Process and costs
One fixed price, agreed before the slab is poured.
Here is how a Karamatsu house goes from a first walk on your plot to the blower-door test, what each stage costs, and what is in the figure we sign.
Each stage, and what it costs.
Payments follow work you can see on site. Nothing is due before the design is agreed.
- Month 0Plot visitWe walk the plot with you, look at sun, drifting snow, ground and access, and give a first range.Free
- Months 1–3Design and energy modelFloor plans drawn with you, three meetings, every room modelled for heat loss and summer shade.¥880,000, credited to the build
- Month 4Fixed price and contractItemised price, build programme and warranty signed. Building permit filed by us.10 % on signing
- Months 6–9Slab and workshopInsulated raft poured before the frost. Wall and roof panels built indoors in Memuro.30 % when the slab is poured
- Month 10RaisePanels craned into place in four days, roof closed, windows taped in.30 % when the roof is closed
- Months 11–14Finish and testInterior, heat-recovery ventilation, blower-door test, certificate and keys.30 % at handover
What a house costs, by size.
Prices for our standard specification on a level plot in Tokachi, 2026, consumption tax included.
Included in the figure
- Design, structural calculation and building permit
- Passive-house energy model and certificate
- Insulated slab, frame, windows, cladding, roof
- Heat-recovery ventilation and one heat pump
- Kitchen, bathroom and timber floors from our range
- 10-year structural warranty, 2-year finish warranty
Outside the figure
- The plot, survey and registration
- Ground improvement if the soil test asks for it
- Water, sewer and power connections to the plot edge
- Garden, driveway and garage
- Furniture, curtains and lighting fittings
What moves the figure.
- Shape
- A simple rectangle with a pitched roof is the cheapest form to keep warm. Every extra corner adds about ¥400,000.
- Plot
- Slopes, soft ground and long access roads for the crane are the largest variables. We price them after the plot visit.
- Glazing
- South glass pays for itself in winter sun; large north glass does not. We show you the trade in the energy model.
- Finishes
- Our range keeps prices fixed. Your own kitchen or tiles are welcome and priced at cost plus 8 %.
Questions families ask at the first meeting.
Are there subsidies for a passive house?
Yes. Every house we build qualifies for the national net-zero-energy home grant and the Hokkaido high-performance housing support, together worth up to ¥1.4M in 2026. We prepare both applications.
Does a passive house change my mortgage?
Our houses meet the top energy grade for fixed-rate long-term loans, which lowers the rate for the first ten years. Two local banks we work with also offer an extra reduction for certified houses.
Can we bring our own architect?
Yes. We then build to their drawings and run the energy model alongside them; the design fee is replaced by a ¥330,000 review fee.
Do you build outside Tokachi?
Within about 150 km of the Memuro workshop — Kushiro, Furano and Hidaka included. Further away, panel transport and crew travel add 4–7 % to the price.
What if the price changes during the build?
It does not. Timber and material prices are fixed when you sign at month four. Only changes you ask for afterwards are added, priced in writing before any work starts.