Granada Hills, CA · April – August 2022 · LADWP / LADBS

The wood under the array was rotten.

Thirty squares of covering came off this roof, and what was underneath had to be replaced before a single mount went down.

An array is held down by fasteners into the roof structure, and each one carries uplift for the life of the system. Rotten wood will hold a lag bolt — for a while. There is no way to check the substrate from outside a finished roof, which is why the only cheap moment to find it and fix it is while the covering is off.

At a glance

System

6.00 kW DC / 5.55 kW AC

Modules

15 × REC400AA Pure Black, 400 W

Microinverters

15 × Enphase IQ7PLUS

Roof covering

30 squares, composition shingle

Found underneath

Rotten wood, replaced before mounting

Priced

As a separate line, once the extent was known

Permission to operate

11 August 2022

Utility / AHJ

LADWP / LADBS

The story

The array on this house is six kilowatts, fifteen modules, one plane. It is not the interesting part. The interesting part is what was found under the covering when it came off.

A finished roof tells you nothing about its substrate. From the driveway, from a drone, from a satellite image, composition shingle with sound wood underneath and composition shingle with rot underneath look identical. There is no inspection that sees through it and no measurement that reveals it. You find out when the covering is removed and not one day earlier.

Here the covering came off — thirty squares of it — and the wood underneath had gone in places. It was replaced before any mount went down.

Why this cannot be deferred: every attachment holding an array is a fastener into the structure, and its job is to resist uplift for twenty-five years. Wind does not pull steadily; it works a fastener loose over seasons. Sound wood holds. Wood that has been wet holds too, at first, which is exactly what makes it dangerous — the failure does not announce itself at installation, it announces itself in a storm some years later, and by then there is an array on top of the problem.

The commercial detail is worth as much as the technical one. The wood replacement was priced as its own line, separately, once the extent was known — not folded into the original number. That is the right way round, and the reason is simple: nobody can quantify rot through a roof. A contractor who prices it in advance is either padding the job against a risk that may not exist, or absorbing one that might be much larger than expected, and neither serves the owner.

Ask for it that way. When a roof is being opened, the sequence that protects you is: quote the known work, open the roof, look, price what is found as a separate item with the quantity stated, then proceed. What you are buying with that structure is the ability to see the number rather than take somebody's word for a contingency.

The array that went on afterwards is ordinary and that is the point of doing the boring part first. Fifteen REC 400-watt modules on fifteen Enphase microinverters, split eight and seven, at 18 degrees, three hundred and fifteen square feet of module on a roof of two thousand six hundred.

Permission to operate came on the eleventh of August 2022, and a year later the owner came back to price a battery — which is the ordinary sign that a job went the way it should have.

One line to take away, whatever you are having done: if the covering is coming off anyway, that is the only moment the structure underneath is visible, and the only moment fixing it is cheap. An array installed over a substrate nobody looked at is a problem with a twenty-five-year fuse on it.

Cali Energy cut the rot out and replaced it before a rail went down, and this Granada Hills array has run since August 2022. The electrical side of the same project is on a new panel with a bigger busbar.

How it ran

The covering came off first. That is the only reason anybody saw the wood.

What we did

• Replaced the roof covering before the array went on, 30 squares, permit closed out.
• Found and replaced rotten wood in the structure while the covering was off.
• Priced the wood replacement as a separate item once the extent was known.
• Set fifteen modules on fifteen microinverters over a substrate that had been checked.
• Carried the project to permission to operate in August 2022.

System specifications

Is your project like this one?

• Your roof is near the end of its life and solar is on the table.
• You have been quoted a contingency for unknown roof repairs and want to know how it should work.
• You are wondering whether the substrate under your covering has ever been looked at.
• You want the roofing and the solar under one contract rather than two.
• You are comparing quotes and one of them is cheaper because it assumes nothing is wrong.

Cali Energy in Granada Hills

Frequently asked questions

Can rotten roof structure be detected before the covering comes off?

Not reliably. A finished roof hides its substrate completely, and no survey from outside sees through it. Sagging or staining inside can hint at it, but plenty of rot gives no sign at all. The covering coming off is the inspection.

Why not just mount the array around the bad wood?

Because an attachment has to land in sound structure and the layout is driven by the array, not by the damage. Working around it also leaves the rot in place under a roof that now has a system on it, which turns a cheap repair into an expensive one later.

How should wood replacement be priced?

Separately, with the quantity stated, once the roof is open and the extent is visible. Nobody can measure rot through a covering, so a number given in advance is either padding or a gamble. Quote the known work, open the roof, then price what is found.

Does this delay the project?

Usually by days rather than weeks, if the covering was coming off anyway. What causes real delay is finding it after the array is mounted, because then the modules and the racking have to come off before anybody can reach the wood.

Does Cali Energy check the roof structure before installing in Granada Hills?

Yes, and it is the reason to do the roof and the array together. Once the covering is off, the sheathing underneath is visible for the only time in twenty years. On this Granada Hills roof Cali Energy found rot, had it cut out and replaced before any racking went down, and only then set the array over it.

What this would look like on your roof

Related

• The panel came out. What went back has a bigger busbar Granada Hills, CA · 6.00 kW DC · 225 A busbar, 70 A of headroom left Solar
• The roof was measured before anything was quoted Studio City, CA · 12.95 kW · survey, then a 27-square re-roof, then the array Solar
• A hundred square feet of roof, and the array had to come off first Studio City, CA · one square · modules off, roof replaced, modules back Solar
• A roof, and nothing else. Here is what eighteen squares buys North Hollywood, CA · re-roof only · no array Solar

This timeline reflects this property and this permitting path. Updated September 2026.