Filling / sealing a gap against siding

[JHZR2]

This relates to my butyl caulk thread. We replaced a through-wall AC system in our home. The hole was already there, and the cases are roughly standard but not quite. I think the older unit was slightly shorter but wider.

Anyway, wanted to show the picture of the gap so all suggestions can come forth. How would you seal this? Would I need to fabricate a metal channel to fill/fit this well? The old unit was just perfectly sealed tight.

The gap is between 1/2 and 1", except at the bottom, where the gap gets wider... Though that's more of a critter than a water ingress issue...

The old caulking material, which was really flexible and somewhat soft looks like this:

Thanks!!

 

[pcoxe]

Precut and paint a strip of wood that closely fills the gap, caulk both sides and push it in. The siding won't look so ragged if it butts against a square edge.

 

[JHZR2]

Interesting - wood filler for the hole...

So the caulk adheres it to the AC cabinet and then on the other side just seals the crack?

Last time the nice caulking that was on there hid the siding cuts and it looked really well-finished. Very smooth, straight caulking lines.

 

[LeakySeals]

Heres the way it should be done:

There should be no unsightly putty or adhesive touching or showing on the vinyl siding. Vinyl siding expands and contracts, leaving a gap that allows water to penetrate and get into your wood siding. What should be around the AC at the Vinyl siding level is J-channel only. Insulation/caulking of the AC should be between the AC and the wood.

So..

Take some of the the Vinyl off. Unpops from the bottom, a couple of fastening nails.

Install an expanding insulator foam followed by that putty, or flex seal as on TV (mask off to prevent overspray) Into the crack between the AC and the wood sheathing of the house.

You should have a vapor barrier with that siding. add some as close to the AC as possible on the wood sheathing of the house.

Install J-channel vinyl edge around the AC, cutting and trimming to fit. Over the top of the vapor barrier. The Top J-Channel should overlap the sides to channel away rain.

Re-install the vinyl siding. Now the siding can move, and has the J-channel for any water.

look at the rest of the house for examples of the overlap, and lack of caulking at the joints.

Have a look at J-channel. Click on the "Trim" tab.
http://www.bestbuymetalroofing.com/mitten-vinyl-siding.html

 

[LeakySeals]

Flashing works too. Look at your window. But I prefer the J-channel on the top of the AC because unlike the window, you really don't want water running down the siding, then rolling over the top of the AC. Better to channel it off to the sides. Hope this all makes sense.

 

[LeakySeals]

Sometimes pictures are better than descriptions. Just took a pick of my wall AC, check it out.

This is on the bottom of all vinyl - drains. Why its not that critical that everything's sealed.

 

[LeakySeals]

Gasp. Its not vinyl. Done so many vinyl repairs recently that's all I see.

Different set of repairs, but the same idea. Box it in like a window.

 

[JHZR2]

thanks! So I can just get aluminum like that, do four mitre cuts to get the angle, and then just attach it?

And does that channel just nail to the material under the siding, then the siding just snaps back into place? Or how does the channel attach to the house?

Thanks very much!

 

[LeakySeals]

This picture is for a window, but the same would apply for the AC. The oval holes are where nails would go into the plywood/wood sheathing behind the siding. Then the siding would go back on, all you would see is the trim edge.

Hook that pops off the siding
http://www.acetogo.com/product/siding-removal-tool.html

But...Need to know what kind of siding this is. Its hard to tell from the pic. At first it looked like may be a vinyl or aluminum, now I'm wondering if its a solid material. If you look at my pic of the drain hole, there is a gap between clapboards. The gap means each panel is hooked in, the hook tool pops it out. On yours its flush. No room for a hook, so I'm leaning to traditional siding. You don't want to be taking that down unnecessarily, maybe thats why the PO just threw putty in there.

If it is solid traditional there are still other options to pretty that up at least. One option is box it in like a window, but that would require cutting the siding back. Another is trim the J-channel removing the nailing surface. Then slide the J-channel into that crack. White calk between the AC and the j-channel like my pic will keep it in place. Same on the clapboard side. Then the putty and whatever else is buried underneath from sight.

As far as vinyl or aluminum, not sure you can find aluminum anymore. If you can its a fortune. Vinyl is cheap, easy to cut, works good on small projects like this.

 

[JHZR2]

It is 8" aluminum siding. It is still available, though I have no idea if the trim and channels are...

I hate the thought of popping off siding from 40+ years ago that is all straight and looks really good. scary...

Did it on the back of my house, but that was because I had to replace a few pieces.

Ive read that J channel isnt good to use on the top of stuff because it holds water in the channel...

Instead, flashing should be used as a watershed to direct water down and away...

 

[LeakySeals]

In the pictures above they are giving an example of using j-channel for the wrong application. In those pictures, the j-channel is underneath the siding blocking the drains as shown in my drain closeup pic. No No!. In the application we are talking about, the j-channel sticks out like a gutter. See post #2714029 (siding removed) and #2713462 (with siding put back on). J-channel has built in flashing. Installed correctly water backup is no issue. Its a redirection like a gutter would do. An AC is not like a window, it protrudes. So with just flashing your rolling water over the AC and off near the exhaust vent and recirculator like a waterfall.

Both are ok. You can always swap it out later.

 

[LeakySeals]

Ahhh I see..they are trying to sell their own product..and somewhat misrepresenting other methods. Showing an incorrect installation, suggesting they all do that. What they are selling is my other suggestion - cutting back the siding and installing flush trim with caulking and flashing. But that doesn't solve water running over the AC.

How about this...

Flashing on top like a hood that covers the ends of the j-channel. Then J-channel around the sides and bottom calked in white to the AC. Will pretty things up. Best of both. Take your chances that the water rolling over the AC wont end up inside the unit.

 

[JHZR2]

All good info, thanks so much! Too bad youre too far north, would love to hire your expertise to do this as you really know your stuff.

Thanks again!

 

[JHZR2]

Another question that is likely stupid...

The gap is big, like 1/2". The. J channel is caulked up tight against the ac. This means that there still is a gab between the end of the siding and the inside "bottom" of the J.

Does this matter? I get it that the j channel slides inside the siding so it kind of self-flashes, but if that space between the siding edge and the bottom of the j is too big, then there isn't enough overlap. Can this be an issue?

Thanks again!

 

[LeakySeals]

Originally Posted By: JHZR2
Another question that is likely stupid...

The gap is big, like 1/2". The. J channel is caulked up tight against the ac. This means that there still is a gab between the end of the siding and the inside "bottom" of the J.

Does this matter? I get it that the j channel slides inside the siding so it kind of self-flashes, but if that space between the siding edge and the bottom of the j is too big, then there isn't enough overlap. Can this be an issue?

Thanks again!

Hard to say without looking. I don't see any drain holes in the bottom of your siding, so..Thanks to the j-channel you can slip some white external caulking in the gap and its hidden from view. Because the j-channel has a lip its hard to apply directly to the gap. No problem if you can't, just use a drywall knife for application. Squeeze some caulk on the end of the knife, scrape it off into the gap. Rub your finger along gap to smooth caulking up. Wipe with water before it hardens..Done.

 

[JHZR2]

Ok, so use the J channel to cut the gap into maybe 1/4" between the AC container and the J channel, and then 1/4" between the siding edge and the bottom of the J channel? Then just caulk to fill the backside gap?

No caulk in the J channel itself where the siding inserts into, right?

Thanks again!

 

[doitmyself]

I'm curious how you are going to address the bottom corners?

Aluminum and vinyl siding expand and contract quite a bit. Flashing/trim is supposed to be designed and installed so that it diverts water without caulk.

What are you planning to do with the J Channel at the bottom corners to keep water that is running down the J Channel from leaking behind the siding below....and then who knows where.


Also, I would have that unit tilting down 2% or more so the large top area will drain away from the house naturally.

 

[LeakySeals]

Originally Posted By: JHZR2
Ok, so use the J channel to cut the gap into maybe 1/4" between the AC container and the J channel, and then 1/4" between the siding edge and the bottom of the J channel? Then just caulk to fill the backside gap?

No caulk in the J channel itself where the siding inserts into, right?

Thanks again!

I don't see drains on your siding, so I was thinking both sides of the j-channel on the sides and bottom. Standard caulking gun between the AC and the j-channel, use the knife to spread caulking between the siding and the j-channel. On top its flashing like a hood with wings that cover the top of the j-channel. That will protect everything and look good too.

You may be able to bend and slide the flashing and j-channel behind the siding without removal. Because your caulking it, that will be what holds it in place.

 

[JHZR2]

There are drains in the siding - verified that.

1/2" aluminum j channel doesn't fit well with my siding, it bows out at the point where the siding cuts back horizontal. I'm going to find something wider. Maybe f channel with the long side against the ac on the sides.

The other problem is that the gap is too wide for the J to span!!

The bottoms are a concern. But there is a whole open area underneath that I'm worried about enclosing. That I'll likely fill with wood and then flash. What I found was that the underside of the unit gets cold and condenses, and I don't want that in the wall.

 

[JHZR2]

Originally Posted By: LeakySeals

I'm assuming at the bottom edge, the j us caulked so water doesn't go behind the siding/?