This document establishes that the repair cannot be confined to the damaged area. VELUX's FS deck-mount installation instructions (VAS 452197-2020-12) state that "VELUX(R) series A21 skylights are designed and engineered to be installed with VELUX flashing systems," and that each flashing system "include[s] VELUX adhesive skylight underlayment in a quantity sufficient to install one skylight of the size for which the flashing system was designed." The same page conditions the No Leak warranty on use of the underlayment packaged with the flashing system — so a re-flash draws on a new kit's underlayment. The document does not state that underlayment is non-reusable; do not claim that.
System requirement VELUX · Skylights · 2020 · 16 pages
A21 series deck-mounted skylights + VELUX flashing systems / adhesive skylight underlayment
In their own words
VELUX® series A21 skylights are designed and engineered to be installed with VELUX flashing systems. VELUX flashing systems include VELUX adhesive skylight underlayment in a quantity sufficient to install one skylight of the size for which the flashing system was designed.
VELUX — A21 series deck-mounted skylights + VELUX flashing systems / adhesive skylight underlayment, 2020
That sentence is not our characterisation of the manufacturer’s position. It is the manufacturer’s position, in the document below, which you can read yourself in about a minute.
Get the document
A21 series deck-mounted skylights + VELUX flashing systems / adhesive skylight underlayment
Issued by VELUX. Published here complete — no summary standing in for the document, no email required.
Issued by VELUX. Retrieved from veluxsolutions.com, August 2026, and hosted here so it stays available in the version quoted above.
What to do with it
A roof or a wall is an assembly, not a surface. When the manufacturer requires underlayment to lap onto the neighbouring slope, or the water barrier behind siding to be continuous and taped, the damaged area cannot be treated in isolation — and an estimate that prices it that way is describing something that cannot actually be built.
- You have the manufacturer’s document. That part is finished. Most homeowners never get this far, and it is the step a carrier cannot argue with — it is not your opinion, it is the company that made the product.
- Put it in writing, to the adjuster, with the claim number. Attach the document and ask one specific question: name the exact replacement product — manufacturer, line, colour, dimensions, exposure, nail zone, sealant design, supplier, quantity available locally — and who will answer for the repair if it fails. Vague answers are the whole game; a specific question ends it.
- Get the position on the record before anything gets installed. Once a mismatched or incompatible repair is on the building, you are arguing about something already done.
If you want the second and third steps handled by someone who does this for a living, that is what we are for — and the review costs nothing. If you would rather do it yourself, the document above is yours either way. That is the point of publishing it.
Related documents
Other VELUX documents
VELUX residential skylights
Re-cladding and re-flashing a hail-damaged skylight is not a repair VELUX endorses. Units made before 2000 cannot be repaired at all because the parts no longer exist, and fixed units from 2010 on have glazing profiles that changed.
VELUX skylight cladding
VELUX requires full skylight replacement where hail exceeds 2″, or where hail damages cladding sealed directly to the glazing — because the factory weather seal cannot be re-created on a roof.
VELUX current limited warranty
VELUX concedes in its current written warranty that products go out of production and out of version, and that when they do, VELUX substitutes a similar product at its sole discretion rather than matching the original form, color, covering or finish. This is the manufacturer's own acknowledgment that an exact-match repair may be impossible on an older unit.
VELUX Legacy (pre-2010) products
VELUX's archived warranty brochure for pre-2010 products excludes anything purchased before January 1, 2004, and states VELUX may substitute a similar product or component when the original version is no longer available.
VELUX Pre-2010 legacy models
VELUX's Product ID Locations document (VELUX Canada edition, V-CDN-PIDL-E-0524, (c)2024) carries a separate "Pre 2010 Products" table naming legacy models FSF (fixed, ID under the vent flap) and VSC (venting) — neither of which appears on the current-line table — plus roof windows GDL, GPL, GHL, GPU, GGL and GGU (V21), of which GHL, GPU and GGU are legacy-only. For pre-2010 SUN TUNNEL skylights it states there is "No ID for sizing, measure the diameter of the reflective tube."
Other manufacturers saying the same thing
CertainTeed asphalt shingles
The code-evaluation report treats a CertainTeed shingle roof as a complete system — compliant underlayment, the specified starter, hip-and-ridge accessories, and fasteners meeting ASTM F1667. A repair that substitutes non-conforming components does not just look different; it falls outside the report and can forfeit the Class A fire classification.
CertainTeed valleys, walls and chimneys
Open valleys are required for Custom Lok 25 and strongly recommended for Grand Manor, Carriage House, Centennial Slate, Landmark TL, Presidential Shake and Presidential TL — their thickness and multi-layer construction are not designed to bend into a valley. A closed-cut or woven valley repair on those products is contrary to the manufacturer’s own manual.
CertainTeed roof deck spacing
Deck board spacing requirements beneath a CertainTeed roof. Where the existing deck does not meet them, the fix is not confined to the shingles.
CertainTeed vinyl and polymer siding
Vinyl siding is hung, not fixed: nails are centred in elongated slots and driven loose, leaving roughly 1/16″–1/8″ of play so the panel can move with temperature. CertainTeed states that deviating from its requirements voids warranty coverage, and that failing to establish a smooth, solid substrate is itself a misapplication.
The rule this document serves
Your policy promises repair or replacement with material of like kind and quality. That is a replacement-cost and indemnity obligation, not an appearance theory — and it is why “matching” is the carrier’s word, not the policy’s. Where the installed product cannot be bought, or cannot be combined with what is still sold, the covered building cannot be restored to like kind and quality by patching it, and that is true before anyone argues about how it looks. The full doctrine, and the other 125 documents, are on the discontinued materials hub.
You have the manufacturer's document. The next part is the argument. Handing a carrier a technical bulletin and getting it honoured are two different jobs. The case review is free, and you pay nothing unless we recover.
See if my case qualifies 770-230-2616