then put caulking every where.

Careful with that. You can do more harm than good.

 

If you start out caulking it will never end. Not good to trust it for anything but looks.

JonMon www.deckmastersllc.com

 

 

I didn't mean caulking literally everywhere, I'm not decorating the house with it. I mean caulk where ever it needs it.



Is that flashing over the decking? What about the detail underneath where the joists are?

 

HI Kenn, it looks like a pretty bad scenario to begin with. Either the joists are running back into and penetrating thru the wall and they blocked in between the joists or they toe-nailed the joists to the siding or rim joist.
Either way your suggestion about he kerf looks like the way to go only I might cut it a bit deeper, say 3/8-1/2". I think you would still be in code compliance as you can notch the joists that deep and close to the ends.
I think that way you really don't have use much if any caulking.


Andy.

 

There's no supporting posts on the other end of the deck. So it is a cantilever, it's just an extension of the floor joists inside the house. Yeah I think my suggestion is the only way to go. I also noticed where water is getting in, there is a cupped joist, causing about an 1/8" gap between the block and the joist. That's basically an open gap for water to run right through. So I think I need a bead of caulk down every block.

 

We did a job sort of like this a while ago. Installed L flashing on top of the decking as opposed to between the decking and the joists. We the first decking board so that it didn't reach the rim joist, leaving 1/2" gap (or whatever it was) for water to drain. It made it through a winter, so I assume its working. :thumbup:

 

I would think a bead of chaulking applied at the yellow mark would stop much of the traveling water but would be more of a band aid.

Perhaps you could cut these joist away and install a better system all together. A new ledger board Rim board to the home with all the proper paper and flashing and a second one over top with 5/8" PT rain screen strips so that it doesn't make contact with the homes board. Then some hangers at this point.

I'm guessing you have support at the opposite end of this deck?

My deck has sat for months now with nothing more than Hydro Ban protecting it. :laughing: The Latecrete boys keep telling me that Hydro Ban was not designed for this purpose but she held up all winter to the snow, ice and rain.

I would suggest reframing this deck and improving on the design if possible - if not a lot of chaulking and a hope and a prayer.


JW

 

I'm guessing you have support at the opposite end of this deck?

Nope, nothing on the other end of the deck but air.

 

I think what's throwing everyone off is the newish looking PT joists.

How old is the house? I haven't seen many houses in our area newer than the early 80's with a cantilevered deck. God they're a bad idea!

My two cents: I'm not sure about kerfing the joists. It would definitely stop back migration water, but I also think it would inject water into the joist. I think a cut and bend of the flashing with graco underneath would serve better.

 

How about installing a raised detail perhaps rip down some PT wood into 1/4"x1/4" strips and pin them around those joists like have layed out on my drawing and another long one down that long yellow line.

This should stop the migration of water.

What is the budget on this job? Do they have the funds to rip out a couple of course of decking boards along the homes edge and the blocking course between the joists? Perhaps you could repaper the area and use some Blue Skin then re-install the blocking courses and couple decking board courses???

I have never seen this set up before and can imagine there has been a ton of head scratching...

JW

 

the assumption being that water is wicking in from the joist may be wrong,i think you need to pull some siding above and below and check the wrb/flashing situation before you kerf anything

you could probably seal the penetrations using a flex wrap around each joist pretty effectively

is it possible to get rid of the blocking?

 

Pulling some siding installing a flashing as planned is the way, I cant see how caulk under the flashing by the joist would be bad.

As long as your at it why not shim over bevel the 1st deck board and cut a kerf in the underside. Then you can flash ontop as well as below. A little overkill but now you would be creating a drip cap senerio.

 

I've done several of these. Tom Struble
is 100 % right make sure its from the joist.
If it is I kerf the joist as minimally as possible for the z metal. I also use a z metal that goes past the block line.

I then run the kerf down the joist to the bottom to give the water a path on both sides. These kerfs barely go into the joist its more of a scratch.

I finish the kerfs with a treatment solution. IMPO its important to lead the water straight down the joist from the flashing.

 

Here it is

I took some more pictures and tried pouring a bucket of water on the deck to see what would happen. It looks like it's doing what I thought, it goes right under the flashing. I don't see anything to keep it from going past the blocks either.

I've done several of these. Tom is 100 % right make sure its from the joist.
If it is I kerf the joist as minimally as possible for the z metal. I also use a z metal that goes past the block line.

I then run the kerf down the joist to the bottom to give the water a path on both sides. These kerfs barely go into the joist its more of a scratch.

I finish the kerfs with a treatment solution. IMPO its important to lead the water straight down the joist from the flashing.

Sounds good but I'd be leery to put kerf cuts down the side of the joists. There's nothing else holding the deck up and it's a long ways up in the air.

 

Now that I see it better I think it calls for some really special flashing.

3" high min. under siding, extend 1" past the outer face of the blocking, create saddles to go over each joist and extend to nearly the bottom of the blocking in the corners where the joists meet the blocking.

Lot of work for a sheet metal guy.

Andy.

 

Now that I see it better I think it calls for some really special flashing.

3" high min. under siding, extend 1" past the outer face of the blocking, create saddles to go over each joist and extend to nearly the bottom of the blocking in the corners where the joists meet the blocking.

Lot of work for a sheet metal guy.

Andy.

I agree something like this.

 

is that the side thats leaking?that door looks suspicious from here

 

Nice detail Rock.

Andy.

 

Way to Go Rock!!!

Thats about the only way I can see to make it happen. Flashing over the deck will help a little but not near enough.

JonMon www.deckmastersllc.com

 

Pretty much just what ScipioAfricanus posted just in drawing form. I need to see a detail to wrap my head around it.

 

Yeah, that means I'll have to fabricate it myself then take it to a metals shop and have it welded. I was hoping this wouldn't be such a pain. I can still picture water running down the sides of the joists and through the blocks even with saddles like that. Maybe it needs some bituminous tape in the crack.

 

A bead of caulk under the saddle isn't a bad idea.

I use a couple of local shops that can churn those out for about $15-$20 each. I have saddles made like that all the time for deckwall to wall intersections. You may already have the resources but if not I can PM you the info.

 

you you can get the same results with flexwrap,welding not needed

 

You don't think the material will break down over time if it's exposed?...Also could be a little unsightly on a 2nd story deck...

I like your method along with a Z flash sliced but not notched over the joists for added protection in suspect areas! Hadn't thought of it, I'll use it.

 

i'm speaking about installing it under the siding/blocking,not over it

the only way thats going to be fixed is to start over

 

ahhh, I'm following now.

 

i usually keep a small roll of it in my truck,works great for irregular flashing details and bonds very well to most clean surfaces and tenaciously to itself

 

I still think if you pulled a plank, put a kerf into the bottom of the plank itself you will break any water roll back. Flash the house joint like you would any ledger and re assemble. Then if you sloped that plank and flashed above it you would keep water 5.5" away from the house and have triple protection. If the water is kept far enough away from the blocking you should be safe. If not, then I would remove each block flash,caulk and re install.

 

and i still think assuming it's roll back is the wrong approach,Ive seen too many flashing over the top of paper installations to think the obvious solution is the right one

that blocking was probably put there so the siding would not have to cut around each joist,i think it needs to go and then the siding and paper could run thru the deck,no z flashing necessary,space the decking away from the house

 

That makes sense to Tom. I have had to put blocking in there though because of the way the decks were designed on the print. If you removed the blocking would you not still flash the individual joist?

 

I can appreciate your view Tom. And I have done that as well but that opportunity has has passed and doing that creates an opportunity at every joist for something to go wrong. Then you have to allow the water your channeling around each joist to weep back out.

Its no easy task thats for sure and meticulous details are needed in either approach.

 

doing that creates an opportunity at every joist for something to go wrong. .

but Tom that opportunity exist no matter what flashing detail you use

by eliminating all the horizontal breaks in paper and cladding save for each 1 1/2'' joist top and bottom will reduce the likelihood of failure significantly

 

imho

 

The detail I posted is a newconstruction detail it is not drawn to go over the blocking. I would use vycore over the flanges of the saddle and integrate the saddle into the WRB. The blocking if required would go over it.
We have used a very-very similar detail on condo's many times and it holds up well.

 

It ain't near this complicated

 

:laughing:my company motto is ''i make every job a project'':blush: