Monthly Archives: February 2014

What’s the Big Deal With Mold in Houses?

What’s the Big Deal With Mold in Houses?

Mold is ubiquitous in nature, making up approximately 25% of the earth’s biomass, and thrives in many outdoor environments.

Molds, yeasts and other certain related forms constitute the organisms (microbial agents) known as fungi.  We have all seen fungi growing on rotten fruit, bread and damp leather.  They may by green, black or white and may appear to be fuzzy or sooty. Fungi are plant-like & many consist of two parts – hyphae, which are fungal filaments that form the body – and spores, which are seed-like structures than can be used for reproduction.  Some spores contain mycotoxins and have been termed “toxic mold”.

 Fungi must subsist on organic matter such as wood or paper products.  In order for fungi to thrive, the following conditions are necessary: An ambient temperature range of 40-100 degrees F; a humid rich environment, generally greater than 60% humidity though usually greater than 70%.

Why is mold in real estate a potential concern?
I was once at a home inspection with noted indoor air investigator, Jeff May, and he gave me a copy of his book entitled “My House is Killing Me”. In it he says that mold causes four main types of illnesses in humans: allergies, irritation, infectious disease & toxic effects. Microbial agents may serve as irritants to the respiratory tract causing an increase in mucus flow and other types of symptoms.  These agents may cause infections in two manners: pathogenic infection – this can develop in a relatively healthy individual with a normally functioning immune system; and opportunistic infection – this can develop in an individual with a compromised immune system or those with or on chemotherapy, diabetics, asthma or antibiotics, HIV or AIDS, physical or mental conditions affecting the immune system.  Some factors responsible for the concerns are the ability of the agent becoming airborne in sufficient concentrations and the ability of the agent to be respired by the susceptible host.

Are there any buildings more vulnerable to mold growth?
Any dwelling with a history of current water infiltration problems as well as those structures with consistently high indoor humidity levels or those with poorly designed components such as inadequately vented attics and crawl spaces, as well as poorly designed or maintained HVAC systems.

How do I know if mold is present within a dwelling?
Mold growth should be suspected when surfaces are discolored i.e. “mildew” or if damp mildew odor is present which can represent mold by-products such as – microbial volatile organic compounds (or as I call it eau de mold). This is especially true on organic natural materials.

If mold growth is suspected what should be done?
A trained indoor environmentalist or mold remediation specialist should be consulted to determine the presence of mold, its cause and cure.

Are there any threshold limits in which mold is a concern?
Because all individuals have varying degrees of sensitivity to mold there are currently no threshold limit values.

What is toxic mold?
Toxic mold refers to certain mold species that have spores that contain mycotoxins such as stachybotrys, also called Black Mold.  Mycotoxins are opportunistic pathogens and may be a greater health concern for certain individuals.

If mold growth is confirmed within the indoor environment what should be done?
Depending on the amount and depth of the mold growth, the solutions may range from removing surface mold via HEPA vacuuming and washing.  To the extreme of removing and replacing all effected material, it is strongly suggested that only those with specific training and experience conduct any mold remediation work.

How can mold growth be prevented?
Mold requires several conditions to thrive.  An organic material (wood or paper), oxygen, appropriate ambient temperature, a high moisture content and/or a high ambient relative humidity of 60% or greater.  The most controllable factor of these conditions is the moisture content, which is usually controlled by removing moisture sources (water infiltration) and reducing and maintaining the indoor ambient humidity level to below 60%.

Need an expert?
Call me, I can recommend several.

How Hard are Hardwood Floors, Really?

How Hard are Hardwood Floors, Really?

Just  the other day I was at a home inspection (representing the sellers) and the buyer’s home inspector was commenting on the Brazilian Cherry floors in the Study, telling the buyers that “this wood is very soft, so you’ll want to be very careful when you walk on it.”

Having grown up in the household of a high school shop teacher, I’ve had a great education in woodworking and made lots of projects with my Dad.  Over the years I’ve worked with Brazilian Cherry and for a fact I know it is a very, very hard material.  It takes forever to sand and holes for fasteners have to be pre-drilled very accurately and sized correctly. But I kept that knowledge to myself and decided to share it with you instead.

Many woods are used for flooring and although today’s design trends and color schemes often drive the choice of materials, over time the most popular woods for this area of the country, are: Brazilian Cherry, Mahogany, Pecan, Maple, White Oak, Red Oak, Walnut, Teak, Pine, and Fir. Of these, Red Oak is the most commonly used (it’s considered the most color-neutral and affordable of the woods) and thus it is considered the standard or benchmark in wood hardness.

If you Google hardwood hardness you will inevitably encounter the Janka Hardness Scale. It is the industry standard for judging the ability of woods to withstand the beating that wood takes from normal wear and tear: denting, gouging, pet scratches, heavy furniture, etc. Janka measures the amount of force in lbs-force that it takes to push a half-inch diameter (okay it’s really .444 inch) steel ball half of its diameter down into the wood. While this gives a general sense of the wood’s hardness, there are many factors that also contribute to a wood floor’s hardness and durability, including how it is cut from the log and how it is finished.

How the tree is cut has an effect on its hardness and suitability as a floor covering. Hardwood flooring is produced by milling wood from trees. There are three basic ways to cut a tree into lumber, called “plainsawn”, “quartersawn” and “riftsawn”.

“Plainsawn” wood is just that, the log is sliced lengthwise from one side to the other in a series of parallel cuts, sort of as you’d cut a block of cheese. This gives the best yield from the tree but for flooring it tends to result in a very inconsistent grain pattern and tends to expand and contract in unpredictable ways. Wide-pine floors (found in many Antiques and Antique Reproduction homes) are the typical example of “plainsawn” wood that most of us will encounter.

“Quartersawn” wood is the most common way that flooring material is made. In this method, imagine that the log is cut down the middle, then both halves are cut down the middle, and the boards are then cut from the “quarters” with the point facing straight down (a series of parallel cuts starting perpendicular to the centerpoint of the tree). This gives consistency to the grain of the boards (as consistent as any natural material can be) and a predictable stability that makes it perfect for flooring. For the purposes of this blog, I am using hardness factors derived from “quartersawn” wood.

“Riftsawn” wood is the absolutely ideal material for consistency of grain and stability but is very hard to find because it is so expensive to manufacture. In this method, the log is cut into a series of wedges that are perpendicular to the rings of the tree. The wedges are then sawn into boards and the excess material becomes waste. Because of the low yield per tree the cost per board foot is very high and you will probably never see “riftsawn” flooring unless touring a mansion or a castle. By the way, there are a couple of specialty sawmills in the Sudbury area that will produce “riftsawn” boards for you, but hold onto your wallet.

As mentioned earlier, the finish also has an effect on the hardness. I am not qualified to comment on what finish is harder or better (best to ask a flooring expert) but I can tell you that the typical finish penetrates into the top ¼” of the wood, at most, so logic would have it that finished versus unfinished wood would be harder but much beyond that I can’t really say.

So how hard is my hardwood floor?

Below is a list from softest to hardest:

FIR
  • Latin: Abies sp
  • Other Common Names: White Fir, Balsam Fir, Fraser Fir
  • Janka Hardness: 400

WHITE PINE

  • Latin: Pinus alba
  • Other Common Names: White Pine, Eastern White Pine
  • Janka Hardness: 420
  • Hardness Compared to Fir: 1.05 times harder

SHORTLEAF PINE

  • Latin: Pinus echinata
  • Other Common Names: Southern Yellow Pine, Shortstraw Pine
  • Janka Hardness: 690
  • Hardness Compared to Fir: 1.725 times harder

AMERICAN CHERRY

  • Latin: Prunus serotina
  • Other Common Names: Black Cherry, Cherry, American Cherry
  • Janka Hardness: 950
  • Hardness Compared to Fir: 2.375 times harder

TEAK

  • Latin: Tectona grandis
  • Other Common Names: Plantation Teak, Burmese Teak
  • Janka Hardness: 1000
  • Hardness Compared to Fir: 2.5 times harder

WALNUT

  • Latin: Juglans nigra
  • Other Common Names: Black Walnut, Eastern Black Walnut
  • Janka Hardness: 1010
  • Hardness Compared to Fir: 2.525 times harder

HEART PINE

  • Latin: Pinus palustris
  • Other Common Names: Long Leaf Pine,
  • Also Commonly from: the Center or ‘Heart” of Yellow pine
  • Other Notes: mostly from recycled or underwater harvested, swamp trees
  • Janka Hardness: 1225
  • Hardness Compared to Fir: 3.0625 times harder

RED OAK

  • Latin: Quercus rubra
  • Other Common Names: Northern Red Oak
  • Janka Hardness: 1290
  • Hardness Compared to Fir: 3.225 times harder

WHITE OAK

  • Latin: Quercus alba
  • Other Common Names: Old Oak
  • Janka Hardness: 1360
  • Hardness Compared to Fir: 3.4 times harder

MAPLE

  • Latin: Acer saccharum
  • Other Common Names: Rock Maple, Hard Maple, Hard Rock Maple, Sugar Maple
  • Janka Hardness: 1450
  • Hardness Compared to Fir: 3.625 times harder

PECAN

  • Latin: Carya illinoinensis
  • Other Common Names: Hickory, Satinwood
  • Janka Hardness: 1820
  • Hardness Compared to Fir: 4.55 times harder

 

MAHOGANY

  • Latin: Swietenia mahagoni or Swietenia macrophylla
  • Other Common Names: West Indies Mahogany, Honduras Mahogany, Genuine Mahogany
  • Janka Hardness: 2200
  • Hardness Compared to Fir: 5.5 times harder

BRAZILIAN CHERRY

  • Latin: Hymenaea courbaril
  • Other Common Names: Brazilian Copal, South American Locust,  South American Cherry, Jatobá or Guapinol
  • Janka Hardness: 2350
  • Hardness Compared to Fir: 5.875 times har
How Much Does My House Weigh?

How Much Does My House Weigh?

Okay you’re asking yourself, why on earth would anyone need to know this? The answer is, I don’t know, but you might as well read on.

There are a lot of experts out there with opinions but nobody I asked could give me a definite answer. The closest answer I got was from Matt Murphy of Admiral Building Movers who said that for a wood frame building it depends on the foundation size (the footprint) and the number of stories. As his business is building moving, shoring and jacking, he figures weight without foundation and garage spaces and said that if the house interior includes sheetrock and heavy flooring the weight doubles. So I contacted a number of architects, builders and engineers and based on a blending of all the answers I got here’s what your house might weigh (including full interior, foundation and garage):

Average 1 Story Ranch 24’x36′ footprint (864sf) … between 52 and 86 tons   (this one would take between 600 and 1000 people to lift it)

Large 1 Story Ranch 28’x40′ footprint (1120sf) … between 68 and 112 tons   (this one would take between 775 and 1275 people to lift it)

Average 1.5 Story Cape 28’x36′ footprint (1512sf) … between 69 and 139 tons   (this one would take between 700 and 1600 people to lift it)

Large 1.5 Story Cape 28’x60′ footprint (2520sf) … between 102 and 231 tons   (this one would take between 1160 and 2640 people to lift it)

Average 2 Story Colonial 24’x36′ footprint (1728sf) … between 86 and 119 tons   (this one would take between 1000 and 1400 people to lift it)

Mid-Sized 2 Story Colonial 28’x40′ footprint (2240sf) … between 112 and 154 tons   (this one would take between 1300 and 1800 people to lift it)

Large 2 Story Colonial 30’x60′ footprint (3600sf) … between 180 and 248 tons   (this one would take between 2050 and 2850 people to lift it)

Estate Size 2 Story Colonial 48’x90′ footprint (8640sf) … between 425 and 600 tons   (this one would take between 5000 and 6800 people to lift it)

Estate Size 3 Story Colonial 48’x90′ footprint (12960sf) … between 594 and 756 tons    (this one would take between 6800 and 8800 people to lift it)

For extreme contrast, there actually was a house designed by a very famous inventor/thinker, named Buckminster Fuller (he’s famous for his geodesic domes) in the 1920’s called the Dymaxion House which among many other design considerations was designed to minimize its weight. The final design was a 1 Story Circular Ranch style that had a footprint of (1100sf) and weighed just 1.5 tons (this one would take just 18 people to lift it).

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