what's the stuff called that is used in the deep south on flatdeck reroofs, small
pebbles that look like grey and white stones, attached to surface of the topcoat and
also thrown onto the melted tar ?

while the tar was still liquid the crew throws a little of this sand like substance
over the top coating.

does it serve a cosmetic purpose or is it functional in reducing sun exposure to the
surface?

if rain washes away some of this from the surface, is it worth reapplying?

jack wrote:
what's the stuff called that is used in the deep south on flatdeck
reroofs, small pebbles that look like grey and white stones, attached
to surface of the topcoat and also thrown onto the melted tar ?

Pitch and gravel.

--

dadiOH
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dadiOH wrote:
jack wrote:
what's the stuff called that is used in the deep south on flatdeck
reroofs, small pebbles that look like grey and white stones, attached
to surface of the topcoat and also thrown onto the melted tar ?

Pitch and gravel.

Also crushed marble.

what's the stuff called that is used in the deep south on flatdeck
reroofs, small
pebbles that look like grey and white stones, attached to surface of the
topcoat and also thrown onto the melted tar ?

Around here its called a "Tar & Gravel" roof

Also crushed marble.

so I should be able to find crushed marble at local HD or Lowes ?

if rain washes away some of this from the surface, is it worth reapplying?

is it cosmetic or functional (ie. reducing surface temperature) ?

jack wrote:
Also crushed marble.

so I should be able to find crushed marble at local HD or Lowes ?

if rain washes away some of this from the surface, is it worth
reapplying?
is it cosmetic or functional (ie. reducing surface temperature) ?

The main function of the gravel is to reduce UV radiation. UV radiation
degrades the tar.

The light color of the gravel also reflects visible light and tends toward a
cooler roof.

Usually gravel completely covers the roof, but some doesn't contact the tar
and, with nothing to hold it in place, washes off.

To answer your question, re-applying gravel will help. Don't walk directly
on the roof - use wide boards to spread your weight as you maneuver to the
area you want to re-seeding.

jack wrote:
Also crushed marble.

so I should be able to find crushed marble at local HD or Lowes ?

if rain washes away some of this from the surface, is it worth reapplying?

is it cosmetic or functional (ie. reducing surface temperature) ?

Maybe not at the big-box, at least not at a decent price. Local
commercial roofing supply, and/or landscape supply, will have marble
chips. (they are also used to top-dress planting beds, sometimes.) And
on a hot-mop roof, the white chips do reduce the heat load, and disperse
the impact of raindrops. If rain washes it away, your roof sloping and
drains were not done correctly, or the layer of chips is way too thick.
At most, once a year or so, you may need to scrape the high spots over
to the thin spots. The bottom layer of chips should bond to the top
layer of tar on the first few hot sunny days- that is why walking on the
stones is supposed to be kept to an absolute minimum, with walkboards
used for any places on roof that have to be visited on a regular basis.
Any other spots on the roof, you wear soft tennis shoes rather than work
boots, and walk gently.

Note that in current commercial use, they have mostly switched over to
light-colored membrane roofs that do not need any additional topping
material. Just painting the whole roof with a special sealer stuff every
few years, to refresh the fake rubber, and seal the micro-cracks that
the UV creates. More expensive up front than hot-mop, but lasts longer,
and fewer leaks and failures if properly applied. The in-house repair
guys can usually handle the recoating.

--
aem sends...

To answer your question, re-applying gravel will help. Don't walk directly
on the roof - use wide boards to spread your weight as you maneuver to the
area you want to re-seeding.


what is used to make the new marble/rock crush adhere to the dried surface? epoxy?

Note that in current commercial use, they have mostly switched over to light-colored
membrane roofs that do not need any additional topping material. Just painting the
whole roof with a special sealer stuff every few years, to refresh the fake rubber,
and seal the micro-cracks that the UV creates.

that's what this job apparently used but the light colored membrane has microfine
white rocks on the surface. heavy rain washed off parts of it into a small sand pit
under the gutter spout.


I supposed a white rubberized elastomer would also do over the exposed black tar
areas, ie. the exposed areas are very small

jack wrote:
To answer your question, re-applying gravel will help. Don't walk
directly on the roof - use wide boards to spread your weight as you
maneuver to the area you want to re-seeding.


what is used to make the new marble/rock crush adhere to the dried
surface? epoxy?

When the tar gets hot, it get sticky.

I guess, if you want, you can glue each pebble in place. Epoxy is good.