Indoor Air Quality in Our Homes

Indoor air quality affects our health and we should be aware of the types of contaminants that are frequently encountered in our homes. With the quantity of synthetic material and chemicals being used in the materials we build and furnish our homes with, this issue impacts everyone.

Francis Lavoie, a Biologist with Health Canada focused on the health risks associated with indoor air quality, was interviewed via phone to produce this video.


The 13 minute video is a good overview of indoor air quality related issues and explains:

  • what kinds of pollutants are a concern,
  • does duct cleaning help,
  • detecting air quality issues,
  • “tupperware houses”,
  • strategies to improve air quality

Additional Resources

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2014 HomeXam Inc.
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Water is the Enemy; A Home Inspector’s View

Country home

One of the many things a home inspector looks for is evidence of the entry of water into the building envelop. That’s just a fancy way of saying that water has gotten inside and its left a stain or other damage. So is seeing a stain a big deal? Maybe not, but we should always treat it as if it is until we know for sure. The real question is has the problem been fixed and what damage has the water done in the mean time? This can be impossible to fully assess from just a visual inspection and in severe cases contractors may have to be called in to open up the walls. Left for prolonged periods, even modest amounts of water can do a lot of damage to a home. In this article, we will provide an overview of a number of ways that water can enter or be trapped inside a modern home.

Interior water leaks are bad enough when they do cosmetic damage warping hardwood floors, softening drywall and bubbling paint. The repairs can be many thousands of dollars and a severe inconvenience to family routine. Things get more serious when structural damage is done. The presence of water is one of the main growth factors required for mold as explained in Household Mold De-Mystified. Of course another name for mold is ‘rot’ and having the lumber holding up your home rot is a serious issue indeed. Not only is the strength of the building compromised, but the framing is often covered with layers of ruined building materials that must be removed and replaced. The bills can add up quickly.

Let’s start with the roof and work our way down. Although most people naturally suspect the shingles to be the prime culprit, if they are properly installed, it’s much more likely to be the flashings that are at fault. Flashings are metal or rubber trim pieces used to seal a roof in valleys, along surface transitions and around openings like skylights and plumbing stacks. The flashings are intended to sheet water safely over a joint between materials. Unintended openings can start in ageing caulking and from the expansion and contraction of joints. Properly applied, a five dollar tube of caulking can save you thousands of dollars of repairs.

Somewhat similar problems can be discovered as we inspect the building exterior. Door and window openings need well maintained caulking as well. Poorly installed siding can capture water rather than shed it away. Brick or masonry walls that are cracked and let moisture in can be expensive repairs in their own right. Sometimes we see masonry walls that have been built without weep-holes or that have had them plugged up by a well-intended home-owner. The weep-holes are there to allow water otherwise trapped behind the wall to drain out. Blocking the holes defeats the purpose of the weep-holes and can cause significant damage to the wall and house framing behind it.

At ground level, we look to see that precipitation is able to readily drain away from the foundation. I don’t think most people appreciate the importance of handing all the water that can fall or run onto a property. Even a moderate rain can deliver thousands of gallons that all flows downhill. We want to keep that water from flowing into your basement. The remedy starts with the eves-trough. They capture all that water that falls on the roof and discharges through the downspouts in am attempt to get it away from the house’s foundation. In nearly every house that we visit, we find that the downspouts drain too close to the foundation wall. We routinely recommend the installation of downspout extensions to take the water far enough away to protect your basement. We recommend a six feet as a normal objective and to make sure that it end on ground that slopes away from the building. See Tips to Help your House Make the Grade

City building departments all ask for grading plans for new houses these days. They know that all that storm water needs to be properly dealt with. This applies to all houses, but especially if your house is built at the bottom of a slope or below the level of your neighbours, you need to be careful that grading around your foundation runs water away. Its very common to find settling of the fill around the foundation wall has created a depression that feeds water right to the wall. Your driveways, patios and sidewalks should also be modestly sloped away from the house for the same reason. Even-though builders often wait months to pave driveways, the majority of subdivision homes have significant settling in front of the garage door. Besides being a trip hazard, water ponds and freezes creating slip and fall opportunities for home-owners and unsuspecting guests.

We’ve worked our way down to the foundation walls. If the property is doing a good job of draining water away from the house, we are much less likely to find a damp or out-right wet basement. That being said, there can be groundwater to deal with as well. Modern poured concrete foundations are damp-proofed with tar and a dimpled plastic membrane that channels water to the foundation drainage tiles. Sump pumps or natural drainage is used to to handle any water that might otherwise accumulate underneath the slab. Properly functioning these measures eliminate water outside the wall that might try to find it’s way in.

Now we need to consider the potential internal sources of water in a home. People underestimate the amount of water that is in the air of a modern home. Indoor plumbing has brought water problems indoors too. In the old days, homes weren’t sealed so well and if things got damp the air leakage helped dry things out fairly quickly. Nowadays the water that enters a home stays there unless we take steps to remove it. Excess humidity can come from many sources: steaming cooking pots under an unused range hood, long showers without bathroom fans on, and blocked clothes dryer vents are just a few examples. Once that moisture is in the air it travels to a cold surface and condenses depositing water on surfaces that may rot or produce mold. Some times one water problem leads to another. A toilet that runs continuously can waste a lot of water, but it also chills the toilet tank and supply piping which can create puddles in the wrong places. If the humidity levels get high enough, mold can show up anywhere there is an appropriate foodstuff.

We’ve covered a lot of ground, but these are only some of the ways water can enter a modern home. Fortunately many techniques and technologies have developed to protect us from water entering our homes and others to help us to remove it when it does gets in. We have heating, air conditioning, heat recovery and other ventilation systems that attempt to manage our comfort, air quality and humidity in our homes. This all adds to the complexity of our homes. I’ve tried to give an overview of the many vulnerabilities to water that our homes have. You can follow the links provided to other articles which address specific concerns in more depth. The most important message I can offer you is that if you notice a water problem starting to occur, the faster and more professionally you deal with it, the less trouble and expense you will have to go through over the long run.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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Household Mold De-Mystified

Mold are asexual fungi. They reproduce via spores which are small enough to be easily carried in air currents. As a consequence, mold is virtually everywhere. It’s not a question of whether there’s mold in a any given house; it’s a question of how much. As a home inspector, I know my clients are concerned about the levels of mold in the house they are considering buying, but determining the quantity, variety and measures to be taken for remediation are beyond our standard of practice. In fact, we even resist using the term ‘mold’ before the buyer has test results in hand. We will however raise questions should it become apparent that further investigation is warranted. Specialists can come in to take samples for examination at a lab.

Attic hatch seal Basement wall
Air leak at attic hatch Damp floor wicks up wall
Discoloured roof sheathing Toilet condensation
Poor ventilation in attic space Condensation from toilet
Wet bedroom wall Wet subfloor around toilet
Wet bedroom wall Wet subfloor around toilet

Buyers and agents often focus on the suspected mold as the problem. They worry about the health risks of exposure and allergic reactions. Legitimate concerns, but they need to understand that mold is actually a symptom of other underlying problems. For mold colonies to grow they need four things: a few spores to seed the colony, organic material to feed upon, moisture at suitable temperature and time to sporulate or reproduce. Our homes are full of organic materials like, wood framing and trim, paper coatings on drywall, exfoliated skin cells and soap scum in bathroom fixtures. We can’t eliminate these materials, nor change the temperature range we maintain in our housing. The factors we must control are the presence of moisture and how long it remains. Without fail mold colonies are found in moist environments.

Home inspectors are trained to look for signs of discoloured building materials in damp areas. Attic spaces are susceptible due to high humidity levels if ventilation is poor or through other poor building practices such as terminating plumbing stacks or ventilation ducts inside the space. It happens more that you would think. That moisture produces black patches that can cover the entire underside of the sheathing. Long, hot showers without turning on the bathroom fan can trap a lot of moisture in a home. Condensation from toilet tanks and leaking seals can be a source of moisture that rots wooden floor sheathing. Blocked clothes-dryer vents are a common source of humidity. Basements are particularly susceptible for a number of reasons, not the least of which, is that water will run to the lowest level it can. Less obvious sources are back-drafting furnaces and gas water heaters that can produce large amounts of humidity, not to mention deadly levels of carbon-monoxide. Unfortunately we can’t tear things apart to look for problems inside walls so there’s a limit to how much can be detected visually.

Modern homes are designed to remove as much excess moisture from a home as possible. Improved attic-space and bathroom ventilation, damp-proofed foundations, weeping tiles, floor drains, sump pumps and heat recovery ventilators are all innovations designed to control interior moisture levels. Humidity can vary greatly but as long as high levels are brought under control relatively quickly (under 48 hours), mold doesn’t have the time to sporulate and its growth is curtailed. So the best strategy is keeping things dry and if a mishap occurs make sure it gets taken care of in short order.

Mold is a surface phenomenon. Test kits are available if you want a lab to pin down specifically what you are dealing with. But in general if it smells funky, it’s there somewhere. If you recognize a small problem area early enough you can clean it up yourself with soapy water or by wiping with alcohol. This won’t address any staining but it will kill the fungi. Dead spores are just as toxic as live mold so get rid of any rags or sponges used in the cleanup. Anything very extensive will require professional removal or remediation, but this can be a significant cost. So get a handle on any problems early on and remember that any repairs you make to keep your home dry are helping to avoid major expense and potential health issues later.

Author: Rob Cornish is a Home Inspector in Ottawa, Canada. © 2013 HomeXam Inc.
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