Flashing question

[BThomas]

I have to add a small 8x8 addition to an old church to allow a accessible entrance to the building. The exterior wall I am building the addition on is 2 X 8 framing 12" OC with the clapboard siding nailed directly to the framing. The building was later clad with 8" aluminum siding by applying vertical 1x firing first to the clapboard.
I am figuring to cut the aluminum siding to the shape of the new addition walls and gable roof allowing for step flashing at the roof.
To install the step flashing I am planing to cut the clapboard and install the flashing behind it with kick out flashing at the bottom section. I am figuring to add a corner flashing over the clapboard but behind the aluminum siding.
My question is is this the correct way to flash this type of construction and if not does anyone have a detail I can view?
Thanks
Bill T

[tjbnwi]

When ever I have had to tie into an sided building, I cut the siding up higher at the roof line, the additional height of a x6 or x8 +3/4". This allow the step flashing, to be installed easily. I then bend a "Z" flashing and slide this behind the WRB (if there is one) and the siding. "Roll" the X6 or X8 in place, hold it up off the roof/tight against the bottom of the "Z" flashing and fasten in place. I find this works much better and you are not fighting to get things in place.

The kick out flashing is handled on a case by case basis, it does need to be there.

Tom

[BThomas]

Tom
I like the "z" idea but how do you handle the bottom most parts with the additional depth? and how would you install the kick out with this detail? Behind the 2X not just the Z?
I have one other issue to figure also. There is blown in insulation between all the balloon framing and there is no way to access the interior wall. This means that I can only cut a line in the existing siding. I will be framing over the siding not removing it to the studs.

[tjbnwi]

Bill,

I really suck with SU, but I'll try to model my idea for you. If I can't do it in SU, I'll do it in Solid Builder, but may have to email that to you.

Once I carefully cut the aluminum siding (I would use my rail saw for this, many times I have screwed the rails to a building to make cuts.) Once the facade was out of the way, I would either get a few lengths of bevel siding and install pieces with the "thick" edge up, this should plane out the wall. Or....all of my routers will run on my guide rails, I may just "machine" the surface of the siding flat. You also have the option of just fastening the 1st intersecting wall stud to the high points of the claps, foam the gap. Remember, at the existing wall, plumb both directions may not be possible. The stud will follow the walls vertical plane. You can adjust the top plate length to get the farthest stud from the wall plumb both direction.

I don't know what you mean by "bottom most part". If you are referring to where the roof plane meets the siding at the lowest point, I would make sure my 5x or 8x was built up deep enough to be proud of the aluminum siding. That is why I bend my own "Z's", make them any size I want. The kick out would be tabbed in behind the raked board, the vertical leg tight to the siding.

Making a vertical cut with the TS for a replacement door install. Cut the cedar back to install 6/4 rough sawn cedar that covers the nailing flange. In this case I used the Rapid Clamp to hold the rail in place.;

http://www.youtube.com/watch?v=ris8_OdlGYc
Tom

[BThomas]

Tom
It sounds like you know what you are doing but I am having a hard time visualizing this detail.
I agree about the plumb cuts not being possible. If not possible than there can not be any kick out at the end. Just a lot of caulking?
I can't seem to find the time to learn SU. And I went though all my books but can not find this situation anywhere.
If you can draw a detail I would appreciate it.
Thanks
Bill T

[tjbnwi]

I don't know how well tis will show on the forum.

I see I forgot to label the rafter, it is the piece below the roof deck.

Tom

[BThomas]

P1010136.jpgP1010134.jpgP1010122.jpgTom
Thanks for the detail.
You would only flash behind the al siding?
Your drawing shows the Z over the clapboard but behind the al siding.
I never trust al or vinyl siding to be weather tight ( especially near windows ) and thought that the flashing would need to go behind the clapboard. There are windows just above and on both sides of the new addition. See attached photos.

[tjbnwi]

The furring works as a rain screen. If you go behind the claps, you may do more harm than good. I would let the baby tins take care of water movement from that area. When you cut the siding off, you'll have a better idea if water does penetrate the cladding.

Tom

[BThomas]

Tom
Thanks again.
Your way is much easier than what I was thinking.
I will be attending a Katz Roadshow tomorrow with a section on waterproofing doors and windows. I will present this there at break to get their view. I think that I am over thinking this thing. I would rather be doing trim, even base molding. LOL
Thanks again
Bill T

[tjbnwi]

I looked at you pictures and read your concerns. I did make a few changes and add a few items.

I show the wood claps flattened and the baby tins set back to them. I would not remove them, I feel the tins need support on the vertical leg.

This is a link for the flashing tape I show behind the tins, this product has a tenacious bond;

http://www.eternabond.com

I also added the J-channel for the cut aluminum siding.

The overhead view shows the order in which I would install the pieces. The kick out flashing goes in first, then the tape then the tins.

The depth of the new raked filler will have to be determined by you in the field. I would hold it off the claps so the rain screen drains on the baby tins, water can then exit the wall at the kick out. You may need to do a segmented build up on the back to hold it off properly.


I see you have a permit, just a reminder-The ADA allows a maximum of 1.25" of fall per foot of run on a ramp in remodels. 1" on new construction. Your AHJ may have changed it, so check with them.

Tom

[BThomas]

Wow Tom - You really put some effort in this reply - Thanks
I like your approach and will use it. Thanks for the Eternabond link. I see my supplier has it. I have not heard of this but most of my work is finish carpentry.
We have no "ramps" and the walks are way within the 1/20 and 1/4 range.
This happens to be my ( everyone's ) church and I want it to come out as nice as possible. I did the accessible bath last year and they put the lift in this past spring. The accessible entrance I am working on was supposed to be done this past summer but the town declared the building "Historic" so we than had to go to many historical meetings and planing board meetings before we finally got the permit.
Thanks again for all you effort.

BTW - I was at a Katz Roadshow earlier today. I presented this question to as many people as I could, including Mike Sloggert who was one of the presenters. 50 - 50 on over or under the clapboard / behind the al. All had their own reasons. All professional carpenters.

Bill T