Concentrated runoff can stain a lower roof, carry debris, remove granules and increase moisture around walls and flashing. Malarkey recommends directing upper-level downspouts toward the lower gutter with a suitable trough or enclosed connection
Malarkey technical bulletin: Draining of One Roof Onto Another.
What this means for your roof
Concentrated runoff can stain a lower roof, carry debris, remove granules and increase moisture around walls and flashing. Malarkey recommends directing upper-level downspouts toward the lower gutter with a suitable trough or enclosed connection. Its manufacturing-defect warranty does not turn drainage-design damage into a covered defect.
A useful question for your contractor
Ask where each upper downspout discharges and whether the proposed drainage detail keeps concentrated water off the shingles.
Ask for the answer to be tied to the actual roof condition and the exact product being installed. Keep the agreed repair or installation detail with your estimate and project photos.
Bulletin edition: August 2026. The date shown identifies the manufacturer document used for this summary.
Read Malarkey: Draining of One Roof Onto Another
This homeowner summary explains the cited bulletin. The complete manufacturer document and current product instructions govern the installation details. A requirement for one manufacturer or product should not be transferred to another without checking.
Discuss your roof with Barnes N’ Roofs
Cover image: Malarkey, from the linked manufacturer bulletin. Read the complete source for the full detail and its limitations.