Modified Bitumen (MOD) roofing systems are a petroleum-based roofing system in which mastics are heated to a liquid state, applied to felt, and then bundled into rolls which are either mopped or torched onto the roof substrate.

Common Problems

Any petroleum based roofing system is constantly curing. The solvents that keep it pliable are continually evaporating. Exposure to ponding water and UV radiation accelerate this process. In a MOD, when the solvents evaporate, the layers begin to delaminate; the system shrinks, cracks, and blisters.

Standing Water

Standing water is a very adverse condition for a MOD as the presence of water dramatically accelerates the curing process, and also attacks the seams. If the existing roof deck is not sloped appropriately or if there is no tapered insulation system to promote positive drainage, the existence of standing water will shorten the lifespan of the roof.

One indication that water has penetrated the membrane of a modified bitumen roofing system is the appearance of “blisters” on the roof’s membrane.

Edges and Flashings

MOD is a very rigid roofing system, and installers need great care and skill to effectively waterproof a horizontal to vertical transition. Even in well-installed systems, the details are frequently compromised by building movement and seam failure.

With a MOD, penetration flashings are commonly problematic. This is primarily due to the use of rigid and dissimilar materials to make this critical transition. As the mastic used to seal the seams in the MOD ages, it loses its ability to absorb the building movement pulls it apart.

Our Best Recommendation

For a permanent, warranted solution, we recommend installing a complete mechanically-fastened Springfield SmartRoof™ System.

The Springfield SmartRoof™ System is entirely maintenance free.* Certified Springfield technicians will install this system, and completed in strict accordance with the manufacturer’s specifications. It will be 100% inspected by the Springfield Team, and then by an inspector from the manufacturer. The manufacturer will then award a full 20-year warranty, which is the best on the market.

Springfield Smart Roof*Annual inspections and debris removal are recommended and included at no charge for the first two years of your roof’s life. These inspections help us track the performance of your roofing system and also keep abreast of any new developments that could occur over time. Please contact your Project Manager to schedule your inspections.

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