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mgbinspect

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  1. If the house was constructed in the winter time and accelerators were used in the mortar or concrete, it may higher concentrations of calcium and salt from the accelerator.
  2. Indeed, Jim. I've removed the words "large". "soluble" and "coagulant" from the original post. I stand by the fact that lime can and does refill small cracks and newer more cementicious mortars do not experience the same degree of autogenous healing. Thanks for your assistance in being clear.
  3. Certainly, it was the first search result on the net when I typed "lime mortar autogenous healing" http://www.slcc.edu/tech/techsp/arch/co ... mortar.htm http://www.zatang.com/categories/busine ... edlime.htm http://www.graymont.com/applications_be ... lime.shtml This information was given to me by an old brick manufacturer in Winchester, VA. He was a pretty interesting man and knew volumes about masonry. And, of course it was my life and passion for about 12 - 15 years depending upon whether you wish to count my estimating and management years. Coagulant is the word that he used to describe the characteristics of lime but he did qualify it with "it acts more like a coagulant." In fact he also used the word scab as in a human scab. His analogy was indeed stalactite and stalagmite action. Unfortunately, Mr Barr is dead now. I agree that lime is only slightly water soluble. And, maybe Mr. Barr's use of the word coagulant was not the best analogy, but his point and mine is that lime actually will migrate and reset or rebind. If you have a better analogy, Jim, I welcome it. Of course lime mortar could never fill large cracks. I was referring to slow ongoing settlement. And, the new more cementicious mortars do not enjoy the level of autogenous healing that old lime mortars do. The flip side, lime can and will eventually wash out of a masonry system that is getting too wet or especially has water passing through it due to lack of flashing etc. I've seen many portions of masonry where the lime was all but gone and the sand could be raked out with your finger. Along the same lines, when we started using type "S" and "M" mortars in school construction it backfired on the designers. The high levels of cement removed all the flexibility from the system resulting in wicked settlement cracks. Architects quickly retreated to type "N" mortar in most of their applications again. Thanks for your assistance, Jim.
  4. Have you ever wondered why you may not see cracks and voids in an old masonry building's mortar joints even when the masonry has settled? Some assume it is because the old lime mortars are more flexible. Actually, it is the result of a rather miraculous feature of the old lime mortar called "autogenous healing". Cracks form in the old mortars as easily as in any mortar. The difference is the characteristics of lime. When a crack forms, over time the lime with the assistance of water migrates to and fills the crack much like the formation of stalactites and stalagmites. Autogenous means self-produced or self-generated. The old lime mortar is self-healing.
  5. Ok, Mike! That article is up and waiting for you. Me
  6. Will do, stay tuned.
  7. Mike, I'll post an article tonight on the do's and don'ts of pointing early Amarican masonry and the catastrophic damage caused by doing it wrong.
  8. Thanks for your contribution. That's amazing stuff! I unfortunately left the trade shortly after this event and don't know how they adressed that masonry problem.
  9. Fritz, We take so much for granted these days. People like Benjamin Thompson, Thomas Jefferson, Benjamin Franklin and John Adams accomplished so much without the aid of laptops, slide rules or calculators. Many of these guys spoke two, three and four languages fluently and we think we're so smart. They would probably consider us lazy and mentally challenged.
  10. A man with understanding.... That is why I say if I had it to do again I would opt for the the chimney top damper. The available dampers didn't work with the Rumford design. Now and then however I would find a steel damper that was the proper dimension. They were hard to find, though.
  11. It was my life and passion for 12 to 15 years. If you have something you wish to know about masonry suggest it and I can most likely write about it.
  12. Well John, it's funny you should ask with your ninja suit and sword. I practice Aikido and Thai Chi. Some of fireplace function and theory is as mysterious as martial arts, and I wish someone would confirm some of it through aerodynamics. But, allegedly coming down through that spiral of up rising exhaust is return air. Allegedly. if you had closed glass doors, return air coming down the flue will continue to fuel the fire. I readily admit, it's beyond my understanding. I just built them and am not a master of aerodynamics or pyrotechnics. Much of masonry fireplace construction is tradition and what has proved to be reliable. But, more than any other mason, Benjamin Thompson actually seemed to understand what he was doing and why. Every dimension of his fireplace construction was ratios based upon the original fireplace opening. In fact, I love listening to and reading books about the founding fathers. John, it appears that those guys back then were so much more educated than we are today. Their understanding of mathmatics, language, science, and botany was sobering. I fear that many of those men would consider us in comparison dunces today! Sad, but true. I've spoken to men from Europe that have made the same claim. I've been told that our college was European High School! Kinda scary. At any rate, to answer your question as best I can, cold return air bounces off the smoke shelf and joins with exhaust to rise again up the chimney flue. That's the best I can do with this mystery. For more info refer to "The Forgotten ARt of Building a Good Fireplace" by Vrest Orton
  13. In the early 80's somewhere in Texas (I believe Houston) a whole section of brick veneer fell from the exterior of a high rise building literally smashing a parked car below. This incident was the first indication that the marriage of brick veneer and metal stud wall construction was going to be a major problem in high rise construction. What led to this disaster? The chain of small failures that led to the major failure are logical and fascinating. The chronology and key contributing factors are as follows: 1.) Wind and Barometric Pressure: When we enter a very tall building you will often hear the low howl and feel the rush of air into or out of the building. Changes in barometric pressure cause an imbalance between internal and external pressure in large buildings that takes a while to equalize. 2.) An inflexible veneer over a flexible structure: When you put a brittle brick veneer system over a flexible steel stud structure, something's got to give - the wrong thing. Wind and quick changes in barometric pressure exerted considerable forces upon the wall envelope of the building. This constant in and out flexing caused the bond between mortar and brick in bed joints to fail. The resulting hairline cracks went un-noticed and no one would have imagined this as the beginning of catastrophic failure. 3.) Moisture Intrusion: Unequal barometric pressure within and without of large buildings casts a whole new light on moisture intrusion forensics. Negative internal pressure can literally draw moisture into the cracks and crevices of a building by the gallon and did. 4.) Corrosion: Wet steel rusts and corrodes away. These last two factors sealed the fate of a system that appeared to be well thought out. Negative building pressure literally sucked water in through the failed bed joints. This in turn was wetting the anchorage system. Although the metal studs and the wall ties were galvanized steel, the self-tapping screws through the studs exposed raw unprotected steel. Eventually the steel stud around the anchorage fastening screw failed. Finally, high wind or extreme pressure caused whole sections of the brick veneer to literally fall out of the wall to the street below.
  14. The Rumford Fireplace: Safety vs. Efficiency Count Rumford, actually an American by the name of Benjamin Thompson, gained fame by rebuilding more than 500 fireplaces in England. It became a matter of pride to have a fireplace constructed by his masons. In the 80's, as a journeyman mason, I began to study and build his fireplaces which became a real problem with the Montgomery County, Maryland building department. The Rumford breaks all the rules. In the end, I convinced them to permit the shallow firebox in trade for a deeper and wider hearth. Another challenge to constructing a Rumford was the cast iron dampers were too big. I was able to overcome this by bringing the top of the firebox back forward of the damper flange, but if I had it to do again I would use a chimney top damper. Anyone that I ever built a Rumford for will happily tell you that the heat they produce will drive you from the room. Before we consider the design of the Rumford it would be helpful to understand what are the most common problems with a masonry fireplace. What causes a masonry fireplace to smoke? 1. An insufficient throat area. If there is not a sufficient space just above and behind the fireplace opening and below the damper for smoke to collect and roll prior to passing through the throat it will come back into the room. The height of the opening is not critical, but this area behind the top edge of the opeining is. 2. A flue that is too large. That sounds crazy, but bear with me. Smoke is actually heavier than air. As smoke cools, it becomes heavy and the moisture (sap) in it begins to condensate on the sides of the flue in the form of creosote and glazing. In the 80's I constructed a radical masonry wood stove chimney flue under the direction of Professor Jess Brown from the pyrotechnics department of Auburn University. The wood stove exhaust was an 8" diameter. We used round terra cotta flues all the way up and surrounded them with perlite insulation (good to 2000 degrees) Three years of monitoring revealed that the flue never needed cleaning. All heat and creosote remained in gas form until released from the top of the flue. 3. Taller objects near the flue. The top of a tree or roofline that is near and taller that the chimney can cause wind to curl over and down into the flue. What are the unique and successful features of the Rumford? 1. The fireplace opening was huge by todays standards. Most masons would look at a Rumford and conclude that it's going to smoke, but it doesn't. 2. All firebox surfaces were angled to radiate the heat directly into the room. 3. The throat was a mere 4", just large enough to prevent smoking while minimizing heat loss. 4. The smoke shelf was just large enough to permit the passage of exhaust and return air. 5. A plumb bob held in the center of the flue also hits the center of the firebox floor. (Heat rose directly up without any restriction.) Unfortunately, to meet todays safety concerns and standards the masonry fireplace has returned to the inefficient dark ages. Next: Why brick veneer was falling out of high rise buildings onto parked cars in Texas.
  15. That I suppose is prudent.
  16. Actually, the concern with ventless gas logs in a woodburning metal pre-fab fireplace isn't relative to the ventless gas logs at all. No problem there. It has nothing to do with the fireox materials either. No problem there either. IT has to do with excessive temperatures in the damper/throat area when the damper is sealed shut. Apparently, the metal gets too hot as in red hot. Zero clearance woodburning fireplaces are designed around and relying on the damper being open and the heat moving smoothly up the flue which pretty much regulates and limits the upper temp. This information came from certified sweep and author, Jim Brewer who travels as a speaker and has written numerous books within the sweep industry. He cautions that closing the damper in a wood burning metal pre-fab fireplace because ventless gas logs have been installed is a VERY bad idea and that the manufacturers of those units are concerned with this new and unintended use. He points out that the design for ventless gas log fireplaces is quite different and the cost of them is considerably higher all to meet the increased temperatures experienced at the top of the unit. He cautions that the metal in the top of these units can become red hot! It all makes perfect sense to me. I have a pretty good understanding of fireplace design and actually worked with Dr. Jess Brown in pyrotechnics at Auburn University in TX with some new fireplace flue designs. I built very unusual chimneys to his specs which never needed cleaning. But, for those who doubt this concern with the ventless gas logs with a closed damper please contact him jbrewer@magic-sweep.com He is the past, director, pres and vp of the national chimney sweeps guild. He is also a master instructor for the Chimney Safety Institute of America.
  17. Well, nobody likes to claim expert status these days... But, I am a 12 year journeyman mason and am familiar with most types of fireplaces and wood burning stoves. (lived in two 100 year old houses that only had wood heat... even had a copperclad cook stove! You know.. with the high medium and low lids? That sucker had a firebox the size of a shoe box! It went through tons of wood that had to be split very small. I finally converted it to coal! At any rate I used to cut and split about 7 cords a year for me and tons more for sale to others during the winter when masonry was slow... definitely warms the man twice!) If it had functional glass doors, it was most likely designed for wood in the beginning and was converted to gas logs and returned to wood. If it has a damper and an 8 - 10" diameter flue, it's a pretty sure bet that it was originally designed for wood. A far bigger concern is when people take a metal pre-fab fireplace designed for wood-burning and install ventless gas logs and seal that damper closed.... Now THAT can burn the house down! Manufacturers of such fireplaces are pretty nervous about this unintended use! As someone previously said, a gas log fireplace unit will have a much smaller diameter "B"-vent flue and will most likely not have a damper. I don't believe I've ever seen working glass doors on a factory build gas log fireplace? They usually have a fixed pane if they have one at all.
  18. Oh, well. Guilty as charged. I'm afraid I tend to just go with the flow. (Need more time and practice with all this. While I've inspected for 14 years, I'm brand new to all these boards.) I hope you guys will look me up at future conventions and introduce yourselves personally! (MGB Publications, Inc. www.mgbpublications.com) At the last three conventions many did and it was great! MIke
  19. Why be sorry, Brian? Indeed he was a great man. I read several books about him by those closest to him. All admit he was not brilliant, but he had a simple ardent wisdom that would not yield or compromise. At times his advisors were concerned with his stances and were not truly on board with him, but later had to admit with amusement and amazement just how right he was. A couple stories from those books: The last time he rode his horse he became disoriented and nearly fell. As someone close to him approached to inform him that was his last ride, the President cut him off and with a sad reassuring smile said, "I know, it's ok!" Near the end of his life when he could not communicate very well any more he simply reached out and grasped the hand of his body guard and kissed it. As they say, a picture's worth a thousand words. I voted for him and thought to myself, gosh the international world must think us awfully fickle to make a movie star president. He turned out to be one shining star. It was rich to hear most of the world admit just how great he truly was at his passing. And, saying goodbye to him was one misty eyed ordeal for me. Here's to Ronald Reagan, a truly great American!
  20. How can ya not love the Gipper? The same guy that said, "I didn't leave the Democratic Party, they left me!" He told it like it T I S tis!
  21. About three years ago I was sitting at a table finishing up my report when the room swayed a tiny bit twice followed by a low rumble. I thought to myself, "Man, these people must live really close to a quarry!" But, it was Virginia's only earthquake in 150 years! I was shocked.
  22. This is interesting? When I was taking architecture, all details always showed anchor bolts through sill plates with washers and nuts. Those books were circa 1940s. In the Richmond area, most old buildings are solid masonry with firecut joists in pockets. But, most old frame houses here usually have either bolts or 1/8" strap iron anchors. Not seeing anchors at all here would be very rare. It was common in older homes (you know back when architects thought of just about everything) to nicely countersink the washer and nut. You might feel along the top of the sill and make sure that isn't the case. AS a mason, we used to carefully measure our bolt heights for countersinks when called for.
  23. When I started my business in 1992, I joined just about every organization out there. AAHI, HIF, NAHI, ASHI, FREA and more. Some of these organizations simply required a check to join and I soon abandoned them. As Kurt has mentioned, striving to be and appear professional is good for your business and the entire industry. I've remained an ASHI Member and a NAHI CRI because I know that these organizations promote professionalism, keep us informed regarding late breaking and needed information and keep an ear to the legislative rail to protect us. I also own a publishing company and as an industry vendor, I am a member of NACHI as well. Each association has its strong cards. As far as I can tell, all of them are committed to offering great education if that is what you seek. As Jim has pointed out, the message boards can get pretty volatile. Egos sometimes abound. Just expect it. I would encourage you to join any organization that is as Kurt said, comitted to making us and the industry more professional. For most of us the cost of membership in each organization is just one home inspection fee. So, why not?
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