Construction Informer

Seldom do I come across an item that is being sold to the makers of construction equipment and materials. So when this crossed my screen I thought a closer look was in order.

The company, Tah Industries, is offering a packaging solution for adhesives, epoxies and urethanes that makes it possible for the people using the product to just use a standard caulking gun. Ingenious. I remember using a few of these materials. One was used to cement rebar into concrete where one pour was joining another. The side-by-side dispensers always seemed a bit mystical - like you were employing some special skill or something to use them. Clip the ends evenly, push the plunger evenly, and until they started coming with caps, you had to use it all or loose it.

Since the product specific containers can now be abandoned, we ought to see the costs of some of these materials come down…right?

Photo: Business Wire

Many people think of homes as the place where panelized construction is most common. If that is true then the idea is being challenged by companies in the commercial sector.

A case in point is the recent announcement by Codding Steel Frame Solutions that it had manufactured and delivered 1000 linear feet of exterior wall panels for the construction of a Whole Foods store.

The company claims that steel framing members provide more dimensional stability than lumber and they will not rot or support mold growth. The green aspects claimed include a high recycled content and material that is 100 percent recyclable at the end of its life. Codding does the manufacturing of the panels in a solar powered factory.

Codding claims that two people can build 250 linear feet of wall in 12 hours and erection time at the site is cut by at least 50 percent using half as many framers.

The initial hurricane Ike damage assessment is in from the Institute For Business and Home Safety (IBHS). After two days of surveying damage in Houston, Galveston and the surrounding areas the researchers discovered water intrusion at roofs was the greatest point of concern resulting from this storm.

As might be expected older roofs didn’t hold up as well as newer ones and the points of damage initially originated with the underlayment rather than the sheathing. Of course buildings in Galveston that weren’t elevated above flood stage received the worst damage. Newer shingle, tile and metal roofs performed well. The report didn’t define “newer.”

Interestingly, areas 50 miles removed from metropolitan areas had higher wind gusts. Houston damage was called similar to category 1 hurricane conditions, while those in Raywood were rated similar to category 2 conditions.

The IBHS recommends in this publication that roof underlayment in many of the Atlantic and Gulf States use a full layer of self-adhering polymer modified bitumen membrane that meets ASTM D1970. Outside of those areas where local codes don’t allow that system you can use other products like reinforced synthetic underlayment to substitute for 15# and 30# felt. They have a higher tear resistance and can survive longer in the elements before deteriorating.

Another option is at least 4 inches (w) of self-adhesive flashing tape used at all horizontal and vertical roof deck joints. Asphalt impregnated 30# felt installed with ring or deformed shank fasteners that have at least one-inch diameter caps and are spaced six inches along laps and 12 inches in the field is another option. This process also requires a self-adhering polymer modified bitumen cap sheet or a similar treatment applied with a hot mop method. Closed cell urethane based foam adhesive\insulation applied to the attic side of all joints between roof sheathing panels is another method of achieving secondary water protection.

You can see several photos of the damages to buildings from Ike here.

As I was writing this post, Josveek Huligar weighed in on the radon and granite topic with a very long comment. That comment is available for reading here.

Huligar is associated with the NSRA (National Stone Restoration Alliance) and is understandably miffed about recent news reports claiming that granite poses radon risks. So much so that from September 6-8 Huligar was having a piece of radioactive granite installed inside his home. The event was on live web cam (don’t you just love this new technology). At about 6 pm on 9/8 the plan was to test the radon level in the home. Also at this site you can view some great pictures of granite slabs that are being tested for radon.

While it is clear Huligar went to a lot of time, trouble and treasure to pull this off I don’t see how it could confirm there is no radon threat from granite. Not everyone’s home is like Huligar’s, or built on top of the same type of material, or made of the same things and with the same level of tightness, etc. And while the granite sample is representative of a granite slab bearing the highest radiation, the amount used is unique to this home. At best, this will prove that the particular piece of hot granite installed at Huligar’s either increased the home’s radon levels, or didn’t.

For those of you who need to catch up on this ongoing story you can find an older post here that gives some of the history going back to 1995. In July 2008 the Marble Institute of America (MIA) issued a press release ostensibly quoting the EPA that granite countertops cause no significant health risk.

Now, in view of recent media coverage MIA continues its insistence that granite countertops pose no health threat related to radon. The latest release names numerous studies showing:

No scientific evidence exists to suggest that granite countertops are a source of meaningful exposure to radon.

And later:

This study is consistent with all the studies we’ve conducted in the past, which have found that granite countertops pose no health risk.

As I’ve followed this unfolding war of words I wonder why MIA isn’t listening to what some people are saying. Instead it blames “the media” for fabricating information. From my readings the questioners of granite safety are not concerned with “meaningful exposure,” it’s about any exposure at all. How much exposure to radon is acceptable to a mother or father with children? That probably depends upon how much they trust the EPA’s assessment of what an acceptable level of exposure is, and how much radon exposure their particular home generates. Some people may feel that there is no acceptable level of radon exposure. Are they incorrect to feel that way?

The results of exposure to most substances aren’t really known for lifetimes. So to say there are no health risks associated with granite could be similar to someone saying back in 1940 that there were no health risks associated with smoking cigarettes.

But to focus on the big picture, this whole debate isn’t just about granite. Rather, it’s about how the pursuit of profits compels the sale of products without knowledge of the long-term consequences that will result from their use in particular situations. So it comes down to the buyer being aware, and of course that implies them having enough information to be aware.

Rather than repeatedly claiming there is no risk associated with granite in the home the industry might serve itself better to present the latest evidence it has and then let the potential buyers make up their own minds as to whether or not the level of risk is acceptable. Because, there is a risk. There is always a risk.

Geothermal power generation is on track to deliver enough power to electrify the cities of Los Angeles, Phoenix, San Francisco and Seattle, according to the Geothermal Energy Association (GEA). There are currently 103 projects underway and that represents a 20 percent increase just since January 2008.

That’s the geothermal electrical generation picture, but geothermal has been in use to heat and cool buildings since the 1940s, and today there are more than 50,000 of these systems installed in the US every year.

I was involved with the construction of a log cabin in a remote and mountainous area a number of years ago where one of these systems was scheduled. In this instance we dug five, six-foot deep trenches, 125 feet long and four feet wide. Into the bottoms of the trenches the installer coiled a poly-type of pipe that used fused connections. Eventually the pipe ends, one incoming and one outgoing, connected to a geothermal heat pump. This heat pump used fluid to collect heat from the ground, or from the house, depending upon the season, and effectively heated and cooled the place very well. At that time energy savings estimates were at 70 percent over traditional competitors.

This project was a very expensive add-on to that home of a little over 3,000 square feet, but with a 70 percent reduction in energy bills it still had a ROI of about eight years in that climate. The equipment used in these systems today have a 25 year life expectancy and the ground loops are expected to last 50 or more years.

At the time there was another source of heat sink\rise being used - well water. As long as a well had a production capacity exceeding nine gallons a minute you could pull the well water to act as the heat sink\riser. That’s how much had to be allocated for the geothermal operation, so for a typical household with an average- sized pressure tank you’d need at least a gallon a minute more than that to furnish the household water.

For a good primer of these kinds of systems take a look at this Department of Energy site. If you have a project where you’d like to explore using one of these systems and your plumber is reluctant to take the plunge you can most often work it out so a factory rep from the maker of the heat pump will be on site to assist with technical knowledge and skill-building.