More home.
Same land.
Before looking for another property, look at the potential of the one you have. Lantern Box adds a new home above it, carried on its own frame.
It starts as a one-storey loft and can grow to two, while the house below stays in use. It works for a single home or across a portfolio of properties.
The old house does not carry the new one.
New columns and foundations carry the addition to the ground, so there is less structural work inside occupied rooms and the sequence is easier to control.
- New frame firstColumns and foundations go in along the outside of the house.
- Existing house stays intactThe addition touches the old structure as little as possible.
- Shell before fit-outAn enclosed shell, connected to the house, comes before interior work.
- Plan for changeFuture floors, access and services are allowed for from the start.
Build the box, then fill it in.
Settle approvals, structure and the order of work before choosing the interior layout.
Phase 1A · Site and foundations
Survey, setbacks, access, services and the first independent supports.
Phase 1B · Frame and shell
Structure, weather protection and the connection to the existing house.
Loft fit-out
One storey with a kitchen, washroom, its own entrance and a tall living space.
Optional upper floor
The stair and service routes are already in place, so bedrooms, an office and a full bath can be added later.
The frame stays fixed. The use can change.
- 01
Long-term rental
A complete dwelling with its own access and services, subject to approvals.
- 02
Family annex
Space close by for adult children, parents or long-term guests.
- 03
Live and work
A studio or office alongside a residential loft.
- 04
Two-level home
An upper fit-out adds floor area and bedrooms.
- Loft
- 1 bedroom
- 2 bedroom
- Art studio
- Open office
A different order of work.
| Conventional addition | Lantern Box |
|---|---|
| Opens up the existing house early | Works outside and above first |
| Relies on the existing structure to carry the change | Gives the new work its own load path |
| Commits to the full program at once | Starts with a single storey that can expand |
| Disrupts occupied rooms sooner | Keeps the house in use longer |
| Starts from scratch every time | Adapts a tested design logic to each property |
Actual occupancy during construction depends on scope, permits and site conditions.
One property, two homes.
An illustrative scenario: a single-storey Lantern Box rented out for income.
- Existing asset
- $1.0M
- Illustrative house and land value.
- Addition budget
- $750K
- Illustrative project budget, with $650K of Phase 1 borrowed through a HELOC.
- New floor area
- +1,000 ft²
- A leasable one-storey loft after Phase 1.
- Rent recovery
- 20 years
- Gross-rent recovery target at $3,125 per month, before expenses and financing.
Once the loft is built, an owner can move from a home equity line of credit (typically up to 65% of the house's value) to a mortgage on the house plus the addition (up to 80% of the appraised value).
Illustration only, not financial advice. Lending limits, appraisals and terms depend on the lender and borrower.
Not every house should become a Lantern Box.
A feasibility review answers the practical questions first, including whether to go ahead at all.
Survey, setbacks, access and servicing.
Existing conditions and an independent load path.
Zoning, building and site-specific authorities.
Phases, allowances and where to stop or expand.
Occupancy, sequence, lead times and protection.
Use, income, future conversion and exit options.
- Site
- Structure
- Approvals
- Cost
- Delivery
- Value
- Shortlist
A strong candidate has
- Unused zoning volume or lot capacity
- A strong reason to stay on the property
- A reason to phase the spending
- Several plausible future uses
- Room for a separate new load path
Explore alternatives when
- Zoning or site access rules it out
- Connections between old and new would be very complex
- A simple addition would perform better
- The existing property is still mostly mortgaged
- Future flexibility has little value to you
The same vertical addition principles apply to commercial buildings, as in our Carbon Canopy study. Lantern Box grew out of studies like Nepahwin 2.0.
Screening many properties.
Choosing which houses suit Lantern Box matters as much as the design.
- Neighbourhood
- Scan
- Select
- Lantern Box
Screen
Review planning, capacity, access, servicing and building condition.
Identify
Find unused zoning and lot capacity where a new frame is feasible.
Rank
Shortlist the strongest, with a one-page finding for each property.
Deploy
Adapt the same tested design to each selected site.
Start before the project brief.
Lantern Box feasibility review
Test fit, approvals, structure, access and phasing for your house, and a clear next step.
Property feasibility scan
A one-page finding for each property, a ranked shortlist, an opportunity and constraint matrix, and next steps with a budget.