Princesses, Pirates, and Perfectionists – How to Replace Sheetrock Window Returns with Traditional Trim

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finished after shot

Have you ever done something with your house that you thought was going to look really great, but turned out to be a total dud? I have.
About three weeks after moving into our new house two and a half years ago, my wife and I were already sick of the sheetrock returns around all of the windows. For some reason, when the house was being built, we picked them because we thought they looked slick and modern or something like that. But after looking at them for less than 30 days we just decided they looked, well, cold and boring. So trimming out these windows went on to our list of future home improvement projects. Unfortunately, the project never had enough priority to get done.
Fast forward a couple of years. A new baby is on the way and the guest room needs to be turned into a nursery pronto. This is going to be our first and perhaps only girl, so she will definitely be our little princess. And a princess deserves a nursery devoid of unsightly sheetrock returns! Time to get to work. Read on for a window trim idea to spruce up boring sheetrock returns.

before trim
A before photo from a different room, but you get the idea – boring!

Before going ahead with making this window look good, the ugly had to be banished first. And that meant ripping out the sheetrock around the window in a finished room. Look, I love DIY and home improvement projects, but I hate drywall dust. And I’m definitely not fond of hearing my better half say “Arggh! This white dust is everywhere!” (That’s right, I married a pirate. And a particularly clean one at that.) Not wanting to be forced to walk the plank, I proceeded carefully with sheetrock removal. This goes much better when you remove the sheetrock in as large of pieces as possible and throw them into a bucket or trash can immediately. It’s also a good idea to vacuum up the smaller chunks as you go so they don’t get stepped on and ground into finer particles.

Removal was pretty straightforward. I used a flat bar and a hammer to break the corner bead loose, and carefully pried it off with a screwdriver and my bare hands. Next I got in behind the sheetrock with the flat bar and pried it off. Pretty easy so far.

removing corner bead
A flat bar and a hammer worked great for carefully popping the corner bead loose

Prep Work – Warning: Math Ahead!

Our house is a two-story with a traditional layout, so we wanted to trim the windows out in a way that fit with the feel of the house. We decided on a trim design with a pronounced lower ledge that extended out beyond the wall with mitered casing around the top and sides and an additional piece of casing underneath the ledge to finish it off.

Before ever getting started, I measured from the inside of the window frame to the finished surface of the wall. In this case, the distance was exactly 5-1/2” inches so I could use 1×6 boards for the top and sides of the extension jamb, and a 1×8 for the lower ledge.
The whole job was slightly complicated by the fact that custom blinds were already installed in every window of our house. I refused to buy them again so I knew that the extension jamb had to fit in the existing rough opening and allow the blinds to operate freely inside it. I measured the width of the blinds and added 1-3/4” to get the extension jamb outer width (+1/4” of “wiggle room” for the blinds, and +1-1/2” for the two 1×6’s that made up the sides of the extension jamb). Luckily, this dimension was less than the width of the rough opening, but not by much.

In a Jamb

I could have chosen to piece the extension jamb and lower ledge together in the window opening. Instead, I decided to build the entire jamb/lower ledge assembly out in the garage then install it in the opening in one piece. This made it easier to keep everything square and level during the installation process.

The first part of this process was making the piece for the lower ledge. I cut the 1×8 board 5” longer than the extension jamb width calculated above to allow it to wrap around the surface of the wall by 2-1/2” on each side. Then I routed a 1/8” radius on the top and bottom edge of the front and sides of the board. I finished it up by notching a 2-1/2” by 5-1/2” section out of the ends of this piece with a jig saw.

Lower ledge routed and notched

To calculate the length of the side pieces, I measured the height of the rough opening and subtracted 2”. This would give about ¼” on the top and bottom to play with when I installed the extension jamb assembly. I planned to fasten the assembly together with pocket holes and screws, so out came my trusty Kreg jig to drill two holes on each end of the side pieces.

kreg pocket hole jig
This Kreg Jig is the best money I have ever spent on a tool. Period.

After cutting the top piece, all four pieces were screwed together for a dry test fit.

test fit
All ready for a test fit

Will it fit?

At this point, I’m going to be honest; I was getting a little nervous about whether this whole thing would fit in the rough opening. Because I had to fit the jamb to the existing window blinds, I knew it was going to be tight. I had taken quite a few measurements, and checked the squareness of the opening in every way possible. I even test fit the top and bottom pieces to be sure that the ever-critical width was correct. But still, I couldn’t be sure it would fit until I put it in place.

So I held my breath and carried it upstairs. And… It didn’t fit. At least not at first. So I attacked it from a slightly different angle and it slid right into place (with the persuasion of a few well-placed palm-smacks). Success!

test fit
It fits!

Rollin’, Rollin’, Rollin’

Once I was satisfied that everything fit in the opening and that there was room to get the jamb leveled and square it was time to break the whole assembly down for paint. Painting the pieces when they are apart is much easier than painting the entire assembly. For one thing, you can use a foam roller, which prevents brush marks and results in a slightly “orange-peeled” but very consistent final finish. Secondly, the pieces can be laid horizontally so there are no nasty runs that show up just when you think everything is perfect.

If I were building several of these extension jambs, I would put all of them together and spray each of the assemblies with an airless sprayer. But in this case, the hassle of setting up and cleaning the sprayer outweighed the benefit of a super speedy paint application. I rolled on two coats of primer followed by a quick sanding with 400 grit paper to knock down any roughness and/or high spots and then applied two coats of semi-gloss white. Once the paint dried, the jambs were reassembled for the final time with wood glue.

pieces painted
Feel free to be in awe of the fancy tilty effect on this picture

Level? Check
Level? Check
After “gently” coaxing the jamb into place with a few blows from my manly bear-paw-like hands (ha!), it was time to get to work leveling and squaring the jamb assembly. Starting with the bottom ledge of the jamb, I shimmed up one side until it was nice and level. I wish I could say that was the end of that, but it wasn’t. Next, I measured diagonally from the lower left corner to the upper right corner and made a mental note of that measurement. Finally I measured from the lower right corner to the upper left corner. I hoped this diagonal measurement would be the same as the other one, because that would mean that the jamb was square. Of course, it wasn’t, so I added a shim in the upper right corner to push it a little to the left. This shortened up the distance between the upper right and lower left, and brought the whole assembly into square.

Square? Check
Square? Check
Once I was satisfied that everything was level and square, it was time to break out the finish nailer and make everything permanent. I first nailed in the locations where the shims had been placed to keep them from moving around. Next, I added a few more nails across the bottom, sides, and top of the jamb. If there was a gap between the jamb and framing, a shim was slid into place to make sure that the force of the nailer would not “bow” the jamb. Later on, these shims were scored with a utility knife and snapped off so that they wouldn’t interfere with installing the casing.

Cue the Perfectionist

With the jamb securely in place, it was time to move on to my favorite part: installing the casing. I love this part, because this is where the project starts to look like it is complete. Some people hate this part of the process. I get it – it can be a little tedious. But it’s the perfect task for us anal-retentive detail freaks. (Proving my tendency toward this behavior, I just Googled “anal-retentive definition” to make sure I was using it correctly. And yes, it is hyphenated.)

Anyway, when it comes to installing trim I try to use the tape measure as little as possible. I swear that thing changes length on me from the time I take a measurement to the time I mark my cut. As much as possible, I like to transfer cut marks directly from the jamb to the trim piece. To do this, I started by marking a 3/16” reveal at the corners with a speed square. I also added a couple more marks down the side and across the top to make sure that the reveal was consistent along the length of the jamb.

Hold the square in position like so
reveal marked
and make intersecting lines at the corners

Next, I held a piece of casing in place and transferred the marks on the extension jamb to the casing. I also added a quick chicken scratch as a visual reminder of the general angle of the cut. The same process was repeated for the sides.

trim marking tip
No tape measure? No problem – marking trim in place is more accurate

After cutting the casing on the miter saw, it was time for installation with the brad nailer. I started with the side pieces, nailing at the bottom first then adding a few more nails (both into the jamb and the wall) until I was approximately halfway up the casing. The upper half was left loose so that it could be aligned with the top piece. Once it was in place, everything was fully nailed to the extension jamb only.

You may have noticed in some of the earlier pictures that the jamb stuck out beyond the wall, especially in the top corner. If I would have nailed the casing directly to the wall in this corner, it would have pried the top and side pieces of casing away from each other, opening up a nasty gap. To remedy this, I slid a shim in behind the joint to provide support and keep the miter joint nice and tight. I also glued the faces of the joint together. This prevents the normal expansion and contraction of the wood from splitting the joint and revealing an ugly looking crack. Once the glue was dry, I removed the shim and cut it so that it would be hidden behind the trim. Finally, I drove nails through the casing and shim into the wall.

casing shimmed
Shims: the perfectionist’s best friend

Finishing off the bottom was much easier. I simply measured the outside edges of the previously installed casing, and cut a piece to the same length with a 45 degree miter on the ends. Then I cut a smaller piece of casing (mitered in the opposite direction) and glued it to the end of the long piece to create a nice return. Four or five brad nails held it to the wall, butted up tightly against the bottom of the lower ledge.

casing return
Creating a return is key to a pro-looking job
lower casing
Lower casing in place

Wrap Up

Well, that’s pretty much it. All that’s really left is to fill the nail holes, caulk the seams, and do some touch up painting. That will come when we paint the walls. (Do you think a shade of pink might be involved?) Right now, the next item on the agenda in the nursery is crown moulding. How about you? Have you ever had to re-do something in your house because you made a bad choice? Tell us about it in the comments section below.

finished after shot
The finished product – fit for a princess!

Guest Author Bio

charlie-guest-headshotCharlie Young didn’t REALLY marry a pirate, but his two boys have watched Peter Pan about 500,000 times. Maybe that’s why he hums “You Can Fly” while he DIY’s. When he is not busy at his day job as an engineer (read: anal-retentive perfectionist), raising a family, or visiting a home improvement store just to enjoy the smell, he is probably working on his website, Chips and Dust, where he discusses tools and home improvement.

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8 thoughts on “Princesses, Pirates, and Perfectionists – How to Replace Sheetrock Window Returns with Traditional Trim”

  1. You just created jamb extensions. I’m not sure I would have built the stool and sill into it, but the pocket screws were just the right idea to do it.

  2. If you removed 1/2″ thick drywall returns and replaced them with 3/4′ thick wood jambs, how did your interior dimension remain the same for your blinds to fit as before? Seems to me you would have lost 1/2″ and your blinds would not have fit.

  3. Great Job…….But forget the DIY…you should quit your day job and be a writer….very well written–and entertaining. Thanks.

  4. Well done, but truth be told, the lazy man in me would’ve done the sill (apron and stool, if you wanna be all techno about it), smacked 3 bits of trim around the side and called it a day. FWIW, paint grade returns can be readily faked by a slightly angled cut on the miter saw and a minute of work with a round rasp and a utility knife.

    On a slightly serious note, if I went to the trouble of building the entire unit, I would’ve made the width of the boards fit the smallest depth of the opening, so no nasty sticking out beyond the drywall. The other corners could be held out flush (and caulked between the window and the jamb) or the drywall could be gently persuaded with a hammer to sit closer to the plane of the jamb.

    • I’m intersted in what you mean by the faked paint grade returns with miter, rasp etc? I’m contemplating which route to go with this (rebuild or trim right over the top).


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