Basement Finishing

The proper way to insulate and finish inside concrete walls is in the following manner:

Identify the outside grade level, and then transfer this measurement to the inside of the concrete wall. From that point, use a level and draw a line on the wall 6” above the grade line all the way along the interior of your concrete wall. This now becomes the height of your polyvapour seal – 6-mil polyethylene (available in 10’ widths). Spread a bead of acoustic adhesive along this line (acoustic adhesive is available at your local building supply store in tube form). This adhesive will stick your 6-mil polyethylene to the concrete. Apply the same adhesive down the inside of the concrete wall and out onto the floor. This stops any moisture emanating from the concrete to the wood studs.

Build stud walls that are 1 ½” shorter than the actual wall height. This allows the walls to be tilted up and put into position and you can then screw them to the underside of your joists up tight against the concrete wall. Cut Styrofoam or polyurethane foam in blocks (1 ½” thick) and position them every 2 feet along the bottom of the stud wall. Pound a 4” common nail (it doesn’t have to be a concrete nail) through the bottom plate and the foam block and into the concrete, stopping when your hammer rings. The wall will remain in place because it is now screwed to the underside of the joist and nailed into the concrete floor.

Now you are ready to prepare the wall for insulation. If there is a pony wall above the concrete, remove any polyvapour seal from this wall. Stack R12 insulation batts behind, lying on their side above the concrete wall and the joist above, thus covering the pony wall section if it exists. Put insulation batts in green garbage bags making insulation pillows. Put these “pillows” in the joist header areas (where the joist runs over the plate to the outside joist fascia). Run insulation batts between the newly studded wall from the joist line to the floor.

Finally, take the extra polyethylene vapour seal that is lying out on the floor (the excess of the 10 ft. width) and bring it up around the studded wall as far as it will reach and staple it in place. Staple another piece of polyethylene from the top area onto the underside of the joist 12” out from the studded wall bringing it down the wall to meet the polyethylene coming up from the floor. Overlap them and seal with acoustic adhesive. You have now totally encased the finished interior framing wall and will prevent any moisture that may emit from the concrete to get into the wood fibre and/or insulation causing a musty odour.

Proceed to drywall or panel. Now no moisture will ever get near a wood fibre. If there is ever a crack in the wall or floor, the moisture will run up against the polyethylene, run back in behind and out onto the floor and will be identified at the floor line rather than up in behind your panelling or drywall.

What is the difference between ventilation and air leaks?

While some homeowners believe that air leaks allow fresh air to enter the house, they don’t realize that the consequences of air leaks are often negative. Air leaks are a sign of a poorly sealed or degrading house. In cold, windy weather, too much air could be drawn into the house, causing high energy bills, cold spots, drafts and moisture damage. In spring and fall, with changes in wind and air pressure, not enough fresh air would be supplied. In other words, air leaks are uncontrolled. The solution?

Control your airflow.

Controlling airflow involves three aspects:

Preventing uncontrolled air leaks
Providing for air exchange (supplying fresh air and removing stale and/or polluted air)
Providing draft and combustion air for fuel-burning appliances

It’s important to remember that your house works as a system. Keeping your home airtight is one part of the system. Airtightness combined with proper ventilation leads to greater energy and dollar savings, improved comfort and protection from moisture damage.

What is ventilation?
A proper ventilation system exhausts stale air, supplies and distributes fresh air throughout the house and can be controlled. Today the National Building Code of Canada requires that new homes ventilate one third of an air change per hour. This means that one third of the total volume of air in the home is replaced by outside air every hour. How does your home compare?

An EnerGuide for Houses evaluation will show you how well your home measures up. By conducting a “blower door” test, the EnerGuide for Houses advisor will show you where and how to seal your air leaks, analyse your ventilation system and recommend ways for you to save money, be more energy efficient and live in a healthier home!

Find out how you can get an EnerGuide for Houses evaluation. Call 1-800-387-2000 today!

This information was gleaned from the website of The Office of Energy Efficiency (OEE), a part of Natural Resources Canada. To visit their website for more information on energy effeciency, just click onto the Natural Resources Canada link on the bottom/left of our home page.