Mold issues in local climate

We are looking at buying a house in the upcoming months - Zone 7 Capd Cod - we are surrounded by water on all sides and it is very damp and moist from spring until fall.

The last 2 rentals that we were in had huge black mold problem - our current situation has a basement that I'm dumping about 2 gallons of water out of a dehumidifier daily in the summer. I have a good idea of where the moisture is coming from but this isn't my house, its a rental. The fall is here and its starting to dry out a bit but we are very antsy to move.

Any ideas on lessening humidity within a household? We plan on heating with a wood stove in winter which will be dry but the summer is what I am most worried about. I've thought about possibly running the wood stove in summer but that would be very hot. We need to move air and moist air around the house somehow.

We will be purchasing an older house and not building and was also looking for any tips you may have to spot issues that may be alarming. Are there any good books on this subject?

Thanks.

What you said:

I'm dumping about 2 gallons of water out of a dehumidifier daily in the summer.

If you are close enough to the water that the humidity is effectively 100% at night, then you need to have a dehumidifier running. My experience is with coastal Southern California, not Cape Cod, but the difference is only one of time of year. Southern California has the cold Pacific current, not the warm Gulf Stream and that changes which are the wet months and which are the dry. Mold grows during those months with very high humidity and then goes dormant during the dry times.

You could try wiping down every available surface with bleach at the end of the dry season, and then try to keep the humidity low inside the house with a dehumidifier, that would be your best bet. If you approach it as a yearly maintenance task, something that has to be done to try and stay ahead of the spores that blow in at all times of the year, that will help you avert most of the problem. The dehumidifier is better than running the wood stove in the summer, because the wood stove just dries things out by raising the overall temperature, it does nothing about the water content of the air. When you have the dehumidifier pulling water out of the air (and it is an energy using appliance, so it will add some heat inside the structure), that water is gone for good until it gets replaced by air exchange from outside.

If you feel like you need A/C in the summer, a window unit can also act as a dehumidifier, since inside air passes over the coils, condenses water on them, and then that water is conducted outside to drip off of the exterior of the unit. I used to run a dehumidifier inside the house in the summer, but I have found that a window unit, acting in concert with the house's forced air HVAC system lowers the Southern humidity to a level that I am comfortable with.

Thanks John - the humidity hasn't run 100% but has got into the 90's at time. It's mostly in the basement which runs up into the house. The issue I think is that there is a sprinkler system (why? I hate lawns) that I think has sprung a leak in the soil which leaks into the foundation and into the basement. There are wet marks in the basement in the concrete which is suspect.

I'm not a huge fan of A/C but if that may help the situation I'd check it out. We are hoping that the house that we buy will not have such mold issues - it should have some moisture just because of our climate but hopefully manageable. Try baking soda with sea salt instead of bleach, we both have allergies to bleach so try not to use that. There also is a product called B-Brite that is more environmentally friendly we have found useful.

One thing I'd like to understand is the movement of air and heat to help the spores not starting. Would a solarium with fans blowing dry air into the house be an option? What are some alternatives?

C Gallas : With a true Zone 7 climate you may be able to use a solar chimney to continuously suck dead stall air out of different places within your home.
Of course the solar chimneys ability to move cold Air with a high moisture content and thus heavier will be diminished.

Lets talk walking up to prospective new homes. At this point you need to show the Realtor you are in charge and its time to start working for you, faults
can be used to knock down the price ! You are going to look at the roof and ask how old while eyeballing the amount of overhang and the condition of
the gutters and eaves. More modern houses with requirements for setbacks from the property line often have smaller Overhangs to put a bigger house on
a small lot. Good overhangs and gutters are your 1st line of defense of your foundation! Down spouts should run continuously from the eaves down and 2
-3 feet away from your house or into a foundation Drain, Is the entire house perimeter landscaped to drain standing water away from the foundation all
the way around the house ? Can they BE landscaped to run water away from the house? Are the outside concrete foundation walls insulated outside, was
the foundation waterproofed, and perforated drain piping buried in coarse gravel installed at the footings and running down hill to day light !

We will discuss the basement after you grasp the idea that all houses breath, and all houses breath the same way, breathing warm moist conditioned air
out -from the top most places of the house and cooler air in at basement and 1st floor cracks and penetrations! This is something to understand at a
basic level when you get to properly tighten up your house google cold climate housing and search that site from information on stack effect and whole
house stack effect !

Basements and crawl spaces, over 30 million basements and crawl spaces were built to the then correct code but need serious tightening up! Do not buy
a house with a finished Basement and a sump pump, The only exception would be where the original owner installed the sump pump and it has never
run since it was installed! Trust your nose on this one! Again we want a dry cellar and with all the care that the foundation got your basement should be
dry, a few cracks well patched is not a problem, nor are painted walls, be very leery of multiple mismatched coats showing where some one tried to seal
the sub grade portion of basement walls with a waterproofing coating !

Crawl spaces, again concrete is not waterproof, with a high water table it WILL leak moisture to its surface and increase the moisture content of
your air the same holds true for dirt floors!

At 70% moisture content mold starts and stops, at 90% Humidity Rot starts and stops!

The ground under a crawl space should be clean, have a carefully installed vapor barrier that covers that floor and up the side walls widely overlapping
sheet edges, with all penetrations carefully sealed with construction adhesive and heavy duty tape support piers should be wrapped carefully in vapor
barrier and well sealed, above the Virginia Penn border constantly open vents from the cellar space to the out doors is a left over from cheap oil !

The top of the foundation is called the sill the wide flat beam that sites on top of it is the sill plate the perimeter board and the individual floor joists that
the floor is laid on sit on it and are nailed together, old code allowed the 'Box beam' where two floor joists meet the perimeter board to be insulated with
fiberglass insulation, regardless of temperatures water vapor will travel from areas with high concentrations of water vapor to areas of low water vapor
therefor the fiberglass insulation will be damp and the perimeter boars at outside temps will collect condensation most of the year, with frost which ruins
the r-value of the fiberglass insulation much of your heating season !

Todays codes require going back in there and pealing back removing fiberglass insulation and putting in hard foam board and spray foam to seal the
cracks and penetrations. All Electrical should be looked at for safety,and all pumping checked for leaks and where they penetrate the outside way or the
floor above carefully sealed ! Additional insulation to further insulate the crawl space should be on an outside wall, but it can be done on the inside usually
as a last resort !

This is one of the few places where almost all of the u-tube videos are good, again the people at cold climate housing research center know their stuff !

Maritime Climates always leave you dealing with high levels of moisture problems, the affect is increased when warm moist air makes contact with cold
basement surfaces, gas clothes driers and the newer model gas hot water heaters can easily be gimmicked to run just the fan motor acting as blowers to
push air out of the basement. Many places in new england have problems with radon gas, there are fans to evacuate low lying areas of basements to
reduce your exposure ! A sure sign you have problems is any house with heavy water condensation on the window !With all these areas carefully looked
at and addressed! you should fairly if ever need to run a dehumidifier

With a house with problems running All/some of these various fan/blowers run on sunny days, actually any low humidity days, is a temporary way to buy
time where you are now or in a new home ! This just requires the will to do so, a quick morning check on the weather chanel and the expectation that You
will end up replacing a fan motor or two periodically !

This should help you house hunt, fight for a good price, and allow you to move in with your eyes wide open ! For the good of the crafts! Big AL !

Big Al- thank you so much for the post, so much good information for me to start my research while looking at houses and property.

C Gallas wrote:
One thing I'd like to understand is the movement of air and heat to help the spores not starting. Would a solarium with fans blowing dry air into the house be an option? What are some alternatives?

Warm air from a solarium may seem dry, but it actually isn't. If you take an air mass with a certain dew point, let it sit in the sun for a while, it warms up so that the relative humidity goes down, but the dew point and the absolute amount of water the air holds stays the same. When that air blows into the house and cools off, it still has moisture that can cause problems.

You may want to start paying more attention to the dew point when you look at weather forecasts. On sites like Weather Underground, they give you the dew point, but to those with no meteorology training it has little meaning. Dew point is the temperature at which relative humidity reaches 100%, and water can start condensing out of the air onto any available surface. Like when the fog rolls in and it seems to be raining - drops of water are falling onto the ground-- but if you look up, you see that it is really all the fog condensing on the leaves of the tree you are standing under. If you move out from under the tree, the "rain" stops.

Dew point is also important in staying comfortable. If the dew point is above 55F, we start to perceive it as "humid", like the difference between Albuquerque and Dallas. When the dew point is above 70F, then people start calling it "sweltering" and compare it to summer in Georgia (which it has been most of the last three months ). A lot of the comfort factor from A/C comes from the reduction in humidity. If the coils are at 50F, then the dewpoint of the air coming off the coils is also about 50F, much drier than what went into it. Even after that air mixes with the rest of the air in the house and comes to temperature equilibrium, the humidity is not the same, having been lowered by the drying effect of the A/C.

If you start paying attention to dew points, you will begin to see where your own personal comfort point is. If the summer dew points are significantly above where your comfort zone is, fans and open windows and solariums are only going to be a temporary respite. Some more air flow may temporarily dry you off, but when the air stops and you begin sweating again, you will be uncomfortable. That's why I suggest a small window unit. Even a 5000 BTU unit, which can't cool more than a couple of rooms, can dry out a much larger volume and keep the dew point of a whole house down to a tolerable level.

We are in the same sort of moist seaside climate here in coastal Rhode Island. In the summer our shoes grow fur in the closets.

We cannot bear the thought of closing the windows and getting AC. Perhaps someday it will come to that, in the meantime we are trying different methods of getting moisture out.

One great thing we did this year was to build an outdoor shower! Also we put a fan in the bathroom, which was really tricky in our homemade odd shaped post and beam.

We got everything that could get moldy and harbor spores out of the basement. Storing things in cardboard boxes is not a good plan!

The next big project is improving the gutters and drainage around the house.

Cross breezes make a difference. Sine areas in our home always develop mold and some never do.

I love Cape Cod and visit there often. There is a huge hungry market for local produce there, I hope you plan on growing food! When you get settled in to your place I'd love to come visit, permies unite

Matu Collins wrote:
One great thing we did this year was to build an outdoor shower! Also we put a fan in the bathroom, which was really tricky in our homemade odd shaped post and beam.

Excellent suggestion! Water that you aren't adding to the air won't be there later to make you miserable.

Thanks Matu - we'd love to have an outdoor shower or build one at our new place so its good hear that this has helped out. Yeah its def. an issue in our areas but I have seen really dry basements of friends and such so I know there have to be solutions to these issues. We have fans in our bathrooms here but they are about as powerful as a handheld fan.

Yes I've been growing annuals for about 10 years and we have been part of a few community gardens here where we've been doing intensive growing in a 20x20 plot. I'm interested in perennial systems now and have picked up some tree seeds online & foraging (beach plums) for stratification this winter - already getting ready to start the system once we get settled in the spring. Depending on how much land we can get, we might do some market selling but we'll see (as you know land is a premium up here) - there is a huge demand for locally grown produce/products which is great. I'll let you know when we are more established for a visit.

Thanks again for the information John, the humidity and heat doesn't really bother us. We actually welcome it because our summers are so short. We do care about the moisture levels though. I'll do more research on the Dew point, I did take a meteorology course at one point of my life and I'm a surfer so I'm always watching the weather, winds, tides and such.

What about sky lights? Would anything having to do with passive solar systems dry a home out or at least help?

C.G. : open sky lights will let high temp air escape to be replaced with what ever mother earth can provide! There are instruments that register and control extremes of moisture content !

Below george it is a common practice to squeegee the walls of your shower to prevent mold growth that it goes un-mentied ! Ask your local sports club what they do to 'condition their air!

If they are any where near honest- you will cancel your membership !


You Goal, to have a dry basement is easily possible, and the future is yours, a truly dry basement without a lot of energy inputs is possible ! Excess humidity can be modified with frequent
air exchanges, just be sure that your next air-exchange does not make the air in your house worse ! Big AL

Late nte, make sure you are not part of the problem, a house full of overwatered plants, long showers and cooking and simmering food for hours adds excess water vapor ! A.L.