**For a continuous floor at the same height, the installer needs to correct the subfloor height difference before laying the laminate.** The laminate itself won’t bridge a substantial step safely.

There are three usual options:

- **Raise the lower areas:** Add securely fastened plywood of the appropriate thickness in the living room and hallway to match the dining area. With the layers you describe, this is a likely approach.
- **Lower the dining area:** Remove extra plywood if it is unnecessary underlayment. The installer must first establish that those layers aren’t needed structurally or supporting cabinets.
- **Keep the different heights:** Install the laminate separately on each side and use a matching **reducer transition strip** at the change. You can use the same flooring throughout, but there will be a visible transition. [Shaw’s transition guidance](https://pdf.lowes.com/productdocuments/428664b4-81fa-4e5b-93f5-aeda8536b995/07740912.pdf)

After matching heights, the installer may still need to address small dips or uneven seams. Laminate needs a firm, flat base within the particular manufacturer’s tolerances; extra layers of soft foam padding are not a substitute for this preparation. [Pergo installation instructions](https://int.pergo.com/-/media/imported%20assets/flooring/5/b/b/pginstallationlmpherringboneenpdf288141.ashx?filename=Installation+instructions+Pergo+Laminate.pdf&rev=ffc0e06a5b09412ba904a28450338bf2&type=original)

**Have the installer inspect the exposed floors and include the preparation in the quote before installation starts.** Ask specifically whether the finished rooms will be at one height, and have them check door clearance, adjoining floors, and kitchen appliance clearance—especially whether the dishwasher can still be removed.