Can a roof be cleaned right after the pavers were sealed?

The first question is not about the roof at all. It is which sealer went on the pavers, and whose label that sealer carries, because every waiting period on this page belongs to that label.

A sealer is a product, not a category with one set of rules, and how soon water may reach a freshly sealed surface is set by the company that made it. The invoice or paperwork from the sealing job may name the product, and the installer who applied it can say what it was. No document read for this page publishes a separate rule for water coming off a roof onto a sealer that is still curing, so the label is the only source that speaks to that surface directly.

Beneath every label sit the general lines in ICPI's Tech Spec 5, and they do not replace the label. It says to “Prevent all traffic from entering the area until the sealer is completely dry, typically 24 hours.” It also says that “Water based sealer curing time will vary with the temperature, wind conditions and humidity.” Those are two different finish lines, dry enough for feet and tires and fully cured, the difference the cure time entry defines. ICPI's word is typically, and for a water-based sealer a humid, still day is the kind of condition its curing sentence names.

One maker's warning shows what moisture can do to a sealer. Techniseal tells readers of its product guide to wait until pavers are dry before applying one of its Protectors, because “The Protector could react with moisture and leave a white film on the surface.” That sentence is about moisture under a sealer as it goes on, which is the subject of sealer applied to wet pavers, but it names the result a homeowner is trying to avoid: a white film where a clear finish should be.

A roof drains onto whatever is below it. Cleaning solution, rinse water and the loosened growth all run down the slope and off the eaves, and a driveway, walkway or patio under that edge receives the runoff.

No source measures what that runoff does to a curing sealer. It is reasoning from the way water moves, and it is enough to put the roof on the wrong side of the sealer's clock: water arriving from the eaves reaches the same surface a rain shower would. How soon rain itself can fall on a new coat is set out under how soon rain can follow a sealer.

The chemistry is a separate matter from the timing. ICPI's stain guidance for concrete pavers lists household bleach as the treatment for leaf, wood rot or tobacco stains, so bleach is not a foreign substance to a concrete paver. That says nothing about a sealer film that has not finished forming, and whether roof runoff marks the pavers at all is argued under whether roof cleaning stains pavers.

ICPI's site instructions point the same way. It tells anyone cleaning or sealing pavers to turn off all automatic sprinkler systems during cleaning, sealing and drying. That instruction treats stray water on a drying surface as something to stop at the source. Water from a roof overhead is one more source, even though ICPI never names it.

ICPI says who to ask about a sealer that has clouded, and the answer is not a cleaning.

Tech Spec 5 names the conditions under which a sealer can turn cloudy and says that a clouded sealer must be removed or re-dissolved. Its next sentence is the routing: “Consult your sealer supplier for advice on treating this situation.” Those causes are set out under why sealed pavers turn white or cloudy, and the faults ICPI attaches to the application day itself are under the conditions, faults and limits of paver sealing.

When both jobs are still ahead, the order does the work. ICPI asks for at least 24 hours without moisture or surface dampness before most sealers go on, and a roof wash sends water onto the pavers under it, which is why the reasoning on cleaning the roof before the pavers lands on the roof first.