Friday, March 26, 2010
Our roof insulation is the absolute!
In Home Made, the asphalt shingle made in North America is usually used.
This roofing material is comprised of asphalt and glass fiber. So, it is light and highly flexible.
And the color of the surface is taken out by a grain of a natural stone and there is no color fade. It's different from Japanese painted roof material.
It is guaranteed for 30 years, though Japanese one should be painted after 10 years.
This roof material is soft, therefore, it was difficult to install some outside ventilation system in the roof up to now.
We are settled by high-density polypropylene which is twined like a net on the roof wrap sheet (shown it as white sheet in photo).
When you use an attic as a room, it will block heat from a roof off. And we install cellulose fiber insulation in the rafter. So, we achieve the double heat insulation system on the roof.
Air (humidity) goes through the roof wrap sheet, but water isn't let through it.
Even if interior humidity is passing through roofing plywood, we become able to release humidity at the space made by the polypropylene net for ventilation.
The other house builders install asphalt roofing sheet directly on the roof plywood as waterproof sheet. So, dew condensation is caused between the waterproof sheet and the roof plywood. And they cannot resolve the problem that water degrades plywood.
Of course, We, Home Made, use the cellulose which has function of absorption and desorption of moisture in a roof. And I also get the inside ventilation system to release humidity from a ventilation layer inside the roof.
Even if this outside ventilation system isn't adopted, roofing plywood isn't degraded.
Therefore to save the budget at the house building, I think it isn't even necessary to install the outside ventilation system, if you do not use an attic area.
Dulability depends on as natural providence and high quality in building technology.
You also know that a low-cost isn't compatible with high quality of course, right?