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Open Floor Plans: What They Cost to Build, How to Keep Them Quiet and Warm, and Where to Put the Walls You Keep
Plans and design Open plan From a builder
Open Floor Plans: What They Cost to Build, How to Keep Them Quiet and Warm, and Where to Put the Walls You Keep
Everyone wants the kitchen open to the family room now, and most of the time they are right. The part the magazine leaves out is that every wall you take out was holding something up, blocking some noise, or hiding the dishes, and each of those jobs has to go somewhere.
Short version: An open plan trades walls for beams, and beams cost: a 20 to 30 foot clear span needs an engineered LVL or steel beam, a post or two, and footings under them, which adds $5,000 to $25,000 over a plan with bearing walls. Noise and cooking smell travel through the open space, so the fix is a real range hood vented outside, acoustic ceilings or soft surfaces, and a door on the office and the TV room. Open plans heat and cool well in a tight house because the air mixes; they heat badly in a leaky one with a two-storey ceiling. Keep walls around the pantry, the mudroom, the office, the powder room and the laundry, and define the open area with the ceiling, the floor, the island and the furniture rather than with partitions.
What the open plan costs
| Span | Structure | Added cost over bearing walls (2026) |
|---|---|---|
| Up to 12 ft | Built-up lumber or LVL header | $500 to $2,000 |
| 12 to 20 ft | LVL or PSL beam, posts to the foundation | $2,000 to $8,000 |
| 20 to 30 ft | Steel beam or deep LVL, engineered connections, pad footings | $8,000 to $25,000 |
| Flush (hidden) beam vs dropped | Flush beams need joist hangers and deeper framing | Add 30 to 50 percent to the beam line |
| Two-storey open ceiling | Taller walls, bigger glass, more heat loss, scaffolding for everything | $10,000 and up, plus the bills |
The cheapest open plan runs the beams where the engineer wants them and lets them show; the dearest hides every one in a flat ceiling across a 28-foot room. In an ICF house the exterior walls carry everything and interior spans are the only question. Designing to a target budget is where this decision gets priced.
Noise and smell
- The range hood is the one appliance an open plan cannot skimp on: 400 to 600 CFM, ducted outside (never recirculating), with makeup air in a tight house, over a range on an exterior wall if you can. Bacon in an open plan is everyone’s bacon.
- Hard floors, drywall and glass bounce sound. Rugs, upholstered furniture, bookcases, drapes and an acoustic ceiling treatment in the big room bring it down; a wood ceiling with a sound-absorbing backer is the good-looking version.
- A door on the room with the television, the office, and any bedroom off the main space. The open plan is for the kitchen and the living room, not the whole house.
- Appliances: a quiet dishwasher (under 44 dB) and a fridge that does not hum, because they are in the living room now.
- In-wall and ceiling speakers on zones rather than one loud source. Lighting and outlet planning is where the zones get wired.
Heating and cooling an open plan
Open plans mix air, which is good: one thermostat, even temperatures, a heat pump that sees the whole space. Where they go wrong is the two-storey great room in a leaky house: the heat stacks at the ceiling, the floor is cold, the glass wall loses it all at night, and the fan runs forever. The cure is the envelope (an ICF house with triple-pane glass has no cold wall to stand beside) and the distribution: radiant floors put the heat where the people are and do not care how high the ceiling is; forced air wants returns high and low; a ceiling fan on reverse in winter helps either. Radiant heat vs forced air and building an energy-efficient home cover both halves.
The walls worth keeping
- A pantry with a door: the open kitchen stays tidy because the mess has somewhere to be.
- A mudroom between the garage and the kitchen, with a door.
- The office, with a door and a closet.
- The powder room, nowhere near the dining table, with a hall or a vestibule in between.
- The laundry, behind a door, near the bedrooms.
- Primary bedroom suite separated from the main space by a hall, not an archway.
- A wall to put the television on, the one the sofa faces. Choosing house plans walks the plan room by room.
Defining spaces without walls
- Ceiling: a change of height, a beam line, a tray or a wood ceiling over the dining area says “this is a room” without a wall.
- Floor: one material across the whole space (transitions look like leftovers), with rugs to anchor the seating and the table.
- The island: the island is the wall between the kitchen and the living room; make it long enough to be one.
- Furniture: a sofa with its back to the kitchen, a console behind it, a bookcase that stops short of the ceiling.
- Light: three layers on separate dimmers so the kitchen can be off while the living room is on. LED lighting design.
- Half-walls and columns where the structure needs a post anyway; a 42-inch wall with a cap hides the kitchen counter clutter from the sofa.
- One palette through the whole space: paint, trim and cabinet colours that belong together, because you see them all at once.
Related guides on this site
Sources and further reading
Questions people ask
What does an open floor plan cost extra?
The beams and posts that replace the walls: $500 to $2,000 for a short span, $2,000 to $8,000 for a 12 to 20 foot LVL beam, $8,000 to $25,000 for a 20 to 30 foot steel or deep LVL span with footings, more to hide the beams flush. A two-storey open ceiling adds $10,000 and up plus heating cost.
How do I keep an open plan from being loud?
A ducted range hood for the smell, soft surfaces and an acoustic ceiling for the sound, quiet appliances, zoned speakers, and doors on the office, the TV room and the bedrooms. Keep the open area to the kitchen and living room.
Does an open plan heat and cool well?
In a tight, well-insulated house, yes: the air mixes and one thermostat covers it. In a leaky house with a two-storey ceiling and a glass wall, no: heat stacks at the ceiling and the floor stays cold. Radiant floors, a good envelope and a ceiling fan on reverse fix most of it.
Which walls should I keep in an open-concept house?
The pantry, the mudroom, the office, the powder room, the laundry, the bedroom hall, and one wall to put the television on. Open the kitchen, dining and living room; keep doors on everything else.
Have a plan already?
Send it to ICFhome.ca and we will tell you what it costs to build and where the drawing is spending money you may not want to spend.
Reviewed and updated October 2026. Costs are Ontario ranges, not quotes; code references are to the Ontario Building Code in force at that date.
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My wife and I would like to build our first home together this year, but we haven’t really been able to decide how we want our floor plan to look. The article mentions that an open floor plan can be beneficial for families since it is more conducive to high flow. We don’t have any kids yet, but we anticipate staying in this home for a very long time so maybe an open floor plan would be good for our long term plans.