Ok, so I realize that modular homes or system built home (not HUD home/trailers and not mobile homes) are not a new concept. I have researched these and am still on the fence about them. Their system seems very sound and logical in building in sections, much like SIPS, in a factory and them assembling all the pieces at the home site. They advertise that the cost savings is significant over stick built homes for a variety of reasons (again, all logical and I can see how they save money). My question, is what are peoples opinions of modular homes and does anyone have any personal experiences they would be willing to share?

I'm a custom builder, had the same questions so I decided to build one & sell it. All in all it went well, except that it was a cape with unfinished second floor which I finished on site. I realized too late that getting all the trades into the house hadn't made sense in terms of evaluating the mod company. Cost turned out to be comparable to building on site. A house that did not need further finish like a ranch, would probably end up a little cheaper. My one problem was that both main floor sections were racked at the joining beam about 3" in opposite directions. the setting company recommended by the manufacturer shrugged his shoulders & refused to deal with it; likewise the manufacturer, so I spend some time tapering the wall joint & repairing the problem. I should mention I had specified a 16' opening where the two units met - I don't know if this would have happened if it had interior drywalled walls. Interior finishes done at the factory were done well.

The house is cheaper than site built when it leaves the factory, but it isn't complete. It still needs a boiler & connections, water pump & tank & connections, electrical panel, foundation, exterior steps, plus finishing roof shingles, exterior siding, exterior trim and interior finishing where the units join. Some dealers go cheap on these things to keep the cost down, so you should look at some units the dealer has completed & pay special attention to what he did on site.

There were too many complications (heights/widths etc) in building trhe type of houses i was interested in, so I did not pursue it further. There is a new manufacturer locally now who is building very energy efficient buildings, so I will check them out.

I have worked on several modular projects. Four different suppliers, and both conventional and SIPS construction. Each had its own pecularities, both good and bad. As Bob said, they all start out less expensive at the factory, but loose some or all that cost difference by the time they are finished on site. I like the concept, and under the right conditions, I think they are a good value. The quality is generally as good or better than site built, they are certainly built stronger than site built conventional stick frame. If I had a good source closer to my location, I would defiantly use them for some projects.

I recently completed a home with R40 SIP walls built modularly in PA.  My home is in Massachusetts.  I have posted everything about the project on a website I created to help people like yourself.  While I GCd the project, I am not a builder.  The site deals with everything from the foundation to the finishing touches including how I dealt with many of the issues along the way.

Yes, there was still quite a bit of work to be done onsite.  However, I am fairly certain that I could not have afforded this house if it were not built in a factory.

Check out www.GouinGreen.com.  I also advise you keep trolling through the tons of useful stuff on this site. 

Good luck,
Ed