Does a rim header affect the need for an additional separate header above a window and door, and must it be the same size without a rim header present for a first-floor bathroom renovation?
Asked by Maria Smith 
3 months ago
Last Updated: October 4, 2024
I’m currently working on replacing a window and sliding glass door, and I’ve heard that a specific size header is usually required for this type of project. I’m wondering how having a rim header already in place would affect this – do I still need an additional header above the window and door, and does it need to be the same size as if there wasn’t a rim header already there? The first floor is above, and the floor joists connect to the rim header along the external wall (with a plumber’s box planned above the powder room for the upstairs bathroom toilet waste pipe). Thanks in advance for any insight!
Are you only replacing the current window/door? Are you worried that they weren’t framed correctly during the initial installation?
I’m replacing both. The new window is a bit larger than the old one. I’m a bit puzzled about the sliding door though, since it was framed differently originally. My question is whether we still need a traditional header because there wasn’t one above the sliding door before.
There used to be a traditional header above the original window (which was located beneath the header joist), and I’ve restored it. The picture below shows the original window arrangement.
That’s a good question. It might be worth consulting a structural engineer. Best of luck!
Can’t quite make out the header in the picture. Typically, if replacing like for like (size), you shouldn’t need to make any changes. However, that rim joist/’header’ might need to be at least doubled in size. Not sure how you’d fit a second one in there if you needed to double up, but there’s usually a way to make it work.
Here’s a clearer photo of the rim joist already in place. I’ve also installed a triple 2×8 and a top plate (I think this should ideally go on top of the 2x8s…), but there’s no space for an additional (double) top plate (even after lowering the step as shown in the picture below). That’s why, considering the existing rim joist, I’m questioning if it can support the weight above the sliding door.
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The current single rim joist measures 2×10.