Examination no. 07 / sequence

Granules and the Age of Your Roof

The reason a good screen guard sometimes disappoints has nothing to do with leaves and everything to do with the surface directly above it.

What an asphalt roof is doing all the time

An asphalt shingle is a mat saturated with asphalt and surfaced with crushed mineral granules. Those granules are not decoration. They are the shingle's sunscreen: they take the ultraviolet load so the asphalt underneath does not dry out and crack.

They also come off. A new roof sheds loose granules heavily in its first season, which are simply the ones that were never firmly bedded. Then the rate settles down for most of the roof's life. Then, as the asphalt hardens and loses its grip, the rate climbs again, and by the last years of a roof's service life it is shedding steadily every time it rains.

All of it goes into the gutter. Every one of those granules is sand sized, angular and heavy, and every one of them arrives at the exact place a gutter guard is fitted.

A large roof plane stripped back to bare wooden plank decking studded with old nails, with scraps of felt caught between the boards and a mounded pile of loose tan mineral granules in the foreground, a figure bent over at ground level beyond the roof beside a neighbouring grey house, other houses, a car at the kerb and bare winter trees under a clear blue sky — **Plate 9** · The pile in the front of this frame is loose mineral granules swept off a roof during a tear off. That is the material a fine mesh guard has to keep passing water through, and this is what a roof at the end of its life had been putting into its gutters, a rainstorm at a time, for years before anybody stripped it.

What you will be told

Get the guards on now and you are covered whatever you do about the roof later.

What happens on the roof

This gets the order backwards for two separate reasons, and both cost money.

First, a roof approaching replacement is producing the heaviest grit load it will ever produce. Fitting a fine mesh into that is fitting a filter to its worst possible input. It will blind faster than it would on a roof with life left, and the owner will conclude, wrongly, that the product was rubbish.

Second, a tear off means everything at the eave gets disturbed. A guard tucked under the shingle course has to come off before the course above it can be stripped, and going back on is another labour line. Paying to fit, remove and refit inside a couple of years is a straightforward waste.

The order that saves money

Roof has years leftFit the guard whenever the gutter itself is right. The grit load is at its lowest and most predictable point, which is when a fine screen performs best and lasts longest.

Roof is close to replacementWait. Clean the gutters this year, replace the roof, then fit guards onto the new assembly. The gutters are already accessible while the crew is there, which is the cheapest moment in the whole cycle to do gutter work at all.

Roof has just been replacedThe best moment there is, with one small caveat. A new roof sheds its loose surface granules through the first season, so if a fine mesh is going on immediately, expect the first spring check to find more grit than the second one. That settles.

Roof age unknownFind out before buying a guard system. It is a single inspection, and the answer changes the recommendation more than any other input.

Broad expanse of a newly laid brown, tan and charcoal multi tone architectural shingle roof with a capped ridge and dark ridge vent along the right side, two black box vents and a metal flue near the far end, and a back yard with a large tree, a chain link fence and a neighbouring roof below — **Plate 10** · A finished replacement. This is the point in a house's life at which a gutter guard makes the most sense: the surface above the trough is new, the grit output is about to fall to its lowest sustained level, and the eave has just been worked on so nothing has to be disturbed twice.

How to tell where your roof is, from the ground

Look in the splash zone. At the bottom of a downspout, or on the ground beneath one, granules collect as a small drift of coarse dark sand. A little is normal on any roof. A visible accumulation that rebuilds after every storm is a roof shedding at the far end of its life.
Look for a change in colour. Patches where the shingle reads darker or shinier than its neighbours are patches where granule cover has thinned enough to show the asphalt underneath.
Look at the shingle edges. Cupping, curled corners and edges that have lost their straight line mean the mat has dried and is deforming.
Do not judge by the gutter alone. A gutter full of grit tells you granules are coming off. It does not tell you whether that is a new roof shedding loose surface or an old one giving up, and those two lead to opposite decisions.

Why this desk keeps saying it

Guards and roofs are sold by different companies with different incentives, so nobody in the transaction is naturally responsible for the sequence. Keys does both, which is the only reason this page can be written without it costing somebody a sale. If your roof is close, the honest recommendation is to spend nothing on guards this year.

Once the sequence is settled, the remaining decision is which family of guard suits the trees over your house: the screen guards, or a reverse curve hood, which is the one option that does not blind at all.

Keep going

Granules and the Age of Your Roof

What an asphalt roof is doing all the time

The order that saves money

How to tell where your roof is, from the ground

Why this desk keeps saying it

Tell us how old the roof above the gutter is