Renovation & Design
Renovation & Design
Insulating exterior walls minimizes condensation and mould growth
Question: I enjoyed reading your previous article about basement mould, as it was a very timely read. I am in the process of finishing my basement. It is a newer home that I am building an hour south of Winnipeg in sand and gravel soil. It has a walk-out basement, meaning only three foundation walls are cement and the other is wood. The basement was poured 10 years ago, with eight-inch cement walls, and I have yet to find a crack, probably due to the soil conditions that do not shift like Red River gumbo.
Knowing I would not be finishing the basement for quite some time and wanting to conserve energy, I wrapped the whole house on the outside with 1.5-inch blue Styrofoam insulation for an R7.5 value and triple-pane windows. Moisture is controlled by an HRV system. I have never had any frost buildup in the basement. The main floor was insulated inside with R20 batts, 6MIL poly and black acoustic seal, to achieve R27.5 in the walls. I would like to have the same R-value in the basement.
Since I have wrapped the house in this way, do I still need to blow foam into the rim joist cavity created between the floor joists? I am also looking for any advice when floating the stud wall away from the cement to accommodate the R20 batt insulation? The walk out basement wall is of 2X6 construction and will be R20 on the inside.
Looking forward to your response. I thank you in advance, George Beaudry.
Answer: There are many different opinions on the best way to insulate exterior walls, and foundation walls, on a home in our climate. The traditional method of batt insulation on the interior covered by a thick polyethylene air/vapour barrier is still the standard, but may not be the best method to prevent condensation and moisture issues. Your method may be somewhat superior, and I will answer your question while explaining some newer theories about why the exterior insulation method should work.
Innovative home builders have been looking for a better way to insulate our homes for several decades to prevent common condensation, moisture, and mould issues that can occur in our wall assemblies. Because warm, moist air is contained within the living space, it must be prevented from entering the cooler wall cavity to prevent condensation. For this purpose, the use of traditional 6MIL polyethylene sheathing, combined with plastic tape, acoustical sealant and drywall sheathing can be effective if several factors are properly addressed. Firstly, the thermal insulation in the wall must be sufficient to prevent significant temperature drop, even in our coldest weather. Secondly, the poly air/vapour barrier must be continuous and have no holes, gaps, or breaches that are not well sealed. The first criteria may be accomplished with traditional batt or loose-fill insulation in a 2x6 wall cavity. The second factor is more difficult to achieve due to common building practices and site challenges. Because of this, warm air leakage into exterior wall cavities is a common occurrence.
One method of minimizing the problem of condensation in this wall assembly is to place some of the insulation on the outside of the wall sheathing, instead of all of it within. The common concern with that method is improperly locating the air/vapour barrier. Because exterior insulation is often extruded polystyrene insulation (XPF), or similar foam sheathing, it can have a good air/vapour rating and act in a similar manner to the poly on the inside of the studs. If that happens, we can theoretically create a double air/vapour barrier which can trap moisture between the two. In a standard wall assembly, warm air and moisture that does leak into the wall should be able to "breathe" to the exterior. If we trap too much moist air inside the wall assembly, it can lead to rot, mould and other undesirable results.
Recent studies, many being done by a few innovative building scientists in Southern Ontario, suggest that there is little concern with a double air/vapour barrier when insulation is installed outside the exterior wall sheathing. The reasoning for this is that adding the insulation to the exterior warms the inside of the cavity much better than batt insulation between the studs. Because the wall cavity is warmer, there is much less chance for any warm air that leaks inside to reach its dew point, which causes it to condense. If the moisture dissolved in the warm air does not condense, there is little cause for concern. The significant number of homes that were constructed in this manner, in the last several decades, seems to support this conclusion. Most do not have major rot or mould growth in their exterior walls, as previously feared.
What does this mean for your basement insulation methods? Because you have wrapped the exterior walls and foundation of your new home with foam insulation, you may not have too much concern with common mould issues between your floor joists above the foundation walls. Installing blown-in foam will give you excellent thermal protection, but the added expense may not be necessary. Because you have covered the outside of your home and foundation with a complete layer of insulation, the foundation walls may not become cold enough to allow sufficient condensation or frost to form, typical in many other new homes. You should still ensure any insulation you install from the inside is continuous, even behind the studs if there is a gap, to prevent uneven temperatures and convective currents.
Your use of rigid polystyrene sheathing on the complete exterior of your home and foundation may not be a new idea, but it is one that may be superior to more traditional methods. This material will certainly warm the foundation and wall cavities, and prevent thermal bridging, which should minimize the chances of condensation and mould growth between the floor joists and on the foundation. This will negate the need for costly blown-in foam and make insulating and sealing the basement walls easier, as well.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the past president of the Canadian Association of Home & Property Inspectors -- Manitoba (cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at trainedeye.ca.
trainedeye@iname.com
Renovation & Design
Pool, Spa & Patio Show: on now at RBC Convention Centre
It's been a long time in the making, and has finally come to Winnipeg: the Pool, Spa & Patio Show, which is on now at the RBC Convention Centre.
"It's the first-ever show of its kind in Canada," said Oasis Leisure Centre's Jason Lawrence. "The prairie chapter of the Pool and Hot Tub Council of Canada felt it was time to showcase the great group of pool and spa professionals we have in Winnipeg. If you're looking at getting a hot tub, pool, sunroom or patio, everyone will be together under one roof to answer your questions."
The purpose of the show is not only to showcase the city's fine collection of pool and spa professionals, but to also connect consumers with a reputable group of contractors, he added.
"All the businesses at the show are members of the Pool and Hot Tub Council of Canada. Everyone has been vetted, and has to abide by a strict code of ethics. Not only that, but they have liability insurance and workers' compensation coverage. When you enlist the services of one of our contractors, you'll be assured they're reputable and dependable, and aren't a fly-by-night contractor."
The skills of those contractors will be fully on display in strategic spots on the show floor, said show co-ordinator Jay Lemieux. "For example, J & D Penner will be putting up not only a basketball court, but a putting green as well," he said. "We just want to show that when it comes to your home and back yard, you can do anything. If you have an idea, one of our pool and spa professionals can bring it to life for you."
Make no mistake, the concept of making backyards into a retreat is on the rise.
"With the low Canadian dollar and cost of owning and maintaining a cottage, more people are turning their home and yard into a private vacation retreat with the addition of a sunroom, deck or patio, hot tub or pool, or a combination of those options," said Lawrence. "The idea is to be able to take two steps out to your backyard retreat, rather than spending two hours driving to your cottage."
Inspired by TV shows on networks like HGTV, many people are electing to go with the full distance with the home retreat concept.
"People are now going with a hot tub, pool, patio and are putting speakers outdoors to stream their favourite music -- Advance Electronics will have an outdoor speaker system on display to show what's possible on that front," said Lawrence. "Other trends include mod, rectangular or curvy lagoon-style or geometric-shaped pools, automation and UV (ultra-violet) water sterilizers."
Not only does making your yard into a private retreat make sense as a long-term investment, but it also makes sense from two other standpoints -- health and safety, said Lawrence.
"The water in your pool is heated, healthy and clear with no algae blooms to worry about, and if your kids and their friends are in the pool in your backyard, you know where they are. You can also spend quality time with your kids there after work, and make memories for years to come. We invite everyone to come out, and see what our pool and spa professionals can do for you."
The Pool, Spa & Patio Show kicked off Friday and runs through to Sunday at the RBC Convention Centre. Tickets for adults are $10; children 17 and under (accompanied by an adult) get in for free.
Visit poolspapatioshow.com for more information.
tlewys@mts.net
Renovation & Design
Thereâs more than one way to tie your shoes
QUESTION: I am overweight and have had both my knees replaced. The problem is the shoelaces on my shoes are round instead of flat.
The laces constantly come undone. How can I prevent this? I also have another pet peeve about new winter coats. Manufacturers only provide one extra button.
What am I supposed to do if that one button gets lost? Julie, Winnipeg
Answer: Aside from the obvious suggestion of double knotting your laces, here are a few other suggestions to try: 1) Lace your shoes from the bottom to the top so the bow is at the top. 2) After tying shoes, tuck the aglets inside of the shoes. 3) Make a loop with one hand and wrap the other lace around the loop, just like normal. Wrap the same lace around the loop again to make untying difficult. Finish normally. 4) If all else fails, superglue your laces and slip your foot in and out of the shoe without ever untying the laces.
After purchasing a new coat, take a few moments to sew the extra button to the inside of the coat with a few stiches. Doing this prevents the button from getting lost; if you need the button cut the threads. For extra buttons, check out second hand stores; they often sell bags or big jars of assorted buttons.
Question: I want to share with you a handy tip to remove orange coloured stains from the toilet bowl, due to iron in well water. Drop a couple of denture tablets in the bowl in the evening and by morning the bowl should be clean. Repeat if needed. Also, do you have a home remedy for cleaning an oven? Ray, Winnipeg
Answer: For people who do not own a selfcleaning oven, the oven mess does not have to become a dreaded chore. The world’s easiest way to clean an oven is to sprinkle the bottom with baking soda. Pour white vinegar over the baking soda, let bubble and soak for 30 minutes. Wipe and rinse with water. In the meantime put an old towel on the bottom of your bathtub, fill it with hot water and one cup of washing soda. Let oven racks soak overnight and in the morning (while wearing gloves) rinse the racks and wipe with vinegar. Clean as a whistle. Do not leave water in the tub if small children live in the home.
Question: My wife has round hairbrushes that she wanted me to clean. In the past I used a one thin pick type tool. This time I used a fork from the kitchen drawer. It took me less than 40 seconds to put the fork underneath the hair and lift up the hair and clean the entire brush. Also, what can a person do to remove red hair dye from regular carpet? Terry, Winnipeg
Answer: Thank-you for the hairbrush cleaning tip. The trick to removing hair dye from carpet is to clean the carpet with dish soap and water, as soon as the dye spills. If you wait more than six hours, the fibres take on the dye solution and the mark may be permanent. The challenge with red hair dye is that even if you budge the stain, you might end up getting some of it out but a pink circle sometimes remains. Consider calling a professional to assist you with this challenge.
Some people had good results by pouring one cup of water onto the stain. Blot with a white towel.
Pour half a cup of white vinegar onto the stain.
Blot with a white towel. Pour half a cup of rubbing alcohol onto the stain, and blot with a wet white towel.
Handy Tip of the Week
I make my own bread and to make it extra healthy I knead it in bran instead of flour. No one in my family has ever noticed the difference.
— Ruth
Note: Every user assumes all risks of injury or damage resulting from the implementation of any suggestions in this column. Test all products on an inconspicuous area first.
I enjoy your questions and tips, keep them coming.
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