Diamond Recover is our roof over roof recovery program and used when the integrity of the roofing membrane is no longer reliable yet the roof is still viable. Roof replacement involves removing all existing roof material down to the roof deck, including vapor barrier, insulation, membrane and flashing.
In some situations, it may be viable to leave the existing roof including the membrane in place and install a new membrane over the top. Roof recovery is promoted as being environmentally friendly and, with its inherently low cost, is often chosen as a viable alternative. However roof recovery is not always viable, so it's important to Hire a Professional Contractor that understands these concepts to help guide your decision...
The performance of the membrane in a roof recover option will only be as good as the substrate.
Therefore roof recover should never be undertaken where the existing roof, insulation or deck is known to be unsound.
A roof recover should not be done over an existing wet roof or roof containing wet insulation.
While surface moisture can be easily detected and dried, the detection of moisture in the insulation will require the
use of non-destructive testing such as infrared thermography. Wet areas should be replaced with dry insulation before
a roof recover is carried out. The cost of such replacement should be included in the contractor's price.
If the amount of wet insulation is excessive, it may be more cost effective to just replace the whole roof.
Most recover options will require the use of insulation on the existing roof prior to installing a new membrane.
This new insulation will provide a smoother base for the installation. Prior to the application of insulation all irregularities
in the existing roof should be removed. The insulation should be applied over a reasonably even surface and with
enough asphalt or mechanical fasteners to prevent lateral movement. Some membrane manufacturers recommend special insulation and fastening methods for roof recover which should be used for the warranty to be valid.
The addition of new insulation and membrane creates a new plane for vapor condensation in the system.
The recover option should be evaluated and any detrimental condensation should be reduced by changing the design.
The height of the curbs, perimeter, joints, drains and other penetrations
will need to be raised to accommodate the additional material thickness of the roof.
This will add cost to the roof recover option. Unfortunately many contractor's skip this step to keep their estimate low,
but it dramatically reduces the life expectancy of the roof - so it's important to consider the future costs associated
with having to prematurely replace your entire roofing system.
One condition that cannot be practically evaluated without removing the existing roof is the condition of the deck.
Often in place where the roof insulation has been wet, the deck may be deteriorated or rusted and may need replacing.
If a roof is recovered there remains a risk that potential areas of deteriorated deck will go unnoticed and my cause
future problems. Other unknowns include the extent of wet insulation and the adherence of the existing
roof to the deck. Although the risks associated can be minimized as much a possible,
it's important to understand they may never be eliminated completely.