20×24 Modern Tiny House Plans | 1 Bed, 1 Bath, 480 Sq Ft ADU
$99
- 480sq ft
- 1bed
- 1bath
- 1story
- 16sheets
A 20 by 24 modern tiny house in light timber siding with a covered porch running the full 20 ft front. One bedroom, one bathroom and an open living and kitchen space, all on a slab with no stairs and no loft. $99 instant download: 16 sheet PDF plan set plus material list.
- 16 print ready sheets
- Fully dimensioned floor plan
- All four elevations and section
- Foundation, roof plan and roof framing
- Electrical, plumbing and HVAC
- Material list included
Best for building it as drawn
Need editable CAD files or a change to the design? Request it here and we will quote it.
- Instant PDF download after checkout
- 160 sq ft covered porch, not an afterthought
- Sized to suit many ADU and accessory dwelling rules
- Material list included with every download
- Questions? We reply within 1 business day
Description
The 20×24 Modern Tiny House is a 480 sq ft, 1 bedroom, 1 bathroom single level plan with a single slope roof, light timber siding and a covered porch 20 ft wide and 8 ft deep across the front. You get a 16 sheet print ready PDF with the dimensioned floor plan, all four elevations, a building section, roof plan and roof framing, foundation, electrical, plumbing and HVAC, plus a preliminary material list, delivered the moment you check out.
- A 160 sq ft covered porch, which is a third as much outdoor room as there is indoor room.
- A living and kitchen space 19 ft long, so a sofa, a table and a kitchen run all fit along one axis.
- A proper 12 ft by 11 ft bedroom with a door, not a loft you climb into.
- A ceiling that rises from 9 ft to 12 ft front to back, with clerestory glazing at the high end.
- A slab on grade with thickened edges, so there is no floor framing and no crawlspace.
- 480 square feet puts it inside the size cap many cities set for an accessory dwelling unit.
Quick specs
- Plan number
- THP-20×24-MT
- Overall footprint
- 20′-0″ × 24′-0″
- Heated area
- 480 sq ft on one level
- Covered porch
- 20′-0″ × 8′-0″, about 160 sq ft
- Bedroom
- 12′-0″ × 11′-0″
- Bathroom
- 11′-0″ × 6′-8″, 1 full
- Living & kitchen
- 19′-0″ × 11′-8″, open plan
- Width
- 20′-0″
- Depth
- 24′-0″
- Loft
- None, single level plan
- Roof height
- About 9′ low side to 12′ high side
- Roof style
- Single slope, front to back
- Side shades
- 2′-0″ left, right and rear overhangs
- Exterior finish
- Timber siding over sheathing and house wrap
- Wall studs
- 2×6 with R-15 batt insulation
- Foundation
- 5″ reinforced slab over 4″ gravel
- Slab edge
- 12″ × 30″ thickened edge footing
- Porch slab
- 4″ thick, isolated with an expansion joint
- Suited for
- ADU, rental, guest house, retirement cabin
- Format
- PDF instant download
- Sheet count
- 16 sheets + material list
- Licence
- One build, unlimited prints
Room by room
All 16 sheets, nothing held back
What is and is not in the set
Included
- Floor plan, fully dimensioned
- All four elevations and a building section
- Roof plan and roof framing plan
- Foundation plan with slab and porch details
- Electrical, plumbing and HVAC layouts
- Door and window schedule
- Preliminary material list
Not included
- Engineer or architect stamp
- Site specific structural calculations
- Siding or finish specification
- Site plan, septic or utility design
- Editable CAD files, available on request
These come from a professional licensed in your state. The full PDF set is what they need to review and stamp.
Can I use this as an ADU?
Often yes. Many US cities cap an accessory dwelling unit somewhere between 500 and 1,200 square feet, and at 480 sq ft of enclosed floor this plan sits under the lowest of those caps. What differs locally is the paperwork and the site rules, so before you buy, call your planning and building departments and ask:
- What is the maximum floor area for an ADU on my lot?
- Does the covered porch count toward that area or toward lot coverage?
- Do you require an engineer’s stamp or structural calculations?
- Do you require an energy compliance form and a site plan?
Because you receive the complete PDF set, a local engineer can review and stamp it without redrawing the project.
What will it cost to build?
Contractor built, 480 sq ft at roughly $130 to $270 per square foot.
One kitchen and one bathroom keeps the wet work to a single zone, which is where the saving is.
You hire out the slab, framing, roof and glazing and finish the inside yourself.
The porch adds roof area and posts, so price it separately rather than per square foot of house.
Figures are planning ranges, not quotes. Costs move with your region, site access and the finishes you choose.
Who this plan is for
A backyard ADU
Small enough for most size caps, with a real bedroom and a full bathroom so it rents or houses family properly.
Short-term rental
The covered porch is what guests photograph, and one bed one bath is the easiest unit to turn around.
Downsizing
No stairs, no loft and a level slab floor throughout, which matters more every year.
Owner-builders
A plain rectangle, one roof slope and a slab floor. The porch is the only framing that needs care.
Need it changed?
A second bedroom, a wider porch, the bathroom moved, a crawlspace or pier foundation instead of a slab, or editable CAD files: tell us what you want and we will quote it, usually within one business day.
What you are buying
Your licence
One purchase lets you build this design once, on one lot. You can print the set as many times as you need for that build. You may not resell, share or redistribute the files.
Delivery
The download link appears on screen and is emailed the moment payment clears. It does not expire. Find a drawing error and we correct the sheet and resend it free.
Questions buyers ask
How many square feet is a 20×24 tiny house?
Twenty feet by twenty four feet is 480 square feet of enclosed floor. This plan adds a covered porch of about 160 square feet in front of that, so the building footprint including the porch is roughly 640 square feet.
Does it have a loft?
No. Everything is on one level. The bedroom is a full 12 ft by 11 ft room with a door, and the ceiling rises from about 9 ft at the back to about 12 ft at the front instead of being split into a loft.
Can this be built as an ADU?
In many places yes, because 480 square feet is below the size cap most cities set for an accessory dwelling unit. Size caps, setbacks and whether a porch counts toward lot coverage all vary, so confirm with your planning department before you buy materials.
What is in the bathroom?
The bathroom is 11 ft by 6 ft 8 in, long enough for a shower, vanity and toilet with room left for a washer and dryer stack. It is drawn on the floor plan and on the plumbing sheet.
What foundation does it use?
A 5 inch reinforced slab on grade over 4 inches of compacted gravel, with a 12 inch by 30 inch thickened edge under the exterior walls. The porch sits on its own 4 inch slab, isolated with an expansion joint.
Is the porch roof included in the drawings?
Yes. The porch is 20 ft wide and 8 ft deep under the main roof, and it appears on the floor plan, the elevations, the roof plan and the roof framing plan.
Does it include electrical, plumbing and HVAC?
Yes. The 16 sheet set includes an electrical plan with legend and panel schedule, a plumbing plan with riser notes, and an HVAC sheet.
How is it insulated?
The wall detail shows 2×6 studs with R-15 kraft faced fiberglass batts, OSB or plywood sheathing, house wrap and gypsum board inside. Upgrade the batts if you are building somewhere cold.
Does the plan come with a material list?
Yes. A preliminary material list is included, prepared from the same 16 sheet drawing set, with approximate quantities for budgeting.
Can I build it more than once?
One purchase covers one structure. Write to us for a multi build licence if you plan to repeat it.
Need two bedrooms instead of one? Compare it with our 24 by 36 lean cabin plan, or browse the full cabin plans collection.
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