concreteflooringlaminate
I'm getting laminate flooring fitted in my lounge, porch and toilet and need to prep the concrete floor before it goes down.
The living room was easy as it only had carpet down. The porch and toilet had ceramic tiles which we've now removed (including adhesive). The concern I have is that there is a 1mm difference in the level of the floor between the lounge and the porch/toilet. Is this too much of a height difference for the laminate flooring to be laid evenly?
It depends on a couple of things. How much time you want to invest, how your current baseboards are installed, size of current baseboards, and what you want everything to look like.
As long as it isn't a HUGE deal to take baseboards out I would almost always go with removing them.
Take the baseboards out, freshen them up while you are at it, install floor, pop baseboards back. Touch up paint and caulk where needed. Not taking them out starts the job faster but then after your install there will be quarter round regret (because of point #1).
If you choose to use plywood, go with the 3/4" T&G for the layer under the carpet. The trough were the heat pipes used to be can be spanned by the 3/4" plywood too. Also since the carpet compresses under foot, keep the plywood below the hardwood layer about 3/8" or so lower. That way when you step there, the transition will feel level.
Best Answer
Each flooring manufacturer has specific guidelines for the amount of tolerance for their product. It varies, but it is usually something like 1/8" (2 mm+/-), using a 4' or 8' straightedge. If your condition is a little drop, not a gradual difference, I would grind it down to make the transition over a larger area, say 1-2 ft out, or get a little thinset and fill it a bit.