I just ordered two new all wood Jeld-Wen windows to replace some 90 year old double hungs at my house in Oregon. The sills and frames were totally shot, so I needed all new instead of the easier option of sash replacement in this case. The new windows will have an applied brickmolding measured to match the old opening which butts right against ceramic asbestos siding. I don’t want to disturb the siding if possible so my question is what is the best way to flash and weather seal the new window with minimal disruption to the siding? The siding is the original T&G fir lap siding with a layer of tar paper and then ceramic shingles on top of that. There are no flashings for any of the old windows now, just caulk at the top. Are there any suitable flashing/sealing solutions that will make the new window installation tight and rain proof? Any particular installation mistakes to watch out for in this scenario?
Thanks for the help!
Replies
Why not remove the old window and slide a drip flasing up behind the siding. Caulk the siding edge at the sides both before and after the window is in place.
Sounds good...should I try to install a sill pan as well or is that unnecessary in a retrofit install?Thanks for the tips...
Well, a sill pan is always a good idea. There are a number of factors that have contributed to their necessity now. Some of them being window construction, insulation and changes in building materials and methods. If you can get one in, it would be a good idea.
You can make "sill pans" using vycor or strips of ice and water shield. If there's enough room in the rough opening, tack a strip of beveled siding on the rough sill first (pitched toward the outside of course), then wrap the bottom and about six inches up the sides of the rough opening with membrane. Bring the membrane a few inches out and stick it to the sheathing.
I saw something neat today. I was removing brick mold on ~30 yr old Andersen casements. The backside of the brick mold on the vertical sides had a 3/8" wide by about 3/16" deep groove plowed into it with a rubber gasket fastened into it. This was nailed snug to the sheathing with vertical siding butted up tight to the brick mold. The top had a piece of aluminum drip cap but no gasket on the backside.
In your case, I'd try to trim out the original wood siding so you can set the brick mold snug to the sheathing, preferably with a thick bead of either silicone or polyurethane sealant between the molding and the sheathing. Caulking to the asbestos siding along the outside edge of the molding is temporary at best. Definitely slip some aluminum drip cap on the top.