorrow for some renovation work I'm doing inside, I'll be sure to ask him about this situation as well. The Inspections and Permits department of the town government seems to like me...
    – John
    May 21 '13 at 18:24
  • Who pays for the water damage to your house, the rotting of walls, and higher utilities? Also how did this deck get built without a permit/inspection. You saying that you have the city coming out for your work and the city not checking their work seems very off to me. I never heard of a homeowner pulling a permit and HOA flying under the radar. I think you do have leverage. Take you dues and apply them to a company fixing your deck.
    – DMoore
    May 21 '13 at 18:27
  • No, the contractor pulled a permit for the deck with the city. I'm just not sure they (the contractors) actually did things right, versus doing this "close enough" to pass inspection.
    – John
    May 22 '13 at 11:55

You should have flashing every time you have a change or intersection of structure or material. The flashing should be lapped with building paper.

See Image for an example of proper flashing.

The siding should not be caulked to the deck, in most cases you should leave at least 1/4" between the siding and the deck boards (but always check siding manufacturer's installation guidelines.)

Ledger Flashing

The ledger board is generally installed after sheathing. However, the ledger being over top of sheathing or not should make no difference in water penetration and is up to the structural engineer or local building codes and should be fine if it passed inspection.

Your flashing and cladding details are what will either cause or prevent leaks.

Also, if you have any details that rely on caulking to stop water infiltration, you have a future leak waiting to happen.

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