20x45 two story or 20 x 80 one story

[dablack]

Ok guys, I guess this is my intro thread as well. 

Situation:  I'm a mechanical engineer living in houston.  My wife and I have two girls and we are adopting two more children.  We are also trying to become debt free.  We currently live in a 2200 sqft house near NASA that was built back in 68.  We love the house and neighborhood but it will take 30 years to pay it off (one income family).  With the four kids, I know we are going to need about 1800-2000 sqft.  NOTE:  I know my dimensions above don't give 1800 sqft, I plan to put a utilities room (washer/dryer/etc) on the back of the house. 

Background:  I have restored lots of furniture, built automotive engines, painted cars, pulled and replaced tubs, replaced house siding, done lots of tile and wood floor work, and I'm pretty good at drywall and texture.  I'm about to order some granite and replace the counter tops in the house we have now.  If I can't do it, I will keep trying until I can. 

After the adoption is done, we would like to buy some property in the country and start building a house.  The wife doesn't like two stories but I do like the simplicity of the 20' width.  Which would be cheaper and faster to build?  A 20 x 45 two story or a 20 x 80 one story.  I know the two story would be bigger.  I know the one story would have lots more roof. 

Later I will post asking general questions about keeping the costs down on which ever plan we pick.

thanks for the great site.  I have been reading and reading for about a month now.  I used to want to build a timber frame house but seeing how long those things take, moved me towards stick building. 

thanks
Austin 

[JRR]

"Welcome!" It reads to me as though you have most of the skill sets necessary to launch into house building.

Usually roof area is considered a high cost area ... both initially and long term ... so, the conventional wisdom says to minimize it.  But there are other cost factors ... so my answer is: ... "depends".

My choice, for use and appearance, would be the two-floor plan.  A 20x80 single floor plan would result in a long and skinny looking structure ... and you would have to dedicate a hallway thru most of the length to make it servicable.

The two floor 20x45 plan could be functional with no hallways.  The entrances could be placed in the middle, the center section dedicated to "open eating and living" and would the common access conduit to all the other rooms.

[Squirl]

 

I really like one story living.  You can lose a lot of space to a set of stairs.  The roof isn't the only expense added to a 20x80.  The foundation is also not free.  Although you live in Texas so you don't have to worry as much about frost lines and snow load.  So not much more.  But you probably will lose a bit of square ft to a 3 ft hallway.

[dablack]

I had thought about losing space to the stairs but didn't think about the long hall way that would be required for a long house. 

I'm just going to have to overrule the one story "want" that she has.  I'm sure I will be able to explain the cost of the roof and how much a hall will eat up and move her in the dirrection of a 20x45 or 20 x 50 two story.  Last night on scrap paper, I drew up a two story with five bedrooms.  It was basically a 20x30 two story with two bed rooms side by side stacked on top of each other.  We home school so one of the bedrooms will be a school room. 

Austin

[Erin]

Just echoing everyone else, generally, the more compact you can make it, the better.  Ie, smaller footprint, smaller roofline.  Go two story.

[John Raabe]

Unless there are access reasons to have a one-story layout your building will be more efficient (surface to volume issues) and more visually pleasing if two-story.

20x80 would probably tend to look like a motel. 

[MountainDon]

I agree that 20x80 might look like a motel, trailer or some sort of industrial building. Is there any reason to build a one floor, 20 x 80? Why not a one story L shape or a U-shape?   If this was built on a concrete slab, as many homes are here in NM, floor joists are of no concern and almost any width can be accommodated with roof trusses.

I do agree that if land space is at a premium, or if one is trying to achieve the absolute best use of materials, roof or foundation in particular, a two story is likely best. However we all don't like stairs. I am a one story guy.

[firefox]

Just curios, what are the trade offs with a single story square house
on slab with some internal structural walls or columns?
Bruce

[MountainDon]

... not sure what you mean, Bruce. 

Our on slab home is about 30 feet wide at it's widest point and has no interior lead bearing walls at all. It's not square but a rectangle with a short leg to make an L-shape. Plus a four foot bump on one wall and a protruding garage on another.

[Squirl]

Also the closer to a square you make a building the more efficient outer wall to square feet it will be.  A 20 x 80 with 8ft walls single story has 1600ft of exterior walls. (80x8x2 = 1280 + 20x8x2 =320)  As opposed to a 40x40 with 8ft walls has 1280 sq. ft of exterior walls.  This can add extra savings too because exterior walls require insulation, sheathing, and siding.  The less there are per square ft. can lead to a lower cost per square ft.  This also leads to less square ft of foundation footings too.  This can save a lot in concrete costs.  Technically the closer you get to a circle give you the maximum floor sq. ft. to wall sq. ft., but it does not work in a practical sense.

[firefox]

Squirl answered it for the most part. I was curios as to what other
problems might occur with a square versus rectangular structure
seeing as the square structure appears to have a lot of cost benefits.
Bruce

[MountainDon]

Just an observation: When we were looking at what we wanted in a new home back in 1984-1985 we looked at what we wanted in the floor plan. Where rooms would be positioned in relation to each other, where the garage would be, the laundry, etc. Twenty years+ later when we were thinking about what we wanted in a cabin, again we looked at the floor plan. We knew it would be small, we more or less knew what we wanted to contain within the walls. The plan grew accordingly. In neither case would a square have given us what we wanted.

I suppose our approach could be looked at as reprehensible. What a waste of materials with our long L-shape home or our rectangular cabin! I do think we achieved a balance though. The main home could have been larger as many in the neighborhood are. It could have been a little smaller too. Ditto for the cabin.

That's not to say there is anything wrong with designing for minimal waste or best use of materials in a more or less square or cubic design. However, since I'm likely to be using my creations for many years I like to look at what will be most useful to me as one of the prime criteria.

Just my 2 cents worth.

[dablack]

Don,

I think you nailed it pretty well.  Yes, a cubic house makes the most use a bulding materials, but if that was the only concern then we would all be living in spheres (I love saying that word).  My aunt has a house she has been living in for 40 years.  It looks like a capital U that is squared off at the bottom I_I.  The left side of the U is kitchen, laundry, and garage.  The bottom of the U is dining and living room.  The right side of the U is bedrooms.  The inside of teh U is lined with huge windows that show the courtyard.  I love that house and it is a beautiful home.  If you brought the two sides of the U together to make a more rectangular house, you would lose all the windows and you wouldn't have that beautiful court yard. 


Austin

[JRR]

Your criteria has changed a bit .... we all go through this as we "plan".  Carry on ...

[dablack]

JRR,

I think you missunderstood me.  I'm not planning on building a U shaped house.  NO WAY.  I have decided on a 20 x 45ish two story. 

I was just pointing out that there are some houses that don't make good use of materials but are great houses. 

thanks
Austin

[MountainDon]

There are a good number of U-shaped older homes here in the SW. I've always liked most of them.