Insulation panels for roof

Hello everyone, I purchased a home before this past winter and realized after the first cold month and a $250 gas bill that my insulation is inadequate. The ceiling of the house is T&G wood with exposed rafters, I want to keep this look and I am not willing to insulate from the inside.

From an area of the house where the cathedral ceiling meets the attic it looks like there is about 1" of foam board for insulation…in Chicago this is highly inadequate.

I have looked up an option for this, it was using a product called Hunter Cool-Vent panels. I think Johns Manville also makes a similar product. Has anyone used these panels? What would I need to do in the areas where there is an attic in the house, would I run these panels over the attic space in the house also?

What are you willing to do?

First you say you want to change your insulation, but you are unwilling to make any changes inside. So, are you willing to install a new roof to add insulation? Because really that is your option if you only have an 1" space that is currently insulated with foam board.

If you are willing to build up on top of the existing roof deck, then you can insulate your roof from the topside with something like this: … 36713.html

Of course, you’ll have to close off the perimeter edge of the roof where the insulation is exposed, but if you are willing to throw money at the problem from the roof rather than from underside of roof you kind of limit yourself.

We are talking a sloped roof, right?

Now, if aesthetics is not an issue whatsoever, there are other options available.

Here is a picture of the ceiling, sorry about the light coming in the skylight. I understand that the only other option is to insulate from the outside of the house, that is why I said there are hunter cool-vent panels similar to the link you posted. I was seeing if anyone has used them or another brand that would be recommended.

The panel in the link you posted does not incorporate an airspace for venting while the cool vent panel does. I imagine the venting layer in the panel will help keep the roof cool.

I am planning on replacing the roof next summer, and want to plan on installing the proper insulation during this time. I don’t know whether I need the vented panels, foam with plywood glued to it, or maybe there is a way to lay the foam board down and then lay plywood over that?

Does anyone know where I can find information for insulating the top of the roof with rigid foam?

You have so many options, but remember you don’t want to penetrate the roof deck and have exposed fasteners. So, you will need to adhere the insulation to the deck, and how to best do it depends no the type of insulation and the type of roof. For example, if you went with a new metal roof system, I would recommend a system of wood sleepers horizontally, that are fastened to the roof deck directly over interior roof beams so fasteners are not exposed. Polyiso can be used to fill-in between the sleepers, and the metal panels can be properly clipped or cleated into place. If you want shingles, then a nailboard might be best for you. It just all depends on what kind of roof you want; metal, shingle, slate, tile . . . And yes, I’ve used the cool-vent panels before somewhere, but can’t remember where, and I doubt I ever went back to check on its performance.

Is metal or composite roofing a lot more expensive than asphalt shingles? I’ve only installed asphalt shingles on a roof. I don’t have any experience with the other types of roofing materials out there.

I did some further searches on google and found out that they typically call these insulated panels “nail base insulation panels”. With this search I found many more companies that make these panels.

This is going to be a big undertaking to get all this work done. I really only have 2 weeks to do the whole roof and insulation.

I’ve used this product on a building with a cathedral ceiling that was having heat issues (no ventilation causing the shingles to curl).

If you can’t nail to the roof you will have to look into glue or hot asphalt, which may leak through the T&G (unless you leave the existing insulation board…)

Most polyisocyanurate insulation manufacturers make a product called vented nail base. This product is, basically, iso board with 3/4" to 1" air space and OSB all laminated together. This is mechanically attached to the existing roof (best if screwed into the beams rather than the 2x’s) with the OSB side up. You then install a new roof over this system. Add a ridge/eave vent system and you are all set.

This system allows you to have a vented attic, which will aid in keeping the heat and cold from impacting your home.

I think the vented nailbase would be the best choice since it should help with energy savings and my ice damming issues. I was thinking I should remove the 1" insulation and plywood covering then install these new panels. The rafters are approx 4x8"and the T&G wood is around 2-2.5" thick. Do you think it would be an issue to fasten to the T&G?

I also am unsure how to go about the height difference between the exposed rafter section of the roof and the attic area once i remove the current insulation and decking. The height difference will be the thickness of the insulation and plywood. How would I go about getting everything back to the same height? Here is my 2nd grade drawing of the house.

For some reason on can’t get my picture to load…hmmm