Step 21b – Install Rim Joist and Corner Trim

With the window trim completed, it was time to move on to the corner trim. I purchased two different sizes so that I could attach them together at a right angle but still have both sides extend the same distance from the corner. With two pieces of the same size, the one that runs past the other to form the corner would be shorter. I used Gorilla glue and 6 different clamps to hold the two pieces together as the glue dried.

After 24 hours had passed, I beveled the ends and painted the cut parts. The beveled edge will ensure that no water pools where the two sections of vertical corner trim meet. Anytime you can, you want to avoid having any horizontal surfaces because it gives water a chance to pool.

I used the same stainless steel trim screws as I used on the window trim to attach the corner trim to the furring strips. The last pieces to go on were the rim joist trim, which are simply there to add a little spice to the siding, which would otherwise extend uninterrupted from the bottom of the house up to the top.

I screwed some scrap wood to the furring strips to act as an extra pair of hands for me, as the 12 foot long trim pieces were too heavy to hold and screw at the same time. Just like the windows, the rim joist trim must be crowned with a drip cap to prevent water from collecting on the horizontal top surface.

Although it isn’t necessary, I decided at the last minute before applying siding to use trim boxes for the exterior lights. The lights are often attached directly to the siding but the trim boxes give it a nice look and more importantly, do a better job of ensuring proper water drainage.

First, I used a QuickFlash electrical flashing to fill the gap between the water barrier and siding, and then I screwed a SturdiMount flashing to the furring strips. The SturdiMount comes with a built in drip cap and looks really sharp, and both flashings together are under $15.

2 Comments on “Step 21b – Install Rim Joist and Corner Trim

    • They are very popular. Called Sturdimount. Its actually fiber cement so built to last. I’m really happy with them. Used one on every single exterior penetration except the vents which are pretty well covered by overhangs.

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