Waterproofing Solution Leaking Skylights

waterproof skylight


The pumping stations skylights were leaking, with water leaking on to switchgear and electrical equipment below.


At a previous site the leaking skylights had been removed and the roof refurbished at a significant cost. We were contacted to provide a cost effective but long term solution. We proposed the application of a seamless polyurea waterproofing membrane from Specialty Products Incorporated (SPI).

The leaking skylights were first cleaned using a high pressure spinning water jet to remove organic growth and contamination. This would provide a clean substate suitable for the application of a polyurea waterproofing membrane.

When dry the skylights were primed with a damp tolerant epoxy primer to seal the fiberglass matrix. We had not originally intended to primer as it is not necessary for adhesion due to Specialty Products Incorporated’s Ultra Bond molecule. However due to the breakdown that had occurred through UV degradation the lights had become porous which would lead to outgassing in the polyurea membrane. Therefore at our cost we decided to prime the skylights to ensure the highest quality.

Following priming the skylight gaskets were detailed using a high modulus polyurethane sealant to isolate points of movement and remove angles that would be difficult to spray.

Only once satisfied with the preparation works did we undertake the application of the polyurea membrane. We had specified SPI Watershield III as it is specifically engineered for roofing solutions with over 900% elongation. This allows the material to accommodate the expansions and contractions that occur through thermal cycling without cracking and splitting.

One challenge that we did face in this project was accessing the skylights. Initially it was thought that the roof was too fragile to be accessed and mobile elevated work platforms (MEWP) were selected gain access. However due the time of year the ground was too soft to allow the MEWPS to be used safely. Therefore following a rough condition assessment it was discovered that the roof could be accessed using crawl boards fitted with guard rails. Working with the main contractor we adapted our process of work and managed to complete the project safely without additional cost to our client.

It is worth noting that we have access to clear polyurea resins from SPI that would allow light to pass if this was required.