Don’t Forget Your Apron – Window Casing, Sills, and More!

by Tim Layton on March 18, 2009 Google+

in Trim and Moldings

I’m a huge fan of nice trim work! One of the reasons I love it so much is that something relatively simple can finish off a job to look a million times better.

Take a look at this room and imagine how different it would look if it had simple “drywall returns” to the windows. The woodwork has a truly impressive impact on this room.


You Can Do This!

I’m telling you, this isn’t as hard as it looks! There really aren’t that many parts and it’s all just wood that’s going to be painted.

The part around the inside of the opening is called the “jamb” or “frame”, depending on who you ask. Whatever you call it, it’s usually just a piece of 1X4.

The part that creates the pretty “picture frame” effect is called the casing. You can buy this at any building supply seller in a number of great shapes, called profiles.

At the bottom, of course, is the window sill. And this particular window is done in my favorite fashion, which sports an “apron” under the sill.

When you look closely, you can see that there really isn’t anything complicated in how this all goes together.

Do the Sill First


The sill is cut in one piece which extends from one side of the rough opening to the other. To create this look, the sill should be cut with small returns that will provide a solid place for the bottom of the casing legs to rest.

The Apron is usually just a piece of the casing turned upside down. There are a number of ways to finish the end of the apron trim. I’ve included a video at the end which shows you one of the best ways.

Miter the Top


I like the look of a cleanly done 45-Degree corner at the top. Just like this picture here. This allows the profile of the casing to carry around the window and frames the opening nicely.

Another option is to use rosettes. Rosettes are nice because they eliminate the need to do a miter cut, which is really helpful if you don’t have a miter saw! The video shows how to use rosettes, but I say get a miter saw! You’ll use it for project after project!

Door trim is very similar and if all you’re doing is replacing the casing, it’s even more simple than this window!

I have so many more great trim options to show you. I’m just starting to learn that it’s better if I don’t try and do it all in one post! So if you’re not already a subscriber, I encourage you to join The Crew by signing up for our RSS subscription or our regular blog updates by email. It’s free and then you won’t miss anything!

Here is the video:

So, what do you think? Ready to give it a try? Talk to me!

Article by Tim Layton


1 Tammie March 18, 2009 at 2:59 pm

How do you go about doing this if you already have a window sill? Do you need to replace the original window sill or can you build from that? Ours only extend out past the window about 2 inches. Is that too short to add moulding?

I love your blog and am so happy I came across it!


2 Julie March 18, 2009 at 7:43 pm

Our home is about 7 years old and has the drywall returns. I would love to frame them with trim, but we have “rounded corners” (the bended metal shapey things) in all of the “formal areas” in our home. What do you do about that?

3 Mary Jean March 18, 2009 at 8:03 pm

Enjoying your blog! I do have a question for you. I recently saw a product near the spray paint home depot that I’m curious about. It is a laminate countertop paint made by Rust O leum. My friend has tired white laminate and would love to update it. Do you have any experience or knowledge about this product????

MJ Taylor

4 Heather March 18, 2009 at 8:12 pm

I can’t wait to try this on my next house! I love the look of a heavily aproned window. If that’s a term. I’m coining it!

Heather’s last blog post..Ooooh, some juicy BPA gossip!

5 Mrs. Q March 18, 2009 at 8:43 pm

Oh…I love the look of those windows…we could definitely update ours that way! But for now, we’ll focus on our family room remodel! My husband is hard at work laying the sub-flooring as I write!

Mrs. Q’s last blog post..Frugal Failure

6 Mrs. Q March 18, 2009 at 8:45 pm

Oh and I had a question about the concrete counters…

I excitedly told my husband about them and he said that we would need a solid bit of concrete under the floor to substantiate the weight that the concrete would create. Otherwise, he said, the concrete would crash through the floor!

Is there a way to get around this pesky detail? :)

Mrs. Q’s last blog post..Frugal Failure

7 Misti England March 18, 2009 at 11:21 pm

Wow! You must tired already, all of these questions and all. I just want to say thanks for all the great information you give. Your posts with Nester are awesome. You guys make a great team! Oh, and my miter box is very well loved!

Misti England’s last blog post..Chair Repair: A Dog Story

8 Liz March 19, 2009 at 12:15 am

I’ve heard that the new trend is 5″ baseboards instead of 3″. These window trims look wider to me, too. How many inches are they? And is it okay to have the window trim and baseboard be different widths or does that look mismatched? Thanks! Your blog is great & I love the posts with Nester, too!

9 Amy March 19, 2009 at 8:19 am

Hi Remodeling Guy
What a great blog…..very informative!!!!
I think it’s a great strategy to talk about one trim project at a time. I look forward to the next tutorial.
I have a question that maybe you can answer about reading blogs…..I subscribe to blog feeds through posts atom then I can look to see which blogs have a new post then I go to them….is there a more efficient way?

10 SoBella Creations March 20, 2009 at 3:07 pm

I’m not sure why…but in our house we don’t have window frames. But, we do have window sills that seem to be marble/granite or some material to that effect.

Molding, window frames etc are all on my project list to making my house look beautiful.

SoBella Creations’s last blog post..National Craft Month

11 STACY March 21, 2009 at 10:10 pm

Hi again! I would love to frame out my windows, but I also have the rounded corners…any ideas? Is it still possible?

Thank you,

12 Remodeling Guy March 21, 2009 at 11:09 pm

Hi Stacy -

As soon as I saw your question, I knew I had missed one…Julie asked the same question a day or so ago and I neglected to answer. Sorry Julie.

The rounded corners usually don’t make a difference as long as you wrap the interior of the opening with wood. You can use a 1-by or even plywood and create a Jamb around the interior of the opening. Just extend the front edge of this past the rounded corner until it is even with the face of the wall. Then you can place your casing on the wall face, and bring it over until it meets the jamb, and you’ll be all set.

There will be a small void behind the trim that nobody can see. If you watch the video I linked to in the post, you’ll see all the steps and they are the same with the “bullnose” drywall returns.

Hope this helps!


13 Megan March 23, 2009 at 1:12 pm

I have always wanted to replace the casing around my doors and add to my windows but I don’t know how to and my hubby isn’t handy. Looks like I might be learning a new skill. The sill is my biggest fear!

14 AnNicole@OurSuburbanCottage March 24, 2009 at 12:15 pm

LOVE this! I think I secretly want to become a carpenter. I’m dying to get a miter saw. Then LOOK OUT!

AnNicole@OurSuburbanCottage’s last blog post..THE LOOK FOR LESS: MASTER BEDROOM

15 Carol May 14, 2009 at 1:26 pm

We have drywall returns. Our aluminum windows sit back from interior walls about 5 inches and have 7/8 inch aluminum trim surrounding the glass. Do we have to remove the drywall before putting the wood around the window (jam extension)? Or can we put the wood right over the dry wall? If so, what should the width of the wood be? Thank you.

16 Derek June 1, 2009 at 2:25 pm

In my kitchen is a double bump out window that I would like to add trim and casing to. The sill is almost deep enough to sit in since it is in a bump out. All of the corners are rounded drywall (yuck). I plan to just cover the corners and jams with a thin wood. My concern is with the top of the jamb, it’s about 12″ deep and we have faux wood blinds. Would it be ok to glue and nail the “plywood” to the “ceiling” in this area and then just remount the blinds thru the wood into the “ceiling” joist??

Thanks for any help!

17 Kristen August 12, 2009 at 5:06 pm

We are putting an addition on our house and replacing all of our windows in the entire house as well. We are on a budget and don’t want to spend a lot more on extras, but we want our house to look nice. Our house currently has crown moulding and window casements of wormy chestnut from our property, but, I love the “white” look and am tempted to use it for our moulding and casements in our addition. Would it look goofy to have white in one room and the chestnut everywhere else? Also, the new windows are white. Will that look okay in the the chestnut casements or should I redo those as well? Thanks you !

18 Dave August 25, 2009 at 2:22 pm

Great write-up. Looking do to this same thing but our house has marble sills that don’t extend beyond the opening. If we add side casings there would be no sill underneath. Would you recomend replacing the sills or maybe add a notched wood sill around the front of the existing marble to extend the sill out past the side casings?

19 Tawn January 20, 2010 at 11:08 am

RG! THanks so much for your blog! It has been so much help to me in my first remodeling project!
I decided to case my son’s windows (also did wainscotting and paint all around. I had to stop the wainscotting when I decided to add the casing. I’m stuck now because it took so much to get the window sill out that I did some damage to a 6 inch section of dry wall. This is a piece of dry wall that already had a crack in it. Should I replace with another section of drywall or just cover it all up with the Apron that I am planning to put there?

20 Remodeling Guy February 22, 2010 at 12:02 am

If the apron will cover the damaged drywall, then you don’t need to worry about a patch. Now the only concern is if there are other problems with your wall assembly such as bad framing or siding. What you don’t want is the casing or apron to be the only thing between the interior of the house and a line to the exterior. In other words, if you can look in that hole and see light from outside, then you might want to patch the hole or find and fix the problem outside.

21 Sharon February 22, 2010 at 9:36 am


I am trying my hand a home repairs, I noticed in my living room that the base of the window (apron) is separated from the wall. What can I use to fill and seal this gap? (something that won’t rot or get mole) and seal. Thank you.

22 Rodney February 25, 2010 at 7:52 am


I currently have stained fluted window casings throughout my home, without an apron. I would like to paint the casing and jamb white as I believe it gives a more updated appearance. How do I go about painting the casing and jamb? Do I use an oil or latex primer first? Which primer offers fewer fumes with the best result? Do I remove the casing first and paint it or paint it in place? I have Anderson windows that open outward as opposed to upward as your pictures above show. I would love to add an apron on some of the shorter windows. I guess in this situation the casing would need to be removed first?

FYI – your windows above look very nice!

23 Rodney February 25, 2010 at 7:56 am

One more think…the current fluted casing is 3 1/2 inches wide. Is this unusual or not common these days?

24 KS March 13, 2010 at 3:21 pm


My question is very similiar to Carol’s post:

We have drywall returns. Our aluminum windows sit back from interior walls about 5 inches and have 7/8 inch aluminum trim surrounding the glass. Do we have to remove the drywall before putting the wood around the window (jam extension)? Or can we put the wood right over the dry wall? If so, what should the width of the wood be? Thank you.

I have the same project problem – our windows have the drywall returns. How are drywall returns suppose to be cased if one wanted to add the molding back to get the more traditional look???

25 Lacey May 23, 2010 at 3:56 pm

hi.. I want to add trim to the windows, I love the way it looks in the picture, where do you purchase all the items needed… I am mainly looking for a kit can you briefly describe the needed material I would greatly appreciate it thank you!

26 Chau July 20, 2011 at 12:54 pm

Instead of making the casings yourself, you can purchase the casings from us. It’s quick and easier to install. Look at the website for more information.

27 Tim Layton July 20, 2011 at 1:09 pm

I normally would remove a comment, such as the one above that simply says… buy from us! But I thought I’d comment on it myself instead…

The product offered at the site above (reached by clicking on the commenter’s name) is a great idea and if you’re going to do one or two windows it might be the option for you. I know nothing about the product or the company, but a kit is a kit and often times it reduces effort.

However, if you aspire to become a perpetual, habitual, home remodeler then you want to learn the carpentry skills that this process will teach you. It’s an easy project that is a great stepping stone toward more advanced woodworking in the future.

Give a man a fish… teach a man to fish… you know the story.


28 Robyn March 15, 2012 at 5:16 pm

HI! We are finishing our basement! YAY! I am looking for window sills that are 10″ deep. CAn you tell me where I can find some that deep or any other material we could use?

29 DAN July 13, 2012 at 6:46 pm

how do you take off the apron of window sills from the 60′s

30 Stacey August 25, 2012 at 2:18 pm

I have the typical builder framed windows with a very short and narrow sill (acout 2 in past window on either side) and no molding on drywall. Is there a way to just add width to the sill so that I can put moulding around the window? Instead of ripping the sill out and starting from scratch? Thanks!!!

31 Lynn September 15, 2012 at 12:26 pm

How do you go about doing this if you already have a window sill? Do you need to replace the original window sill or can you build from that? Ours only extend out past the window about 2 inches. Is that too short to add moulding? There is an apron already but on casings.

32 Tim Layton September 20, 2012 at 12:59 pm

Note: I emailed Lynn for more info and found out she had a wood sill that was similar to the ones in this post, but didn’t go far enough beyond the window and were installed without any casing.

Lynn – That’s not uncommon. If you have a full two inches you might consider using a 2.25″ casing and then going with one of the following options.

  1. If you wrap the inside of the opening with 1×4 material then you’ll have enough sill for the casing to rest upon. Because the casing will go over the edge of the 1x and therefore be about 1/4″ shy of the end of your current wood sill.
  2. Cut the casing down. You can rip the casing on a table saw to make it just under 2″ and then use it. It won’t look as great, but still good. You could try one and just see. before you even paint it or finish nailing it up you’ll know if you like it.
  3. Extend the sill. Wood is a wonderful material for adding on to. Especially if it’s painted. You can probably square off the end of what’s there and simply glue an extension on it with some really good glue. Then after you put your casing up, you can shoot a little brad nail up under the extended piece to hold it better (nailing it to the casing). A little bondo or wood putty to make the patch go away visually.
  4. Hope these ideas help!

33 Therese May 12, 2013 at 1:22 am

I’ve searched everywhere am about to give up and just do something I’m sure not to like… I have an older has and want to trim out my window just as you have done with apron but I have a marble sill which unfortunately will not come off without much grief… Any ideas of how to just build around… It is same length of window and stick I out only about 1/2 inch… Hope to hear from someone!

{ 10 trackbacks }

Previous post:

Next post:

Use of this site constitutes agreement with the SAFETY DISCLAIMER!, Privacy Policy