Adding New Roof Insulation Over The Old Insulation

Adding New Roof Insulation Over The Old InsulationWhen was the last time you decided to take the ladder and go up the attic? In most cases, it will be years or in some cases, you would not have gone up at all. But, it might just be the time for roof insulation. Remember, roof insulation keeps the home feeling comfortable and energy-efficient. However, it may be damaged and it could be the time for getting the home re-insulated. You may wonder whether it is possible to add new insulation on top of the old one or whether you need to remove it completely and replace it. Both options are there but it depends on the situation.

Adding New Roof Insulation over the Existing Layers

The new roof insulation can be added over the old layers of insulation unless it is wet. In case if it is wet or you can observe that the old insulation has been wet previously you need to take into consideration the reason for the wetness and then repair the issue. Wet insulation can be troublesome as it leads to mold mildew and many times rotting of roof rafters or the whole ceiling. In most cases, the roof installation professionals will handle the situation for you. However, keep in mind some tips about removing older insulation and installing the new one over the old one.

  • You should not place faced insulation on top of the existing insulation inside the attic. When you try to install batt insulation or new roll on top of existing insulation inside the attic it has to be done without a face or vapor retarder. The face has to be placed on top or between various layers of insulation and can trap the moisture. All the existing roll or batt insulation in the attic should be facing the attic drywall flooring or otherwise not facing at all.
  • The blown loose-fill insulation also called fiberglass or cellulose insulation or rolled and batt insulation may be installed over the old insulation.
  • The roof insulation must be rolled out perpendicular to the joists and here you need to use unfaced rolls.
  • It is not necessary to track down the rolled insulation. R-value may be reduced when the insulation is flattened or squashed.
  • It is significant to test the vermiculite insulation found in the attic. In case this test reveals the presence of harmful chemicals, the vermiculture needs to be removed by certified professionals before you install more insulation.
  • It is highly recommended to use air seals before installing new insulation as the air leaks will hinder the insulation performance and decrease the insulation performance. It will also decrease energy efficiency significantly and as a result, reduce the comfort levels of the house.

The Best Time for Roof insulation

The best time to do the roof insulation is when you are replacing the roof. It is typically true when you are installing rigid foam insulation. You are required to tear off the shingles for accessing the sheathing anyway. In many cases, the roofers help with blown-in insulation also. They just remove a small piece of decking and bring in the hoses from the rooftop. It might be a good idea to ask the roofer about the services they are providing.


After all this, it is important to remember that there is no need to worry about doing all this on your own. Insulation professionals such as Done Rite Insulation can do this in the Tampa, FL area for you. They will reply to all your queries about placing new insulation on top of the existing insulation. They can also handle the whole project from scratch.