Insulation for Oregon Home
The vapor retarders in the attic may face the heated area directly if there is no insulation installed. It is not good to install new insulation having the vapor retarders over an already installed insulation. In whole house only one vapor retarder is essential and that must be installed in a way that it remains in contact with the heated ceiling.
If the attic in the house has insulation with vapor retarder already than before installing new insulation you need to slash it with the help of a sharp knife in gaps of 6 inches each. The insulation must be so added in the house so that there remains no space or gap between the insulation and the heated part of the house.
If the new insulation that is added is compressing the older insulation than the over all R-Value must be R-38 or more than that. Once the insulation is added you must take care that the soffit and eave vents are not blocked. The Kraft facing is one kind of vapor retarder. If this is added, it must be in contact with the heated ceiling of the house.
If loose fill insulation is installed in the house than it must be leveled and smooth and must have a uniform R-Value throughout the house. The bag count specified by the manufacturer must match exactly to the number of bags used to in order to have that desired R-Value. Before installing the loose fill insulation the needs of baffling and damming must be reviewed.
In case of batt insulation type same procedure must be repeated as in case of loose fill insulation. Here also there is no need of vapor retarders. In case if the attic is not insulated any time before than batt insulation with vapor retarders available in the market must be installed. But as specified earlier they must be in direct contact with the ceiling.
Batt can be cut very easily to fit in the place as per the requirements. They must be fitted close to each other so that no gap is left behind. Only where heat producing areas are there, a little place must be left around them. If possible try to put a row of batts in between the joists and another one upper to the previous one but at right angle to it. If your house consist of lower ventilations, baffling is extremely necessary so that the insulation is not wind washed.
If you have a flat with open attic or if it has attic knee walls, both the kind of insulation will work effectively, the spray foam and the rigid foam. But they must be in accordance to the R-Value specified and may also be in contact with the heated ceiling. As per the jurisdictional building codes of Oregon the insulation must also meet the ignition barrier requirements in case of plastic foam.
If you are insulating on the top of roof sheeting than all the cavities in the ceiling must be rigidly insulated to the highest possible value. The over all insulation must be equal to or more than R-19. The specified value for ceiling cavity insulation must be minimum R-19 value. The ratings for insulating the cavities of recessed lights must be IC or ICT. It is also necessary that all the vents in plumbing, the fans of bath and kitchen are vented outside new roof.
During the process of quality control checks you are required you present them the name of manufacturers of that insulation and the information regarding the use by date of it. So you must have a detailed record of this.