2015 Michigan Energy Code Amendments and their flaws

In 2015, Michigan amended its energy code for residential construction, which brought tighter requirements to increase energy efficiency. While the goal may have been to increase the green footprint of new construction, some of the methods in the code are flawed. This article will focus mostly on the new requirements for basement insulation. Basements in Michigan are common, and the new code requires a minimum R value for the basement walls. While the intent looks good on paper, achieving this minimum R value for a new basement can be somewhat problematic. This article focuses on major issues we found with our new basement, specifically surrounding the new code requirements.

The new code can be found on the State of Michigan website:


Basement Materials

Common basement construction consists of either: concrete block, poured wall, modular system (like Superior walls), or other hybrid materials. When we built our home, we almost went with Superior walls as the insulation is built in to the pre-cast pieces and it met the minimum R value requirement of the 2015 Michigan Energy Code changes. However, after a fair amount of research, and seeing the Superior walls in person, we decided against it. Our decision was influenced from my own concerns with the Superior walls being able to completely seal out moisture. The pieces of the Superior walls are attached and bolted together at the time of assembly at the home site, and the seams between them caulked. I was not convinced that this would be a complete seal against moisture from the surrounding soil, and if it would hold up over the years. To me, a home foundation is what holds up the entire house, and I did not want to go with a product that we were not completely confident in. Instead, we chose a poured wall foundation. In my opinion, not only is a poured wall pretty much indesctructible because it's 8 inches of solid concrete in thickness, but it has been proven over many years to hold up. In addition, a poured wall has essentially no seams to it, unless of course it cracks (which, we did have happen and which I will go in to more detail with later). The outside of the poured wall is normally sealed with tar to help keep moisture from penetrating. Optionally, foam boards can also be attached to the outside surface of the poured wall for additional insulation. We ended up going with just a straight poured wall, with the tar sealant and no foam boards on the outside face.


2015 Michigan Energy Code Requirements

We ended up going around and around with our local county to try and figure out just how we could meet the requirements of the new 2015 Michigan Energy Code amendments. Basically, for a poured wall, we needed an R11 blanket to be attached to the concrete surface of the basement walls. The alternative would be to frame the inside of the basement walls and insulate with another media that has at least R11 (closed cell foam, or fiberglass). We opted to go with the 8 foot basement blanket mainly due to cost. We simply could not afford to frame in the entire basement walls at the time of initial construction of the home. The basement blanket is basically a large roll of R11 fiberglass insulation that is 8 ft wide, and in various lengths that can be attached the the basement wall. The backing is typically a fiber reinforced plastic material.

The joke of this, is that only 8 feet of blanket was required, and our walls are 9 feet high, so the blanket was installed and the bottom foot was bare concrete. Sure, we could have gone with a 9 foot tall blanket, but that would add even more cost that we would not get any return from. I asked the insulation installers to only put in enough concrete nails and staples to just hold up the blanket, as we would be ripping it back down someday to frame in the basement with permanent insulation.


Uncovering a Major Issue

You may already see several flaws in the basement blanket. Here are a few obvious ones that we encountered:

However, in our case, we discovered one more flaw, which is probably more serious than the above two. About a year after the basement blanket was installed, I noticed some water dripping down the bare concrete walls just under the blanket in several spots. Remember we had one foot of exposed concrete wall under it. At first, I thought that we had a crack in the wall and that water was seeping in, however it was in February that I made the discovery, and the ground is mostly frozen on the outside. After peeling back a few sections of the basement blanket, I quickly discovered that the water was actually condensation forming behind the blanket. The concrete wall was wet, and I mean to the point where it was dripping down the entire wall. And, it apparently had been wet behind the blanket for quite some time, as I soon found large areas of mold along with it. At first, I thought maybe this was because there was an air gap between the insulation face of the basement blanket and the bare concrete wall, but in may areas this was as tight as the installers could get it where it was nailed and stapled to the wall. There's really no way to get a complete or airless seal between the fiberglass surface and the concrete.

The next thing we knew, we were ripping down the rest of the blanket in order to assess just how much mold and wall damage was behind this blanket. In our case, this was about 180 feet of linear wall. What I quickly found was that the mold was particularly heavy in areas where the concrete wall is exposed to the outside (meaning it is above ground), and in areas underground it was less but there was still some spots. Corners in areas above ground were the heaviest concentrated areas of mold.

So, at this point, we knew the next step would be to mix up a bleach solution, and probably get out some sort of brush, and start scrubbing our walls to kill all of the heavy mold areas and clean it off. What ended up happening is we let the walls dry (without the blanket) and the mold has been stagnant. About a year later, without the basement blanket installed, the walls are fine and there's absolutely no further evidence of condensation or spreading mold. We have yet to break out the brush to clean it off but that will be the next step for sure before we even think about putting up anything else on the wall.

At the same time, we now have a pile of 180 linear feet of an 8 ft wide roll of R11 fiberglass insulation that we have no idea what to do with. About 70% of it has heavy mold on it. We cut the pieces out that had little to no mold, and those could probably be sold to somebody that might need it. But we don't think we can do anything with the pieces that have heavy mold that is embedded in to the fiberglass. Should it get thrown in to a landfill? Unfortunately, that is the most likely scenario. That's a lot of waste.


Good on Paper, Bad in the Real World

There are no real words that can express how much disappointment we have in the State of Michigan for coming up with such ridiculous code changes, without a means to support it in the real world. The code makes absolutely no sense from an implementation standpoint. If homeowners are going to be required to install basement insulation on a new home, there are three isssues:

  1. This is un-necessary other than increasing the energy efficiency of the home, which is minimal. Typical basement walls are around 55 degrees, because of the soil temperature. It should be the homeowner's choice of when and how to increase the energy efficiency of their home. The energy bills alone should be persuasive for a homeowner to improve their home, not our state government.
  2. A newly constructed home should not finish its basement right away with foam insulation or other forms of insulation such as a finished or framed wall, especially with concrete block or poured concrete walls. Why? Because natural settling is almost certain to happen and cracking of the walls can occur. If this happens on a finished basement, it is very difficult and expensive to fix. Either you will need to remove the inside wall or framing (and insulation) to get to the crack, or the outside needs to be excavated all the way down to the footing. In our case, we ended up developing two cracks in our new poured walls, which needed to be repaired. The cracks ran from the top to the bottom of the wall, and water was starting to seep through near the bottom in one of them. See photos below of this as well. After everything has had a chance to settle, that is when basement walls should be insulated and finished.
  3. Extra cost of installing temporary material that will be discarded later. In our case, additional costs and time were added to do the cleanup of the mold damage that was done.

In our case, we contacted our local county to let them know of this serious issue with the Michigan Energy Code. We did not receive any response. I assume they are busy with other matters, but they don't have control of the code so we didn't expect them to do much, other than let their contacts at the state level know that this is a serious problem and the code should be changed back to how it was before.


Photo Evidence

Included below are full size photos of the damage done. Click on each to bring up the full size photo. The timeframe for the condensation was 1 year, from the time of installation (in February) to the following year in February when these photos were taken.


Insulating a New Basement Properly

If we had the opportunity to do this process over again, and adhere to the flawed requirements of the Michigan Energy Code, we would do the following:

  1. Have the basement blanket installed at the time of construction, and remove it just after inspection has passed. This will avoid any condensation and damage for occurring.
  2. Give the house foundation a good year to settle, taking in to account all temperature differences, so that in a year's time I would assume any cracks that develop are there and no others will (hopefully) form after. Only after a good year or so, would I start to even think about insulating the basement walls.
  3. After giving the foundation enough time to settle, I would frame the outer walls with 2x4s, spaced 16" on center, and have 1.5 - 2 inches of closed cell foam installed against the concrete surface. Don't forget to run any wiring before the foam is installed, otherwise it would be difficult to run after.
  4. Have wet cellulose blown on to the walls, over the closed cell foam, allowing a few days for it to fully dry, then have drywall installed to prevent the insulation from falling.



We have not received any response when trying to bring this issue up with government entities, so instead we are publishing this information and our experiences here in hopes that others will see it and avoid making the same mistakes we did by trusting the Michigan Energy Code as-is. Steps should be taken to correct this. An insulation expert would have caught this flaw immediately and would have been able to correct it at the time the code was written, however that doesn't seem to be the case.