Dry stack concrete block to build a garage w/apartment over it?

[Panks]

Thanks Jcarlilesiu! I hadn't even thought of precast concrete. I can't believe there is a building method I hadn't looked into! I just hope they are allowed in CA.

I really love the idea of a precast concrete roof..I could use that as a deck area. Nice

Could you tell me if its possible to build a false/fake roof in the front of a house and going back a few feet (ideally the gable end) that conceals a flat roof in the back? I have a stucco ranch with metal shingles so I think a totally flat roof would look out of place. But I'd love to spare myself the expense of adding a matching roof over the garage plus the idea of a balcony /roof is really nice also.
I thought a mansard roof would fit the bill but from pictures on google it doesnt seem to be the right type??

[jcarlilesiu]

Originally Posted by Panks

Thanks Jcarlilesiu! I hadn't even thought of precast concrete. I can't believe there is a building method I hadn't looked into! I just hope they are allowed in CA.

I really love the idea of a precast concrete roof..I could use that as a deck area. Nice

Could you tell me if its possible to build a false/fake roof in the front of a house and going back a few feet (ideally the gable end) that conceals a flat roof in the back? I have a stucco ranch with metal shingles so I think a totally flat roof would look out of place. But I'd love to spare myself the expense of adding a matching roof over the garage plus the idea of a balcony /roof is really nice also.
I thought a mansard roof would fit the bill but from pictures on google it doesnt seem to be the right type??

If I am understanding correctly, you currently have a sloped metal roof on the building on the property that you would like to try and match.

It isn't advisable to utilize precast concrete for the roof as its usually too heavy and due to shear loads, requires quite a bit of reinforcing to meet loading requirements. Precast is a good application for walls, but for floors and roofs... there are cheaper options.

Like I said, you could use metal framing members to support the floor of the apartment withe metal deck and a light weight concrete. You can even get an insulating lightweight concrete.

For the roof, if your concern is matching the existing structure on the property, I think you have multiple options.

I understand that you would also like to have a roof top deck. Its a bit hard to design being that I have never seen the property, existing building, or conceptual design for this structure, but Ill throw out there my initial idea.

Why not just have half of the roof area a deck or balcony? You could then pitch the other half and roof it to match the existing structure. It will look intentional that half of the roof is flat for the roof deck while still making an effort to match the existing building. You could also provide access to the roof top deck from the attic space below the pitched roof by way of a sliding door and stair case in the gable that is adjacent to the pitched roof.

Just an idea.

[bryan.w.t]

The original comments re surface bonded concrete block are what caused Google to lead me here as I am investigating feasibility in SoCal too. Some of the comments posted reveal some misunderstandings. I'll quickly mention what I've found.

Dry stacking refers to stacking the block without mortaring it. There are no mortar joints to serve as a weak point in the wall. The cores are reinforced with rebar and concrete at intervals, or alternatively all cores are filled in addition to the rebar. The walls are surface bonded using a fiber reinforced cement product such as Quickcrete brand's Quickwall product on both sides. This spreads loads evenly across the entire wall rather than just at joints, and reportedly is multiple times stronger than simple mortared block. The Haener product allows for both vertical and horizontal rebar placement, and requires all cores be filled for structural use. The horizontal rebar reportedly increases sheer and tension load capacities tenfold over traditional mortared block, which is a big plus in quake country. Haener can also be surface bonded. Haener requires a 15k block minimum order at $1.75. An additional possibility to deal with sheer and tension loads during an earthquake with surface bonded block (or grouted too) is post tensioning, in which a mega long bolt embedded in the footing extends to the top plate where it is tensioned prior to surface bonding. Before you disparage block in SoCal, check out every big box store youe enter this month, and you'll see their shell is block construction! For the most part mortarless at that.

jcarlilesiu, you suggest precast as more economical method. I ask, without knowing the answer, if that is true for the owner-builder who could design a block structure, get an engineer's or architect's stamp, and build with minimal equipment, greatly saving on both design and labor. Dry stack block is rapidly gaining as a feasible owner-builder method. Those interested, check out the ASTM C-946 publication Standard Practice for Construction of Dry-Stacked, Surface-Bonded Walls. There are quite a few sites on the web a simple Google can reveal on drystacked construction by owner builders, as well as a drystacked site giving laymen the tools to design a structure to their liking, which they can then take to a licensed architect or engineer for review, feedback, and stamping. I expect such professional services are much cheaper than a full design (which one firm informed me would run $50k just for design/engineering), and for those on limited budgets, that can make the difference between a feasible project and a dream. I was reading the construction journal of a guy out of state that's almost done building a 2 bed earth-bermed dry-stacked home, and aside from the land, he only has about $30k into the whole building, including subbing out the foundation pour, and paying a couple of laborers along the way. He did it without a mortgage, looking for some security in this economy, and got it livible just in time when he was layed-off. Though there is still finish work to be done, he has his land free and clear, no mortgage to pay, a mix of solar and conventional electric, wood heating from his own land, and the ability to survive on a much reduced income as he launches a home-based business. It would have been catastrophic had he not been able to owner build mortgage free at a low cost as he did. I'm personally facing foreclosure on my current home, and am looking to make the low-cost owner-built mortgage-free home reality myself.

I've been looking at the possibility of a career change to architecture or landscape architecture/civil engineering myself. From what I've seen, there's a bright future, but right now a lot of architects are out of work, and low-end work I described above could provide some needed income on the one side, and a needed affordable service on the other. A win-win.

[Rickers]

To the OP. I think you are trying to put the cart in front of the horse. I would first start by looking up your building codes or have a long talk with a city building inspector before even thinking about materials or design. I think the way you are going about this will result in just about everything you have mentioned being rejected by the city. Your plans will have to be approved before you even start preparing the site. I agree with the poster who said expand what you have on a remodeling permit or just sneak it on little by little but a neighbor may turn you in and you'll have to get a permit to even remove what you have built and start from scratch.

[Panks]

bryan.w.t
I am truly sorry to burst your bubble but I checked into it also and there is no way you can do it in LA ..I called and even went down to the building & safety desk. Its really insane imo..but there it is...

BTW, if u liked the dry-stack idea, you would flip over earth bag buildings..but they are not allowed either

[pepe1]

Originally Posted by Panks

Thanks Jcarlilesiu! I hadn't even thought of precast concrete. I can't believe there is a building method I hadn't looked into! I just hope they are allowed in CA.

I really love the idea of a precast concrete roof..I could use that as a deck area. Nice

Could you tell me if its possible to build a false/fake roof in the front of a house and going back a few feet (ideally the gable end) that conceals a flat roof in the back? I have a stucco ranch with metal shingles so I think a totally flat roof would look out of place. But I'd love to spare myself the expense of adding a matching roof over the garage plus the idea of a balcony /roof is really nice also.
I thought a mansard roof would fit the bill but from pictures on google it doesnt seem to be the right type??

Precast concrete is not a viable option if you are budget concious. It is one of the most expensive types of building materials you can use. Precast construction is generally more common in cold weather climates (like the midwest) where there is a greater scheduling benefit to having a factory cast product produced during winter months - this scheduling benefit counters much of the additional costs accrued form using precast. In more moderate climates (like California) tilt-up construction is far more common than precast since it is less expensive.

Still, tilt up construction would be exponentially more expensive than simply doing a typical wood framed structure.

[bryan.w.t]

Panks,

I'm actually not really into earth bag. For a while I was really wanting to do bale in the desert. I've become more ambitious in my desire to achieve a home that will require absolutely no heating or cooling costs. It's been done here in Imperial county's 120+ summers where I live now, as well as in extreme cold places like Colorado and Minnesota.
Actually, what I'm looking to accomplish is an earth-sheltered home, in which mostly all but the south exposure is covered with earth, roof included, and both the concrete and earth serve as a thermal mass which cools in the summer and heats in the winter...thus no heating or cooling bills at all. Google the terms PAHS and earth-sheltered. I'm not looking in LA county, but rather more likely riverside county rural, maybe San Bernardino, possibly Missouri (where codes are near non-existent in rural areas, and all you have to do to become a contractor is hang a shingle--except septic, for which the state requires a couple days of classes). I found someone who built an earth-sheltered home in Riverside county in the area I'm looking at property in, but she didn't use block in her design. An article written 9 years after she moved in states she was achieving 72 degree temperatures year round 24/7 with absolutely no heating or cooling other than the solar passive with 5 feet of earth on the structure. I'm not bent on block, but it is an appealing owner-builder method. Another option is to build the forms and place the reinforcement, and just pay a crew to do cast in place concrete foundation and walls, and after cure, place standard steel roof trusses like you see in big bog commercial construction, but at MUCH closer spacing (determined by engineer) and pour a concrete roof on top. A guy in the Northeast did this for his earth-sheltered home supposedly at a great price since he used standard commercial methods in a really beefed up residential project.

Regardless of the building method ultimately chosen, if the original poster is able to go the owner-builder route, he could achieve a low budget project by doing most of the design and build with some contracted assistance. BTW, I had hoped I could get by with empirical design with block (no professional stamps required) at least with the first structure, which would be a garage/shop, but no dice due to the codes defining the whole state as seismic zones requiring a full engineered design...except standard light frame construction.

[Gandalara]

bryan.w.t - you might find the following thread interesting

Lisa and Mike's Berm House

It's a huge thread if you try to read every single post. But Lisa's posts (with pictures) show the building process from start to finish.

[Panks]

I think it's a great goal to have zero heating and cooling costs but the lack of light/windows in the earth bermed homes make it a complete deal breaker for me (even if LA allowed it).

I think the straw bale is a terrific idea. Its just amazing that LA doesn't allow that either despite having programs called green building program / sustainable building program..what a load of .

I guess deciding which one to do would depend on which resource was the cheapest where you are planning to live. I do know you have to be careful with strawbale to make sure the straw was dried properly before it was baled and that you have to make it completely impervious to water after the house is finished or you will have problems there also.

I have a big hill behind my house so building with earth was a good option for me. Rammed earth building is also a nice economical option if you can get away with it.

I wonder how much you could get for a bermed house if you had to sell it? If you are really set on a bermed home remember that if you are not married yet, your future spouse will also have to enjoy live in a cave

[bryan.w.t]

Gandalara, good link. You're right, long thread. There's a house (Tom's) on fugadeideas.org that is similar, but gets more efficiency than Lisa's likely does. By covering the roof, using thermal breaks, and using the earth as additional thermal mass, insulating & additional vapor barrier on the dirt instead of insulating the house's shell, and increasing south exposure glass, you can really have a deep impact on heating and cooling efficiencies. Tom's house on fuga doesn't reach some of the better efficiencies available by running earth tubes through the earth thermal mass. The fuga site has some real good links on there as well.

Panks, in modern earth-sheltered homes, there can be plenty of light. Ususally the south exposure has a lot of glass. Also, sun tubes or sky lights can project above the several feet of earth on the roof to bring light in. Sun tubes bring light without solar gain. Bale is very doable not only in arid climes, but wet too. Andrew Morrison is a bale guy who has done a lot of bale in the pacific northwest (strawbale.com I think). The dry bale part is easy, you just check with moisture meters, but beside that, the walls breathe in a bale home, so any moisture can evaporate out easily in the dry socal environment.