Installing a Foundation for a Modular Raised Ranch
In my last post, I talked about the advantages of a modular raised ranch. Now I’d like to discuss what your general contractor (GC) needs to do to “button-up” one.
Let’s start with what your GC needs to do to create a “split” entry at the front door. Since this requires that he elevate the main floor above “grade” (ground level) at the front of the home, he will need to install a 4’ tall concrete foundation below grade and a 4’ tall wood framed “kneewall” on top of the concrete. This will make the total height of the foundation 8’ at the front door. When the set crew places the modules on top of the 8’ wall, the main floor will be 4’ above grade at the front door. This will leave the basement floor 4’ below grade and place the entry halfway or split between the main and basement floors.
The foundation walls for the other three sides of your home will also be 8’ tall from the basement floor to the bottom of the modules. Depending on the lay of the land, the top of the foundation for each of these walls may be set at grade, 4’ above grade, or elevated a full 8’ above grade. Any walls 8’ above grade can either be concrete or wood framed. Either way, they will sit atop a 4’ concrete “frost” wall that will be installed below grade, making these walls 12’ tall. Since the basement floor is at ground level for these 12’ tall walls, the GC can install full sized windows, which will brighten any rooms finished in the basement. The GC can also install an exit door, which is why these walls are known as “walkout” walls. If you build a drive-under garage in your basement, the foundation walls will also be 8’ above grade.
Completing the Split Entry of a Modular Raised Ranch
The completion of the split entry of a modular raised ranch requires a bit of work on-site by the GC. After cutting the temporary rim joist installed by the modular manufacturer to strengthen the home for delivery, the GC must build the entry landing, install the front door, and construct the stairs up to the first floor and down to the basement. The walls framed on each side of the stairs, combined with a door at the bottom, will close off the first floor and stairway from the basement. This step is required by the building code, unless you immediately finish the basement. You will have to instruct the GC whether you want him to finish the split stairwell with a railing or half wall. If you select a railing on the first floor overlooking the foyer and the manufacturer does not install it, the GC will have to do so.
The electrician must wire the foyer light so it can be turned on from the top of the stairs, the front door, and the bottom of the stairs. He should wire the front-door light to be turned on from the top of the stairs and the front door. The modular manufacturer should wire the home to facilitate the electrician’s work with both lights. The electrician should also add a receptacle at the landing, and the HVAC contractor will need to bring some heat to the foyer.
Completing the Exterior of a Modular Raised Ranch
On the exterior of the home, the GC will need to install the siding on the kneewalls and walkout walls. If you cantilever the top modules over the basement, the GC must insulate and cover the exposed area under the overhang. Non-perforated vinyl soffit can be used as the cover.
For more information about building a modular raised ranch, see Designing a Modular Home, Modular Home Specifications and Features, and The General Contractor’s Responsibilities for Building a Modular Home in my book The Modular Home.
My First Home – A Raised Ranch
My wife and I bought our first home a year before I learned about modular homes and became a builder. It was a raised ranch built in the 1960’s. It had everything we needed: three bedrooms and two bathrooms on the main floor and a drive-under garage, family room, and third bathroom in the basement. It also had a lovely yard framed by an attractive stone retaining wall.
What is a Raised Ranch Home?
A raised ranch is a one-story home built with a split-level entry on top of a raised foundation. It consists of two levels separated by stairs. The upper level contains the bedrooms, kitchen, living, and dining rooms. The lower level is a finished basement.
In our home, the entry was “split” in that it was built halfway between the first floor and the basement. A platform at the front door connected two sets of stairs, one going up to the first floor and one going down to the basement.
To make the bi-level design work, the foundation was elevated 5’ above the finished grade at the front of the home. The back of our raised ranch had a wood framed walkout with a slider and some full sized windows.
Why You Might Want a Modular Raised Ranch
There are several reasons why you might want to build a modular raised ranch. Elevating the foundation out of the ground can solve problems caused by a high water table. It is often easier to minimize excavation costs on a sloped property by building a raised ranch. Also, if the property has sufficient slope, the low side of the basement can be used for a drive-under garage, which is considerably less expensive to build than an attached or detached garage.
In addition, a raised ranch with a Cape Cod design that has an unfinished second story, offers you a chance to affordably expand your living space. The raised foundation allows you to finish the basement with larger windows. In addition to providing good natural light, the larger windows allow you to build bedrooms in the basement while meeting the building code requirement for egress.
In designing modular raised ranch floor plans, you will need to decide whether you want the front of the house flush with the front of the foundation or cantilevered over the top of the foundation. A cantilevered home, which is often preferred for its look, will have a foundation that is a foot or two narrower than the main floor, which means it provides less usable space in the basement. You will also have to decide if you want the front entry to be flush with the front of the house or recessed. An advantage to a recessed entry, in addition to its appearance, is that it provides some overhead protection from the weather for anyone entering the front door.
When thinking about the basement floor plan of your raised ranch, pay attention to where the split-level stairs are located. This is particularly important if you are building a drive-under garage, since the stairs should not intrude into the garage.
Modular Split Level Homes
“Split-Levels” are usually T-shaped ranches that are composed of a ranch on one leg of the T and a raised ranch on the other leg to create a tri-level design. They offer some of the advantages of a raised ranch, although they do not work well on a flat lot with a high water table unless the ranch wing of the house is built on a crawl space. As with a raised ranch, split levels can also be built with either a flush or a cantilevered front and a flush or a recessed entry. And they can often accommodate a drive-under garage.
For more information about building a modular raised ranch, see Designing a Modular Home, Modular Home Specifications and Features, and The General Contractor’s Responsibilities for Building a Modular Home in my book The Modular Home.
Nominal Lumber Sizes
A two-by-six is not a 2 x 6 when it’s construction lumber.
The framing materials we use for the walls and ceilings of our modular homes are mostly two-by-sixes, two-by-tens, and two-by-fours. You might assume, as I did when I first started selling modular homes, that these designations refer to the actual dimensional sizes of the lumber. But a two-by-six is not 2” x 6”. It’s actually 1 ½” x 5 ½”. In fact, the 1 ½” dimension can be as little as 1 3’8” or as much as 1 5/8” and the 5 ½” dimension can be as little as 5 3’8” or as much as 5 5/8”.
Why Is Lumber Labeled with Nominal Sizes
In residential construction in the United States the framing materials are designated with a “nominal” value, which approximates its size. For example, a 2 x 10, which is close to 2” x 10” but actually 1 ½” x 9 ½”, is given the name “two-by-ten”. This makes sense when you understand a little history.
In the past, the nominal dimensions given to the lumber were the sizes of green lumber before it was dried and planed smooth. This process shrunk the lumber by about ½” in each dimension. The lumber sold today for residential construction is already dried and planed. But it’s still sold in the historical sizes with each size retaining its nominal name. That’s why your modular home will built with “two-by-sixes”, “two-by-tens”, and “two-by-fours”.
Nominal Sizes of Modular Floor Plans
Nominal values also play a role in designating the width of modular home floor plans. For example, a “twenty-eight x forty-four” home is actually 27’6” x 44’. In this case, the width is rounded up by 6”.
For more information about nominal lumber size, see Designing a Modular Home in my book The Modular Home.
My Introduction to Radiant Floor Heat
Twenty years ago I visited another modular builder’s residence on a cold February day. It was a nicely appointed cape cod with a front-to-back family room on one side and a complimentary garage flanking the other side. When I entered the family room I was immediately struck by how comfortable I felt. At first I thought it was the number and style of windows that looked out onto a peaceful snow covered patio. Then I thought it was the decor, which was richly traditional. The builder’s wife, who was giving me a tour, smiled and said, “You look confused, and I bet I know why. Your feet are warm.” I undoubtedly looked even more confused until she explained that the tile floor had radiant floor heat.
Forced Air Heat vs. Radiant Floor Heat
Have you wondered why you sometimes (maybe always) feel cold even though the thermostat for your forced hot air heating system is set to 72 degrees? It’s not you! It’s because the warm air rises to the ceiling and falls back down as cool air. Your toes become cold why your head stays warm. This effect is amplified by the on and off cycling of the system, which warms you quickly but then chills your bones when the air stops pumping through the ducts.
With radiant floor heat, on the other hand, the heated floor transmits its warmth to the surrounding objects. You remain comfortably warm because the coldest air is at the ceiling rather than your feet, and the floor and everything it touches remains at a constant temperature. By warming you from your feet up, radiant floor heat keeps you feeling toasty at a lower temperature.
Radiant floor heating systems can heat an entire home or individual rooms. Bathrooms, kitchens, and mudrooms are popular candidates for this enhanced comfort. When installed in selected rooms, the temperature is controlled with individual thermostats. The remaining rooms are heated with a conventional system.
Two Types of Radiant Floor Heat
There are two basic types of radiant floor heat: hydronic and electric resistance. Hydronic systems pump heated fluid through small tubes under the finished flooring. The fluid is usually a mix of water and anti-freeze, such as propylene glycol The heat source is a boiler, water heater, or heat pump, with the heat transferred by the recirculation of the fluid between the floor and the heat source.
Electric resistance systems work with electric wires set underneath the floor. They function much like the wires in an electric blanket. Because they use fewer components and are easier to install, they are less expensive to set up than hydronic systems for single rooms. However, they are more costly to operate.
Installation of Radiant Floor Heat
Both types of radiant floor heating systems can be set in a concrete, mortar, or gypsum bed, placed under the floor covering, or attached directly to a wood sub floor. The tubing for radiant floor heat can be installed in specially made plywood with precut channels, which enables you to install carpeting and wood flooring directly over the plywood. Ceramic tile floors should be cast in a mortar bed or on a cement backer board, while vinyl flooring needs to be placed on an underlayment.
Finished Flooring over Radiant Floor Heat
You can use most any type of finished flooring over either type of radiant floor heating system, although some materials work better than others. Tile, stone, and concrete transfer and hold heat best. Solid wood floors will shrink and expand because of the heat, but the new “engineered wood” floors hold up better. If you install vinyl or laminated flooring, make sure they can withstand the heat. Keep in mind that carpets will reduce the heat flow, as they will act as insulation.
Advantages of Radiant Floor Heat
Radiant floor heat has a few notable advantages over conventional systems in addition to superior comfort. Many people like the fact that they’re hidden and silent. If you’ve ever lived with banging radiators or whistling registers, you’ll appreciate radiant floor heat. Anyone with allergies will value them because there is no dust- or allergen-blowing ductwork. And for those who want to increase the energy efficiency of their home, radiant floor heating systems are an efficient way to heat, increasing comfort as they reduce energy costs.
For more information about installing radiant floor heat, see Modular Home Specifications and Features and The General Contractor’s Responsibilities for Building a Modular Home in my book The Modular Home.
The Advantages of One-Story vs Two-Story Homes
There are a variety of ways to compare the advantages of a one-story vs two-story modular home. In part your choice will depend on your personal taste as well as your local real estate market. But you will likely also consider the distinct advantages of each. Here’s a list of the advantages most often mentioned by my customers.
One-Story Benefits
- More living space
- You don’t need to use square footage for a staircase to the second floor, although you will need one to the basement
- You might need fewer bathrooms
- More attic space for storage
- More basement space for storage
- More convenience
- You don’t need to run up and down stairs to cook, clean, keep an eye on your children, do the laundry, or get a snack
- Safer for younger children and easier for older/mobility challenged individuals
- You can “age in place” more easily and affordably
- Easier to evacuate in case of a fire
- Less noise transmission, since sound does not travel through the walls of multiple rooms on the same floor as well as it travels between floors
- TV or stereo on either floor
- Foot traffic on the second floor
- Stair traffic
- Easier – and cheaper – to heat and cool.
- More consistent temperature zones, since all rooms flow into each other
- Trees can provide more shade
- Second story rooms easier to heat, since heat rises
Two-Story Benefits
- Greater separation of public and private spaces
- More privacy for second story bedrooms, which is especially valued by parents and older children
- Bigger yard
- Can build a bigger home on a smaller lot
- Easier to deliver modules down narrow streets and onto a small, tight lot, since each module can be half the length to create the same square footage as needed for a one-story
- Safer to open second story windows at night
- Smaller roof to maintain
- More expansive views from second-story
- Good exercise using the stairs everyday
- Better for the environment, since less land is disturbed during construction
For more information about the benefits of building a one-story vs two-story home, see Designing a Modular Home, Modular Home Specifications and Features, and Finding and Preparing a Building Lot for a Modular Home in my book The Modular Home.
