Window flashing, brickmould, and J chan.
I’m curious as to the proper way to flash and/or seal around windows that have wood brickmoulding, without covering the molding in metal, when installing vinyl siding. I’m seen a lot of houses with just J-channel around them- and I know this can’t be right. With new windows and fins, I would just put flashing around them, overlapping the fins, and then overlapping the very top of the first full piece of siding below the window. But with brickmould, no fins, but I still am sure you should flash. Drip channel on top I get, but on the sides?. I’ve also heard j-channel should not be caulked to the brickmould, but seen that done too. If I were a sadist, I could rip the brickmold off, flash beneath, and put it back, but the back would still get rain behind it, and the wood prob rot. Breaked metal with a small lip up the sides? Caulk the J channel??
Any sources, ideas, or the correct method? And I know vinyl is evil, it is for older folks, and the house has aluminum which was storm damaged – low maintenance = happy for them!
Thanks . . .
Replies
As you may know, vinyl siding expands and contracts a lot. That's why the nails it hangs from "must not" be driven tight, or the siding will buckle. The j-channel hides the edge of the siding where it meets the brick molding. Otherwise, you would see the gap when the siding is contracted, such as on cooler days.
Yup, I understand that part of the J channel (I work with polymers :-) But I am at a loss (well, at least the "right" way to do it) on how to flash with brickmold and no fins, or fins covered up by brickmold . . . I know that vinyl siding isn't waterPROOF, so I know something is needed. . .
I hope someone can answer this question. Manufacturers instruction and the books/videos I have seen seem to gloss over this glaring water infiltration potential. I have started using a wide, sticky tape, forget the name, that is advertised for installation over the sheating, over the window flange if it has one, and under the J channel. This would provide some protection if folded up on the side of the brickmold where flange is not available. Even if you have flange nailed windows, it seems the water still can enter between the window and J channel. Once there, the water would seem to have a clear path to the sheeting, even with the tape I describe. What are we missing?
Drip cap ontop...right....and what I've done for yearssssssss is to use a good silicone next to the J channel up to the brick mold. HAsnt failed yet but if youre paronoid as I use to be until after more then a dozen years of zero failures is....you could bend on your brake a sort of Z bend that goes behind (siliconed to the sheathing or felt paper if you wanna get heavy....up alongside the brick mold and in front of the brickmold about a 1/4" )
Use white aluminum coil on white channel.yada yada yada...Kinda overkill IMHO but if it helps you sleep at night thats cool. Silicone the channel to the brickmold bro and be done with it cause it works really well.
Be well
Namaste'
Andy
It's not who's right, it's who's left ~ http://CLIFFORDRENOVATIONS.COM
I wouldn't so much worry about it but that some of the brickmold has already rotted out with the existing aluminum siding, and the siding subcontractor says no tyvek or felt is needed at all behind the siding (none there currently). I've thought about bending metal on the sides with a slight (1/8) lip over the brickmold, as you say. I'm more of an interior person when it comes to remodeling have done drywall and such, never done siding. I might go with the metal, or replace all the trim and get them to use the brickmold j-channel instead of the actual brickmold. I'm definitely going to demand felt or tyvek beneath the siding though!
If you are residing and have rotten brick mold, replace it. Use a strip of 30 lb. roofinf paper under the edge of the new brick mold as aflashing for the window. On windows that do not have rotted brick molding lift the outer edge of the molding and slide the paper beneath it. Details of this can be found in one of the issues of FHB, but I can't locate the issue number right off hand.
Around here when sidng a home with vinly or alluminum the general purpose is to make it it as maintenance free as possible. With that in mind, we take your brick mold side flashing idea one step farther. We break alum. to cover the brick mold completely, and all of the way to the outer parting strip of the window sash. Before these pieces of break metal are installed an L shaped flashing piece is installed agianst the side of the brick mold, and the break metal is installed over it. This creates a cover for the whole assembly, that if done properly creates a drainage plane behind the J mold and siding.
Your siding contractor should know this technique. It is common in the siding business. J chanel alone, butted next to the brick molding will not provide an adequate drainage plane. Caulking is not forever, no matter what the manufacturers say. It is a maintenance item.
Cover it all and you never have to paint the molding agian plus you solve the flashing problem.
Dave
Edited 6/14/2002 4:57:09 AM ET by DAVERICHESON
The aluminum brick mold flashing as stated above in standard here also. Still doesn't solve the theoritical problem, just moves it down the wall. Think about most flashing. It doesn't prevent water penitration but channels it back to the "outside". Even an aluminum flashed window doesn't move the rain water that has penetrated back to the outside of the wall, it simply doesn't allow the water to get to the window edges. I think the answer to this entire thread is aluminum flash, tyvec, felt or tape simply keeps most of the direct water off the wall. Not enough water enters past the J channel to continueally run down the wall causing problems. Otherwise, there would be many, many failed walls out there. I think I will build a test situation, try the different methods, and see how much water ends up down the wall. Maybe use a calibrated hose (5 gal bucket and stopwatch) and sprickler head.
A scientist I see! I would be eager to see the results. I am probably going to go with that flexible tape up the sides of the brickmold, a drip cap on top, and then cover it all over with felt. Still deciding on caulking the j-channel to the mold, seen it done and not done . . . shoulda just put in vinyl windows with the fake brickmold that serves as the j channel! In any event, I'll use the plastic brickmold to replace the wood where I can!
Be done with it already and use gorilla glue...lol
AndyIt's not who's right, it's who's left ~ http://CLIFFORDRENOVATIONS.COM
thatguy:
If the siding is already installed get a very good caulking that has fexability. If it it not yet installed use a vapor berrier between the siding and the sheathing.
Charlie