tmurray
SAWHORSE
So, there are solutions, just the IRC doesn't make them mandatory.
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Blower Door testing
- Thread starter Blower Door Expert
- Start date
jar546
CBO
Correct.
Wooly
Member
Slab on grade is inherently difficult since your volume to exposed surface area is so skewed. That why the code is slowly changing to equivalent leakage area. That's the only correct blower door number not ACH50.
Wooly
Member
The two most expensive things people have in life come with no owners or instruction manuals, kids and houses. But yet I got a pictogram instruction with the bottle opener I just bought!?!?!
Energystar
SAWHORSE
You guys need to get with the 21st century. The IRC has required blower door testing since 2012. Zones 3-8 were then required to be 3 ACH50 or less. It also required whole-house ventilation.
Spending extra money to seal a home so that one must then spend still more money to ventilate it may at first seem parodoxical. However, a home is not smart enough to breathe on its own. Leakage is mainly driven by temperature difference and/or wind. In order for ventilation to occur, there must be an opening and a pressure difference across it. In a leaky home without forced ventilation when the weather is moderate as in the spring or fall, the home will suffocate. During extreme weather, ventilation will be maximized leading to loss of comfort and high energy bills. Some people like to open their windows during the shoulder months but unfortunately this is when allergens are at their peak (pollen, mold, etc.).
The amount of ventilation required by code to keep a home healthy is trivial—typical around 60 cfm continuous. It is much heathier to seal the home and force this modest amount of air that is dependable 24/7.
Our homes range from about 0.7 to 2 ACH. In average to large sized homes we install ERVs. In small ones we use an inline fan in the attic with a speed control. In either case, we pull the air out of the bathrooms thereby negating the need for bath fans. Each bath needs 20 cfm continuous which is normally very close to the code required ventilation amount. No more worrying about those teenagers forgetting to run the bath fan during hot, 30 minute showers.
In my experience, the source of leakage that is most commonly overlooked is through interior walls and openings in the ceiling, i.e., fixtures and smoke alarms. Interior walls are full of switches an outlets. Air also leaks through the base of the walls. From here it simply passes between the top plates and drywall through the insulation and into the attic. Builders around here foam or caulk these areas and have little trouble passing the 3.0 BDT.
Spending extra money to seal a home so that one must then spend still more money to ventilate it may at first seem parodoxical. However, a home is not smart enough to breathe on its own. Leakage is mainly driven by temperature difference and/or wind. In order for ventilation to occur, there must be an opening and a pressure difference across it. In a leaky home without forced ventilation when the weather is moderate as in the spring or fall, the home will suffocate. During extreme weather, ventilation will be maximized leading to loss of comfort and high energy bills. Some people like to open their windows during the shoulder months but unfortunately this is when allergens are at their peak (pollen, mold, etc.).
The amount of ventilation required by code to keep a home healthy is trivial—typical around 60 cfm continuous. It is much heathier to seal the home and force this modest amount of air that is dependable 24/7.
Our homes range from about 0.7 to 2 ACH. In average to large sized homes we install ERVs. In small ones we use an inline fan in the attic with a speed control. In either case, we pull the air out of the bathrooms thereby negating the need for bath fans. Each bath needs 20 cfm continuous which is normally very close to the code required ventilation amount. No more worrying about those teenagers forgetting to run the bath fan during hot, 30 minute showers.
In my experience, the source of leakage that is most commonly overlooked is through interior walls and openings in the ceiling, i.e., fixtures and smoke alarms. Interior walls are full of switches an outlets. Air also leaks through the base of the walls. From here it simply passes between the top plates and drywall through the insulation and into the attic. Builders around here foam or caulk these areas and have little trouble passing the 3.0 BDT.
A little late to this discussion, In the last building position I had, I was the project manager for a developer/builder, literally built 700+ houses over a 20 year span.
I was lucky, in 06 the owners asked if I wanted to goto an "insulation" class.. turns out it was BPI's building analyst.. then, shell, then heating, then what's this HERs, then Thermography, then passive.. all while I was still building houses.. we applied the knowledge gained from all of these certifications immediately. I had a great 5 years of building to see the differences. My takeaway is, you cant build it too tight If its actually ventilated right. Imagine a seesaw. When one end goes up the other side (being on a pivot) goes down. The side going down (infiltration) HAS to have the other go up. Now imagine this pivot to one side more than the other (lever) a great reduction in infiltration needs only a little more ventilation. In the thousands of homes I have tested, 80% did not meet code for adequate ventilation. Most times a simple fix, but what I saw was builders understand the tightness issue, but the trades failed on the execution of ventilation.
All of this and the 1 huge drawback for a tight homes with unconditioned basements was damp basements. Infiltration allowed the basements to dry out (up through the house) tight homes wouldn't let the basements moisture move up and out, mold on basement stair and drywall above boilers and staircase (within months) was common to ANYONE who did not install a basement dehumidifier.
Moving the thermal barrier from the basement ceiling to the basement walls and actively conditioning that space solved the problem. Next issue was atmospheric drafted heating equipment in the basement needed fresh air, build a boiler room. Next issue was that equipment with fresh air to the outside was in an unconditioned space (like it was before) so get fresh air kits for the burner intake shroud.
The point of all of this is all of the issues that come with more advanced technology have solutions (again more advanced solutions)
Someone said earlier that lack of air movement causes condensation. If they are talking about infiltration, I disagree. If they are talking about the simple act of air movement itself, I disagree.
Condensation needs humid air to move over a cold surface. Period. Full stop. If your seeing condensation you have 2 problems. Cold surfaces with air having too much moisture in it (RH) and a dew point being met. Full stop. You have to ask your self, why is the airs RH so high, or why is the surface so cold. Has absolutely nothing to do with lack of air movement unless the mechanical systems are failing, or there is a source of moisture that shouldn't be there, or the insulation is missing.
Back to the question of biggest areas for infiltration. In my life I have seen that any where a walls top plate meets an unconditioned space, that that wall needs a drywall gasket on the lower of the top 2 plates.
Its simple, does the top of that wall (exterior or partition) have fiberglass insulation above it? If yes, the drywall needs to be gasketed ( not caulked) to that top plate. Period. Full stop.
As the studs dry, a space is created between the drywall and plate. Every cavity, every bay now becomes a chimney to the unconditioned space above. While the space between the drywall and plate may only measure 1/16" I have see in existing homes 1/8-3/16"! Now multiply that by however many linear feet of top plate ( again, partition walls (x2) and exterior walls). The effective leakage area on that alone can easily be 5sq ft. Its like having a Windows open to the attic all winter long.
Most builders i now see are shocked when they try the gasket out for the 1st time. I have built and seen many traditional fiberglass insulated homes have blower door numbers lower than many spray foamed homes. Not always, but sometimes. Point is, that is in my opinion the biggest and best low hanging fruit...
I was lucky, in 06 the owners asked if I wanted to goto an "insulation" class.. turns out it was BPI's building analyst.. then, shell, then heating, then what's this HERs, then Thermography, then passive.. all while I was still building houses.. we applied the knowledge gained from all of these certifications immediately. I had a great 5 years of building to see the differences. My takeaway is, you cant build it too tight If its actually ventilated right. Imagine a seesaw. When one end goes up the other side (being on a pivot) goes down. The side going down (infiltration) HAS to have the other go up. Now imagine this pivot to one side more than the other (lever) a great reduction in infiltration needs only a little more ventilation. In the thousands of homes I have tested, 80% did not meet code for adequate ventilation. Most times a simple fix, but what I saw was builders understand the tightness issue, but the trades failed on the execution of ventilation.
All of this and the 1 huge drawback for a tight homes with unconditioned basements was damp basements. Infiltration allowed the basements to dry out (up through the house) tight homes wouldn't let the basements moisture move up and out, mold on basement stair and drywall above boilers and staircase (within months) was common to ANYONE who did not install a basement dehumidifier.
Moving the thermal barrier from the basement ceiling to the basement walls and actively conditioning that space solved the problem. Next issue was atmospheric drafted heating equipment in the basement needed fresh air, build a boiler room. Next issue was that equipment with fresh air to the outside was in an unconditioned space (like it was before) so get fresh air kits for the burner intake shroud.
The point of all of this is all of the issues that come with more advanced technology have solutions (again more advanced solutions)
Someone said earlier that lack of air movement causes condensation. If they are talking about infiltration, I disagree. If they are talking about the simple act of air movement itself, I disagree.
Condensation needs humid air to move over a cold surface. Period. Full stop. If your seeing condensation you have 2 problems. Cold surfaces with air having too much moisture in it (RH) and a dew point being met. Full stop. You have to ask your self, why is the airs RH so high, or why is the surface so cold. Has absolutely nothing to do with lack of air movement unless the mechanical systems are failing, or there is a source of moisture that shouldn't be there, or the insulation is missing.
Back to the question of biggest areas for infiltration. In my life I have seen that any where a walls top plate meets an unconditioned space, that that wall needs a drywall gasket on the lower of the top 2 plates.
Its simple, does the top of that wall (exterior or partition) have fiberglass insulation above it? If yes, the drywall needs to be gasketed ( not caulked) to that top plate. Period. Full stop.
As the studs dry, a space is created between the drywall and plate. Every cavity, every bay now becomes a chimney to the unconditioned space above. While the space between the drywall and plate may only measure 1/16" I have see in existing homes 1/8-3/16"! Now multiply that by however many linear feet of top plate ( again, partition walls (x2) and exterior walls). The effective leakage area on that alone can easily be 5sq ft. Its like having a Windows open to the attic all winter long.
Most builders i now see are shocked when they try the gasket out for the 1st time. I have built and seen many traditional fiberglass insulated homes have blower door numbers lower than many spray foamed homes. Not always, but sometimes. Point is, that is in my opinion the biggest and best low hanging fruit...
Inspector Gadget
REGISTERED
I can concur.
Also, we've been finding a lot of contractors not cluing into the requirement to
1) have vapour barrier run behind demising walls
2) have vapour barrier continuous through concrete slabs (although this is admittedly minor)
3) seal electrical wire penetrations through studs going into exterior walls/ceilings
4) have vapour barrier (air barrier) sealed to windows.
tmurray
SAWHORSE
We had a issue where a builder missed a vapour barrier inspection in a basement. It wasn't his fault. The future owner decided to hire people to go in and finish the basement while the house was under construction and did not communicate this at all with the builder (whole thing was wild). Anyway, we did an inspection with a thermal imaging camera and found really odd cold spot on the bottom half of an interior demising wall where it intersected the exterior wall on the walk-out side of the building. I got the builder to rip the sheetrock off one side so we could see what is going on and it was #3 in your list, along with a exterior hose bib.
Contractors loved that thermal camera. A few told me if we needed another one and were having trouble to get funding, to let them know so they can explain to council how much time and money it has saved them. Best $1200 I ever spent as a department manager.
jar546
CBO
You can do that? Please elaborate.
tmurray
SAWHORSE
Unlike how they are shown in the movies, thermal imaging cameras cannot see through walls. All they do is tell you the temperature of the surface using colour gradients.
We wait for a day with a large temperature difference between outside and inside (easier to see any issues). We do it very early in the morning before the sun comes up (prevents solar radiation from influencing readings).
Other than that, it just requires a moderate understanding of thermal bridging because you expect to see cold spots from structural components (studs, lintels, corners). If there are cold areas that are different than we would expect from thermal bridging, we open it up. Normally we would just find areas that didn't get sealed properly and had air infiltration/exfiltration.
To clarify, we didn't do this for contractors we hadn't worked with on a regular basis. Just contractors who normally did things right and we were just looking for things that got missed/forgotten. And we sure didn't do it with do-it-yourselfers.
jar546
CBO
I was just surprised that a municipal inspector would have this, that's all.
tmurray
SAWHORSE
Yes. I think at the time we were the only one in our province. Much larger jurisdictions were shocked when they found out, but our jurisdiction largely did not have an issue with buying staff the right tools to do a good job. We had an issue where a contractor blew up at staff and ended up complaining to council over us ordering the removal of sheetrock in a house. We were asked by council to evaluate other options and this was the outcome.
Funny enough, that contractor would not have been one of the ones we trusted enough to go just based on thermal imaging, so while he was the reason we purchased the equipment, he would not benefit from it.
Inspector Gadget
REGISTERED
Each of our full-time guys has a cellphone with a built-in infrared/thermal imaging camera system.
It has been ... interesting. I had one part 3 building where the temps were subzero. Concrete slab poured the day before, turned onsite at 10am, heaters had just been shut off. Took some pics... the images showed temps on the slab were ~7C and (presumably) going to drop fast in -5C-plus-wind ambient temperatures.
Designer called back about 15 minutes after I filed my report and started to ask questions about the source of the images and "was it calibrated." I explained, no, it wasn't .... but it was nonetheless indicative of decreasing temperatures. "The structural documents specified concrete being placed and cured according to CSA A23.1, and as I noted in the inspection report, it's up to the engineer - that's you - to verify that the heating remains in place per 7.2.2.2 .... Which usually means three days or 40 per cent per the table, and I don't think it meets that. I've covered our office's liability by bringing the data to your attention, it's your job to do the more exact measurements and the like. So now it's your call.... How will you proceed?"
Lordy, I get *so* many Christmas cards.
See my novel above. Inexpensive infrared tools exist now.
mtlogcabin
SAWHORSE
The fire department has one. They provided a camera and a firefighter to operate it for us a couple of times when we asked
tmurray
SAWHORSE
If the response is not "thanks for the heads-up, I'm heading to site to check it out", my next call is to the engineering society. I think design professionals should check things out for themselves. If they have a different measurement than me, it's reasonable to have the "who's is more likely to be right" discussion. Attacking the concern before checking it out for themselves shows complete negligence for their duties under their association's by-laws.
These posts are dead on. Sorry about thread drift.
I support building better, more comfortable houses with good ventilation. The tighter the better, and the mechanical systems should be properly designed to keep the house and the occupants healthy and comfortable. This is quite doable for the affluent and the well educated.
The problem with making it mandatory is the existence of poor people. I grew up, as many of us did, in a low-income family. When the furnace went out, we used space heaters and window air conditioners because we could not afford to replace the furnace. For several years. We actually only got a new furnace through a federal grant that my mother saw in the newspaper. We had a two parent family, owned the home, were never on welfare. We were not trashy deadbeats. We fixed things when we could. These were systems that affected our lives every day, and we did not fix them because we genuinely could not afford it. A significant portion of the population has similar or worse financial circumstances. Many do end up relying on space heaters and window air conditioners.
Now just imagine a home designed for affordable housing that relies on extra systems like dehumidifiers, ERVs, etc. When those items break, they are not going to get fixed. And so, the house will start to fall apart. The homeowners usually won't know that there is a problem until it is too late. We are told that it is necessary to "educate the homeowners" - but it actually doesn't matter because they have the amount of resources that they have and they will fix more important systems first - like the one that keeps them warm in the winter or gives them hot water. That pretty much exhausts the available resources, and the air quality is low on the hierarchy of needs.
So, as these systems fail, we will have houses that become virtually uninhabitable within a decade or two, that could have been built before the energy code and last much longer with almost no maintenance. The municipalities will have to deal with these houses long after the developer and builder are gone.
mtlogcabin
SAWHORSE
I grew up in south Fl, my dad was an HVAC contractor and I have never lived in a house to this day that has had AC.
Inspector Gadget
REGISTERED
I think the next call was to the GC, who was particularly frosty - pardon the pun - at my next visit. Since, he's wanted to follow me all over the site during inspections. This has been quite useful, because there have been issues.
I have been very tempted on more than a few occasions to bring the eng. association into discussions on conduct.