Sloping or not sloping window base plate?
robbyve
| Posted in Construction Techniques on
Hello guys, I read about so many different ways to frame a rough window opening, and I wonder which suggestions you might have.
Somebody likes to slope the base plate, and somebody else says that it’s not necessary. What are your thoughts or ways to do it? I appreciate any suggestions. Thanks.
Replies
Have never seen nor done a slope in the framing.
Sill pan, yes.
Thank you Calvin!
I was brief before.
I have laid a pc of beveled siding along that sill rough frame. Just enough slope for the homemade sill pan.
Thank you Calvin, Sounds good to me.
The decision to opt for a sloping or non-sloping window base plate hinges on your design and aesthetics. A sloping base plate can impart a contemporary, streamlined appearance while facilitating water drainage. Conversely, a non-sloping base plate retains a more classic look. To make the right choice for your project, take into account your architectural style, local climate conditions, and overall design objectives.
It's the slope that's important- it helps any intrusive water get back out again- but it doesn't matter how you create it. You can add a piece of bevel siding like calvin, you can angle the top of the cripples and install the sill at an angle or you can bevel the sill itself with a belt sander or a grinder.
If you're a finish carpenter by nature, you can run the sill through a jointer. If you have a table saw on site while you're framing, you can rip the sill at an angle. Some people create a dam on the interior side of the sill, which I disapprove of- the water won't get inside, but it may just sit there, allowing mold under the window.. I don't use the bevel siding method because how many sites have bevel siding readily available these days?
It doesn't matter how you achieve the slope- just make sure it happens. Then make sure you create a water-tight sill pan so the water has to drain out. And don't nail or caulk or tape the bottom of the window, so the water has a path to the exterior. I just came across an interesting video from Josh Salinger, Birdsmouth Construction on Portland, OR, a notoriously rainy environment.
https://www.finehomebuilding.com/2021/08/24/adu-rainscreen-and-window-integration
Bobbomax, thank you! I appreciated it!