Roof Ridge Tape: Why It's the First Line of Defense Against Moisture and How to Install It Correctly
The roof ridge: a small element with a very big role
The roof ridge is the highest line where two roof slopes meet. This point is exposed to the greatest weather stress — water, snow, wind, and sun all "meet" right here. It's no surprise, then, that the ridge is the most common source of leaks and damage, especially on older roofs or ones installed less carefully. Roof ridge tape is the element that protects this vulnerable spot and keeps rain and moisture on the outside.
The Alenor roof ridge tape 310mm x 5m (RAL 8004) is a product specially engineered for sealing the roof ridge. It's a flexible tape with a butyl rubber base and an aluminium-polymer surface layer that withstands large temperature swings and UV radiation. The brown RAL 8004 colour is the most popular roofing finish colour in Latvia — the tape blends visually with the roof without disrupting its overall look.
Why roof ridge tape is necessary
The risk of water leaks without sealing
Without quality ridge tape, water can get from one roof slope under the other — especially during heavy rain or when melting snow creates runoff. Using metal or ceramic ridge caps without additional sealing is often not enough, since small gaps remain between the ridge caps and the roof covering. It's exactly at these points that wind drives water underneath the roof, damaging the rafter system, the insulation, or even the ceiling structure.
In Latvia, with its frequently changing weather — sudden heavy rain, ice forming during freeze-thaw cycles, strong wind — protecting the roof ridge matters even more. Alenor's ridge tape is engineered exactly for these conditions — it stays flexible from -30°C to +100°C and is UV-resistant, meaning it will last for years without needing to be replaced.
Preventing air leaks
The roof ridge isn't only a water-entry risk — it's also a source of air leaks. If the roof structure lacks sufficient ventilation, or if the ridge isn't sealed, cold air can enter the attic space, increasing heat loss. Ridge tape forms a physical barrier that prevents both water and air transfer through this critical point — helping to keep the house warm and reduce heating costs.
How to properly install roof ridge tape
Surface preparation
Quality installation starts with surface preparation. The ridge area must be cleaned of dirt, algae, moss, and loose material. If there are old sealant residues or cracked material on the roof, they must be removed. If the surface is porous or absorbent, it can be treated with ALENOR SUPER FIX primer to improve tape adhesion. The surface must be dry — installation should be done in dry weather, at least 24 hours after rain.
Applying the tape
Apply the tape symmetrically across the roof ridge — half the tape's width on one slope, half on the other. The 310mm width is optimal for most standard roofs: it provides wide enough coverage on both sides to prevent water ingress even in strong wind. Apply the tape evenly, without wrinkles, pressing firmly with your hand or a pressure roller to ensure good contact with the roof surface.
Longer sections of tape should overlap by at least 50mm, keeping the joint airtight. If the tape is applied in cold weather (below +10°C), it's recommended to warm it slightly with a heat gun so the butyl rubber becomes more flexible and bonds better. It's best to start from one end and work steadily along the whole length of the ridge, applying even pressure.
Renovating existing roofs
Ridge tape is especially useful when renovating older roofs where the original ridge solution has worn out or been damaged. It can be applied directly over the existing roof covering — there's no need to fully remove the old ridge. This significantly reduces renovation costs and time. The tape also keeps the roof protected during the transition period, while a full roof repair is pending.
Ridge tape and the overall roofing system
Roof ridge tape is one of several elements in a complete roof insulation and waterproofing system. It's excellently complemented by Alenor BF butyl tape for joints around chimneys, roof hatches, and other penetration points, as well as the Alenor Repair Patch for small local damage or gaps. Using this full combination of products makes it possible to build a complete roof waterproofing system whose service life is measured not in years, but in decades.
Conclusion: start at the top — and everything else follows
Properly sealing the roof ridge is the foundation of the whole roofing system's durability. It's a relatively inexpensive investment that prevents a far more costly risk down the line — moisture damage to the rafter system, mould in the insulation, or stains on the ceiling. Alenor's roof ridge tape is available online with delivery across Latvia. Check out Alenor's full range of butyl products too, and get your roof ready for the next rainy season!
