I have prepared my house to re-side. I have wrapped it with Typar, it had tar paper previously. I have installed all new windows but I am stuck now on what to do over the top of them...

I flashed the bottom of the window sills with flashing tape.
I chaulked the top and sides of the nailing flange and nailed in the windows.
I flashed over the sides of the nailing flange with flashing tape.

Now I am confused as to where to put my aluminum drip cap???

I am supposed to put flashing tape over the top of the window nailing flange, lap the flap on the Typar over that and tape the 2 side cuts on top of that... But where does the aluminum drip cap go in all this? Does it go under the flashing tape? Over the flashing tape and under the Typar flap? or over all that and then get taped to the Typar with Typar tape?

I am planning on putting LP SmartTrim around all of the windows and I see the aluminum drip caps on newer homes extending to cover the 2 side peices where it butts up. so I know this drip cap is supposed to be there but I just can't figure out which layer to put it under or over???

Does anyone know? I had thought that the best thing would be on top of the flashing tape under the Typar flap so that if any water gets on it and is driven back it couldn't penetrate the flashing but I don't know.


Also... does the Typar flap get taped down other than on the sides of the flap? To complete the air barrior?

 

New construction windows often come with a top flashing. If not, check with the manufacturer, or check a local lumberyard, NOT big box. The verticle flashing goes under any housewrap, then cover with your flashing tape, The edge should overhang the window edge, and slope to form a drip edge. Caulk under the flashing/window joint.

 

As an additional thought, since you are using LP SmartTrim around the window, I might suggest using the method that JustBill explained, but put the drip cap over the top of the LP SmartTrim. That way you won't have water getting behind the trim, wetting the unpainted back side.

When putting on LP, I always make the head piece full length, the sides fit under that, and either sit on top of a sill nose, or run long. If there is a bottom trim, it fits between the side pieces which extend beyond the bottom of the window.

 

So, put the drip cap on top of the smart trim instead of the window and then put flashing tape over the flange of the drip cap and the housewrap?

 

You slit the housewrap at the edges of the dripcap, fold it up and out of the way, tape the dripcap to the sheathing, then fold the housewrap back down and tape the slit.

If I was doing it, I'd put the dripcap over the trim instead of over the window. But if you have several units mulled together, there may be a leak potential where the units come together, and a drip cap over the window itself would be important. But if it's a single window, I think it would be okay to put it over the trim.

 

Thanks.

So when you fold the flap back over the drip cap, you tape the sides and then tape the slit. like tape the bottom of the flap to the top of the drip cap?? so the wrap would be taped to the aluminum?

 

Yes, cut the housewrap up about 1/2 from the top of the trim, then tape it if you are going for an air barrier. If not, I've heard some recommend skip taping that bottom edge (a piece here and there) so that any water behind the housewrap can get out over the drip cap.