“Pondering” – Taper roof design.
Does water flow to the roof drains?
What roof slope is needed for drainage?
Is your roof warranty void due to ponds?
How do cover boards benefit roof performance?
How can I specify pre-cut crickets to avoid material waste?
Good questions regarding water and low-slope membrane roofs where slope in the structural roof deck may not be adequate. Tapered roof insulation and crickets are designed to provide effective drainage for EPDM, TPO, PVC and Built-up (BUR) membranes. The CrickEZ™ system helps to simplify roof crickets with Quicket®. Polyiso, XPS and EPS roof insulation all work well with Quicket®.
Since roof drains are rarely placed in the lowest point of a structural sloping roof deck, crickets are usually needed. Columns, beams and supporting walls usually occupy the low points forcing drain placements to be moved further up hill. Without crickets the area between the drain and the wall remains low and collects water. Crickets that are sized longer in this situation will overlap behind the drain and help push water off the wall.
When a long flat valley exists between two drains, Quicket® diamonds are a simple solution when placed under the membrane, effectively pushing water to both drains. Pre-cut diamond sizes can be ordered to match the distance between the drains.
When a long flat valley extends between the drain and the wall, Quicket® twin packs are sized to push water the full distance from wall to drain.
Cricket size and shape is important. Long and narrow crickets may create larger areas of water that ponds. A length to width ratio of 2 to 1 can maximize water flow especially when deck slope is 1/4 inch per foot (2%).
Quicket® can be installed between two layers of roof insulation or placed under an approved cover board. Quicket® is engineered to elevate the membrane surface as the distance increases away from the roof drains and scuppers. Most commercial building codes require ¼” per foot slope of the membrane. Quicket® material slope of ½” per foot combines with and reverses the ¼” deck slope to net a ¼” per foot finished slope.
The additional insulation thickness may require increasing some parapet and curb heights. Fastening treated 2×6 nailers on top of existing curbs or parapets may help re-roofs to accommodate the added thickness. Packages of pre-cut “EZ Shims” are designed to direct water flow around skylights and other small objects up to 7 feet wide.
Insulation cover boards can provide firm membrane support that helps resist hail penetration damage. Cover boards range from 1/4 inch to 5/8 inch thick and can provide additional protection of the roof assembly from construction traffic and in some cases fire.
Polyiso, XPS and EPS roof insulation all work well with Quicket®. Tapered insulation thickness can be accomplished in one single layer when using EPS.
Additional benefits of Quicket® include:
Smooth transition along thin edge avoiding 1/2″ step of other cricket products.
Supplement thermal insulation as part of the building envelope.
Protects roof warranty status when ponds are eliminated. Please review your roof warranty regarding inclusions and exclusions.