How to Create Deep Window Sills

It seems like everybody loves deep window sills. Who wouldn’t, right?

As all of you know, John built 2×4 walls on the perimeter of the original house to install insulation, electric boxes, Cat 6 and RG6 boxes; this was also the beginning step for creating deep window sills. Without the 2×4 walls there wouldn’t be deep sills.

When we show people the house, the first thing that everyone notices right away or their first comment seems to always be about the window sills. It’s a nice custom look that adds character to any room.

After installing Sheetrock (drywall) on the top, left and ride side of window, John installed metal corner bead on the three sides as well.

John used his snips to cut the corner bead to length and inserted each piece on the three sides. If any of you ever use metal corner bead, be careful, the edges can be razor sharp.

What you need: Drill, snips, corner bead, drill, 1 1/4″ screws, levels and Sheetrock/dry wall & joint knife.

The corner bead is nailed with 1 1/2″ aluminum roofing nails. Since it’s our house, he used more nails. When you hire someone, they’ll use less nails. If a contractor walked in and looked at the corner bead, he would probably say, “You don’t need to use that many nails!” We know that but John uses more nails because he can. Same with the drywall, he used more screws because it’s his house.

Down the road, if any of you hire dry wall contractors, watch to see how few screws they use. And remember, screws are expensive. It behooves them to use less screws.

John started at the top of the window and then installed the corner bead on left side.

All three sides must be level and plumb. John’s 2′ level came in handy.

But a 4′ level is better! Remember to wear ear protection. His doctor told him years ago, the best thing you can do is always wear ear protection.

Kiwi is the job supervisor. By the way, check out my latest find for keeping your dog or cat safe (under $3.00).

Time to hammer the roofing nails.

The drywall was omitted from the sill because John is going to make the sill deeper than the 5 1/2″ it already is. He’ll install an oak bull nose piece of wood which will extend an 1″ or 2″ over the framing. This will allow 6 1/2″ or 7″ for me to place potted plants or anything else that I might like on the window sill.

Installing the last piece. Because of the corner bead, trim is not required around this window or any of our other windows in the original part of the house. After painting the walls, it’s finished. No trim!

After the corner bead was installed, John used his trusty pallet in his left hand to hold the spackle in an awkward position.

John is pulling the spackle down with an 8″ Walboard knife making sure there aren’t any bubbles.

To take the bubbles out of the joint compound, attach a mixing paddle to a 1/2″ corded drill (do not use a cordless drill, it will destroy it).

Add water while mixing to get it to the desired consistency.

Looks perfect!

The job site supervisor approves!

(Bubbles create imperfections in the finish.) Avoid bubbles by stirring the spackle in the beginning which will eliminate them.

Since this window is in the future “home office,” which faces south, I’ll most definitely have potted plants on the deep sill.



One thought on “How to Create Deep Window Sills

  1. Absolutely ear protection.

    My Dad added on to our house and used a radial arm saw for years when working. Never wore ear protection.

    Now he’s mostly deaf. I’m sure a lot of it is due to age but it started early probably because of the lack of ear protection and is probably more severe because of it.

    I remember us having a deep sill window growing up. My Mom used to save bottles with interesting shapes and put water in them colored with food coloring and then put them in the window. Very cheap and fast decoration. I save maple syrup bottles for the same purpose. I’ve got a star, maple leaf and a snowman.

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