Expanding our deck from 120 SQ/FT to about 550 SQ/FT

It wouldn't pass code because the wall leg of the flashing has to go behind the housewrap or paper above .

Think of it like this :

When you apply shingles to a roof , the top edge of the shingle below goes under the shingle above . This insures that any water travelling down the roof drips on to the layer below

This same " shingle lap " principle is used in wood shingles or any type of horizontal siding on a wall .

The very same principle should be , and by our code has to be , used on housewrap and building paper and any horizontal penetrations of them like flashings .

Essentially , flashings are designed to divert any water that gets behind the siding from getting behind the housewrap or paper and into the wall assembly

 

Subbed. I was planning to put a deck out back here a few years ago until property values continued waning (actually plummeting would be more accurate). The last thing I wanted to do was drop $10K on a deck just to watch that value instantly disappear. Now that things have pretty much stabilized, I'm starting to look at this again. Good project OP and I'll be sitting here with eyes/ears open and mouth shut trying to learn what I need to know to do my own. Thanks for making this a thread!

 

there is not no. there is a couple of inches then where the house meets the foundation

 

Oh I get you on code, and their reasoning behind it. I was just saying that my way, if done correctly, still would prevent moisture from getting behind existing house wrap, and into the building.

I also get the way shingles are laid to prevent rainwater from reaching the sheathing. Of course living in Florida I also know that shingles can still be penetrated. (During 2005 when central Florida was hit with 3 hurricanes in 5 weeks there were over 1000 homeowners who were denied insurance claims because the hurricane winds forced water up underneath the shingles, causing water damage to the homes. The insurance companies classified this as "wind driven rain" and thus denied the claims because their policy did not have a "flood rider" on the policy.

I know this is getting WAY off course, but the point I am trying to make is this, (Take this as EXTREMELY hypothetical, and pretty much near impossible BUT) if rain water were somehow forced behind the siding, and the house wrap was overlapped on top of the flashing, this same water COULD get underneath the wrap and between the house wrap and the flashing. This would allow the water to reach the wood underneath. Now if the house were fully wrapped, and my method was used with the flashing attached OVER the wrap and the deck joist , even if moisture were forced underneath the siding, it would run up the flashing, and get stopped by the house wrap, because the house wrap is BETWEEN the house and the flashing.

Again that is a super hypothetical situation, and in the OPs case it would be a monsoon that would have to cause this, but the people in Florida never expected it to happen either. I can see the code and their reasoning behind it, but I just personally think my idea would offer better protection.

 

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Right, but at this point your water is on the face of the house wrap. There's still a chance of it now running down the house wrap behind the flashing and into the wall penetrations (anchor bolt holes).

 

7-27-13

one of the scariest things I've ever done. This was just to save 100$ on delivery fees.



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Just concrete , correct ?

and the bottom of your ledger is lower than the top of the concrete , correct ?

 

It's looking awesome so far! Great job!!!

 

Bingo. This is why you need to either use a tape to adhere the top of the flashing to the wrap, or let the wrap lap over the top of the flashing. I agree with OZ, you do not want any water getting behind the flashing, otherwise you might as well not have it. Flashing is there to direct the water over the wood, if water can get behind the flashing, it'll sit on the board and rot it away.

 

when I get home I'll have to look again. I forget exactly where the ledger meets exactly

 

this reminds me, I will also have to look and see about the original deck and whether or not any flashing or protection was installed there either.

EDIT, just looked at a few photos, looks like they used the black tape material, but I'll see if I can pickup some more

 

Which is why all roofs should have a felt or synthetic underlayment under all roofing materials

Water behind the siding , running down the exterior of the housewrap goes behind your flashing and is trapped between the ledger and the housewrap instead of being directed outboard of the ledger

In order for water to get behind the flashing as I described installing it , the water behind the siding would travel down the exterior of the housewrap , get to the flashing where the housewrap covers the flashing wall leg and is taped to it , gets behind the tape , travels vertically 4' and goes behind the flashing

Housewraps fell out of favour in our area prior to the introduction of the 10mm rainscreen cavity code because when wood ( siding or ledger in this case ) is in direct contact with housewrap , the pores in the housewrap become clogged with surfacants bleeding out of the wood , in the case of siding that is usually tannins and in the case of the ACQ treated ledger could be the treatment itself

This contamination causes the pores to clog and the housewrap loses it's water shedding ability and is prone to allow transfer of moisture through capillary action

Think of a tent fly when you are camping , the fly will shed water if it is raining no problem until you touch it with your finger , then the water comes through the fly from capillary action , same idea

This is why I prefer 1/2 lapped 60 minute tar paper over housewrap when I build but that is another debate all together

 

Here are the most recent photos as of this morning, this span doesnt seem that large but it is 28 feet in length



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I cut some really crappy jagged edges in the composite when trying to do angles etc. but overall I'm pretty satisfied. any suggestions on the side boarding below the decking? can I just paint those white?

 

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You could paint them or, over time, they will grey out as the sun naturally bleaches them.

 

Use a solid stain, i would wrap it in azek but thats pricey.

 

I normally use a white 1x12 PVC on the ribbon board. You cut the decking flush with the framing so you have no overhang, then install the PVC on the ribbon flush with the decking with stainless steel trim screws. There is a PVC caulk for filling the screw holes.

 

Cortex screws FTW!
http://www.fastenmaster.com/details/product/cortex-concealed-fastening-system-pvc-trim.html