Transom Window Trim & Sidelight Casing at the Entry Door
The new entry unit came with sidelites and a transom, and the installer cased the door and quit.
Reply within one business day. Or call / text 763-250-3621.
Transom window trim and sidelight casing around an entry door is done as one unit: continuous casing around the outside of the whole assembly, mull covers over the joints between the door frame and the sidelites, and a stool under the sidelites when the style calls for it, inside and out. JMB Builders installs it across the Twin Cities metro. Priced per opening, quoted from photos, with a reply within one business day.
- Priced per opening: door plus sidelites and transom
- Interior casing and exterior brickmould or trim boards
- Mull covers at every frame-to-frame joint
An entry door with sidelites and a transom is one big unit made of three or four frames mulled together. The problem shows up at the joints: where the door jamb meets each sidelite jamb, and where the transom sits on top of all of it. Trim each piece separately and you get casing legs running into each other, four extra miters, and a caulk line at every mull. Case the whole thing as one rectangle and it looks like the door it was sold as.
Inside, that means one run of casing around the outside of the whole assembly, mull covers over each joint between frames, jamb extensions if the unit is shallower than the wall, and either a stool and apron under the sidelites or a mitered bottom to match the rest of the house. Outside, it is the same idea in brickmould or flat trim boards, with a drip cap over the transom head and the joints sealed against weather.
Trim goes in primed, filled and caulked. Painting is quoted as a separate line — or leave it primed and caulked and paint it yourself. Exterior PVC trim can stay white without paint.
Get a written quote for this job
Three photos and a sentence is enough: a reply within one business day, or ask for a free in-home estimate. Or text the photos to 763-250-3621.
What you supply
- A photo of the entry from inside and one from outside, far enough back to see the whole unit
- A close-up of the joint between the door frame and a sidelite so we can see what the mull looks like now
- The casing profile you want inside, or a photo of trim on another door in the house
- Paint or stain color if you want us to finish it — painting is quoted as a separate line
What JMB supplies
- Continuous interior casing around the door, sidelites and transom as one unit
- Mull covers over every joint between frames, inside and out
- Jamb extensions where the unit is shallower than the wall
- Stool and apron under the sidelites, or a mitered bottom, to match the rest of the house
- Exterior brickmould or PVC trim boards with a drip cap over the head
- Filler, caulk and exterior sealant at every joint
- Painting or staining of the finished trim when you want it done, quoted as its own line
- Photos of the finished entry in your job folder
How it is priced: per opening
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- Interior only, exterior only, or both sides of the wall
- One sidelite, two sidelites, and whether there is a transom across the top
- Whether jamb extensions are needed because the unit is shallower than the wall
- Stock casing vs. matching an existing profile, and stain-grade vs. painted
- Exterior trim in PVC or wood brickmould, and whether stone or brick is tight to the frame
- Painting or staining, quoted as a separate line
One photo from inside, one from outside and one close-up of a mull joint make the quote firm. Say whether you want both sides done.
How long it takes
Interior trim on a door with two sidelites and a transom: most of a day. Add the exterior and it is a full day or a bit more.
How your project works
- 1
Send photos, get a written quote
Send three photos of the space and a sentence about what you want. You get a clear, itemized reply within one business day. Prefer a look in person? A free in-home estimate is always an option.
- 2
Pick materials, or bring your own
We help you choose profiles and materials that fit the house and the budget, or match your existing millwork exactly — or you buy the door or trim yourself and we install it. Everything is confirmed before the crew is scheduled.
- 3
Clean, precise installation
The crew shows up on time, protects floors and furniture, and installs with tight joints and consistent reveals. Photos of the finished work go in your job folder.
- 4
Walkthrough and invoice
We walk the finished work with you. If anything is not right, we fix it before we call the job done. Then one invoice, paid by check or direct deposit — no card fees, no payment links.
Situations and options
Continuous interior casing
One run of casing around the outside of the whole assembly, with the sidelites and transom inside the frame. Mull covers hide the joints between units. This is the standard look and the cleanest one.
Craftsman header over the whole unit
Flat 1x legs down each side and a wide head board across the top of the transom, with a cap. Fits bungalow and farmhouse trim packages and handles the extra width of the unit well.
Exterior trim and mull covers
Brickmould or flat PVC trim around the outside, covers over each joint between the frames, and a drip cap over the head. The mull joints on an entry unit face the weather; they need a cover and sealant, not just caulk.
Mull covers only
If the casing is already on and only the joints between the door and sidelites are bare, we make and fit the covers to match the existing trim. A short job, best combined with other trim work in the same visit.
Transom Window Trim & Sidelight Casing at the Entry Door: questions, answered
Do you trim the door, sidelights and transom as one piece or separately?
As one unit. The casing runs around the outside of the whole assembly, and the joints between the door frame and each sidelite get a mull cover instead of their own casing legs. That is fewer miters, fewer caulk lines, and the entry reads as one door the way it was designed. Trimming each frame on its own is how you end up with casing legs bumping into each other in the middle.
What is a mull cover on an entry door?
Where two frames are joined side by side — the door jamb to a sidelite jamb, or the transom on top of the door — the joint is called a mull. A mull cover is a strip that hides that joint and the fasteners in it. Inside it matches the casing; outside it is a trim board or brickmould piece sealed against weather. Most bare-looking entry units are just missing their mull covers.
Can you trim just the outside of an entry unit with sidelights?
Yes. The outside is often the part that gets skipped, because the installer sealed it with caulk and moved on. We add brickmould or flat PVC trim around the unit, covers over the mull joints, and a drip cap over the head so water runs off instead of into the joint above the transom. PVC can be left white; wood brickmould gets primed and painted.
My sidelights have drywall returns and the door has casing — can you make them match?
Yes. We add jamb extensions and casing to the sidelites so they match the door, or wrap the whole unit in one continuous casing so the returns disappear behind it. Which is easier depends on how the drywall was finished; a photo of the joint between the door and a sidelite tells us.
Do you paint the trim around the transom and sidelights?
Yes, painting is quoted as a separate line on the same quote — or leave it primed and caulked and paint it yourself. Interior trim goes in primed, filled and caulked. Exterior PVC can stay white with no paint; wood brickmould should be painted the first season.
What photos do you need to quote trim for an entry door with sidelights?
Three: the whole unit from inside, the whole unit from outside, and a close-up of the joint between the door frame and one sidelite. If the walls are thicker than the unit and you can see drywall or framing between the frame and the wall, get that in the close-up too, since it tells us whether jamb extensions are needed. The quote is firm from those without a site visit.
Recent JMB work, from our job log
59 installs recorded across 30 Twin Cities communities since Dec 2025. Window and door installs for homeowners and the builders we work with. Counts come straight from our job log; no customer names.
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Read morePage reviewed October 1, 2026 · JMB Builders LLC, MN license BC809005 · All window trim pages
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