Preparing , preparing , you're always preparing . OZ-T's "Just build the damn shop already build ".

WRB is the weather resistant barrier , ie the housewrap

the primary flashing over the window needs to be continuous with the housewrap layer by our code but in my case there is 2" of Comfortboard external insulation between the housewrap and the face of the window where the flashing is so to make a continuous connection from the housewrap to the flashing , when I installed the Comfortboard I applied a wide foil flashing tape just above where the flashing would eventually go , cut the Comfortboard below the tape at 10 degrees and extended the tape out beyond the exterior face of the Comfortboard by about 3" , leaving the lower portion of the split release paper that comes on the back of the foil tape intact .

Now that I have installed the flashing over the window , I pulled the release paper off the exposed part of the tape and stuck it down to the wall leg of the window flashing

In a side cut away you would see the foil tape going from the housewrap , sloping 10 degrees to the exterior (where it goes through the Comfortboard) and coming down over the top of the wall leg of the window flashing so that any water that made its way back to my WRB (housewrap) would drain down , out through the Comfortboard plane by way of the sloped foil tape extension , and on to the flashing above the window

 

WRB is weather resistant barrier ie the housewrap , sorry should have explained the building envelope speak

 

Like this ~

you have to imagine there is housewrap (WRB) on the plywood , I didn't have any scraps laying around

 

Ok. This makes sense. I think my 2 little brain cells didn't put together that there was Comfortboard behind the window flashing.

 

Test fitting the bathroom window to make sure all my trim math is correct (I measure the actual window and add offsets to cut and assemble my exterior trims as units)

I have an old adage , "lets cut and try one before we cut them all wrong" , so this tiny window is my guinea pig . Couple minor tweaks and I can use my numbers to cut the rest of the window trims

 

We call them "mock ups" down here in the states. Smartest way to do it.

 

this is what the head flashings over the windows look like , 13/16" tall end dams folded on the end so water can't travel sideways off the ends and behind the siding

 

And this will be outside of the Comfortboard and over the window trim?

 

Outside the Comfortboard , directly over the window , behind the trim

This is the primary flashing , it is a component of the continuous WRB (housewrap) layer . The rainscreen is outboard of this flashing plane and drains onto this flashing and outboard

There will be a second flashing over the trim above the window that is in front of the rainscreen and is just protecting the siding layer , it does not need to extend back to the WRB

 

That is so much different than I am used to seeing. The primary flashing is usually the only flashing installed down here.

I should post a photo sometime of the particle board window trim on my house and the lack of flashing.

 

we've had a code requirement for a 10mm rainscreen capillary break behind the siding here in BC for about 15 years which changes the way you approach all this stuff

 

10mm thick?!

 

yes , basically 3/8"

 

That's pretty good. We're lucky if we get a 4mil sheet of plastic as the WRB.

 

here there is a code requirement for 3/8" capillary break as well a WRB , and an air and a vapour barrier , typically the air and vapour barrier are 6 mil poly on the interior surface but you can actually satisfy the code with some separate air barrier and vapour barrier solutions like an exterior air barrier of vapour permeable peel and stick with an interior vapour barrier paint etc

 

I'm trimming out these 6 windows as a set , wrapping the corner with the head and sill trims

I'm going to do some kind of feature panel in the corner , not entirely pinned down what yet




This is the nice thing about milling a couple trims from the same board , you can grain wrap the corner

Test fit , no glue yet

 

Do any carving as a hobby? You could do that on that corner.

 

not yet

 

The front of my building faces south and its been really sunny and hot (hot for here) for about a week now so I've been doing mornings on the front side and moving to the back stuff as the sun gets on the front

This morning's project was to measure , cut , assemble and test fit the front window trim

Trim set assembled inside ~




Test fit in place ~




I took this pic as a further explanation to the discussion earlier about the relationship between the primary flashing and the rainscreen cavity

Trim is overlaying the Home Slicker plastic rainscreen matrix , allowing any water that gets behind the siding to drain behind the siding , behind the trim , and exit through the gap I am pointing out with my knife and drain outboard of the window




After test fitting this trim set , I brought it back in to the shop to get coated with Sunfast , I will coat all the trims at once when they are all built and test fitted

 

Beauty wood to work with. How often will you need to re apply the Sunfast?