Ponded Roof Study

The following photo case study is an interesting example of what happens when permeable membranes are left to hold ponded water for too long. 

In this case, the mod bit membrane let the ponding through to soak all of the insulation immediately beneath it. The thick built up roof system below held most of the water at bay, but over the course of 15 years enough moisture pentrated to rust the deck. To make matters worse, the painted deck hid many huge holes and critical splits from view.


Roofing dynamics was able to save money by restricting the roofer's zeal for total deck replacement while replacing what was necessary.

Severe ponding; bad decking result.

Staggered insulation boards properly fastened.

The immediate insulation below is wet.

Equipment removal. Note clean decking.

First day’s work.

Finished product in first area.

Third day.

Close-up of decking that had to be retrofitted.

Area of equipment removal.

Close-up of decking that had to be retrofitted.

Another example of re-usable existing deck.

Piece of deck that looks ok from below.

Reverse side of same piece of deck. Many were worse.

This is deceiving since both areas are identical in quality.

View from below.

The same area being retrofitted with new decking.

The deck in the upper part of the photo looks ok since roofing covers it.

The new decking is carefully installed.

The insulation is properly fastened and elevation deviations checked.

Finally heat welding.