Laminate Flooring at Bottom Of Stairs

[Gary3891]

Planning to lay laminate flooring in my downstairs hallway with my dad.

We have removed the skirtings to save having to undercut them prior to installing the flooring.

My dad is reluctant to undercut the side rails where they meet the concrete floor as he has said this could weaken the staircase structure and could end up costing me a lot of money to fix if it goes wrong.

Is he right or is he worrying about something that will never happen?

 

[foxhole]

Looks like you have two timbers side by side , you can undercut inner one without issue .

 

[robinbanks]

He's worrying unnecessarily

Oscillating multitool cut just enough depth that you aren't chopping all the way through (but even if you did no biggie, just cut a packer to support it)) then chisel out enough to give you a slight recess enough to slide the edge of the laminate under so the cut in the laminate is hidden.

Tip for that btw, put a piece of underlay plus laminate offcut or upsidedown plank next to the stairs and rub your multitool along it. The thickness of the flooring will ensure the cut is where it needs to be and help level out the blade

 

[Flooring365]

I understand your dad’s hesitation — nobody wants to start cutting into stairs without being sure.

That said, lightly undercutting the side rail (the stringer) to allow laminate to slide underneath is very common practice. You’re not cutting into anything structural in a meaningful way, just trimming a small amount off the bottom edge so the flooring can tuck under neatly.

You’re usually only removing the thickness of the laminate plus underlay — so maybe 10–12mm at most. That won’t weaken the staircase as long as you’re only trimming the bottom edge and not hacking chunks out of it.

From your photo, it looks like there’s already a small gap where the carpet sat. If you don’t undercut, you’ll either need to:

• Leave an expansion gap and cover it with trim, or
• Scribe the laminate tightly around the stringer, which can be fiddly and won’t look as neat.

Most people undercut because it gives a much cleaner finish and hides the expansion gap properly.

The key is using a multi-tool or flush cut saw carefully and only taking off what you need. You’re not touching the structure of the stair itself, just the very bottom of the trim/stringer.

So no, he’s not crazy to be cautious — but in this case, it’s a pretty standard approach and very unlikely to cause structural issues if done carefully.

If you’re unsure, you could always do a small test cut in the least visible section first.

 

[Koolpc]

Won't be an issue...