May I ask for some guidance? I was told by a builder that it’s always cheaper to go out rather than up when adding space onto a home. Is that a rule of thumb or is that simply the preference of this builder? I really don’t care which way it goes — I’ve got space on the lot to go back — but I don’t understand the reasoning. Please excuse my ignorance. Thanks.
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Partial list: when you build up, you have to get materials up. Getting materials up takes more time and effort than moving them horizontal. That time really does add up. To drive the point home, think of having your kitchen on one level and the pantry on another. Now prepare dinner. That's about what it's like to move materials and tools all day between levels.
Also, building up usually involves a staircase. Not only is that something that needs to be built and comes with a direct cost, but it has an indirect cost in that it takes up floor space, too. About 40 sf on each floor is lost to the stairway, plus landings, etc.
So what I'm hearing is that, generally, the extra labor costs and roofing issues make going up more costly than going out. Well that makes sense. I guess I just assumed that the costs of preparing a foundation would make more of a difference. Thanks for the info.
Well, no one has yet addressed the issue of making sure the old foundation is capable of handling a second floor addition.
A person with no sense of humor about themselves is fullashid
I could create plans where up is cheaper than out, and others where out is cheaper than up. The difference is usually not huge, at least with my kind of architecture. It's typically small enough that I advise my clients to select the style of house they want to live in, be/c they'll be living in it long after any "savings" have been spent on other things.
and you have more R&R issues with the roof - gotta get the old one off and gone, and then deal with keeping the finished space underneath dry - risk -
anytime the word 'always' is used, it is suspect - I think it would be more accurate to say 'generally' it is more expensive to add up...
Going out has its advantages, but when you go up you don't pay for an excavation and new foundation...
Yes, roof on/roof off is risky, but it can be done fast too - by a very experienced and efficient GC, with a willing crane operator.
Option 1: First prebuild the new roof (sheated trusses) on the ground. Next day, old roof cut in sections then craned off. Frame/sheath the new floor and snap your lines. Crane up the pre-framed wall sections, plumb, line and brace. Then fly up the new roof (most of it already tarpapered). Close up in a day. Shingles the next day.
Wish I were that good.
Option 2: I know one HO whose builder craned off the old roof, built the new floor and walls, then craned the old roof right back on top of the new 2nd floor walls. Sweet.
Option 3: A few years back there was a great FHB article on this. Job was in Vancouver (B.C.). Their approach was to cut openings in the old roof so as to set down some columns/posts - this kept the house protected even though it snowed during the project. GC post-and-beamed the second floor with the old roof still on. Once the new roof was on, they cut the old roof in sections and lowered these to the ground.
Doesn't up or out also depend on how you go up? Around here most folks go up because the modern setback laws will not allow them to go out. Around here people mostly go up by jacking the existing house up and building a new ground floor. I have also been told that this is the more cost effective way to go over legally finishing out an attic around here. I should qualify this by saying this is in a city with mostly older houses that already have good sized crawl spaces-half height bottom floor storage.
Daniel Neuman
Oakland CA
Crazy Home Owner
As has been pointed out, there's no hard and fast "rule" of it.
There is the fact that attic/ceiling construction, before deep insulation was the rule, is generally "lighter" construction than floor construction.
So, not only is there the "exposure" of the roofless house to the elements, but there's the re-engineering of the new upper floor to contend with. That often means ceiling tearouts and other similar joys, few of which make a less-expensive project. Going up also means bringing mechanical services up (and down again), which means aligning spaces, chases, & the like.