Always ASSUME you NEED transitions through doorways until you READ IT in the installation instructions that you do NOT.

Almost ALL floating floors need some sort of transition through pinch-points. Here are the instructions for floating.

https://www.kahrs.com/globalassets/kahrs/consumer/documents/installation/woodloc-5s/kahrs-installation-guide-w5s-en-exp.pdf

Floors installed through door openings or archways must

be divided with an expansion gap which is then covered by a threshold or moulding.

-There's your answer.

But they also say :

In some situations the flooring can be installed as one unit
excluding the threshold or dilatation profile. This situation
demands extra consideration and we recommend you to
contact your dealer for advise.

So I guess you need someone to come and take a look and tell you if you can do it without the expansion gap...

SJ McCarthy, Oana,

Thank you both.

I did some more research, including calling Kahrs USA and a few local flooring companies. Here is what I learnt -

- Kahrs customer service sounded fairly confidence that as long as my total dimension is within the numbers in that installation specification (40feet, 1/2 inch clearance at perimeter) no t-moulding is needed.

- Local floor companies also expressed this(no t-moulding) isn't going to be a problem, as much as they are familiar with the business, they are not installation contractors.

Then I sketched a my floor plan and drew expansion direction in each room and hallway. I have concluded this is going to be recipe for disaster, unless the expansion rate is really, really small, which i think isn't the case given the required 1/2 gap at the walls :

- Assuming each area (rooms, hallway) expansion happens from center and towards walls, I'd have room expansion force, hallway expansion force going against each other at the door, given bedroom is much deeper, likely the stronger expansion force will push the boards in hallway towards the wall opposite of the bedroom, so the movement would be > 3x of the movement if hallway is expanding independently.

- I have another room on the other side of the hallway, about 6 feet down, same thing would happen there, only on different side, this would push the hallway into a slight 'S' shape, which would be pretty visible given the hallway is pretty narrow.

- Above only count for expansion perpendicular to board direction, the force along the board direction would also be different given hallway is much longer, it might not be a problem if the 'click lock' system allows adjacent board to 'slide' , but if that's not the case, the forces in my case, could rotate the boards at the door

for contraction, things would be the same but at opposite direction. combine the seasonal expansion/contraction, my guess would be that in a couple of years I'd either see gaps between boards or the locking loosened.

Now I understand why a expansion gap at the door is necessary, basically it absorb opposite movements in different directions.

Given we don't want to see the speed bumps on our floor, looks like float-in installation isn't an option for us.

Thanks!

X.T.