Can I put solar panels on my asbestos roof?

This enquiry just in from Richard:

“I have 8 solar panels on my roof but they are now shaded by a neighbour’s tree, particularly in winter. 

I'd like to increase my solar.

The best solar access I have is a long fibro garage with a corugated fibro (bonded asbestos) roof.  Are there any roof fixing systems that can be used on fibro and any contractors with experience installing on fibro?  Or is the only option to replace the roof sheeting, which would massively increase the installation cost?

We have gas cooking and hot water plus LED lighting and reasonably efficient appliances. 

For a household of three (me and my two teenage sons) we average around 6kWh per day demand.”

(To estimate your costs for solar and batteries using your daily energy use, see this blog. )

There are three things that come to mind:

1 Many asbestos roofs are old and likely to break with workers on them. For this reason experienced installers generally won’t touch them as they risk having to pay to replace or repair the roof if they break it by walking on it.

2 Experienced installers would not quote without first seeing the roof first hand, usually without charging for the site visit.

3 Solar installers are not concerned with working on asbestos so long as they take standard industry precautions.


Some suggestions:

1 Ask at least two experienced (at least five, preferably ten years in business) installers to quote by first looking at the roof;

2 Consider leaving the asbestos roof in place and putting a metal roof over it with some strengthening below – this will need an experienced and imaginative builder and perhaps an engineer.

Here are two experienced installers I have worked with and who you may wish to contact directly:

Another approach is to replace your shaded panels with panels which operate independently of each other when shaded.  Some older panels cannot do this but recent ones with 'microinverters' can harvest the sun to their full efficiency while those in the shade do not.  

Due to overshadowing, in March 2015 I had to replace my six x 120 watt 1996 panels  with panels with microinverters; the new 327 watt panels with microinverters gave me three times the power in almost the same space and those shaded early in the morning do not 'hold back' those in sun.

Do stay in touch and let me know how you go.

Oh; a tip.  Try to buy your new panels with someone else as you can often obtain a reduction in price by buying in bulk with two or more installations.