Roof Coat

The pale patches are not dirt. They are the fiberglass mat showing through where the granules have worn off, and they run across every tab in the frame rather than collecting in one wind-scoured corner. Granules are the shingle's sunscreen. Once enough of them are gone, rejuvenating oil has nothing left to protect — which is the whole reason this roof got a film instead of a treatment.

The hip tells the other half of it. Somebody had been walking this roof with a tube of sealant, dabbing the cap shingles one at a time. Spot repairs like that are a homeowner buying months. They are also a fair sign the roof has stopped being weathertight on its own and needs a decision rather than another dab.

Later the same day, before a drop of anything was sprayed: the flue is already wrapped and taped. Masking is most of the morning on a coating job and it is the part nobody photographs, so here it is.

Up close the film sits on the shingle instead of flattening it. Every butt line still reads, and so does the wear underneath, because the coating follows the surface it is on rather than burying it. A roof that has been coated should still look like a roof.

Where the film stops matters as much as where it goes. Trim, flashing, and wall lines get masked before the first pass, so the edge is a cut line instead of feathered overspray on someone's fascia.

So the two halves got two different jobs on the same visit. Left of the ridge, oil going into the shingle. Right of it, a white elastomeric going on top of the rolled asphalt — over the field and over every lap, because the laps are where a rolled roof gives up first. The crew member in the frame is standing right on the line between the two scopes, roller pole in hand, with the pail beside him.

The drone went up while the coating was going down, so the shingle side in these frames is just the roof. The oil went on the same day. What a fresh pass of it looks like is on the rejuvenation page, not here.

That is one deck, one sun, one moment, photographed with the job half done. Nothing separates the two halves except the film. The bare side is a gray-brown mineral cap sheet, and it spends a Ventura County afternoon taking in what lands on it. The white side turns a good deal of the same sunlight straight back off the roof instead of letting it become heat in the deck.

We are not going to put a number on your cooling bill. What the roof does with the sun is one input; insulation, whether the ducts run through the attic, and which way the house faces are the rest of it, and none of those are ours to promise. On a low-slope deck with rooms directly underneath, though, it is a difference people feel from inside. It is also why low-slope roofs are the ones California regulates for reflectivity statewide, while most pitched shingle roofs around here are barely regulated at all.