# Replace window drip cap (z flashing) on wooden siding



## alwaysw (Oct 10, 2017)

Hello,

The back wall of my house is wooden shiplap siding, and currently, the drip caps over the four windows and door are rusting. Some spots are worse than others, but they should all be replaced before we repaint. I am unclear on how to replace these drip caps because the top edges of the old ones do not appear to be covered in any way. If anything, the old z flashing is tucked under the siding boards slightly, but that's about it. Please see the photos I've attached.

I understand this may seem pretty straightforward, but I am looking on guidance on how this repair should be done properly. What types of adhesive should be used? Should the top edges of the new z flashing be nailed down? How should the old flashing be removed to not damage the siding? If the siding is accidentally damaged, what should be used to patch/repair it?

Thanks for any advice.


----------



## joecaption (Nov 30, 2011)

Why not just wire brush the rust, prime and repaint?
Most likely the siding will be damaged trying to remove the flashing and to replace it would you would need a brake to custom bend the replacement flashing.


----------



## alwaysw (Oct 10, 2017)

Unfortunately, a few small spots above the upper windows and door are rusted through. We live by the ocean.


----------



## Daniel Holzman (Mar 10, 2009)

Window Z flashing is typically about 6 inches wide, which generally allows at least three inches to be under the siding which is above the window. If you choose to replace the existing Z flashing, you should remove the old Z flashing, and make your own Z flashing using aluminum (low cost) or copper (higher cost, looks nice).

I installed 8 ounce copper flashing over my new windows, same over a French door I installed. You can make your own brake using a simple ripped 2x4 so you have a sharp edge to bend the copper or aluminum. You need tin snips to cut the ends so you can bend the edges. If you use copper, you solder the edges to stop leakage. Not too difficult, you might want to look up a U tube video on how to make Z flashing. 

As long as the flashing is six inches wide or so, you will have plenty of width to insert the flashing under the first row of siding above the window, and still cover the window. Simplest way to install flashing is to remove the first row of siding above the window, pull the nails carefully and you can reuse the siding. You can use silicone when you insert the flashing, or you can put a piece of ice and water shield or similar mastic tape over the flashing before you nail the siding back in place. You will need a few nails to hold the flashing, make sure you use compatible nails (i.e. copper nails for copper flashing). I would use stainless steel nails to reinstall the siding to prevent galvanic reaction with the flashing.


----------



## joecaption (Nov 30, 2011)

Copper would be my last choice for this one.
It would stick out like a sore thumb, will not hold paint well, and very expensive.
Unless there's holes in it, why replace it?


----------



## alwaysw (Oct 10, 2017)

Thanks for the feedback so far. I've attached two more images that show the problem areas better. When I had painters visit to estimate, they all agreed that the drip caps were due for replacement.

Daniel, while I like your suggestion of inserting the flashing underneath the siding, I'm afraid it might open up cans of worms. If you look at the last photo I attached, the z flashing on this window doesn't even touch the siding board above it. It appears to have just been stuck on with some sealant gooped all around it. Surprisingly, the sealant has outlasted the metal, and I'm not ashamed to say that I might just go ahead and do the same. After all, the old work you see there has lasted nearly 20 years in our climate.

The question now is, if I were to pull off those old pieces of flashing stuck under two mils of sealant, how should I go about doing so without damaging anything?


----------



## XSleeper (Sep 23, 2007)

Copper is probably the BEST choice since this is near salt water.. followed by a two part metal primer, then paint.

Needless to say, I think you will need to rent a metal brake or have someone bend this flashing for you. As Daniel mentioned, you want about 3" of it to be covered by the siding above... but if that siding is tongue and groove, and if that trim has been applied on TOP of the siding, I see the problem.

Normally the trim is installed on top of the sheathing and the siding is cut around it. I can't tell for sure what they did there, but it looks like they put the trim on top of the siding, leading to the goofy way the flashing is only 3/4 deep, and doesn't go behind far, if at all. 

:vs_mad:


----------



## joecaption (Nov 30, 2011)

To remove it I'd be cutting the paint and caulking line with my oscillating saw laying flat, If they used small headed nails to hold it in place I'd be using a nail punch to drive them in instead of trying to pry them out, then using a molding bar to pry it off.


----------



## alwaysw (Oct 10, 2017)

Ah, oscillating tool. So that's what they're for.

Just now, I took the liberty to look at my neighbors' houses and they are all the same as mine. In this image, you can even see the flat head nails underneath the layer of sealant. I guess this is partly the reason why half of the houses around here have upgraded to fiber cement shingle siding.


----------



## Nealtw (Jun 22, 2017)

If what you have has worked till now. Doing the same again might make sense. You could do a cut in the siding so the top of the flashing enters the siding a little.


----------



## joecaption (Nov 30, 2011)

An oscillating saw is one of the most useful tools I own, I have 3 of them.
It will do jobs no other tool can do.


----------



## RRH (Nov 24, 2016)

Ok, so if removing siding out of question.
If dont have one rent a brake for half a day.
Get a roll of Aluminum trim coil.

Try and take off old. If to hard or damage to siding. Just go over the old. Adhesive caulk like Quad brand from the box store. Coat the old rust areas good. Couple of stainless trim nails on the highest part.

But make then all like the second pic. Siding should over hang top edge of flashing. So some will need to go up to next course of siding. All will not be the same. Why best to have a brake on site. Bead of caulk at top edge of flashing under edge of siding.
This should last as long as the siding will. 

Or pay a siding guy to just come by and bend them up for you to install.
Should take him less than 10 minutes a window.


----------

