Rusted roofscrews

[des04]

Hi

In 2010 we had solar panels installed by a company called Solar Farmers. Two weeks ago we received a letter from Solar Farmers warned us that they found rusted roof screws on houses where they installed solar panels around Gladstone. The issue was in the media.

I checked a few days ago that the roof screws on the roof were rusted. Do you think what the rusted screws was as a result of poor workmanship or due to hostile corrosive atmospheric conditions?

I am considering lodging a submission to the office fair and trading.

What do you think?

Thanks

[Mike90250]

If panels are expected to have a service life of 20-30 years, all the hardware should have the same service life. Heavy zinc coating might last, but I would expect to see stainless steel for that long life. Some stainless can develop surface rust, but nothing deep. It's all on the installers head, unless you signed a paper calling to save $10 by using plain hardware.

[solar pete]

If panels are expected to have a service life of 20-30 years, all the hardware should have the same service life. Heavy zinc coating might last, but I would expect to see stainless steel for that long life. Some stainless can develop surface rust, but nothing deep. It's all on the installers head, unless you signed a paper calling to save $10 by using plain hardware.

We have to use stainless fasteners here in OZ its the law, plus you just need to do it as its the only thing that will last, cheers.

[bcroe]

I just relocated 9 panels that had been in place for 27 months, and the stainless hardware was
just like new. I am pretty sure zinc would not have held up so well. Bruce Roe

[inetdog]

If panels are expected to have a service life of 20-30 years, all the hardware should have the same service life. Heavy zinc coating might last, but I would expect to see stainless steel for that long life. Some stainless can develop surface rust, but nothing deep. It's all on the installers head, unless you signed a paper calling to save $10 by using plain hardware.

With the price of stainless hardware here it would be a lot more than $10.

[bcroe]

With the price of stainless hardware here it would be a lot more than $10.

The stainless hardware here runs into some hundreds of $. Bruce Roe

[des04]

Thanks for your inputs.

I have just read the warranties in the contract (workmanship on installation 2 years; Inverters 10 years; Performance on solar panels 10-25 years). Is the rusted roof screw issue part of workmanship warranty cover?

I also have just read the Australian Consumer Law on Consumer Guarantees for Products.

It says the

A business guarantees that goods will be of acceptable quality. This means they must:

be fit for all of its usual purposes
look acceptable in appearance and finish
have no defects
be safe
be durable. link

One can argue that the consumer expects all the materials used in the installation must be durable for a reasonable time after installation date regardless of the warranties specified in the contract. As Mike90250 said consumers should expect all materials used for the installation would have the same service life as the solar panels.

Many Thanks

[peakbagger]

I assume Gladstone AU?. If so you are in a coastal climate. Generally coastal climates requires SS hardware. Zinc based coatings are generally not recommended as zinc self sacrifices itself. Generally when the fasteners are installed, the zinc coating can be damaged by the tools used to tighten them. The zinc on the rest of the surfaces will heal the scratches but eventually the zinc gets too thin. Stainless is inherently non corrosive in most weather conditions although improper fabrication and installation with carbon steel tooling can cause iron oxide to get imbedded in the stainless and cause it to have rust spots. For fasteners this is rarely an issue but for fabricated components like brackets that need to be cut and ground, using a carbon steel wire brush prior to welding can raise havoc.

I have a pole mount array in a non coastal but severe environment (-34 C to plus 34C). I installed the majority of it with stainless fasteners, but in some spots I used zinc plated. I disassembled the majority of the racking after about 6 years to change out to larger panels. I had no issues with the SS fasteners, but all the zinc fasteners were noticeably deteriorated and I had to snap a few off with frozen threads. One note is that I use a bit of neverseize on all SS threads and nylon insert nuts instead of lock washers. I buy SS fasteners in bulk from a boat supplier and find that the price is far more reasonable than buying them at hardware stores. Once you get up into the large structural sized bolts they do get pricey.

The issue with rusted fasteners is beside being ugly, the can ultimately deteriorate to the point where they cannot be removed and at some point they will loose tensile strength and start to fail. If you are there for the long haul I would suggest changing them out.

[des04]

Yes. I live in Gladstone QLD Australia.

I just read the media who interviewed another solar panel installers that they have never seen anything that Solar Farmers is describing. It looks like they have used the wrong type of screw and they are offering consumers to replace the screws with stainless steel screws for AUD 449 - 599.

[peakbagger]

In the US, the company and the utilities that recommended the contractor would already have a class action lawsuit on them and they would be replacing the screws at no charge. It does seem suspicious that they will not stand by their installation and wants the owners to pay. I guess every countries legal system is different ;(

[jflorey2]

I checked a few days ago that the roof screws on the roof were rusted. Do you think what the rusted screws was as a result of poor workmanship or due to hostile corrosive atmospheric conditions?

Both. A roof is one of the most hostile conditions out there for hardware. Hot during the day, cold (with condensation) at night. Serious rust is usually the result of choosing the wrong metals for fasteners. One of the most common mistakes is stainless hardware on aluminum racks with just one zinc-coated part (say a lockwasher.) The dissimilar metals will rapidly cause galvanic corrosion.

[bcroe]

One note is that I use a bit of neverseize on all SS threads and nylon insert nuts instead of lock washers. I buy SS fasteners in bulk from a boat supplier and find that the price is far more reasonable than buying them at hardware stores. Once you get up into the large structural sized bolts they do get pricey.

I would never buy any quantity of hardware from the hardware stores. The selection is extremely limited,
and the price too high. Here McMaster gets about anything to me overnight.

I haven't learned to trust nylon lock nuts in this environment yet. Instead I put on a second nut. Tightened
against the first nut, it will never come loose, and it keeps most of the thread covered. And a lot easier
to install, not fighting you all the way on. Bruce Roe

[peakbagger]

I have used nylocks in an industrial plant for years. They work well when applied correctly. They are not good for elevated temperatures but fine on a roof.