H & I Steel Column Penetration Waterproofing for Metal Roofs in Saudi Arabia

Why column penetrations are so hard to seal

An H or I section is the worst possible shape for a traditional seal. Water runs down the flanges, gathers in the inside corners and finds any gap along the web. When the roof sheets are cut to let a column or frame through, the opening is usually rough and oversized, then filled with sealant, foam or a cement collar. None of these stretch, so they part company with the steel as soon as it starts to move.

And it does move. Rooftop plant platforms and AC frames carry heavy, vibrating equipment, and the steel heats and cools at a different rate from the sheeting around it, especially in Riyadh, where fierce summer days give way to much cooler nights. A seal that cannot flex with that movement opens up within a season. EPDM bonded with Promax Bonding Adhesive is made to take this expansion and contraction while holding at surface temperatures up to 120 °C.

Signs of a failing column penetration

• Water tracking down a steel column inside the building after rain
• Rust at the column base or along the edges of the cut roof sheet
• Sealant or foam that has shrunk back from the flanges
• Cracked cement or mortar collars around support legs
• Stained insulation below AC platforms or walkway supports

Our method for H & I column penetrations

1. Map every supportDuring the free survey our engineer locates each column, frame leg and walkway post that passes through the roof and records its condition with photos.
2. Remove failed fillersOld sealant, foam and broken collars are cut away so the membrane can bond directly to the steel and the roof sheet.
3. Template the profileThe EPDM is cut to follow the flanges, web and inside corners of each section, as well as the ribs of the sheeting around it.
4. Bond and dress the cornersPromax Bonding Adhesive fixes the membrane up the column and across the roof, with the inside corners pressed firmly home where water tends to collect.
5. Inspect and recordEach finished collar is checked for adhesion and photographed for your records.

Materials & workmanship

• 1.2 mm EPDM membrane, flexible enough to follow complex steel profiles
• Promax Bonding Adhesive that tolerates expansion, contraction and surface heat up to 120 °C
• Suitable for supports passing through metal roofs as well as concrete roofs
• Working-at-height crews with full PPE and safety lifelines around rooftop plant

Photos from ETCE projects

Site photos from ETCE projects in Saudi Arabia and Bahrain. Tap to enlarge.

Frequently asked questions