Steel Beams for work shop

I want to build a 24* 32 two story workshop. Any idea on the costs of using steel beams to span the 24 feet instead of 2*12s? Would they still need to be put 16 on center? Any advice would be appreciated.

Pat

Reply to
komobu
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Cement block. Steel bar joists on 2 to 5 foot centers depending on depth of concrete floor poured on top. Steel bar joists for the roof structure.

If you just want to develop better load carrying capacity in a wood structure look into I Joists or flat trusses. ______________________________ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

Reply to
DanG

Steel instead of wood would be incredibly expensive. You have other issues here. The steel is strong enough that the spacing can be much greater than

16", but the subfloor for the second story needs more support.

You can run a 32' beam down the center and use 12' joists on either side. You can use some manufactured laminated beams instead of solid wood with very good results.

I suggest you take a serious look at what is available and the costs involved. They can vary quite a bit. What are the walls going to be made of? What type of climate are you in? If you plan to heat the shop, using Insulating Concrete Forms makes it easy to build as a DIY project, and saves a bundle on energy due to its thermal efficiency. There are many brands so find one made near you to keep costs of shipping them low.

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for example.

You may want to look at some steel buildings also. They can be cost effective and go up fast.

Reply to
Edwin Pawlowski

Thanks Edwin...

I live in Va. The Insulating Concrete Forms look interesting and I will check them out. Any idea on the cost of them vs wood frame?

Reply to
komobu

A small bundle, compared to other kinds of walls.

Nick

Reply to
nicksanspam

Not really., Nick. They are very comparable to other types of construction. Please, check out the total cost before you open your mouth. Many studies have been done in both construction cost and cost of operating a house and the energy savings is often 40% or more. BASF is currently doing a test house in Patterson, NJ. Why not go see it as you are not too far.

Reply to
Edwin Pawlowski

I've heard figurer from 5% less to 5% more. They go up fast and can save a lot of labor over a frame house. They are also straight, not so easy with wood these days.

Reply to
Edwin Pawlowski

I disagree, altho "dynamic R-values" can work well at certain times in certain climates :-)

Nick

From: snipped-for-privacy@acadia.ee.vill.edu (Nick Pine) Newsgroups: sci.engr.heat-vent-ac,alt.solar.thermal,alt.energy.renewable Subject: Concrete is not an insulator... Date: 2 Apr 2003 12:04:38 -0500 Organization: Villanova University Summary: How to lie with statistics :-) Keywords: dynamic R-values

I just finished reading a newspaper story, "Energy efficient and mighty sturdy--concrete has considerable insulation qualities..." by Alan Heavens, in the Sunday March 30, 2003 Philadelphia Inquirer. Was this inspired by the concrete industry, who have been "helping" Habitat for Humanity save energy? These concrete guys seem really pernicious. Some of them also push costly and inefficient lukewarm concrete sunspaces via the Passive Solar Industries Council aka Sustainable Building Industry Council...

Although all the members of PSIC, especially the Technical Committee, c Notice how dense a concrete wall is? This denseness, thermal mass, deflects heat in the summer and absorbs it in the winter.

Heat moves by conduction, radiation, and convection. How does it move by "deflection"? We might say concrete acts like a heat mirror, REflecting longwave infrared heat radiation. But it doesn't do that. It can absorb heat, as a thermal capacitor, but that doesn't help keep a house warm or cool in most climates...

The ASHRAE Handbook of Fundamentals says the thermal conductivity of concrete is 0.54 Btu/h-ft-F, ie its R-value (insulation value) is

1/(12x0.54) = 0.154 per inch, vs R5 per inch for Styrofoam or R19 for 6" of fiberglass insulation, which can insulate like 19/0.154 = 123" of concrete, ie a 10' thick concrete wall.

Concrete on the inside walls of a house can help store solar heat that comes in the windows and reduce the amount of energy a furnace has to supply after the sun goes down, ie it can help with passive solar house heating by allowing the use of more south windows. OTOH, windows are poor insulators, so more windows require more "backup heat" on a cloudy day.

Concrete inside a house is also useful for cooling by night ventilation at certain times of year. Open the windows or turn on a whole-house fan at night, and button the house up during the day, storing coolth in the walls. This works better if the occupants are willing to tolerate large temperature swings, but the energy benefits are small in many climates.

On the outside walls of a house (or inside ICF foam walls), concrete can reduce the maximum capacity required for a heating or cooling system, ie its first cost, but it doesn't reduce the yearly energy bill much, except for lucky homeowners located in climates where a massless house might have to be air-conditioned during the day and heated at night for days on end. In that case, exterior concrete can smooth out the daily temp swings to the point that a house only needs AC or only needs heat on a particular day.

That can help lower the energy bill on an average day in March in Tucson, where NREL says the 24-hour average daily temp is 58.7 F, with an average daily min and max of 44.6 and 72.8. It can help in April through June, but not much in July, with an 86.6 average temp and 73.6 and 99.4 min and max. It doesn't help much in August or September. It can help in October and November, vs December and January, with 51.3, 38.6, and 63.9 F. It can help in Phila in June, with a 71.8 F average and 61.8 and 86.1 min and max (but how many people in Phila heat their houses at night in June?). It won't help much in any other month in Phila, eg January, with a 30.4 average and 22.8 and 37.9 min and max. A concrete house has little energy advantage over a frame house in January in Phila. It might use more energy, with more heat storage and less-effective higher-temp nighttime setbacks.

Mr. Heavens continues:

With as little as two inches of styrofoam insulation, R-values of 35 or more can be obtained, depending on geographical location.

But these "dynamic R-values" are rarely applicable. This is like saying a car gets very good gas milage under certain conditions (eg downhill :-)

Mr. Heavens cites Pieter VanderWerf, a "professor of management at Boston University" who did statistics on 29 concrete and 29 frame houses in 1997 and concluded "the insulation qualities of concrete saved the typical homeowner $221 a year for heating and $89 for cooling," and "The percentage of energy saving showed no discernible relationship to local climate." He tentatively concluded that "...these rates of savings should be fairly constant, regardless of location."

A Google search on Pieter VanderWerf shows a National Concrete Masonry Association reference which seems to indicate that Dr. VanderWerf is more than a disinterested management professor--that he is also presidents of Christy Concrete Products and Building Works, Inc., and the Portland Cement Association flies him around the country.

Here's one web review of Dr. VanderWerf's $49.95 book, "The Portland Cement Association's Guide to Concrete Homebuilding Systems":

Not a How to Book

This is the first book I have ever returned to Amazon. I was looking for a book to tell me "How To". This book is more advertising than anything else.

Here's a letter in the January/February 1999 issue of Home Energy Magazine:

Field Testing ICF Article

I wish Home Energy would be more careful in publishing "technical" articles such as the one on ICFs ("Foam Forms Bring Concrete Results," July/Aug '98, p. 27). The ICF industry has consistently avoided the field testing of its product until very recently, unabashedly claiming R-values of up to R-60 without any documentation other than hazily described "research" that is never submitted for review. Even the newest "study" by Dr. VanderWerf is more pseudoscience than anything else. It is not inconceivable that a difference in conditioning energy of 40% could be found between a two-story-with-basement house insulated with ICFs and one with modest levels of above-grade wall insulation and bare concrete basement walls. However, to assert this has been proven through the "research" from the report is dishonest and should be regarded with extreme skepticism.

A matched-pair study design is used to measure savings; however, there is not enough detail in the report to establish whether the "savings" reported by the author are due to anything other than chance. We are not told the actual R-values of the components in the houses, the window areas and U-values, or the infiltration rates. We must assume they are identical (save for the wall type); the study does not document that they are. There is no mention of the types of heating system in the matched pairs; that is, one could contain a ducted heating system and the other zonal heat. The climates used for comparison are not carefully described, so a matched pair in the "Canada" district could conceivably pair a house in a maritime climate with a house on the open prairie. There are many other potential sources of error that are not carefully addressed in VanderWerf's report.

The Portland Cement Foundation (sponsors of the report) would have better spent their money in a more closely controlled prototype analysis in a few climates. In fact, guarded hot-box tests have now been performed on several ICF walls and have found R-values in a range that seems reasonable (R-17 to R-25), given the wall materials and my own experience modeling several of these walls with contemporary simulation programs (under hire to various ICF manufacturers)...

Bob Davis Ecotope Seattle, Washington

Dr. VanderWerf responds:

Many thanks to Bob Davis for raising important and useful issues. Some of Mr. Davis's concerns are covered in our report. We tested the possible role of chance by the conventional method, the confidence interval. This indicated that the savings, with over 97% confidence, were not the result of chance alone. Air infiltration is not assumed to be constant. In fact, we know from blower door tests that it is significantly lower in homes with ICF walls. Reduced infiltration is actually believed to be the greatest single factor accounting for the lower energy consumption of ICF homes.

A few of Mr. Davis's concerns were unfortunately not covered because of the summary nature of the report. During our study, we did determine several details of the HVAC systems used and we corrected for differences. Matched pairs of houses were within 2 miles of each other in 80% of all cases; in a few situations we were forced to go as far as 20 miles to get a fair match.

A few of Mr. Davis's other concerns are about statistical research in general. In any research, it is impossible to control for all variables. Monitoring and measurement studies cope by eliminating or controlling as many sources of variation as are practical. Statistical studies measure and correct for some variation, and determine whether other sources of variation might introduce biases. The researcher checks independent data or a subsample to make sure that uncontrolled variables (for example, fenestration) do not tend to be significantly different for some groups (for example, ICF houses) than for others. We did this and discussed it in our report. With these conditions, statistical theorems show that point estimates (for example, average energy savings) will still be valid. If one does not accept this principle, one should reject our study along with all statistical field research.

Three implied statements in the letter trouble me. The first is that the energy performance of ICF walls can be characterized by their R-value. Work at Oak Ridge National Laboratory and elsewhere shows that several other factors are of comparable or greater importance: reduced air infiltration, thermal mass, and (possibly) conduction of geothermal energy. The energy modeling of ICF structures to date is unfortunately not of much practical significance because it represents the effects of only one or two of these mechanisms.

The second is the implication that controlled prototype analysis is adequate to fully characterize the energy performance of a wall system. The Portland Cement Association and other organizations have sponsored some projects to monitor the energy consumption of side-by-side prototypes. But they have also sponsored laboratory testing, computer simulations, and statistical field studies such as this one. I hope that building science follows the lead of the other sciences by demanding that final analysis of any important phenomenon rest on results from a variety of different research methods, not just one. Each has its unique lessons to offer.

The third is the implication that peer-refereed research by scientists is the only source of useful information. In an 11-year career as a university professor writing almost nothing but refereed journal articles, it has become obvious to me that this attitude, if pervasive, would halt progress as we know it. Virtually none of the important energy-saving products we rely on today had unequivocal, fully documented performance when the first engineers designed with it, the first architects specified it, the first contractors installed it, and the first building officials approved it. It is true that there will always be charlatans who overstate the performance of their products. But unless we can rely on the training, observations, common sense, and judgment of the practitioner to assess product claims and preliminary research, nothing new will ever get off the ground. Let us in the research community take our decade to achieve full precision and consensus on a new phenomenon.

The Google search on Dr. VanderWerf also turned up this:

Florida Polysteel -- Frequently Asked Questions about Polysteel

What is the R-Value of Polysteel?

Walls made of Polysteel perform, on average, like a concrete block or wood frame wall constructed for R-30 insulation. But that's not the whole story. The Equivalent R-Value performance of Polysteel consists of three factors:

the R-Value of the expanded Polystyrene the thermal mass of the concrete the enormous reduction in air leakage

First, the R-Value of the polystyrene alone is R-20. Secondly, the thermal stability of massive concrete walls reduces the temperature fluctuations, and, consequently, the heat and cooling load requirements of a wood-framed or concrete block building. Finally, air leakage (infiltration) can account for 20% to 40% of the heat load requirements of a wood-framed or concrete block building. Polysteel reduces this air infiltration by 75%!

As a result, with the combined performance of the R-Value of the expanded polystyrene, the stabilizing effects of the thermal mass of the concrete, and the reduced air infiltration, Polysteel walls actually perform as high as R-50, or more, in some areas of the country.

Why stop with R50? On a day with average exterior temp T, a 68 F concrete house with 2" R10 Styrofoam walls will lose or gain about |68-T|/R10 Btu/h. With min and max temps Tmin and Tmax, a frame house in the same location with walls with an equivalent R-value might lose (68-Tmin)/R all night and gain (Tmax-68)/R all day, with an equivalent R-value of 5(Tmax-Tmin)/|68-T|.

Here is a list of US locations and equivalent R-values, based on NREL data:

location month Tmin T Tmax equivalent R-value

Philadelphia June 61.8 71.8 81.7 26.2 Phoenix, AZ April 55.3 69.9 84.5 76.8 Flagstaff July 50.5 66.3 81.9 92.3 Prescott June 49.9 67.2 84.5 216.3 Albuquerque September 55.2 68.6 81.9 222.5 San Diego October 60.9 67.7 74.6 228.3 Houston April 58.1 68.3 78.4 338.3 Ely, NV July 48.0 67.5 87.0 390.0 Colorado Springs August 55.2 68.3 81.3 435.0 Las Vegas October 54.3 68.3 82.1 463.3 Elkins, WV August 56.2 67.8 79.3 577.5 Bakersfield October 54.8 67.8 80.7 647.5 Rock Springs, WY July 52.8 68.0 83.1 infinite!

Nick

Reply to
nicksanspam

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