Concrete home construction

[bugstruck]

This house in Danville, CA is about 17,000 sf and has taken about
5 y to build.

5 years...am I reading that right?? Are they working one hour a day? 5 years on a 17,000 footer is unimaginable no matter the methods and materials. That timing would scare anyone. If a contractor can't complete that in 1 year, something is amiss. I could put that up, tear it down, and do another in 12 months if hammered. Unless the assembly method is with spoon and toothbrush of course.

 

[Paddy]

Has any one encountered a home that has concrete floors above grade?

I spoke with a sales person for Insul-deck yesterday. With regards to "engineering" a home, all their products are sold based on spans. They do not and will not eng stamp your design. But all the years I was a "nail banger", I never saw a engineer's stamp either. Agian, I think this is a case 'the US is not as familure" with concrete as the rest of the world.

I made a new friend two months back in Prague, Czech Republic. He works at the Klokner Institute as Head of Experimental Dept. He has PhD in front of his name but you would never know by looking at him. We use the engineering schools lab to test HV ceramic insulators for their mechanical load capabilities. These insulators are used through out the world and require this third party testing, some what like UL testing but much more complex. While witnessing my tests I was able to chat with him on his current research. His work and passion is concrete/masonary construction. Prague is a wonderfull city that was saved from bombing in WWII but, neglected by the Soviet control. Much restoration and building is going on. In the lab, they had a scaled concrete apt building. It was approx 25' tall. They were measureing forces to destruct.

I will be returning to the lab in Sept for more testing. I hope to have lots of litrature from various concrete building methods. I would feel more comfortable have a PhD of Europe, where concrete is an every day thing, review my plans.

 

[dmccarty]

Paddy,

Our house has a concrete slab above grade. The "low" side of our house is something like 18 inches above grade. The "high" side of the house is about 60 inches above grade. Now we have added fill dirt so those numbers are from the native grade not finished. On the "high" side of the house its 60 inches to the top of the slab. In other words our slab is a good 60 inches above grade on that side of the house.

The height really provides a nice view. I wished I had realized this would have happened cause I think we would have gone up another 8 or 16 inches in the foundation height to increase the effect even more.

I have not seen ANY house do this. It is not normal. When the Directv installers showed up they walked around the house looking at the foundation for a crawl space access door. I was on the back of the house with the builder watching them literally scratch their heads looking for the access. When I told them there WAS not crawl space they looked at me like I was a space allien.

What the builder did was just build a regular foundation wall up from the footers. The wall is CMU faced with brick. Inside the wall we filled it with 67 stone. This is a stone up to and inch or so with NO fines. It compacts without mechanical means to the magic 90/95% number that engineers alway want. Before the 67 went in the plumber had put in his waste pipes. Then the stone went in. Then the two inches of ridgid foam was put in on top of the gravel with one inch around the foundation. Then the concrete was poured on top of the foam. I think the foam was EPS. I was very specific on that requirement since it could handle the PSI of the house sitting on top of it.

We also colored our concrete so that its a tan shade which has worked out nicely. Our floor is finished concrete. The color came out just right but around the edges of the floor its not like we would like since the motorized trowel could not get all the way to the edge of the floor due to the walls. But the mass and durability of the finished concrete has worked like we wanted. People thought and still think we are nut for have a finished slab but we can't stand the dirt that carpet holds. The floor is easy to clean and keep clean. If you get water on it you don't really care.....

We did have a plan that we used to cut the concrete to "decorate" it as well as guiding cracking. This worked real well for the most part. The only cracking we have had outside the cuts has been where the slab was stressed due to the shower stall and the front porch. We have a walk in shower with no door or "dam" to keep in the water. To get the shower built we made a form to keep the concrete OUT during the slab pour. This was done so the that plumber could make his final connections and so the tile guy could get his slope to the drain just right. This hole in the slab caused stress and even though we had cuts in the room the cracks went out at something like a 30 degree angle from the shower. The front porch cause a similar problem. The porch is about 16 inches below the house slab and is L shaped. The L caused stress and again even with the cuts there is a crack at that same angle. But they are not big deals And really are not noticable.

In the 19 months we have lived in the house we dont have one crack in the walls. The house has not settled at all and we have done through a couple of very dry and wet spells. We have an expansive clay but so far, knock on wood, it has not been a problem. Our old house in the "city" CONSTANTLY had cracks above the windows and doors due to the movement of the house. The house was on a slab as well with expansive clay.

We wanted a slab for a couple reasons. One the mass. Two durability. Three crawl spaces are a headache as far as I'm concerned. They can be mold and wetness magnets. If our old house had been on a crawl space I'm sure the bathroom floors would have had to have been rebuilt to to water issues. With a slab its not an issue. But crawlspaces in my area are the norm.

Our builder's next project was a light commercial building on a site where he had previously built a structure which used a crawlspace. The sister building had a concrete slab built on a "fill" on 67 stone.

Hope this helps,
Dan

 

[Paddy]

My mistake. I was seeking any one who has a slab above earth suport. Or beter described as self suported. I plan on a slab on ground level, set in to the hill side. Second story slab, ceiling of level one. And also the roof.

 

[ByronBob]

My parents live in Ft Myers Fla,

Everything built there now is block walls all the way to the ceiling. Then trusses are used. Really interesting to see how their built.

 

[dmccarty]

My family has lived in Florida for decades well before the big population movement that start in the 60/70s. Of the aunt/uncles, grandparents, cousin's, greatgrandparents and our houses, I can only think of ONE house that was stick built. I'm talking about homes built in the 50's and onwards. Maybe one other but I just can't remember how that house was built. All the houses where CMUs or what we called cinder block. That was just how houses where built down there for decades. Stick built's seemed to have been done later on. Florida is a big place but my family was in Central and SE Florida.

CMU homes also have issues regarding windborne water infiltration in hurricanes as well as energy efficiency. But they have been used in FLA for many years.

Later,
Dan

 

[dfkrug]

The roof blowing off is one reason I will have a concrete roof as well. Nice systems out there, www.insul-deck.org
I will have a flat roof with 3' half walls extending up above the roof deck. It will be like a elevated patio. Since my home will be lake front, tall is good for great views. Nice part to is the property tax dept will call it a roof, I will use it as a patio!

Concrete floors and roof would be ideal. I would have gone that route
but the expense was just too much. When I was a Polysteel distributor, we
could sell the PanelDeck system. I quoted it for a couple of prospects.
One of the additional costs was the fact even the temporary shoring
required an engineer's stamp. Getting engineers in CA to work with
concrete has always been difficult, expensive, and SLOW.

For my house, I ended up using a lot of structural steel for roof
ridge beams and columns, and floor girders. I have no interior
load-bearing walls. I also had difficulty getting engineers to design
with steel beams/girders, instead of wood.

"I used to be an engineer, now I get to build things."

 

[dfkrug]

CMU homes also have issues regarding windborne water infiltration in hurricanes as well as energy efficiency. But they have been used in FLA for many years.

CMU houses also have the issue that they are not really any stronger
than 2x6 framed houses. Even when they are properly reinforced and
grouted. That is a big issue for earthquake and wind resistance. In
CA, CMU structures have to have an engineer on site to inspect for
proper grouting at every 4-ft of wall height. It is very difficult to get
grout to fill the voids in CMUs due to their absorbant nature. A very
wet (7+ slump) grout is required, which is weak.

When you are done with your CMU wall, you still have to fur it out,
insulate it, seal it, and finish it.

It is interesting to note that 120+ MPH winds actually put more stresses
on a house than MAG 7+ earthquakes.

 

[dfkrug]

5 years...am I reading that right?? Are they working one hour a day? 5 years on a 17,000 footer is unimaginable no matter the methods and materials. That timing would scare anyone. If a contractor can't complete that in 1 year, something is amiss. I could put that up, tear it down, and do another in 12 months if hammered. Unless the assembly method is with spoon and toothbrush of course.

A 3500sf stick-framed custom house with no problems here in CA
will generally take over 2 years of construction time. Also 1-2 years to get site approval and building permits. Plan check of your house drawings is
minimum 6-8 weeks and the resubmittal with corrections/changes will take
at least a couple of more months.

Now increase your house size by 4-5x and run into all sorts of problems.
AND have a customer who changes things. When your bill for windows is
over $200,000, you ain't gettin em from Home Depot. That 17,000sf is
built on a cost-plus basis.

 

[_RaT_]

A 3500sf stick-framed custom house with no problems here in CA
will generally take over 2 years of construction time. Also 1-2 years to get site approval and building permits. Plan check of your house drawings is
minimum 6-8 weeks and the resubmittal with corrections/changes will take
at least a couple of more months.

Now increase your house size by 4-5x and run into all sorts of problems.
AND have a customer who changes things. When your bill for windows is
over $200,000, you ain't gettin em from Home Depot. That 17,000sf is
built on a cost-plus basis.

Add in that the interior and exterior walls are probably 3 coat plaster, cabinets that are months in the making, trim work that has more wood then a typical home has 2X material, stone work, tile work and so many custom contractors all who are swamped and things slow down. I have installed Vantage lighting systems in such homes and find the amount of work in their construction amazing. Myself, I want a nice simple home.

 

[czechsonofagun]

Paddy,

I am very pleased you like my city - Prague - so much. Enjoy your stay in September.

 

[Paddy]

Prokop,

For you I must say Praha! I stay at a 'penzion' near the St. Charles bridge in a small beer hall, U Medvidku on Perstyne 7, Praha 1. They serve the real Budviser beer. I prefer Pilsner Urquel though. Can't beat it, 0.5L beers for $1.25. Rooms are $110 per night. I brought my wife last Sept, '05, she loved it. I would bring her again but I must stop by Thailand the week before. Now that's the long way to Praha! 3/4's the way around the world

So I imagine you know of the Klokner Institute, end of the Green metro line. I work at the lab EGU, www.egu-vvn.cz east of town. It's a short distance from Cerny Most on the yellow metro line. I'm a high voltage enginerd. I spend 6 weeks a year in my favorite city, Praha

When did you leave and how often do you go back to visit?

 

[czechsonofagun]

Paddy,

It is a small small world My dad worked in SVUSS - which is right next to the Klokner Institut for like 30 years. We lived in Praha 2, near Namesti Miru and my old man used to bike to Bechovice every day.
My high school was electrical engineering oriented and I had a month of internship in EGÚ in 1980 or so.

Now Klokner Institut is right next to my college - I have MSc from CVUT FSI (mechanical engineering)

I married an american 1994 and we moved to states 1997 - and I typically go back every year in February/March - in the cheap air ticket season to catch up with my folks and local food and beer and buddies - you name it

 

[BobRip]

Is your house one level? Sounds like your happy with concrete!

Yes, it is one level. We do have a crawl space which has 2 inches of concrete so that the plastic on the ground is protected. The crawl space is not vented and acts as a thermal storage to help stabalize house temperature. At least that's the theory.

 

[bugstruck]

Still a one year to maybe?? 16 month house in Maryland guys. We do make incredible upfront efforts to get all the specialty products and finishes nailed down early. Why wouldn't you go several states out and pay shipping for windows, custom moldings, and cabinetry? Even hire in out of state subs on stone, ceramic, etc. It's cheaper to pay transportation, per diem, and lodging for sub crews than carry debt service on projects that size when they are in the late stages. You can buy a lot of lodging etc. for $15 to 20K or more a month. You're still married to local site contractors, HVAC, plumbing, and electric but much of the other trades could be from anywhere, unless your licensing requirements extend into trades ours don't. Even then you could sublet the subcontract labor. I compete with the Chinease on commercial casegoods that are supplied on jobs with one year and slightly shorter cycles. They aren't getting that product here on planes.

We do limited residential cabinetry but when we do it's super high end. I can turn $200K in custom residential molding and cabinetry from kitchens to wine cellars in 12 weeks max. including shop drawing design and review assuming a week is enough time to bless the drawings. Every stain grade stick and box would be custom stain matched and finished to approved samples too. Exotic finishes could add a week to 10 days. All while doing perhaps two premier restaurants that would dwarf that residential job, two hospitals, 12 to 20 other real jobs. If you were on a one year cycle I'd probably have shop drawings in for submittal review before the house was dried in because we would have started while it was being framed. Nail the design and finishes down, stage the materials orders based on lead-times, pull in every equipment cut we have to interface with, and wait for final field measurements. Then, off to production. We do this a few States away fairly frequently. Mostly 10 to 30 thousand bottle wine cellars. Most of them are 6-8 weeks phone call to punchlist close-out. Every one is full custom. Production time on this type of residential work including finishing and on the truck is seldom more than 3 weeks.

Regarding the State and those permit and review times. Whew. I don't doubt the timing that's quoted, it's just beyond, way beyond, my comprehension.

 

[_RaT_]

Still a one year to maybe?? 16 month house in Maryland guys. We do make incredible upfront efforts to get all the specialty products and finishes nailed down early. Why wouldn't you go several states out and pay shipping for windows, custom moldings, and cabinetry? Even hire in out of state subs on stone, ceramic, etc. It's cheaper to pay transportation, per diem, and lodging for sub crews than carry debt service on projects that size when they are in the late stages. You can buy a lot of lodging etc. for $15 to 20K or more a month. You're still married to local site contractors, HVAC, plumbing, and electric but much of the other trades could be from anywhere, unless your licensing requirements extend into trades ours don't. Even then you could sublet the subcontract labor. I compete with the Chinease on commercial casegoods that are supplied on jobs with one year and slightly shorter cycles. They aren't getting that product here on planes.

We do limited residential cabinetry but when we do it's super high end. I can turn $200K in custom residential molding and cabinetry from kitchens to wine cellars in 12 weeks max. including shop drawing design and review assuming a week is enough time to bless the drawings. Every stain grade stick and box would be custom stain matched and finished to approved samples too. Exotic finishes could add a week to 10 days. All while doing perhaps two premier restaurants that would dwarf that residential job, two hospitals, 12 to 20 other real jobs. If you were on a one year cycle I'd probably have shop drawings in for submittal review before the house was dried in because we would have started while it was being framed. Nail the design and finishes down, stage the materials orders based on lead-times, pull in every equipment cut we have to interface with, and wait for final field measurements. Then, off to production. We do this a few States away fairly frequently. Mostly 10 to 30 thousand bottle wine cellars. Most of them are 6-8 weeks phone call to punchlist close-out. Every one is full custom. Production time on this type of residential work including finishing and on the truck is seldom more than 3 weeks.

Regarding the State and those permit and review times. Whew. I don't doubt the timing that's quoted, it's just beyond, way beyond, my comprehension.

Wow Chris, very impressive, you obviously are organized and know your stuff. Mark

 

[Bill Barrett]

Here check this ICF, little different idea. I like this idea, doesn't burn, it's environment friendly, mass is on the inside which is good if you are doing solar . Remember just R or U value is not the whole story! I do HVAC in ICF’s all the time be sure to get someone who knows what’s going on.
http://www.durisolbuild.com/

 

[5030tinkerer]

I do HVAC in ICF’s all the time be sure to get someone who knows what’s going on.

Funny - I am presently building my home out of ICF's from IntegraSpec and am having trouble locating anyone with a clue on sizing HVAC for an ICF home. Any tips on where I can look?

 

[Bill Barrett]

5030tinkerer just find one that will do a complete heat loss heat gain on the project. Most HVAC guys that do geothermal would be a good start. If you have a electric or gas co-op would be another source.

 

[_RaT_]

Here check this ICF, little different idea. I like this idea, doesn't burn, it's environment friendly, mass is on the inside which is good if you are doing solar . Remember just R or U value is not the whole story! I do HVAC in ICF’s all the time be sure to get someone who knows what’s going on.
http://www.durisolbuild.com/

Excellent point and one that the folks from Nudura mentioned.