Flattening a floor with levelling compound

[spakka]

Hello uk.d-i-y

I could use some practical advice on techniques for achieving a flat floor with levelling compound. I'm happy with my choice of compound and how to mix it.

I'm trying to lay a glue-together tongue & groove hardwood floor as a floating floor. The manufacturers say the floor underneath must be flat to a tolerance of 2mm in the m, but I think they're having a laugh, especially as many boards are warped more than that out of the packet.

I've already flattened some obvious depressions in my floor fairly well, but I've found that my floor has larger scale irreglarities, which I only noticed when I started to lay a few rows of floor and found it wouldn't lie flat. (The room is about 7m long).

My concern is that levelling compound doesn't really level itself as noted in the faq and posts in his group. I've found prevously that it will follow curves of a gently undulating floor, which won't help me.

1st question: How do I map the areas which need levelling compound?

I can roughly locate the low areas at least in one direction by moving the line of already completed floor. I guess I could even chalk a contour map by rotating a spirit level at intervals around the room, but this seems nerdy and obsessive. Is there some special long straight edge tool I'm supposed to use?

2nd question: Does anyone have any tips on how you practically work this stuff to get a flat finish?

I have a plasterers trowel, but I can imagine that a larger spreader might help maintain flatness as you smear it around.

Thank you

[Stuart Noble]

You just need a couple of pieces of 2x1, one for the length, one for the width, and a spirit level. Mark the wall at intervals (on top of the battens), then put the batten and spirit level on the highest mark and run a pencil line. Repeat for the other wall. This should give you the high and low points. Then you'll probably decide to opt for a sloping floor :-) Sometimes it's easier to chop out high spots if there are only a couple throwing the whole thing out. Put a few dollops of mortar on the floor and level them with the batten. Once set they'll give you levels for applying the screed. Plasterers trowel is fine because the stuff I've used is pretty sloppy but you need to work fast because the liquid part soaks into the floor pretty quickly

[spakka]

Genius

Thank you

[Chris Bacon]

ROFL.