Stop Mold Growth
Summary: Mold growth is a major problem, which thousands of people are experiencing due to a number of factors. Mold takes root partly due to poor workmanship, a limited understanding of the dynamics of water and water vapor movement, and lack of adequate training for builders. Toxic mold concerns rarely happened in old homes. Stopping black mold and other mold types before they begin can be done, but your builder must be well versed in how to keep water at bay with modern building materials and proper construction.
DEAR TIM: There has been so much news lately about mold that I am very concerned about what might happen to my family and myself in my new home. When I was growing up, mold was never and issue. What is different now? Why is mold such a problem with newer homes? Older homes seem to be somewhat immune. Chad G., Birmingham, AL
DEAR CHAD: As much as I hate to say it, I think the mold problem is just starting to raise its ugly head. For many years I have witnessed building construction practices that, in my opinion, contribute to severe mold growth and subsequent structural failure from wood rot. The problems can be traced to several things. First and foremost among them, many modern builders simply do not understand the dynamics of water vapor, condensation, ventilation and exterior moisture protection. In the years ahead, I predict that mold discovery and mold related issues will reach epidemic proportions in recently built homes.
Because of these factors and several more, water that triggers mold growth didn't collect inside of wall cavities, on interior wall surfaces and in attic spaces. The drafty nature of the construction allowed the water to rapidly evaporate into the atmosphere. Mold most certainly did grow, but only in places where water leakage had become a chronic problem.
The energy crisis of the 1970's turned the residential construction industry on its ear. There was a rush to seal air leaks in houses and improve the weatherstripping on doors and windows. Vapor barriers in exterior walls became a building code requirement. In many areas of the nation, forced air heating and central air conditioning with its necessary duct work replaced traditional hot water or steam radiant heating systems. Along with the duct work came whole house humidifiers. Humidifiers are a good thing, but if not operated properly, they can become mold's best friend.
The rapid growth in the overall population created a housing boom. This led to an influx of builders and sub-contractors into the residential housing industry that had little or no formal training. These individuals, without knowing it, started a trend of poor building that was, and continues to be, unknowingly passed on to subsequent builders and sub contractors. Just because an individual has been doing something for 20 or 25 years doesn't mean it is right!
For example, go back in time and you would never see a roofer caulk metal flashing in place. Sure, modern caulks are a far cry better than old brittle butyl caulks, but they can and do break down over time. On the other hand, 40 pound tin flashing embedded 3/4 inch deep into a mortar joint has been known to last 70 years or more.
Old builders discovered well over 100 years ago that overlapping layers of ordinary 15 pound tar paper stopped rain water and snow melt from touching vital wall sheathing and wood framing members. Today we have modern air and water infiltration barriers, but many houses are built without this vital secondary moisture protection. Wind driven rain can and will get behind all types of siding. It can also penetrate the single layer of brick veneer that so many homeowners think is waterproof.
To stop mold growth, your builder must be well educated and be able to demonstrate a knowledge of how to use modern building materials in such a way that water does not condense within wall cavities and attic spaces. He needs to build your home to standards that exceed what the building code states. The building code is a wonderful set of guidelines but many code officials will agree that is a set of minimum standards. If he does not agree with this point, it is time to re-open the bidding process on your new home.
If you have mold growing on a surface, it can be removed by using different types of bleaches. Not all bleaches are the same. The most common bleach that most people use is chlorine bleach. It is a liquid purchased at just about any grocery store. The chemical name for chlorine bleach is sodium hypochlorite.
Chlorine bleach is a very effective mildew and mold killer, but its fumes can bother some people. Mixing a 50/50 solution of chlorine bleach and water is often all you need to do to make a powerful solution. Spray it on the mold and mildew and let it sit for several minutes. Scrub it with soap and water and then rinse.
If you want a less toxic bleach, you may want Oxygen bleach. Oxygen bleach is a powder you mix with water. It produces no fumes and it also does a good job or removing mold and mildew, but it doesn't do it quite as fast as chlorine bleach. The Oxygen bleach solution is also safe for any vegetation and nearby plants should you be working with it outdoors.
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from Tim: Years ago while researching a column about cleaning decks, I discovered the wonders of Oxygen Bleach. It is perhaps the 'greenest' cleaner I know of as it uses oxygen ions to break apart stains, dirt and odor molecules. There are no harsh chemicals, and it works on just about anything that is water washable. I decided to create my own special blend using ingredients made in the USA. In fact, the raw materials in the active ingredient are food-grade quality registered with the FDA. I call my product Stain Solver. I urge you to use it to help with your cleaning project. You will be amazed at the results! |
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Comments:
travis 29 Jan 2008, 16:35
we just put a roof on the house this summer and new siding as well. The
upstairs room is unheated and we did not insulate or cover the walls (no
sheetrock or wall panel of any type). We are in Portland, Oregon and this
has been an exceptionally wet winter and cold as well. Moisture has been
collecting on the tips of the roofing nails that protrude through the osb
decking and now we are seeing a large presence of mold on the under
surface. Is this understandable in light of not heating or do we need to
ventilate better or close the remaining air gaps that exist at joints of
wall to roof sheathing? if we insulate are we merely going to trap the
future condensation in the remaining space or will that solve the
condensation problem? Thank you so much for your help and your time!
AsktheBuilder 29 Jan 2008, 18:04
Travis,
Read ALL of my Condensation and Ventilation columns as fast as you can.
Cherie 16 Jun 2008, 07:22
Thanks for your web site which has been very helpful. Here's my question:
We are building a new home in Florida. It is not under roof yet and we are
in the rainy season. What do we need to do to prevent mold until the house
is sealed? Again, thanks.
Dennis 18 Jul 2008, 22:40
Dear Tim,
My problem differs enough from most to require this email. I have built a port-e-chohere/deck using 2x10 beams (3 2x10 per beam). The builder did not use treated wood, but explained that quality paint would be as effective. Nevertheless, after mold ate the supports beams in three year I had to rebuild the supports. The actual decking material is in great condition, but the substructure supporting woods seem to have beem eaten. In some cases it was as if the cellulose had been eaten out of the wood. It was not gree, black, or damp... just brittle. Three months after replacing the beams I noticed the nold growing again. Some is black and grows outward and react like a pollen on a flower, easily blowing into the envirobnment when touched. Another type grows from between two pieces of wood and llie a mushroom. I have used a product from Home Depot and that seemed to work for a month or two, but the mold returns. Oh yes, by the way, the home is on the Brazos river outside of Houston, so it almost always damp. I suppose this is going to be a an ongoing concern that will require monthly treating of color/water 50/50 and then a mildecide. The problem is, the mildecides seem awfully expensive to have to use every month (the porte-chchrere sunstructure is about 26 x 20). This is an exterior problem, so no health issue (unless the supports give way and people get hurt!). By the way, tha e paint was Behr and I added extra over-the-counter mildew protection. Doesn;t seem to have helped much. The last place I cleaned the black powery milder from the paint came right off (only the pressure from a standard sprayer from a garden hose) I value your suggestions. Regards, Dennis
Phyllis 27 Jul 2008, 06:50
I have a damp basement. The water is entering up through the floor. The
walls are dry except where water has wicked up from the floor. Even when no
water is visible, the worn paint patches effloresce.
We have a very high water table here. I had a foundation company visit and look over the basement. He said my only problem was the size and depth of my sump pump - that the pump allowed water to rise until it touched the underside of the floor slab and then the water soaks up through the concrete. A new sump dug, and a new pump with back up will cost me abou $2500.00. I will gladly pay this if it will fix the problem. It almost seems too simple. What is your take on this? (There is no visible water around window wells or on walls. I have cleaned and repaired gutters, raised the ground level near the foundation to ensure a dro in grade away from the house, dug a swale to carry water from between houses into my front ditch) Thanks Phyllis
Amelia 23 Aug 2008, 15:14
We have mold on the drywall in our basement. We are going to remove the
wall board completely but I would like to kill the mold before we start
tearing it out. Would spraying it with bleach do the trick?
Sam White 26 Aug 2008, 08:36
I have mold growing behind a brick veneer. I have moisture barrior paper
and weep holes. It is on a wall that had several appentics working on it, i
amwondering if the cause couldcome form to much mortar being dropped behind
the wall.What are your thoughts?
Frances 26 Sep 2008, 20:25
I have a problem with the rain water collecting in the window wells coming
in and running downthe walls flooding my basement. A well cover is not the
answer what kind of window can Ii replace it with to stop the water from
coming in?
Heather 09 Dec 2008, 13:59
Three years ago my husband and I bought an older home. It was built in
1941. We don't have any apparent mold problems anywhere in the house
except in our one and only very small full bathroom. I can't keep this
mold under control. It's on the ceiling, the tub, on the calk, and
everytime I put up a new shower liner, it is covered in a matter of days...
and these things are only what I can see. The people that lived there
before, put up a shower liner that is very pourous and the mold just sticks
to it-- and it is hard to get it clean. Plus they put up wood
wainscotting/bead board on the bottom half of the wall-- both of these make
me worried that mold may be growing between it and the wall. Aside from
getting very frustrated, I am worried that this could be dangerous. How
can I keep this under control? I bought a "mold test" that I need to do and
send away to see if it is black mold. Does this sound like the only way to
stop it is to rip the entire bathroom apart? If so, that's money we just
don't have. Your suggetions would be GREATLY appreciated!
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