Humidity Issues Around The Home

Humidity Issues Around The Home
Water, its a big problem

Let me start out by saying I am a home Inspector in the Orillia , Gravenhurst, Bracebridge areas and I see it all the time: humidity and moisture intrusion issues around the home cause more health, safety, and structural problems than all the others issues all home inspectors find combined. Dealing with moisture intrusion has always been a case of locate the leaks and repair the system leaking , be it roofing, siding, windows, doors, or the foundation. Moisture intrusion has destroyed more roof framing, sill and floor joists, and wall framing than people can imagine. While both Done Right Home Inspectors are inspecting homes, cottages, and commercial property in the Orillia, Gravenhurst, Bracebridge and Muskoka areas we often report on  structural defects caused by moisture intrusion. Outside, fixing it  is fairly uncomplicated, not always cheap but fairly straightforward. New roof coverings, some new framing, new caulk for windows and doors, dig up a section of foundation and apply new waterproofing etc; if it is leaking then fix the leak while repairing the damage done.  Dealing with humidity inside the home though has always been a more troublesome issue.

Some sources of humidity inside the home are not obvious

Although some sources of humidity in the home are obvious to home inspectors and owners alike there are some that are harder to detect or just not thought about. Obvious sources include laundry tubs, clothes dryers, kitchen and bathroom sinks, showers, and tubs. In addition, other obvious sources of humidity in homes include unfinished concrete floors in basements or crawlspaces, seepage at perimeter edges of poured concrete floors and around footings for walls or support posts, open sump pump pits etc. 

If however you do not realize that there are many other sources of humidity in a home you may not  be dealing with a problem. For instance have you ever noted the vent at the front of most dishwashers that gives off moist warm air when it is running? or the cloud of vapour when you open the door, that is a fair amount of humidity getting into your home. While everyone is pretty much aware that kettles and pots on stoves allow humidity into the home how about when the range is operating say cooking the holiday turkey. That enticing aroma wafting through the air is floating on a cloud of warm moist air that used to reside in the turkey and is being vented out the range vent, yet few run the range exhaust fan when using just the oven. Think of it a 20 lb bird in the store freezer becomes 10 lb after heating and cooking the excess moisture out ( yield is about 8 lbs of meat ) The holiday turkey just put about a gallon of water into the air.  

Toilets are an open source of water in the home and evaporation takes place any time the air in the bathroom is warmer that the water,  as in after every flush, until the water in the bowl gets up to room temperature. This is not a major amount but it does add to the humidity load in the home. Another source often not thought about is washing machines especially now as many homes have them located on the main floors. Every time the washer gets used humidity escapes the machine as vapour when the lid or door is opened. The dryers are vented to the outside but the fan shuts off when the door is opened so you get the same cloud of vapour exiting into the home from it.  Pipes under sinks and anywhere they are exposed in the home sweat and condensation forms. Condensation doesn't add to the humidity load but it is a clear indication there is excess moisture in the air in the home.  Where does it go then? It is not gone moisture in most cases will evaporate back into the air reforming vapour and keeping humidity in the home.  

While inspecting basements and crawlspaces In the Orillia, Gravenhurst. Bracebridge, and Muskoka area we find seasons affect the amount of humidity in the home as well. Air entering every time a window or door is opened brings humidity in. While spring can be very dry, fall tends to be wet in this area. More condensation shows up on toilet tanks and pipes in the home and that is a sign there is higher humidity than what is desirable inside the home.

Dealing with humidity in the home has traditionally been difficult.

Where the source of humidity is known or suspected such as a range top the common vented hood deals with this easily.  Yet as noted what about when just the oven is being used? Few people do or want to run the range hood every time the stove or oven is turned on.

Surprisingly, very few sump pits in use have proper covers available making them an open source for moisture evaporation into the home.  Some newer sump pits have fitted caps available yet we still find them open as well.

Laundry areas are usually unvented. We find them often now on the main floor and still we seldom see anything other than the dryer vent for humidity control. It seems builders do not consider the humidity important. Drilling holes in walls is one of the more difficult choices to make yet that is usually what is required to mount venting fans. Whether it goes to a roof vent or through a wall a duct  drilling holes can be difficult and require finish work to install properly.

Addressing the general humidity in the home has long been an expensive measure. Installing whole home ventilation after the fact or a heat recovery system that deals with humidity can be very costly running well into several thousands of dollars..  Installing a whole home system is worth considering if the home is to be a very long term investment but be advised these systems have a long term payback when installation cost are figured in as well.

You can deal with humidity in the home inexpensively.

You can deal with most of the humidity causing issues in the home in other ways though. Some things are as simple as making, or getting the local handyman to make, an inexpensive fitted cover of plywood over the sump pit. Glue 3 to 4 inches of high density foam to it for insulation and  that resolves the  problem there. There is another simple solution I am going to suggest here that can deal with many of the other issues  causing humidity in homes.

Controlling humidity in some areas is possible.

As a home inspector I have long been an advocate of installing humidistat controlled fans in bathrooms.  I came about this the hard way after learning my teen age sons were unable to understand the concept of turning on and off the venting fan in the bathroom when showering. Worse they would sometimes do one and not the other, either leaving it on all day or turning it off when they got out rather than letting the moisture clear the bathroom. A bad case of mould later I researched and installed humidistat controlled fans in both bathrooms. Even as a DIY project it ran to about $700. At the time I did not have to enlarge the fan opening because I had newer model fans. The older smaller models would have required me breaking open the ceiling and the costs of finishing that out as well. The benefits far outweigh the costs though. A humidistat controlled fan will come on as the humidity rises and shut off as the fan clears excess humidity from the area it is installed in. That means no more wasted electricity from fans running all day, no more excess humidity lingering to create conditions ideal for mould growth, and no worrying about or harping at the kids to turn or off the fans.

Other areas can benefit besides bathrooms

When I began inspecting homes and cottages in the Orillia, Gravenhurst, Bracebridge, and Muskoka areas I soon discovered there were other applications a humidistat controlled fan could be used in to benefit the property owners.  During inspections I find more and more crawl spaces under cottages are closed in as cottages are being used year round. They get sealed up to conserve heat and protect water lines from freezing. Great idea but there is a drawback. In most all cases the floor is either bare rock/dirt or vapour barrier is laid over the rock/dirt. In very few cases is the vapour barrier sealed correctly so it is almost as bad as a bare floor. The earth area under a 1000 square foot home can allow as much as 30 U.S. gallons of moisture into the crawl area a day. My moisture meter often reads 80 to 100%  surface moisture in these areas.  With just a little heat added these are ideal conditions for breeding mould and mildew, not to mention wood rot and sure enough we will often find these issues during the inspection. But, a humidistat controlled fan can alleviate these problems.

A humidistat controlled fan will automatically come on and exhaust the humid air to the outside and relieve the crawl space of excess humidity for about $350 including the short ducting and hood for the outside, add about $ 200 dollars to that for electrical and the project will end up around $550 or so. It is a pretty simple install if you can pick a place to exit the crawlspace with the ducting that goes through wood or vinyl siding.  You should remember that in the winter some way for the fan to draw air from the structure above should be provided, a standard floor heating grate will work. In spring, summer, and fall a vent opening in the sidewall or crawl door would be fine. Fans are available from big box retailers and from hardware stores. Humidstat controlled fans will have the H designation in the model identification. Most will run about $280 with tax.  These can resolve issues in another area of some older homes and cottages as well.

Not just in Crawl spaces

We often find wile inspecting older homes and cottage attics that they have poor or limited venting. Many older structures were built with closed soffits in the belief that that kept the cold from getting in. As building and insulating science evolved people added some insulation, a few installed minimal soffit vents in strips or small round vent holes and added hood vents to older buildings in an effort to keep in the heat they were paying for. As late as the 70's plywood soffits with steel strip venting was commonly being installed. We know today that that is just not sufficient venting to control humidity and moisture in the attic.

Many of the older buildings were ok at first as they were so leaky the attics still got some venting but as more insulation gets added, proper venting becomes more critical to the whole. Installing new perforated aluminum soffit is in many cases done without removing the solid wood or plywood soffit underneath and so totally useless for venting.  In many many cases the insulation added in the attic covers the air path from soffit into the attic area creating blocked venting.

You could tear apart the soffits and fascia and strip out the outside three feet of insulation to create the airpath necessary in these structures to resolve this but it is expensive to do so. Materials and labour probably in the $30 per perimeter foot range.  For an average home of 1100 sq ft about $4000 dollars but, installing one new vent space at one end, new wiring, a humidistat controlled fan, and a new roof vent for about $600. can take all the worry out of having conditions for mould growth in the attic.

Now for some really good news on humidity control around the home.

Over the last year where I am finding humidity issues I have been recommending my home. cottage and commercial clients install the Dew Stop Switch to control humidity. This fairly new switch takes a great deal of the cost and inconvenience out of installing humidity control. You no longer have to remove the bathroom fan in older structures because the new one takes a larger box. If the fan is in good condition it can be left in , if not buy an inexpensive replacement works for about $25 dollars or a new standard bath fan for about $35 and install the Dew Stop switch, about $49 dollars and you have solved bathroom humidity issues entirely, for less than $75 dollars and it is an easy DIY project. 

As long as the switch is in the same space/room as the fan it will come on when necessary and shut down when the humidity drops. It can be turned on manually if desired but unlike teenagers does not have to be told to turn it off again. Even getting in an electrician to move a switch box in the hall into the bathroom  so the Dew Stop switch can be installed should be still a bit less than installing a new humidistat controlled fan especially if the older model fan is the smaller one.

The bathroom is not the only place for the Dew Stop switch.

In the last year I have inspected many homes, cottages, garages, boathouses, and commercial buildings in several dozen for differing reasons I have recommended the Dew Stop switch for humidity control in locations other than bathrooms. Attics have had their share of recommendations as have crawlspaces, perhaps the lion's share, but insulated living areas in boathouses, garages, bunkie buildings, of which there are many in Muskoka and even closed sheds used for storage of summer items over the winter.

In boats being stored it works very well to control humidity and thus that mildew you always seem to get when boats are stored under cover. Imagine, no more mildew odours on beds in bunkies, furniture in boathouses, patio furniture cushions, life jackets and boat sails etc. Whatever is stored will be protected from excess humidity as long as the fan has an intake for fresh air and power. With fresh air things will dry out rather than staying damp and having mould and mildew growth. When combined with an inexpensive standard bath fan the Dew Stop switch is an inexpensive solution to many difficult humidity control problems around the home and cottage.  

Dealing with humidity around the home, cottage, or commercial buildings can be difficult but it is important to do so and prevent mould and mildew growth both of which can be a serious cause of health and structure concerns. While the whole home ventilation and the heat recovery ventilation systems approach is best for new construction and long term benefits, in older construction it may not be practical or cost effective. Other methods like the purpose built humidistat controlled fan can be used to deal with humidity in some instances and they work exceptionally well as I can attest. The new Dew Stop humidistat control switch can be used either in combination with an older fan ( simply replace the switch ) or  with a new standard and inexpensive bath fan. Best of all, when hooked to a  standard bath vent fan and ducted outside the Dew Stop switch can be installed inexpensively and used effectively in many areas where excess humidity is an issue. It's a win win for the home, cottage, or commercial property owner.