Why don't you first check with your local building department (if you have one) to see what drawings, specifications and calculations they require for a building permit and an occupancy permit. Also ask if they require a licensed professional's stamp on the documents. You might also want to check with your lender to see if they have any requirements for the type and detail required for drawings, specifications and calculations.

Good luck on your project.

Thank you for your reply VirgilCarter!

I was wondering if the quality of work and expense of online design was a valid option to consider. As most things on the WWW, one must consider- Is it a sham? That is more to the point of my question.

We had modifications made to the plan we purchased. We did our homework on the company's reputation and did speak with our builder before we signed an agreement to have the modifications done.

we purchased our plans, with modifications, online and the purchase turned out very well
we are building in south texas. inland 1 storm requirements were added by the county storm folks, which took a month or 6 weeks, the builder had no problems at all with the plans
the plan was in southern living magazine for years, but we went to the architect's website to purchase it, modifications were done quickly and at a nominal fee

lethargo, I understand your interest in trying to determine if online plans are a reasonable investment.

And I understand that you are considering that having the online plan source make changes is an additional area of expense and concern.

Many homeowners who consider buying stock plans from plan factories may consider some functional changes they would like in order to make the plans more closely fit their lifestyle and budget. And they wonder how much it will cost to make these plan changes. Is it more economical to have the plan factory make the changes or have the changes made by a local drafter?

This is a reasonable question, but there's much more to consider than simply plan changes.

Homeowners may not even be aware that there may be a number of other changes to the stock drawings and specifications that may be required by local building agencies and lenders before the plans can be approved and construction can be started!

My point was (and is) that stock online plans do not and cannot respond to the local conditions required by the local building authority having jurisdiction and/or a lender for construction and permanent financing. That's because they have no way of knowing what requirements (if any) these two authorities may have.

Over and above that, stock plans do not account for local site, utility, climatic and other special conditions which may require additional design fees and construction cost to the homeowners. In many cases, stock plans do not include site plans; foundation plans; framing and structural plans; electrical, lighting, signal plans; HVAC plans; interior elevations and details; finishes; etc. All of these then become the responsibility of the contractor to price and provide for the owners.

Thus one is well advised to find out what the local requirements are so that it's possible to evaluate what one gets from the plan factories and what additional work and expense may be required.

I'm simply suggesting that there may be a lot more to adapting a stock plan for construction than a homeowner's desire for changing the size of a bedroom or adding a third stall in the garage.

Do all of your due diligence as to what is required for building in your area and get as complete an expense budget as possible (in addition to the cost of the stock plans and any modifications) before contacting the plan factories. Then you will know what has to be done and what would be nice to have done.

Good luck on your project.

Thank you very much for sharing your experiences.

We have some meetings arranged for next week. Very exciting!

Thank you VirgilCarter for your input!

Some pre-packaged design companies provide structural drawings and/or specifications and some do not. Some provide custom alterations and some do not. Some farm that work out to people working from home on their laptops.

Some of the designs are prepared by professionals and some by semi-professionals and some by amateurs/students and many are simply copied from other sources.

Very few of the sites have any idea of architectural style and will list a house design under 3 or 4 different style categories. Unfortunately there is no simple way to describe an Italian Renaissance inspired English Cottage with a hipped French roof.

"...Very few of the sites have any idea of architectural style and will list a house design under 3 or 4 different style categories. Unfortunately there is no simple way to describe an Italian Renaissance inspired English Cottage with a hipped French roof..."

How about nonsensical? Or silly? or just ugly?

Sorry, but I couldn't resist the "simple" challenge...

Back to business...

We purchased a stock plan based on the basic floor plan and outside look, knowing that we already had our lot purchased. I asked for modifications that included a cantilevered window in the bedroom, expanded garage, changing the 1/2 guest bath to a full bath etc.. We are acting as GC. Our builder said that some pieces (floor joist spacing) were undersized and not to code and some parts were just too robust and unnecessary for our build. All in all the build is going well (trades are finishing up next week) and we've run into very few problems. The experience worked well for us but that is in part due to an experienced builder that was able to make slight adjustments to the plan.

I always flinch when anyone bases the design of floor joists on the building code. The code span tables are based on a deflection limit of Length/360 at full design loading in order to avoid cracking plaster on wood lath, an archaic, inappropriate standard.

Floor joists should be designed to avoid a bounce in the floor for greater comfort and that can only be achieved with good judgement from an experienced designer.

Unfortunately that is often not the case with internet pre-designed houses and home builders.

In the absence of experienced professional design I suggest using at least the next strongest joist design in the table.

Beams are also designed to a deflection limit of L/360 which is usually adequate but not always. There is no substitute for experience in the design of buildings. The building code is a minimum standard rather than a reliable design guide.