The full process of how to install window trim to the interior of your home, it’s not as difficult as you would think!
If you did not notice by the title, today we are talking about installing window trim. That’s right we finally have the trim added to our interior windows and you should too because it makes all the difference!
If you missed the previous post about installing the window jamb extensions, you probably should check that out first. Now onto trimming out those windows.
SIDE NOTE: We did decide we wanted a simple window trim.
How much does it cost to install window trim?
The cost of installing window trim will depend on the size of the window, but you can plan on the price to be about $3 per foot around the window for a simple trim.
So for a 36″x 48″ window, the cost would be about $42. Remember this cost is if you install the trim yourself and it includes the cost to finish with paint.
Simple Interior Window Trim Install
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SIDE NOTE: I would recommend that you use a 16 or 15-gauge nail gun for installing this trim.
TIPS: We purchased 4″ pine boards for all the trim (you can use a different size, but your measurements will be different than the tutorial so keep that in mind). You could purchase a pre-primed board too. If you would like to save some time down the road, you can paint the boards before installing them.
STEP 1: Determine the amount of wood needed
To find out the amount of wood you will need, you will measure all the sides of the window opening (top, bottom, & sides) but you will need to add extra inches to the top and bottom pieces because of this craftsman window trim.
The window trim will have an overhang of 1″ on the top and bottom sides. To plan for the extra amount, using the measurement from the top & bottom of the window opening add an additional 4.5″ to both ends.
You are adding 4.5″ because the actual size of the 4″ board is 3.5″ then add 1″, which gives you the additional. So you would be adding 9″ to the measurement of the top and bottom window openings. For example: let’s say the window bottom measured 21″ but we need to add 4.5″ to both sides (9″), our piece would then = 30″.
You should now know the number of boards needed for each window.
STEP 2: Install the window trim
The first step to add the window trim is adding the bottom trim piece. Take the measurement of the bottom trim piece and cut the board at that length (remember to add the extra inches stated above).
Then applied liquid nails to the wood in a zig-zag fashion, like the picture below: (this picture was from adding the window jambs because I forgot to take a picture when adding the trim). This step can be skipped, the reason why we used liquid nails is that our walls are brick with plaster over the brick, so we needed more than just nails to hold the boards into place.
After place the liquid nails side of the board against the wall, 1/8″ down from the window opening (jamb). Center the board and make sure it is level then nail the board into place with 1-3/4″ nails.
TIP: We marked the board 4-1/2″ in from both sides before adding the liquid nails. This step will make it easier to center the board against the window opening.
Now it is time for the side trim. To get the most accurate measurement measure from the bottom trim piece to 1/8″ past the top window opening (add 1/4″ to the previous measurement). Make sure you measure for both the right & left sides of the window because it could be different.
Then cut the side pieces and top piece (remember to add the extra inches).
After cutting the side pieces & top piece, apply the liquid nails to one of the sideboards and place it 1/8″ away from the side opening. Make sure the bottom of the side trim is flush with the bottom trim and level then nail the board into place.
Install the other side trim piece the same way.
Now that both side pieces are installed add the top trim piece, again using liquid nails and placing on top of the side pieces. Make sure the board is centered and level. Then nail the trim into place with 1-3/4″ nails.
Now our window trim is all installed.
And as a note, some of our trim and jambs have some gaps, but this can be filled in with a sealant, this is the next step if you will be painting the trim.
If you want to see how to finish painting the window trim, be sure to check out this tutorial on that.
I hope this tutorial will help you add interior window trim to your windows. Plus this craftsman style window trim is not difficult to install. Update the look of your windows by installing window trim.