Roof Icicles: How We Stopped Them and the Heat Loss that Caused Them

Reader Contribution by Adam D. Bearup and Hybrid Homes
1 / 8
2 / 8
3 / 8
4 / 8
5 / 8
6 / 8
7 / 8
8 / 8

Not many people know about nail-based panels, which are available through our structural insulated panel (SIP) supplier. Nail based panels are designed to be installed on the top of an existing roof deck and are available in a number of thicknesses. Because the house that we were fixing already had good insulation and ventilation, we chose a 5½-inch-thick foam nail based panels to stop the heat loss through the existing roof deck.

There was quite a difference in costs for the three different scenarios that I had come up with to stop the ice build up on the roof. When we sat down and went over the pricing, the path of least resistance and damage to the existing finishes inside the house was the deciding factor. With a nail based panel, the only labor cost we would have is installing the panels. There would be no need for a massive cleanup effort like there would be if we attacked this issue from the inside of the house.

The cost of the nail-based panels are about $2.65 per square foot which is more expensive than spray foam but required minimal effort versus what we would have to do to prep the attic area for spray foam. The SIP company wanted $450 to deliver the panels to the job site, but The Rev opted to go get the panels with his trailer to cut down on costs on this project. The panels are 4 feet by 8 feet — just like a sheet of plywood.

Remember, that the original goal was to put a metal roof on this house, so the nail based panels gave us a great setup for the new metal roof! It was a no-brainer to us; all we had to do was figure out how we were going to do the work four stories above the ground.

The Process, The Fix

I am going to tell you how we fixed this house. This should not be attempted by anyone unless they know what they are doing and have proper fall protection and safety gear. The height of this project was staggering and all necessary safety precautions were taken.

The first step in any project is to make sure everything that you are going to use is staged properly. Moving product around takes time and if you have built up the nerve to work ‘in the clouds’, you want to make sure that you are spending that time working and not digging product out of the snow.

I really wanted to do this fix in the dead of our Michigan winter so that we could see the results immediately, normally, it would be nicer to do roof work during any other time of the year than winter. We started the install of the nail based panels by first cutting the existing drip edge off the roof so that we could have a flush roof edge to flush the nail based panels off of. We left the existing shingles on the roof and any flashing in place because the foam of the panels presses nicely around all the shingles and flashing when we screw the panels down.

When you order the nail based panels, a decent drawing of the exact size of the roof is required so that you end up with the correct amount of panels. They normally do not send out an entire roof layout, just a layout of how a panel should be set. For us, we determined that we would have 3-inch strips left once we laid the panels over the entire roof surface. From experience, we knew that we would put those “rippers” in between full panels and not at the edge of the roof. We need the support of the entire panel for when we put the 2-by-6 sub-fascia boards into the edges of the nail-based panels.

We started on the lower edge of the roof with our first panel. Like anything else, we have to make sure that this panel is set properly because the rest of the roof layout depends on it. This also happens to be the toughest panel to set, because you are hanging over the edge of the roof. We take the extra time to make sure that this first panel is true to the roof lines, and once that panel is in place, we screw it down with the long screws and washers that come with the panels.

We foam between each panel and have found through experience that there is no need to offset the panels. There is the exact same amount of ‘exposure’ whether you offset the panels or not. This exposure is basically where the panels come together. The panels go down quickly and we had the entire roof of panels installed in just a few hours.

Once all of the panels are set and securely screwed down to the existing roof, we install the 2-by-6 sub-fascia around the perimeter of the roof by insetting the board into the grooved edges of the nail based panels. We learned to rip about 1/4-inch off of the 2-by-6 so that we do not have to fight with the board while up in the air. The 5-1/4-inch ‘ripped’ boards slide in the slots without a fight and then we staple and nail them in securely.

We finished this work on an evening that we got about 3 inches of snow. The first thing we noticed when we came in that next morning is that the panels were evenly covered in snow. The existing roof under the panels never had an even blanket of snow on it; the roof was losing so much heat, that it never gave snow a chance to build up on it. We knew that we had fixed the heat loss problem; now all we had to do was blow the snow off and finish the roof.

We bent our own fascia metal using a thick-gauge 12-inch coil stock and a siding breaking. We bent the metal so that there was a 3/4-inch reveal on the bottom and 11-1/4-inch face. Once installed, this fascia not only made the edges of the old and new roof look great, it protected that edge from the elements. With the new, crisp fascia installed, we could then start installing the metal roof and metal roof trims.

The metal roof panels were thirty two feet long and getting them up onto the upper roof was a real challenge. Piece by piece, we installed the metal roof panels and metal roof trims until we were done. The last metal roof panel and edge trim required extra help from a local tree service company who were able to reach the top corner of the roof.

We finished the roof just in time for a 6-inch snowfall. We were all excited to see that there was an even blanket of snow on the new roof and not one icicle! Mission accomplished!

Adam D. Bearup is a designer, green builder and farmer, who learned about biodynamic and regenerative farming for a project he built in Northern Michigan, The Earth Shelter Project MichiganAdam has degrees in marketing and management and a Masters of Science in Green Building. Read all of his MOTHER EARTH NEWS posts here.

All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Best Practices, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on the byline link at the top of the page.