At a Glance: 5 Key Aspects of Counter Flashing Installation
- Upper Seal in a Two-Part System — Counter flashings are the upper, wall-integrated element that seals over base flashings, completing the junction waterproofing.
- Essential for Chimneys and Walls — Counter flashings are critical on chimney stacks, parapet walls, and any masonry element penetrating the roof.
- Mortar Joint Integration — Correct installation requires cutting chases in masonry mortar joints and sealing with flexible pointing compound.
- Material Options — Lead, aluminium, and self-adhesive counter flashings are available; Bestcare advises on the most appropriate choice.
- Nairobi, Kiambu & Kenya — Counter flashing installation services available across Greater Nairobi, Kiambu, and major towns throughout Kenya.
Complete the Waterproof Junction: Counter Flashing Installation by Bestcare
In a properly detailed roof-to-wall junction, there are two layers of flashing: the base flashing (which turns up the wall surface) and the counter flashing (which turns down over the base flashing from a mortar chase in the masonry above). Together, these two elements create a watertight junction that accommodates the different movement characteristics of the roof structure and the masonry wall. Bestcare Facilities Management provides professional counter flashing installation services in Nairobi, Kiambu, and throughout Kenya.
Counter flashing installation is one of the most technically demanding aspects of roofing work, requiring precision masonry cutting, correct lead or aluminium forming, and careful mortar pointing to create a seal that will last for decades. Bestcare’s technicians are trained and experienced in this specialist work.
Bestcare’s Counter Flashing Installation Process
Masonry Chase Cutting — A chase (groove) is cut into the mortar joints of the adjacent masonry wall at the correct height above the base flashing.
Counter Flashing Forming — The counter flashing is cut and formed to the correct profile, with a turned-up leg that seats into the chase and a turned-down leg that overlaps the base flashing.
Chase Insertion and Securing — The upper leg of the counter flashing is inserted into the chase and secured with lead wedges or fixings.
Mortar Pointing — The chase is sealed with a flexible mortar or pointing compound that prevents water entry while accommodating thermal movement.
Base Flashing Integration — The lower edge of the counter flashing is checked for correct overlap with the base flashing below.
Estimated Costs of Counter Flashing Installation in Kenya
| Service Scope | Property Type | Estimated Cost (KES) |
|---|---|---|
| Counter Flashing Installation | Per 3 linear metres | 7,000 – 15,000 |
| Chimney Counter Flashing Set | Single chimney | 12,000 – 25,000 |
| Parapet Counter Flashing | Per 10 linear metres | 15,000 – 32,000 |
| Full Wall Junction Counter Flashing | Per elevation | 18,000 – 45,000 |
| Counter Flashing Repair/Replacement | Per 3 linear metres | 6,000 – 13,000 |
| Counter + Step Flashing Package | Per 5 linear metres | 16,000 – 35,000 |
Prices are estimates. Contact bestcareservices.co.ke for a tailored quote.