Could I undercut door casings myself in an Ottawa home?

Undercutting door casings is one of the few flooring prep tasks that a handy homeowner can reasonably do themselves — it's straightforward, low-risk, and doesn't require a contractor's license.

What Undercutting Involves

The goal is to cut the bottom of door casings (and door jambs) so your new flooring slides cleanly underneath, creating a professional finished look without the need for awkward trim pieces. You're essentially creating a gap equal to the thickness of your new flooring plus any underlayment.

The Right Tool for the Job

The most common approach is using an undercut saw (also called a jamb saw or flush-cut saw). You simply lay a scrap piece of your new flooring flat on the existing subfloor as a guide, rest the saw on top of it, and cut horizontally through the casing. An oscillating multi-tool with a flush-cut blade works well too, especially in tighter spots. A standard handsaw can work in a pinch, but it's harder to keep the cut level and consistent.

A Few Things to Watch For

Always cut slightly higher than your flooring sample to account for the underlayment or membrane beneath it — a thin cardboard spacer on top of your flooring sample works well as a guide. Be careful around door jamb anchors or any fasteners hidden in the casing. In older Ottawa homes, casings may have multiple layers of paint or be made of older hardwood, so a sharp blade matters. If your home has heritage trim or ornate Victorian casings, you may want a professional to handle it to avoid damaging irreplaceable millwork.

Ottawa-Specific Context

This task doesn't require any permits or licensed trades — it's purely cosmetic prep work. That said, most installers include this step as part of the job, so there is usually no need to do it separately - confirm it is in the quote.

Practical Tip

Do a dry run with a scrap piece before committing. Cut one casing, slide your flooring sample under it, and check the fit. The flooring should slide underneath with light resistance — not too tight, not with a visible gap above it.

If you'd like a professional to handle the full installation including all prep work, Local contractors give free quotes to Ottawa-area homeowners.