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Modular homes (also known as prefabricated houses or prefabs) have been around for many years. They were originally designed to give cheap and quickly built housing for people who needed a home and who either couldn’t afford to buy a traditional house or found there weren’t any available. Often this meant they were reserved for economic migrants and victims of disasters.
Prefabs went through a period of being an ‘undesirable’ home, often being built of sub-standard or harmful materials, with little or no regard for energy efficiency. In the UK there were many thousands of prefabs built after the Second World War to house the victims of the Nazi bombings of London and other major cities. They were prefabricated as concrete and asbestos panels and assembled on site to form essentially a concrete, single storey box. These early prefabs were very basic, with probably a tiny kitchen, living room, bathroom and two bedrooms. The walls were a single 4” thick concrete skin with metal window frames. No cavity in the walls and very little insulation. They were very cold in the winter and very hot in the summer. Not very pleasant to live in, but better than being homeless. Prefabs had a bad name!
Today we don’t call them prefabs, we call them modular homes. They are built in a factory and consist of two or more standard designed boxes (or modules). The construction is usually timber frame and incorporates many modern energy saving innovations. The technology is now available to produce a fully 100% energy efficient, safe, affordable and cost-effective home that is fully able to be customised to the client’s wishes.
Modern prefabs (or modular homes) are built in a factory as boxes designed for a specific function. They comprise a timber framed shell (including floor), complete with plumbing, electrical wiring, windows and doors. The shell is fully insulated and incorporates all the modern building codes and regulations required for traditionally built houses.
The customer chooses the number of modules required for their home, depending on purpose of room, how many occupants etc. They can even choose from a variety of external and internal styles and have the plumbing and wiring fitted in the correct locations for their requirements. All modules and the roof are fully constructed indoors so there are no holdups caused by bad weather and poor light. It is easy to inspect the various stages to ensure the building codes are exceeded and to fit modern environmentally friendly accessories. It is perfectly feasible for construction to happen continuously 24 hours a day, 7 days a week if necessary. The modules are then delivered to site to find concrete foundations and a concrete floor ready-made and waiting. The modules are quickly fitted together, made weatherproof and utilities connected to the mains supplies.
Once built there is almost no visible difference between a modular home and a traditionally built home. They are also generally cheaper to build than equivalent in-situ built houses.
Modular homes are NOT the same as:
HUD Homes. The Housing and Urban Development division of the government regulates manufactured homes and mobile homes. They describe the difference as being:
Manufactured Homes. (Also known as mobile homes or trailer homes) These are built in factories like prefabs and modules, but there is no construction that takes place on site. They are built on a steel sub-frame and fitted with wheels. They are towed to site and positioned on a concrete slab. Often the wheels remain in position and are covered by side skirting to disguise the fact that they are manufactured homes. These buildings are usually a simple rectangular single storey box, less than 16 feet wide (as they have to be transported by road). This type tends to have many maintenance issues and a short lifespan. They are removable and can be placed almost anywhere, they therefore do not have to comply with local or state building codes. They do , however have to comply with HUD codes. These homes require a mobile home insurance policy.
Panel built buildings. This is another form of prefab home that uses prefabricated panels, made in the factory and transported to site. The wall panels are then craned into place and fitted together. Commercial buildings are often constructed using this method. It is also less expensive to transport as panels rather than modules. Because these are not movable they have to comply with local and state building codes. These require a homeowner’s insurance policy.
The biggest difference between modular homes and these other prefab types is the standard of workmanship. Modules are built completely indoors with high precision. Using on average 25% more material than either site-built or manufactured homes. They survive extreme weather better than other prefabs and require less maintenance. When modules are assembled on site and connected to utilities, the Building Codes inspector has to inspect these as if they were a traditionally built house complying with local and state building codes.
Yes they are. The main reasons why modules are quicker to build are:
Design. Normally you will be choosing one from a selection of available designs. Even if you are not using a standard design but have decided on a customised one, most of the customised features are usually superficial and are easily incorporated into the standard module. This is mainly because of the restrictions imposed on modular size. Each module cannot be longer than the transporting flatbed truck and cannot be wider than 16 feet.
Controlled factory environment. Modular houses are built inside and away from the extremes of weather. There are no stoppages due to rain, wind or snow. Work can continue in a well heated, well-lit and ventilated factory environment, 24 hours a day, and 7 days a week. Construction workers will not be hampered by having to wear bulky weatherproof clothes. All modules can be cut and fitted together using electrically powered bench saws with templates, pneumatic hammers and screwdrivers, and built on an accessible work bench or platform, unlike traditional building methods where access is often difficult or at height and work is limited by the weather.
More economic use of materials. Materials can be :
Safer environment. Construction of the modules takes place without the use of on-site scaffolding. Site safety can be under stricter control with less chance of accident and injury. All modules are built as a single storey box; it is only on site when they become two or three storeys high. Access is easier. As most power tools are bench mounted there is less chance of personal injury.
Modules can be built at the same time. In a traditional build, all stages must be done in a strict sequence of events.
In a modular build, all rooms can be built, complete with electrical cables, electrical fittings, doors and windows at the same time. Even the roof can be constructed alongside the other modules.
On site, the concrete foundations and concrete sub-floor can be built at the same time as the modules.
It takes fewer man-hours to build a modular home. Not only does it take less time to build a module but the labour charges are less as well. The average construction worker building a site-built house will have multiple responsibilities and jobs. He will have to be an expert in many fields. For example a carpenter will need to be expert in installing flooring joists, windows, doors, roof timbers and much more. He will have to make decisions on how much of the supplied timber length he must cut and must know the correct ways of joining wood together.
He must be able to do all this with the minimum of equipment; most of the equipment is used by hand. He must be able to do all this while the wind is blowing a gale and the rain is pouring down or the snow is drifting. A worker in a modular building factory is far more specialised. The modules are built in the same way as a mass production line. A modular worker may only do just one job every day, all day. He is a specialist in his one job. He can therefore do his job faster than someone on site. The wood machinist does nothing but cut timber to the correct length. The assembler does nothing but assemble the frames. He will do that job faster and more efficiently and needs less training than an on-site worker. His costs are therefore lower.
No-one would be so silly as to claim that their modules were indestructible when subject to extreme weather, but it has been proved many times that modular homes withstand extreme weather better than other types of home, including traditionally built homes. This is mainly because:
The modules are designed as ‘stand-alones’. All the building loads and stresses are contained within the box and do not depend on the structural integrity of other parts of the building like in-situ built houses. The situation can be likened to building a toy house from toy blocks as compared to building one from playing cards. The construction system provides for an inherently stable and rigid structure.
The homes have quality workmanship. Each module is built like a car on a mass production line. It is one person’s job to do just one task rather than many. He is trained for that one task; he has the necessary tools and quality controlled materials cut to the correct size. There is no ‘hit and miss’, everything is constructed correctly every time.
As the homes are built indoors in clean and dry surroundings, the quality control procedures are easily followed. Not only are the modules inspected for local and state building codes but also for quality control at each stage. They are inspected far more than an in-situ house will be.
When looking at the various websites that advertise and offer to build you a modular home, you will find that they all give many and varied costs to build a home. Why is this? What they are quoting is the base price without any extras or customisations. When they are talking about the cost of a module, make sure you know what they are talking about and what the costs are for.
The costs given in this article will only be estimates and be based on the best information available. Your specific costs will be different depending on what you are building and where you are building. When you talk to the modular home construction company always know what the cost should be; what they are talking about and always know the jargon. Make sure you know how close the initial quote will be to the detailed quote and how likely is it that the final cost will vary from a detailed quote. Also know what the ballpark costs should be at every stage.
The Base Price. The base price includes the cost of manufacturing each module using the base plan that you have selected. There will be no additions for customisations or delivery. All this is extra and above the base price.
The Custom Price. When you have decided on the home that will be what you want to actually live in together with any upgrades or added modules such as garages etc, the price is now known as the custom price, but is still only the cost of the work done in the factory.
The Delivered Price. When talking to the manufacturer, he may say something like “This will cost about $200,000 to have your home built and set up.”
Firstly, this may or may not include delivery of all the modules to site. Probably it won’t include delivery because that will depend on how far the factory is from site. Delivery can in some extreme cases be in the tens of thousands of dollars.
Secondly, when the manufacturer says “set up”, you will hear “finished”. Sorry but he doesn’t mean that. “Set up” means putting the modules on the foundations and fixing them in place. This includes fitting the modules together and attaching factory made roofs. It does not include attaching utilities and drainage, any additional roofing and it certainly does not include building the foundation and sub-floor.
Thirdly, Delivery cost is the largest unknown here. Find out if they have delivered a similar number of modules to anywhere in your area and try to get a ballpark figure for delivery from them.
The Finished Price. OK. The finished price includes all the prices we have already spoken about plus:
These tasks are not done by the manufacturer but will be tackled by the general contractor you have hired to do these jobs. These therefore will vary depending on the contractor’s day-rates and material costs that he may quote you.
The All-in Price. This is the total cost of everything mentioned so far in building your home and includes extra costs to do the following:
Ok. So we have now mastered the jargon but how will these different costs change as we go along the timeline from deciding on a design to having a finished product?
|Type of Price||How close will initial quote be to the detailed quote?||How likely is the final cost to be different to the detailed quote?||Average price per square foot.|
|The base price||The same||Extremely unlikely to change.||$60|
|The custom price||Almost the same||Unlikely to change.||$70|
|The delivered price||Very accurate||Unlikely to change.||$75|
|The finished price||Nothing like the initial quote. Better wait for the detailed quote.||Extremely unlikely to the same||$120|
|The all-in price||Wait for the detailed quotes. Don’t even think about the initial quote.||They will be different.||Almost impossible to estimate.|
We now know how the various quotes and costs given to you by the manufacturer and the general contractor will vary from the actual figure you are likely to pay. We can now talk about where all that money is going to.
You must bear in mind that any figure given here is an estimate only. As always, estimates can and will vary depending on many factors. Among the most important of these factors are:
The following table includes figures that while not necessarily exact will give you an idea of the ratio of the different component costs for an average one storey modular home, done in a ranch style with three bedrooms, two bathrooms and having an area of approximately 1800 sq. ft.
|Land||$15,000||An acre of land can cost as little as $1,000 for a building plot or as much as $120,000. Our 5 acre plot cost $10,000 plus fees and tax|
|Base price||$95,000||This is the cost of the home as per manufacturer’s standard plans. This is without customisations and extras.|
|Customisations||$35,000||The manufacturer’s standard design is almost what we want. However it just needs a few alterations and customisations to make it the home that we really would like. Examples are a two car garage, hardwood flooring, upgraded kitchen appliances, better insulation, higher quality doors and windows. Never underestimate the cost of customisations. We are paying an extra amount, just over 36% of the original Base price to get the house as we want it.|
|Site preparation||$6,500||Preparing the site is an essential and our price of $6,500 is quite low. It would have been higher if we hadn’t chosen a plot of land that was fairly flat and didn’t have many tree stumps to pull.|
|Foundations||$22,500||We wanted a basement incorporated into the house for storage and extra living space. It would have been impractically expensive to do this if our surveyor hadn’t noticed there was a large rock outcrop right where we planned on putting the house. We moved the house slightly to avoid this and now have no problems with digging foundations or a basement.|
|Taxes, fees and delivery costs||$11,000||Not only do we need to pay for the flatbed trucks which will carry the modules, but loads like these need escort vehicles to warn other road users that an extra wide load is approaching. The fees and taxes depend on which state you are in, as all are different.|
|Connecting modules and repairing transportation damage. Finishing off||$20,000||After the modules have been craned into place, they need to be connected, any damage or cracks caused by transportation and any other minor work needs to be done.|
|Extra, on-site building||$10,000||The two-car garage was accounted for in the customisations price. The only other extra was the porch which needs to be built onto the appropriate module.|
|Connect utilities||$5,000||If your plot is near the street then this cost can be as little as $5,000. If you are further away, the cost can rise considerably. If we had chosen to have a well and septic tank installed then this cost would have been more like $20,000.|
|Permits||Total $2,100||Permit costs vary considerably depending on which state or county you are in. Not only do the costs for the same permit vary but also the list of required permits can also vary depending on where you are.|
|Pre-plan review fee||$50|
|Certificate of occupancy||$50|
|All-In Cost||$222,100||This is the cost of my new modular home and includes a double garage, porch, basement, three bedrooms, two bathrooms, upgraded modern kitchen and hardwood floors.|
|Cost per square foot of living space||$123.40|
You might look at some of the components in the previous table and wonder what they are, why they are costed at such a high figure and whether you actually need to bother about them. It is probably worth going through some of the more confusing buzzwords and actually consider what is available and what you can get for your money.
The Base Price. We have talked about this previously but it is actually the cost of the modules without any customisation.
Customisations. The easiest modifications to make on your new modular home are to the exterior. Usually this means just changing the style of a window or what kind of siding you want. Be aware that if you add too many windows you run the risk of interfering with the structural integrity of the module. Changing the roof style by altering the angle or height is often a good change and as well as being easy to do is surprisingly not as expensive as you might think. Another good customisation is the addition of a porch with either a gabled roof or an integral roof.
You must be aware when designing a porch that the building line of the house must not be too close to the street. Check with the planning office for any restrictions to the building line. Some interior customisations are also easy especially the minor ones such as upgrading appliances. Although it might seem easier to have the standard ones and upgrade at a later date, if you upgrade at this stage you will be able to take advantage of the manufacturer’s bulk discounts. Make sure you get Energy Star appliances for the most energy efficient models.
Make sure you have considered what type of heating and air conditioning you will need at this stage. It is often cheaper and easier to do it now rather than waiting until later. You can’t have enough electrical power points so make sure you put in more than the standard amount and make sure they are in convenient locations for you, not the manufacturer. If you intend drilling a well or having a septic tank, bring them up at this stage so the manufacturer can install the correct piping in the modules. One last thing that many people overlook is ventilation. Remember that each module is a sealed unit, is much less expensive to heat or cool and is also less draughty. The converse of this is that there is much less natural ventilation available so if you do not have enough ventilation you will have condensation and mustiness occurring. Have enough ventilation outlets to ensure a proper flow of air throughout each module.
Site preparation. While the modules are being built in the factory, it is time for you to start thinking about preparing the site for the delivery. Employ a surveyor to clearly mark off your plot boundary so the general contractor and manufacturer know where they can and cannot go. You will have neighbours so it is worthwhile keeping in their good books right from the start. You don’t want any unintentional trespassing and you want any boundary disputes to be settled now rather than when the modules have been installed. The ground needs to be cleared of any vegetation, trees and large rocks, and then levelled so that the foundations can be set out. When your general contractor has dug the foundations (or footings) it is time to pour the concrete. Be careful at this stage because anything that goes wrong will be much more difficult to put right. Have the plans readily available so everyone can see what should be where.
Delivery preparation. As well as clearing the site for the foundations you will also need to supply a suitable place for the flatbeds to park, crane to work and the modules to be stored. Make sure this area of ground is level enough for a crane. Plan the route the flatbeds will be taking from the road to your plot and make sure there are no sharp bends or narrow gateways. If necessary you may have to remove fences and gates while delivery takes place and then reinstate them afterwards. Always notify your neighbours that a delivery will be taking place and ask nicely that no one parks awkwardly, blocking the road. Always liaise with the delivery company to find out if they expect any access problems.
Do your homework. This is usually called ‘Due Diligence’ and means that you should do some research about the property before you buy it. Some areas of land are subject to planning and building constraints due to environmental protection or you may not be able to build nearer than a certain distance from your neighbour’s boundary. Do not take the word of the plot vendor, ask at the town hall and get the information in writing before you proceed with the purchase. Even if you have clearance to build on a certain plot, there might be some regulations about maximum size or height of property or even what type of construction materials or colour you can use.
These regulations vary depending on the town or state and can even be different from the next street. Check that the land you are proposing to buy is free from pollution especially if you have children or are planning to build a well. Depending on the previous use of the land there may be severe restrictions placed upon it by the town and they may even stipulate that it is not suitable for a residential plot. The next thing is to find out what kind of soil and rock are underground where you intend to dig the foundations. The best way to do this is with some exploratory digging or hire a drilling contractor to take borehole samples. If the soil samples show significant amounts of clay or loose sand and gravel then special foundations will have to be planned.
Similarly you may find an underground stream or a rocky outcrop that will seriously alter the planned foundations and add many thousands of dollars to the foundation costs.
Connecting Utilities. Most people will be getting their water, drainage, electricity and gas from the town or local supplier. Make sure there are the necessary connections nearby or else it may cost you thousands of dollars to run suitable connections to your plot.
Delivery. You have a house built and waiting to be delivered in the factory and a plot of land suitably prepared and waiting. Now the problem is to get the modules delivered. First of all don’t worry about the trucks. The drivers are very skilled and probably deliver loads like this most days. The manufacturer knows that the modules are to be delivered so they will be built sturdy enough to take the transportation.
The haulage company will plan their route and provide the escort vehicles. It is your job to make sure there is an uncluttered access to your plot and there is somewhere onto which the crane can offload the modules. Normally the crane will have to offload them one at a time and place in a convenient location ready to be lifted into position later. For anything other than a large house, it can take less than a day to place the modules in their correct positions on the foundations. If the weather looks like it might turn then be prepared with tarpaulins to make the modules water-tight until the weather clears up again.
Buttoning –up. The modules have been delivered to your plot and placed in their correct position on their foundations. The manufacturer’s task is now complete and it is up to your general contractor to finish everything off or hire specialist subcontractors such as decorators, electricians and plumbers. This is known as ‘buttoning-up’.
Some areas like basements and porches can only be constructed after the modules have been installed so it is the general contractor who is to do these jobs. Usually these extras will only be started after the modules are made watertight and finished off.
We have talked today about what a modular home is. About how we go about getting a modular home built, from the first approach to a manufacturer through design, customisation and build. Once it’s built we then talked about the way to get it delivered to your plot. With reference to the plot of land, we have talked about contacting the town hall; about getting permits and finding out about building codes and regulations. We talked about taking soil samples to check if the ground is polluted and unsuitable for residential building. We have talked about hiring a surveyor and a general contractor to fix the boundaries, prepare the site, dig the foundations and pour the concrete.
We have talked about problems with delivering the modules to your plot and how to make sure the entrance is wide enough with enough room in the road for manoeuvring the flat-bed truck. You will need a crane to offload the truck and move the modules to a suitable storage next to the foundations. You will also need a crane to lift the modules onto the foundations, one module at a time. When all modules were in place, we then talked about fixing them together, and ‘buttoning up’.
We then talked about building a porch, fitting sidings and finishing off with a driveway and garden. We talked about how the estimated costs very rarely agreed with the actual costs and hopefully realised why this happens. We looked at the different kinds of price with which a manufacturer could unintentionally (or intentionally) confuse you so you ended up paying more than you expected. We built a typical modular home and talked a bit about what each stage consists of and the price breakdown at each stage. From this we had an idea of the ball-park costs and the ratios between the costings at each stage. We then found out a final all-in cost for a typical modular home which met all our requirements.