Smoke Vent, Roof Hood and Exhaust Cowl Waterproofing in KSA

Smoke vents, roof hoods and exhaust cowls are among the largest objects on an industrial metal roof, and smoke vents alone typically range from about 2 x 2 m up to 4 x 4 m. That size turns them into a dam for rainwater running down the slope. ETCE waterproofs these units by wrapping all four sides of the upstand in EPDM, held in place with Promax Bonding Adhesive.

Across Saudi ArabiaUp to 15-year warrantyFree roof survey

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SASIB – Dammam

Why large roof vents collect water and leak

Rain running down a metal roof meets the upslope face of a smoke vent and has nowhere to go. It pools there, and the longer it sits, the more chance it has of finding a way in, through the side laps of the sheets beside the vent or through the vent's own base joint. Standing water also rusts the steel upstand from the outside, and in Eastern Province humidity that corrosion spreads quickly into the surrounding sheets.

Sealing the obvious crack does not fix a detail that ponds by design. Wrapping the upstand completely on all four sides with flexible EPDM turns the vent base into one continuous waterproof skin, so pooled water has no joint to enter and no bare metal to rust. One point is worth making clear from the start: our warranty covers the areas we treat. Leaks through a vent's louvres come from its internal gutter system and need to be corrected by the vent supplier.

Signs of trouble around smoke vents and hoods

Water or mud left pooled on the upslope side of a vent after rain
Rust along the lower edge of the vent upstand
Leaks inside directly beside or below a vent opening
Cracked sealant where the vent base meets the roof sheets
Wet insulation around the vent kerb inside the building

How we waterproof smoke vents and roof hoods

Inspect the unit and surroundingsThe engineer checks the base, neighbouring side laps and louvres, and the report separates leaks we will fix from those for the vent supplier.
Clear and cleanPonded dust and debris are removed and rust is cleaned back on the upstand and adjacent sheets.
Measure and cut1.2 mm EPDM is cut to each side of the unit, with enough extra to lap onto the roof sheet.
Four-side wrapThe membrane is bonded to all four sides with Promax Bonding Adhesive, with extra care on the upslope face where water collects.
Close corners and jointsCorners are closed and edges sealed so the wrap forms one continuous skin with no open seams.

Materials & workmanship

1.2 mm EPDM membrane covering all four sides of each vent or hood
Bonded with Promax Bonding Adhesive, which is rated to 120 °C roof surface heat
Protection of the steel upstand against rust from standing water
Warranty applies to treated areas; louvre leaks sit with the vent supplier

Photos from ETCE projects

Smoke Vents & Roof Hoods - SASIB, Dammam

Smoke Vents & Roof Hoods - Saudi Arabian Industrial & Trading Co. Ltd., Dammam

Smoke Vents & Roof Hoods - Salama Radiator Factory, Dammam

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

Frequently asked questions

Why wrap all four sides and not just the leaking one?

Water ponds on the upslope face, but wind can push it sideways and it can also track along the side laps next to the vent. A four-side wrap removes every joint around the base, so the leak cannot simply move to the next side.

Our vent leaks through the louvres. Can you fix that?

Louvre leaks usually come from the vent's internal gutter system, which is part of the manufacturer's equipment, so they are outside our warranty and should be handled by the vent supplier. We point out any we find during the survey so you can raise them with the supplier.

Do you also treat exhaust cowls and roof hoods?

Yes. Any unit that stands up from the roof and blocks the flow of water behaves in much the same way, so hoods and cowls get the same assessment. The report specifies the treatment for each unit on your roof.

Will the EPDM affect how the smoke vent opens?

The membrane goes on the fixed upstand and base, not on the moving parts, and we keep the opening mechanism clear. We still recommend that your fire-safety contractor checks operation during their normal servicing.