Potential Energy

I originally thought our remodel was a shoe-in for a LEED gut remodel project. The concrete slab on the floor of most of the home had to be taken out and replaced. This gave us the opportunity to upgrade with more energy efficient systems and materials. Where we eventually land on the LEED scale of things is still debatable, but there has also been the question of whether we can be a LEED project at all. The “gut” of gut remodel hinges on the language in the document that describes eligible LEED for Homes projects. The LEED for Homes Guidelines for 2008, Document 5482 states:

Gut / rehabilitation
Projects that are characterized as ‘substantial gut/rehab’ can participate in LEED for Homes, as long as all of the prerequisites can be met. In order to qualify as a ‘substantial’ gut/rehab, a project must replace most of the systems and components (e.g. HVAC, windows) and must open up the exterior walls to enable the thermal bypass inspection to be completed.

We definitely are replacing most of the systems, but we were not planning to tear up the crawlspace area of the house. That means that the drywall and existing insulation and thermal bypass layers would remain. Our provider questioned what was meant by “open up” to complete the thermal bypass inspection. This inspection is required for the Energy Star thermal bypass checklist which is part of the LEED Energy and Atmosphere Credit category. The insulation installation is classified according to the quality of the install, gaps in the application etc. Since in some cases the walls cannot be seen, the quality must be determined differently as in this explanation from the Energy and Atmosphere Item 2: Insulation


Gut Rehab Thermal Checklist Requirement

Our project does not remove the drywall or replace the insulation in the crawlspace area of the house. This is a relatively small area inside the red outline in the picture below. Although this is a substantial gut remodel regarding most of the systems etc., this part of the home has walls that are inaccessible. However, due to the discretion given to the rater, the home could still qualify for LEED for Homes as long as the prerequisites are met.

78thPl_remodel sections

78thPl_remodel sections

In this area of the house, there are walls that are underground (about 3/4 of the north and east walls.) These walls are insulated on the exterior so somewhat accessible for inspection. About 1/4 of the walls are above ground as well as the south clerestory and roof in one bedroom. I believed that I could have insulation blown into these walls to satisfy the rater that the thermal bypass and insulation quality had been met. However, since this is at the rater’s discretion, our rater told me that this was not something the company had ever done. They are not certified to judge this area by thermal imaging either. For these walls, our rater will not be able to judge the quality of the insulation install or the seamlessness of the air barrier. Although thermal imaging can check for a consistent air barrier, use of this technique is at the LEED provider’s discretion.

If the rater is not able to verify that a suitable continuous air barrier exists, the project is disqualified based on this prerequisite. In addition to this basic threshold, the installatoin has to be gap free. Our provider has never graded insulation better than the lowest level of installation if they could not see it. So this part of the house will have the lowest insulation score. That will be entered into the energy model with the rest of the house and hopefully the software will show that the house maintains an excellent air and thermal barrier by its overall performance.

This is the policy of our provider. After some email discussion, they have given us the go-ahead to complete the renovation without removing this drywall and establish that there is a suitable air barrier in the existing construction, with the understanding that we will be downgraded wherever the insulation is not completely exposed. The original house was built to higher standards than a typical home so the existing walls in the crawlspace area of the house are 6″ to 8″ thick and have fiberglass batt, plastic sheeting, drywall, etc. to create the air barrier, and the roof has asphalt shingles as well as the 12 inches of fiberglass batt in the clerestory plus the extra layers of batts that I installed in the attic area. From what I have read, no one layer is completely responsible for the air barrier, instead the entire system must be continuous and free of air infiltration.

Since we are replacing the insulation and air barrier in the main part of the house, the rater will be able to model a higher level of installation in most of the building. In my estimation, tearing out drywall in the crawlspace area that does not need to be redone due to soil expansion damage seems adverse to the LEED principles of green remodeling, reducing materials, reusing, and recycling wherever possible, so I am accepting this potential reduction in performance as a reasonable tradeoff.

UPDATE: Energy Logic has researched the issue and USGBC will accept thermal imaging from a Level II certified thermographer as evidence of continuous insulation coverage. But I have to find the thermographer. I called around and found most energy audit companies only have a Level I thermographer but our electrician’s company has a thermographer who is ready to take the exam for Level II so hopefully thermal imaging will improve our rating for the existing insulation install.

I’m choosing to be upbeat about the future and will just do everything we can to make this project qualify and gain the necessary LEED points to score in the certified range. In this case I think we solved the issue of whether we will meet the prerequisites for Energy and Atmosphere.

But while discussing this issue we realized that the drywall in the back bathroom does not meet the minimum standard of paperless drywall in all wet areas. That means that the bathroom drywall, at least in the tub area WILL have to be replaced so the tile will have to come out and we will have to plan to use paperless drywall in all other wet areas too. I am not fond of the tile in the bathroom and have redone several bathrooms with durarock and new tile and paperless drywall so this is not that daunting, but close attention to LEED requirements can be so detailed that it is frustrating.

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