One of the most important parts of building a tiny house on wheels is planning its interior dimensions. With space at an absolute premium, you need to ensure that every centimeter is put to use, and that no area is looked over.

So what are the interior dimensions of a tiny house on wheels? This article is divided into two parts: Part I discusses the trailer, road limits, and size limitations defined by the foundation trailer of a tiny house on wheels; Part II discusses the interior measurements of each room, the art of planning your tiny house floor plans, and the thickness of your tiny house walls.

Part I: Starting from the Ground Up: Your Trailer

For any tiny house on wheels, your trailer defines the potential size of your tiny house. After all, you can’t build a tiny house much bigger wider or longer than the actual trailer it sits on. Most tiny houses have a few inches of overhang on either side – anywhere from 1.5” to 6” on each side – so to understand the potential dimensions of your tiny house, let’s start with your trailer.

How Big of a Trailer Do I Need for a Tiny House?

Tiny house trailers are defined by the road limits. We go more into the actual numbers by state for road limit regulations in another article, but typically you can expect the average tiny house trailer to clock in at 24’ long and 7’6” wide.

Legally, the road limit for a tiny house on wheels without any special permits varies by state, but it averages at around 40’ long and 8’6” wide. However, most tiny house trailer manufacturers insist on sticking to a 7’6”-wide trailer, allowing for about 6 inches of overhang on either side of the tiny house. Going longer or wider than this will make it difficult to find legal towing for your tiny house.

Read more: What Size Trailer Should I Use for a Tiny House?

Can a Tiny House Be 10 Feet Wide?

With the road limits in place, does that mean it is impossible for a tiny house on wheels to go 10 feet wide? Not at all. There are plenty of tiny houses on wheels that are 10 feet wide, but how do they get around the typical 8’6” road limit?

They acquire a temporary wide load permit. A temporary wide load permit isn’t actually difficult to obtain, as these usually need to be processed quickly and promptly in the trucking industry. A temporary oversize load permit is required if your towed tiny house is:

• Taller than 13”6
• Wider than 8’6”
• Longer than 48’ (the trailer alone)
• Heavier than 80,000lbs (which a tiny house will never have to worry about, although a tiny house weighing in at 16,000lbs and above will require a larger rig to tow it)

These permits can typically cost around $65 each, as one permit will be required for each state that you drive through. If your trip will involve crossing the state lines of 5 states, you can expect to pay about $325 in permit fees.

If you do not intend to frequently travel with your tiny house on wheels, then the 10 feet wide option might be a great possibility to consider. That extra 1.5 feet can be the difference between a cramped tiny house with tons of bumping around, and one with just enough space for your family.

Here’s one 10-ft wide tiny house, where you can see ample space that you wouldn’t normally find in a tiny house:

What is the Biggest a Tiny House Can Be?

Now that you know we’re technically allowed to break the 8’6” limit (with the presence of a temporary wide load permit), you might be wondering – how far can we go with tiny house sizes? Is 10 feet really the widest?

While many in the tiny house community already consider a 10-ft wide tiny house “supersized”, there are actually some examples of 12-ft wide tiny houses on trailers. Check out this video from Exploring Alternatives where they talk about a custom-made 12-ft wide tiny house built for a senior who needed all his floors on the same level, rather than a lofted bedroom:

But if you really want to push the envelope with your tiny house, simply going wider and wider might not be the best move (at some point, you might be too wide for the road even with a permit!). To maximize your floor area, consider a longer trailer, with the longest trailers going up to 44’.

At these lengths, you would want something stronger than your typical flatbed trailer. We recommend a gooseneck trailer, which would allow you to build over the gooseneck for a few extra feet. Check out this 37-ft long tiny house, built on a 30-ft long trailer with an extra 7 feet built over the gooseneck:

What does the floor plan look like for a tiny house this huge? Something like this:

If money and time are no concern, then building the biggest tiny house you can build can be a pretty interesting endeavor. But remember, the permit isn’t the only thing stopping you. There are some logistical issues that you will always need to think about, such as:

• Is your tiny house too wide to be transported safely on the road, even with a permit? Will the road have enough space to share?
• Are the axles on your trailer strong enough for the length and weight of your supersized tiny home?
• Is your tiny house’s weight above 16,000lbs, in which case you would need a larger rig? (The average tiny house is about 8000 – 10,000lbs dry weight)
• Is it too tall for certain roads?
• Is it still weather-resistant? You don’t want to stretch one dimension too far, or you risk your tiny house becoming unbalanced.

Part II: Tiny House Interior Dimensions

With tiny houses on wheels, space is a premium. Every inch needs to have a purpose, and every item needs to have one or more functions. To get the most out of your tiny house experience, it is essential that you plan your interior dimensions long before you start building on top of your trailer.

The Average Tiny House Floor Plan

After figuring out the size of your tiny house trailer, you should be ready to start drafting up and planning your interior dimensions, starting with your floor plan. So what is the average floor plan when it comes to a tiny house? 

In an average 8’6” x 20’ tiny house on wheels – not too small and not too big – the average interior dimensions are as follow:

• Great Room: 6’8” x 15’2”
• Kitchen: 4’3” x 8’6”
• Bath: 2’2” x 6’8”
• Sleeping Area (Loft): 6’8” x 8’6”
• Storage Loft (opposite end): 6’8” x 27”

This space makes up about an interior space of 172 square livable feet, without including the bedroom above. With those numbers, the average tiny house floor plan can be visualized like this:

The biggest part of most tiny houses is the great room, or the living room. This is followed by the kitchen and the bath, with no need to account for the sleeping area as this usually sits in a loft above the kitchen and bath.

However, remember that this is the standard layout. Most tiny house owners do their best to find creative solutions to fit their needs. Figuring out your necessary solutions begins with isolating your potential problems – and this means understanding the specific items, appliances, and more that you will have in each room.

Breaking Your Tiny House Up

Your interior dimensions should depend on you and your family’s personal needs. For the typical family, there are certain items you will need for every room, and certain items that might be disposable or unnecessary for your lifestyles. Here are the breakdowns for typical necessary (and perhaps unnecessary) items for every room in a tiny house:

Great Room

The great room is where you will spend most of your time when not in your bedroom loft. This area can be as simple as a couch or chairs that fold into the wall, or if you prefer a few luxuries, this could also be known as your entertainment center. Some items you may want to include:

• Televisions: Most televisions in tiny houses are mounted to the walls. Other tiny house families use a small projector, projecting the image from a laptop onto a roll-down screen attached to the clearest wall.
• Computers: The obvious computer solution for tiny house living is a laptop or tablet; a desktop would take up too much space. For Internet, you can mount your satellite to the roof for signals.
• Sound Systems: There are many small options for great speakers these days – Bluetooth speakers connected to phones or, if you want to get more creative, car speakers can be mounted to the walls with 12-volt batteries. The space is small enough that larger speakers are totally unnecessary.

Kitchen

When you are tiny house living, you will be using your kitchen for every single meal (no deliveries when you’re off-grid!). But with space in high-demand, you will have to decide which appliances are necessary and which are expendable. 

• Microwaves: Microwaves are small and compact, making them a great tiny house companion, but some tiny house owners prefer to do away with the microwave since they do nothing that a stove can’t do. Is it worth the loss of a small extra space or not? Microwaves also use a ton of power, making it more difficult to live off-grid.
• Dishwasher: Dishwashers are a definite luxury with tiny homes, and one of the first kitchen appliances tiny homeowners do away with. The weight and size adds a ton of extra burden to the house, and their function can be replaced with a simple sponge and cleaning towel.
• Refrigerators: You will want a refrigerator that can run on three types of power: AC, DC, and gas. This means you will be able to use it whether you or connected to the grid or not, if you decide to go for solar power, and if you only have gas on hand. Remember: power is at a premium as much as space. You can only get a “normal” residential refrigerator if you have a constant source of grid-connected power.

Bathroom

Your bathroom will depend on your needs and how much time you intend to spend in the tiny house. If your tiny house is to be your new permanent dwelling, then you should invest as much time and thought into your bathroom as possible. If not, there’s nothing wrong with just a small toilet and a sink.

• Toilets: The major potty question tiny house owners have to deal with: compost toilet or regular? If you intend to go off-grid, you will definitely need a compost toilet (or something similar, such as an incinerating toilet or cassette toilet). If you will stay hooked up, you can enjoy your regular RV toilet connected to a water tank.
• Showers: It may surprise you, but showers are not always present in tiny houses. Some people opt to shower outside, wherever they may be parked. For homeowners that need to have a shower, they generally choose to install wet baths, in which the shower hose hangs above the toilet.
• Sink: To sink or not to sink? This depends on you and your family. Are you fine using the kitchen sink for all your handwashing, facewashing, and toothbrushing needs? Will this ever interfere with your cooking? If it’s a problem, then a small sink in the bathroom will be necessary.

Bedroom Loft

Since the bedroom loft is generally not included when talking about the livable area of a tiny house, you can think of this as extra space; although there still isn’t much to go around. Lofts in tiny houses are generally only big enough for a fold-up bed or futon, a small light, some pillows, and not much else. 

An experienced builder can build in some bookshelves along your ceiling, or even install a TV mounted above the bed for that late-night viewing experience. With hardly any space to work with, the bedroom loft is where you will need to be most creative if you want anything more than the bare necessities.

How Thick Are Walls in a Tiny House?

Building a tiny house means accounting for every inch, so you need to think about the thickness of your tiny house walls. Your house’s wall thickness will mostly depend on the thickness of the timbers, which is determined by the thickness of the insulation inside the wall. Thicker insulation requires thicker timbers.

The typical tiny house with standard 2”x4” wood to scale has exterior walls that are just about 5” in thickness, with interior walls that are just about 4.5” in thickness. This is accounting for the drywall.

The typical exterior wall is made up of:

Layer, from inside to out	Size
Interior Drywall (decorated inside)	0.5”
2”x4” Timber frame wood	Only 3.5” due to milling
Exterior sheathing for frame stability	3/8”
Cladding, or exterior siding, can be metal or wood	About ¾” if wood
Total Thickness	Just over 5”, or about 13cm

While 5” doesn’t seem like a huge amount, remember that this needs to be added to both sides of your tiny house, meaning at least 10” of your 8’6” width is used simply for the thickness of your walls. Tiny house homeowners driving through colder areas will also need an extra 1-2 inches of foam insulation, adding another 2-4 inches to your wall thickness.

If you intend to have truly formidable walls, there are tiny houses with walls up to 9 inches thick, but have the most stability and protection from the weather.

Tips For Optimizing Your Tiny House Floor Plan

Ready to start drafting up your floor plan? Here are some tips before you go:

Doors:

• Draw the swing of the door, and make sure that it doesn’t collide with anything else in the room. If a normal door swings out too much, try installing a pocket door instead.
• Corner doors should be given an extra 3 or 4 inches away from the corner, as you will need some room for trim.
• The standard door in a North American home is about 3’ wide, but this can be a problem with tiny house measurements. You might need a custom door, or find a 2’ wide door from a seller.

Windows:

• There are all kinds of windows, and your plans should account for your window choice. Don’t try to imagine the windows before you see them. Know which windows you intend to install and draft them into your tiny house plans.
• Indicate the swing direction of your window, whether it goes out or in.
• The usual widths for windows in tiny houses are 1’-6” and 2’-6”.

Kitchen, Furniture, and Bathroom Dimensions:

• Don’t try to wing it when it comes to planning your furniture. Plan out every chair, table, couch, and more, with a measuring tape if the furniture is already available. Add these numbers to your floor plan.
• Give yourself at least 3 feet to work with in a kitchen; going smaller than that can make cooking incredibly difficult. 4 feet should be even more comfortable, if you can work it in. A foot or two is definitely not enough space for your cooking plans.
• For a good time in the bathroom, you will want to space out 15 inches on either side of the toilet from the center of the toilet. This will give even bigger adults even space to do their business. You should also try to afford at least 21 inches from the front edge of the toilet forward.

Here’s a great sample of a floor plan to scale with the tips from above:

Your Tiny House, Your Floor Plan: Be Creative and Enjoy!

The tiny house movement is all about sustainable, personalized, fun living. We want to live free in our own ways, and that means designing a house to fit all our own needs and quirks. 

Make your tiny house plans with maximum yet realistic creativity in mind – get the most out of your space, in your own ways, and build a tiny house you will share with your loved ones for years.