Here is an example of a roof installation that was doomed to fail the second it was finished. This is about a 10 year old foam roof that was installed over the top of 3 other roofs. When this roof was tore off we found a cockroach infestation. Standing water between layers. And a host of other problems. Had the homeowner obtained a roof inspection prior to the foam roof installation this would have forced the roofing company to tear of all pre-existing roof layers prior to the foam roof installation. In most cases you are only allowed to have one previous layer. This is determined by various factors to include, but not limited to the following:
1. That the roof structure is sufficient to sustain the weight
of the additional dead load of the roof covering.
2. Fire retardant requirements are maintained.
3. The existing roof covering is securely attached to the
4. The roof is structurally sound.
5. The existing insulation (if installed) is not water soaked
6. Roof drains and drainage are sufficient to prevent
extensive accumulation of water.
In this picture it shows the roof layers being tore off and the discovery of water. There had been no recordable rain in at least 90 days.
After a complete tear off, the roof is finished with a new ployurethane roof system. The new roof is properly installed and the homeowner should expect at least 20 years with proper maintenance.