Moisture problems in concrete cause about $1 billion dollars in flooring failures every year. Prevention of such failures requires strict adherence to product specifications and ASTM procedures. Below are some key points to consider.
The concrete slab needs proper curing time, and all lighting, heating, and cooling conditions need to be stabilized.
Any curing compounds used on the slab must be removed.
Regarding the concrete itself, it should have a water-cement ratio of less than 0.50 and a vapor retarder should be installed at a minimum thickness of 10 mils.
Adhesives used for the flooring installation must be allowed their proper cure time, after the concrete has cured.
Finally, it’s critical that the slab be tested for moisture by a certified concrete slab moisture testing technician, according to ASTM guidelines. If you have experienced a flooring failure or require moisture testing before flooring installation, give us a call! We have an ICRI certified testing technician on staff to help you.
1.) My first athletic trophy was for ice hockey. What can I say…I’m a New England Boy! Go Bruins!
2.) Our first cat Squirt played table hockey with me.
3.) My dad use to call me “Ox” and my younger brother, Jim, “Kong”.
4.) My son’s middle name David is in honor of 3 of my best friends (high school, college and current).
5.) I not only drive fast cars, I build them with my son (and yes, they are road-worthy).
6.) My dad said the proudest day of his life was the first airplane ride I took him on after I got my pilot’s license. He had always wanted to be a pilot in WWII, but couldn’t due to an injury.
7.) I have been riding motorcycles since I was 15.
8.) I was voted “Most Scientific” in my graduating high school class.
9.) I love riding motorcycles in West Virginia. All the roads and the people there are great.
10.) I am privileged to truly like my job and the people with whom I work.
In the aftermath of Superstorm Sandy, a lot of people found themselves without power and with a lot of branches and leaves to collect, but how did your windows hold up? Some people out there will tell you that if your windows withstood the winds created by the Frankenstorm, then they can handle anything, but did the storm really test the integrity of your windows?
In order to answer that question, we need to understand how windows are rated. Engineers that specify windows focus on the design pressure (DP) of a window, as it represents the maximum wind load that a window can undergo without sustaining structural damage (i.e. breaking, deforming, etc.).
It is important to keep in mind that the design pressure an engineer specifies for your windows is dependent on many factors. Building type (i.e. hospital, office building, school, etc.) and geographic circumstances (coastal region vs. inland) play a major role. Additionally, engineers will require greater DP values for your windows the higher they are above the ground, as well as if they are near building corners where increased pressures from swirling winds come into play.
With that being said, many mid-rise buildings in the Baltimore-Washington area feature windows that can withstand a wind pressure of 20 psf (DP-25). Converting wind pressure into wind speed, a newer DP-25 window is rated for up to 96 mph winds, depending on the previously mentioned factors. This means these buildings are designed to handle (structurally) wind speeds expected with a Level 1 Hurricane (74-95 mph).
Another window rating system is the Performance Grade, which designates the resistance of a window to water infiltration, air infiltration, etc. The water infiltration resistance corresponds to the DP-rating of a window and is important to us because it indicates when your windows should be expected to start leaking. The average newer window in a condominium or apartment will begin leaking if you combine heavy rainfall with 40 mph winds or greater.
In the metropolitan area, the maximum recorded wind speed (gust) produced by Superstorm Sandy was approximately 60 mph. This means that the event did not produce high enough wind speeds to jeopardize the structural integrity of your windows (DP-25 or better), but the potential for leaks was expected. This really only holds true for new windows; it is not uncommon for older windows to leak at much lower wind speeds due to lower DP ratings and worn out components, such as weather stripping.
If you don’t know what the DP rating of your windows are, look for a design pressure test label such as those issued by the Window and Door Manufacturer’s Association (WDMA) or the American Architectural Manufacturer’s Association (AAMA) on the frame. Since there are many factors at play in window evaluation and selection, a design professional should be consulted to make a proper determination of your window leaks.
The November dinner meeting of the Baltimore-Washington ICRI was eventful for ETC. Bobby Radcliffe, from our Maryland office, was elected to serve a three year term on the Board of Directors for the Chapter beginning in January 2013. Molly Carlson, daughter of Chief Structural Engineer Chris Carlson, received a scholarship from the Chapter to go toward her college education. The photo shows Molly being presented a check by the Scholarship Committee Chair, Brian McCabe of Concrete Protection and Restoration. It appears 2013 is starting off quite nicely for these two! Congratulations!
With winter practically here, you should have already developed your snow and ice removal plan for the year, but it’s never too late to create or amend one. Among the things to consider are areas where snow is to be pushed by plows. The lower ends of parking lots are seemingly logical places to push snow, but that’s often where storm drain inlets are located and they should never be obstructed by mounds of snow. Unless they’re mapped or marked ahead of time by your removal team or contractor, the plow operator may not know where they are and block them. It’s especially important to leave fire hydrants uncovered and accessible.
Other items that should be marked are speed bumps and any utility covers that extend even slightly above the pavement surface. Snow plows can gouge integrated asphalt speed bumps and dislodge or break prefabricated devices.
Snow removal on exposed parking garage decks present another set of problems. If the deck is surfaced with a waterproofing or protective coating, conventional steel-bladed snow plows can damage the material. There can be expansion joints, lighting bollards, stand pipes and other items that should be marked and avoided. A blocked/buried fire standpipe could have catastrophic consequences.
Your crew or contractor should also practice judicious use of deicing agents (salt, calcium-chloride, etc.). Improper use will damage concrete and new concrete (less than a year old) is particularly susceptible. If you’ve had sidewalks, stair assemblies, or curb and gutter assemblies replaced in the past year or so, they should be mapped and treated with extra care with respect to ice control. Consider using sand instead of deicers in those areas.
Hurricane Sandy certainly caused a lot of problems relative to water intrusion issues that occurred in places where they had not been previously seen. Site drainage around buildings is very important and numerous problems were reported due to clogged gutters, downspouts and other water drainage components that need to be carefully checked and maintained on a regular basis.
We have also seen several concerns related to problems with storm sewer systems and underground lines that service basements or low lying drains. If these important drainage features become clogged, a large storm like Sandy can cause extreme water back-up that can readily penetrate into buildings. In order to check storm sewer lines and underground drain lines, consider retaining a qualified plumber to run a camera through these lines to check for obstructions and/or breaks in the pipe walls or joints. Keeping these lines clear can greatly help prevent unwanted problems.
Field work or not, Sandy does not allow us to come back and track dirt into the office. Those that do…pay the price! Luke, our newest engineer, had to learn the hard way. A quick trip to the cleaning closet and he was back in Sandy’s good graces. It’s nice to know this guy can not only operate a Delmhorst, Psychrometer and thermal camera….but also a good ol’ fashion HOOVER.
Just for your information, I wouldn’t ask him to do windows!
It was a true pleasure supporting and playing in the annual Ocean City Development Corporation (OCDC) golf tournament. This dedicated group of professionals works hard each year to ensure a economically sound and socially healthy downtown Ocean City, Maryland for residents and also for those just enjoying some time off.
With fundraising outing such as this one….there’s no doubt more great things are coming to Ocean City. ETC looks forward to many more successful events with this gang.
Autumn is here and soon all those colorful leaves you’ve enjoyed will be clogging your roof gutters. Gutter cleaning time is fast approaching and the earlier it’s done after the last leaf has fallen in your neighborhood, the less unpleasant it will be. Dry leaves are fairly easy to remove. Fermented leaf sludge is just nasty.
The best way to clean gutters is to have a roofing contractor do it. Roofs are dangerous places and ladders are even more so, in the hands of the inexperienced. If you insist on doing it yourself, here are a few basics to consider.
Carefully follow the instructions printed on your ladder. If your ladder doesn’t have any printed instructions, sell it for scrap and buy a new one.
Have a helper hold the ladder. Better yet, send the helper up. Keep an eye out for falling helpers and/or gutter slop flung by disgruntled helpers.
Look for wasp/hornet nests before you set the ladder up. They get cranky when disturbed.
Wear gloves. Cleaning out the debris doesn’t need further instruction, but while you’re there, look for evidence of leaks, especially at joints. If you fix a leak with one of those magic TV sprays that can make a boat out of a screen door, let us know how it works.
Look for evidence of poor drainage (such as standing water or water stains). Also look for water stains on the fascia behind the gutter. Gutters will occasionally overflow during especially heavy rains and they should be installed with outer edges slightly lower than the backsides so water spills out the front rather than onto the fascia
Look for backed-out fasteners (especially gutter spikes). The spikes should have been positioned to penetrate rafter ends, but they’re likely as not to only penetrate the fascia board, which in most cases is only about one-half-inch thick. That’s not enough “meat” to hold a spike and driving one back in won’t fix the problem.
Check the condition of shingles from your vantage point at the gutter line. Uplifted, torn, missing, or otherwise compromised shingles will be far easier to spot from there than from the ground. Damaged shingles should be repaired or replaced by a contractor as soon as possible.
While you’re on the ladder anyway, you might as well check the condition of other building elements (especially wood fascia, trim, etc.) that you can safely reach. A simple check for rotted wood would be to probe it with a knife blade. A pocketknife should penetrate no more than about one-quarter inch under moderate hand pressure. You should also look for insect damage, bird nests in dryer vents, dislodged soffit vents, cracks, bulges, stains, or any other condition that seems out of the ordinary
Is yellow, green, or blue the new black in pavement fashion? It might be if the researchers that are looking into making parking lots more eco-friendly have anything to do with it. By changing the color of asphalt from black to a lighter color they hope to reduce the heat island effect in cities that big parking areas can contribute to.