As a basement waterproofing and mold removal company here in The Bay Area, we’re often called to basement leaks where we find mold infestation behind the sheet rock walls, embedded in the insulation behind it.

So how do you properly insulate a basement?

That’s a question that begs another question. The second one is “what are you going to use your basement for?” If it’s general storage ( I’m assuming it’s already waterproofed) you may be able to get away with wall-bag insulation (generally not recommended) that reaches at least two feet below ground level.

One thing you need to make sure of is that your basement is waterproofed and water is not going to seep through your foundations and ruin your finished walls once they are installed.  If you currently have water or damp issues in your basement, these need to be addressed before finishing your basement.

In certain cases, like having no access to the exterior of the foundation to repair the water leaks, an interior weeping tile system can be installed to remove water as it enters your basement, keeping your finished walls and basement dry.

However, if you’re planning a basement that’ll be used as living space, then you’re going to need to fully insulate the walls and floor. If it this was previously done inadequately, you might have to throw everything away and start afresh. In the end, it’s your choice how far to go.

In this regard, it’s relevant to mention a general tendency to tighten building regulations. We find it remarkable that some homeowners go to great expense when it comes to finishing the upstairs living spaces, yet skimp on basement basics, especially when a moldy basement can lead to extensive repairs and the loss of quality living space in the home.

Essential Principles

  • You need insulation that works all year round to keep your basement warm in winter, and humidity-free during summer months.

 

  • Ground temperature drops as you go deeper underground. When different wall-temperatures mingle, you get condensation that encourages mold.

 

  • Insulated panels between battens covered by a vapour barrier work great above ground where the outside temperature is consistent.

 

  • However in this instance they don’t have to counter a variety of different temperatures that combine to cause humidity and mold below ground.

The Correct Way to Insulate

We believe in doing things the correct way, and right from the beginning. You should install rigid foam insulation that comes ship-lapped, so there are no butt-joints that admit air that mingles with the inside temperature. The correct thickness is one inch on the floor, and two inches on the walls.

It’s equally important to glue the panels directly to walls and floors with the correct foam-rated adhesive, so they are not damaged during installation. Joints must be taped over, and the slightest gaps at edges filled with spray foam.

Once your basement is comprehensively insulated, you can go ahead and install studs for your decorative paneling  If you believe in belts-and-braces, you could add mold-resistant drywall.

How This Works

Rigid foam creates a thermal break that’s impenetrable. You’ll find the same material in those handy coolers that keep your cans chilled without dripping condensation. Toilet tanks lined with rigid foam follow the same principles.

When you apply this approach to your basement insulation, you create a similar barrier. In winter the room stays warm. In summer there’s no humidity, or mold caused by the different temperature outside.

The extra price you pay up-front for this should provide a healthier environment for many years to come, and allow you to enjoy the extra living space that a dry and mold free basement provides.

 

Ideal Humidity in Toronto basementDoes your basement feel like a jungle in Central America during the Winter?  Maybe it’s time to check the humidity levels in your basement.

Humidity refers to the amount of moisture in the air. When air has absorbed all the moisture that it can, we say that humidity is at 100%. When the humidity level is at say half of that, it is defined as being at 50%. In other words, measures of humidity are relative, which is why we speak of RH, or relative humidity.

The Effect of Seasons

Everything expands as it gets warmer, and that applies to the air itself. As a consequence, it absorbs more moisture when the ambient temperature’s warmer. This is why us homeowners in Toronto are plagued by humidity when the heating’s turned up in their basements – especially in winter when the windows and doors are tightly closed.

You can track humidity by purchasing a mechanical or electronic hygrometer that records the RH, although you do need to allow the instrument to settle for twelve hours first. Note that the same absolute moisture-level will produce a different relative reading at different ambient temperatures.

The Human Factor

What we described so far is theoretical. Humans have a habit of changing their environment everywhere we go (and that includes our homes). Air pollution and global warming are extreme examples. It may come as a shock to know that even breathing affects the relative humidity in your home.

Most everything we do in our home involves the use of energy. Energy that is released warms the air. Warm air absorbs more moisture. Up goes the humidity level. It’s as simple as that. But we don’t stop there, do we? We release moisture into the air every time we bath or shower, wash dishes or do the laundry.

The Right Humidity

Our bodies require a level of humidity for health. When it’s too high we may develop respiratory problems because of mould spores drifting through the air. By contrast, if the RH is too low we get scratchy throats and noses, and chapped skin and lips. These are Mother Nature’s natural hygrometers we need to listen too.

After you’ve purchased a mechanical or electronic hygrometer, you can assess humidity more accurately, although do remember that hygrometer readings are relative to ambient temperatures. When your home is nice and snug in winter, it should range between 30 and 50 percent. However when the outside temperature drops to -10c / 14F, you should aim for 30.

When Humidity’s Too High

You can use humidifiers and dehumidifiers to control relative humidity selectively. However you can also influence things by venting clothes-driers, opening doors and windows daily, and taking cooler showers and baths. As you bring your humidity levels down you’ll also have less mould. And that should make your family healthier, happier and more relaxed.

 

photo credit: Flckr