Flooring an Open Plan Ground Floor
Running one floor through kitchen, dining and living areas: expansion, zoning, transitions, levels between old and new, and where a single material stops working.
One continuous floor through a knocked-through ground floor is the single change that makes an extended house feel finished. It is also the job where the most goes wrong, because the area is large, the subfloors are usually mismatched, and the requirements at each end of the room are different.
The kitchen end needs to survive water and dropped pans. The living end wants to be warm and quiet. Choosing one material that does both is the whole exercise.
Why LVT dominates this application
Glue-down LVT is waterproof at the kitchen end, comfortable enough at the living end with a rug, tolerant of underfloor heating, and available in a plank format that runs cleanly through a long space. It also has no expansion requirement across the field, which matters enormously in a large open area.
The alternative most people consider is engineered wood, which looks better to some eyes but needs care around a dishwasher, a sink and an external door, and needs expansion allowance at the perimeter.
The expansion problem with floating floors
A floating click floor has a maximum run length before an expansion break is required, commonly around twelve to fifteen metres in either direction depending on the manufacturer. Many open plan ground floors exceed this in at least one direction.
Exceeding it produces peaking in the middle of the room or a gap along one wall. The choices are an expansion break with a trim, which spoils the continuous look, or a glue-down installation, which removes the problem entirely. In large open plan areas we recommend glue down almost every time.
Matching levels between old house and extension
- New extension slabs and original floors are rarely at the same finished level
- A step of even five millimetres at a knock-through reads as a trip and shows in the light
- Latex screed can absorb a difference of up to around twenty millimetres in one pour
- Larger differences may need a build up in sand and cement or a ramped transition
- Survey the levels before the floor is chosen, because a thicker covering can help resolve a step
Moisture in a new slab
A new concrete slab in an extension takes a long time to dry, and the traditional guide is a day per millimetre for the first fifty millimetres, then longer. In practice, a 100mm slab poured in autumn is frequently not dry by the following spring.
Never take a builder's word for it. Test with a hygrometer or carbide meter, and if the reading is high either wait or install a surface damp proof membrane rated for the reading. Fitting over a wet slab is the most expensive mistake available in this room.
Zoning without breaking the floor
| Method | Effect | Notes |
|---|---|---|
| Large rug in the living area | Strong, reversible | Cheapest and easiest to change |
| Plank direction change | Subtle | Needs a clean line, usually at a structural opening |
| Border or inlay detail | Formal | Adds labour cost, hard to undo |
| Different material each zone | Very strong | Requires a good transition and matched levels |
| Lighting and ceiling changes | Strong without touching the floor | Often the best answer |
Setting out a long run
In a long open plan space, the plank direction should normally follow the longest dimension or the main light source, and the setting out should be planned so you do not finish with a sliver of a plank against the most visible wall.
It is also worth planning where the first full plank sits relative to the kitchen island or the bifold threshold, because those are the two lines everyone's eye follows. A fitter who sets out from the most visible edge rather than from a corner will produce a noticeably better result.
Buying enough material in one batch
On a large open plan area, order the whole quantity in one batch with a sensible wastage allowance, usually seven to ten per cent for a plank floor and more where the layout is complicated or the pattern is directional.
The reason is batch variation. Two production runs of the same LVT can differ subtly in shade, and in a continuous floor with no doorway to break the eye, that difference shows as a band across the room. Running out with three square metres to go is genuinely expensive to resolve.
Keep the surplus. In a room this size a damaged tile is inevitable at some point, and a box of the original batch in the garage turns that into a half hour repair rather than a conversation about relaying an area.
Frequently asked questions
- Can one floor run through kitchen and lounge?
- Yes, and glue-down LVT is the most reliable material for it. Engineered wood works too, with more care around water.
- How long should a new extension slab dry before flooring?
- Roughly a day per millimetre for the first 50mm and longer after, but always confirm with a moisture test rather than a calendar.
- Do I need an expansion joint in a large floating floor?
- Usually beyond about twelve to fifteen metres in one direction. Glue down avoids the issue entirely.
- Will underfloor heating work under LVT?
- Yes, with a temperature limit of around 27 degrees at the surface and an adhesive rated for heated floors.
Keep reading
Choosing between carpet, LVT, engineered wood and laminate in a lounge, covering warmth, acoustics, log burners, pets and how the room is actually used.
How latex self-levelling compound works, when it's needed, and how it differs from full sand-cement screed before new flooring.
Why subfloor moisture testing matters before new flooring is laid, the methods used, and what happens if readings are too high.
See how we survey, prepare and fit LVT across Kent.
See how we survey, prepare and fit engineered wood across Kent.
Talk it through with a fitter, not a call centre
Book a free measure from our Gillingham warehouse and we will bring samples suited to the room discussed here, check the subfloor and leave you with a written quote.