redsky49
Well-known member
Some rather extravagant claims are being made on this forum regarding the performance of certain alternate types of insulation. Most, if not all, of these products do not provide independant third party verification of these claims.
So, in the interest of garage builders everywhere, a few insulation facts:
1. Insulation values are indeed additive. Combine an R-2 insulation board with another R-2 insulation board and you will end up with a total insulation value of R-4. With insulation R- values, more is better.
2. Products such as rockwool or fiberglass blanket or mat depend on the fluffy quality of the material for peak performance, and the insulating value begins to decrease if compressed more than 10 or 20%. Squish it flat and you could reduce an R-13 to about an R-1.
3. The insulating value for a 1/4" air space is very little. In fact it is not even published. A 1/2" air space placed vertically works out to less than R-1 for temperatures the typical garage owner would encounter, and only reaches R-1.4 at extreme conditions. To be beneficial, an air space has to be larger, say a couple inches or more.
4. Total assembly insulating values include every component installed in, for instance, a wall. The siding, sheathing, vapor barrier, insulation and gypsum board all contribute to the total insulating value, plus some other small factors such as the surface air films attached to the inner and outer wall surfaces. In most cases, you have a better insulated wall/roof than you thought.
5. Any insulating material will be compromised if allowed to get wet. Moisture not only negates the insulating performance, it also creates a perfect medium for mold and mildew. There is a reason that vinyl wall coverings (wall paper) are not used in Hospitals. It is a breeding place for bacteria due to the vinyl material trapping the moisture. Aspergillus, Legionella, etc. all thrive in such conditions.
6. Soil does have an insulating value, but it varies according to type of soil, granular size, moisture content, temperature range, etc. It is so difficult to make an accurate estimation of soils, as well as for rocks, that I feel it would be irresponsible to include these materials as beneficial in any load calculation.
7. Reflective surfaces are helpful for both light and heat energy though published heating data mainly is concerned with temperatures of 120 degrees and above. That being said, use it where appropriate.
8. Wood is a relatively good insulator, far better than aluminum, and is a logical choice for a garage door. Insulating values range from about an R-0.8 to nearly R-2 per inch of material. Softwoods are better than hardwoods.
9. There are some super-performing insulating materials, but they are extremely expensive and are not appropriate for large scale applications. They use vacuum panels (this is not the same as an air space) manufactured under precise conditions and are relatively fragile.
The data presented above is published as a result of the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) and is available for review at any large library. It has not been pulled out of my hat.
Be a smart consumer. If it sounds too good to be true, it likely isn't. Hope this is helpful.
As always, offered only as opinion
So, in the interest of garage builders everywhere, a few insulation facts:
1. Insulation values are indeed additive. Combine an R-2 insulation board with another R-2 insulation board and you will end up with a total insulation value of R-4. With insulation R- values, more is better.
2. Products such as rockwool or fiberglass blanket or mat depend on the fluffy quality of the material for peak performance, and the insulating value begins to decrease if compressed more than 10 or 20%. Squish it flat and you could reduce an R-13 to about an R-1.
3. The insulating value for a 1/4" air space is very little. In fact it is not even published. A 1/2" air space placed vertically works out to less than R-1 for temperatures the typical garage owner would encounter, and only reaches R-1.4 at extreme conditions. To be beneficial, an air space has to be larger, say a couple inches or more.
4. Total assembly insulating values include every component installed in, for instance, a wall. The siding, sheathing, vapor barrier, insulation and gypsum board all contribute to the total insulating value, plus some other small factors such as the surface air films attached to the inner and outer wall surfaces. In most cases, you have a better insulated wall/roof than you thought.
5. Any insulating material will be compromised if allowed to get wet. Moisture not only negates the insulating performance, it also creates a perfect medium for mold and mildew. There is a reason that vinyl wall coverings (wall paper) are not used in Hospitals. It is a breeding place for bacteria due to the vinyl material trapping the moisture. Aspergillus, Legionella, etc. all thrive in such conditions.
6. Soil does have an insulating value, but it varies according to type of soil, granular size, moisture content, temperature range, etc. It is so difficult to make an accurate estimation of soils, as well as for rocks, that I feel it would be irresponsible to include these materials as beneficial in any load calculation.
7. Reflective surfaces are helpful for both light and heat energy though published heating data mainly is concerned with temperatures of 120 degrees and above. That being said, use it where appropriate.
8. Wood is a relatively good insulator, far better than aluminum, and is a logical choice for a garage door. Insulating values range from about an R-0.8 to nearly R-2 per inch of material. Softwoods are better than hardwoods.
9. There are some super-performing insulating materials, but they are extremely expensive and are not appropriate for large scale applications. They use vacuum panels (this is not the same as an air space) manufactured under precise conditions and are relatively fragile.
The data presented above is published as a result of the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) and is available for review at any large library. It has not been pulled out of my hat.
Be a smart consumer. If it sounds too good to be true, it likely isn't. Hope this is helpful.
As always, offered only as opinion
