Self Levelling Compound Barrier - Novice

[Hozier]

I need to level a concrete floor ready for laminate flooring. Previously tile and cement. Floor is 4.5mx3m.

Never done this before and unsure how to deal with creating a barrier for the compound. I've attached diagram below but basically 4 sides:

1x patio doors (currently gap of 8mm underneath frame where excess tile cement was)
2x walls with plasterboard (gap 20mm underneath)
1x carpet (where previous doors have been removed)

Should I let the compound run under the patio doors and plasterboard or is that crazy?
Should I be using expanding foam or something under patio doors / plasterboard and slice away excess afterwards?
I'm guessing I'd need a different solution for where the compound will meet the carpet?!

Easiest fool-proof solutions welcome!

Thanks!

 

[dazlight]

A good vac out 1st.
prime all the area.
Fill in the hatch will smoothing compound and granno chips 1st. Let that set a couple of days.
prime again
Then smoothing compound the whole area at 4-5mm.
5 bags smoothing compound and 1 granno should do it all.

let it flow out under the plaster board and doorframe.

make sure you buy a moisture tolerant smoothing compound. A bag and bottle.

ardex NA
Fball 1200
Bostik screedmaster ultimate
Mapei trade plan
Uzin gold

don’t use a water mix if you can help it.

 

[Hozier]

Thanks for the reply.

Re: under doorframe, I’m concerned if there is a small hole in the concrete slab that I can’t see the compound will drip down into it.

I only say this as there is another small hole at the edge of the subfloor in the corner of the room - so Lord knows if there are any other smaller holes ...

 

[dazlight]

Any holes just shove paper in them. Any big holes fill with rapid repair like ardex A46