Installing PV on natural slate roof

[MYLOUBYLOU]

Anyone had this done? The company we contacted said was more complicated to install equating to £1000 additional install cost. Also costs more as we have 3 phase electricity. Just looking for experiences. Thanks 

[BotusBuild]

They are correct because slate tends to be more fragile than the "cement" tiles when it comes to cutting for the brackets to be fitted (don't let anyone fit by screwing through the tiles!!).

 

A good installer will cut nice clean slots in the slates and use flashing to ensure the brackets sit as flush as possible and the tiles then remain flush to each other - difficult to explain without seeing good and poor examples

[bassanclan]

The 3 phase bit should not cost more unless you want it installed across all 3 phases. You can put 4kw on one phase

[BotusBuild]

2 minutes ago, bassanclan said:

The 3 phase bit should not cost more unless you want it installed across all 3 phases. You can put 4kw on one phase

Agreed - missed the 3-phase bit

[JohnMo]

What about using solar limpets, or solar slate plates, don't see why they make the process more difficult.

[SteamyTea]

35 minutes ago, BotusBuild said:

They are correct because slate tends to be more fragile than the "cement" tiles when it comes to cutting for the brackets to be fitted (don't let anyone fit by screwing through the tiles!!).

 

A good installer will cut nice clean slots in the slates and use flashing to ensure the brackets sit as flush as possible and the tiles then remain flush to each other - difficult to explain without seeing good and poor examples

Have you actually seen that done?

When I worked in the PV industry the proper slate tile mounting kit was used.

(we would put in a silly quote to slated houses as we did not want the job)

[BotusBuild]

35 minutes ago, SteamyTea said:

Have you actually seen that done?

Yes, and it is a PITA - hence the extra £1,000 cost on the OP's quote I should think

[BotusBuild]

49 minutes ago, JohnMo said:

What about using solar limpets, or solar slate plates, don't see why they make the process more difficult.

You have to drill though the slates to use these. Slates (older ones in particular) are VERY fragile, and can crack very easily. Many installers are not patient enough and end up cracking so many slates that then have to be replaced (££££). And if they are patient enough it takes them longer to install (££££) - see @SteamyTea's comment about providing a silly quote to avoid getting the job ? 

[JohnMo]

You don't drill through any slates to install the "solar slate plates", the plate replaces a slate and sized to match the slates you have installed.

[BotusBuild]

3 minutes ago, JohnMo said:

You don't drill through any slates to install the "solar slate plates", the plate replaces a slate and sized to match the slates you have installed.

Seems a sound product, but looking at the prices of those there is still addition ££££ to other roof hooks.

 

Something for the OP to consider mentioning to the people who quoted though.

[MYLOUBYLOU]

Yes saw the Solar plates that claim to cut install time of 4kW system to 4 hours. It is a new build house (August). We have ashp and we are kicking ourselves having not asked them to put solar panels on when building.  We want to be environment but not at all cost. The 3 phase costs £150, maybe due to different inverter? He also said can’t have battery. He’s coming for site visit next week. 

[joth]

20 minutes ago, MYLOUBYLOU said:

The 3 phase costs £150, maybe due to different inverter? He also said can’t have battery

My experience (PV and ASHP) is Installers generally only work with a few brands, and often only have experience with a few specific models from that brand, so when they say "you can't do X" they actually mean "I've never done X" or "the brand I work most with doesn't support X" or "X is extra effort so I prefer not to quote for it".

 

Do you have a smart meter? If so, there's definitely no downside to just putting the PV on a single phase. Batteries on a 3 phase installation is also a solved problem. Try some other installers. 

 

To be fair the extra £150 maybe just a faff factor for dealing with a non-standard install, which is  their prerogative.

 

 

Edited January 8, 2022 by joth

[TonyT]

Slates is the common roof finish in my area, and at the start of the FIT my installer had no problem fitting mine, and let’s say the industry was still young in the UK  brackets are available for  each install and like every install each judged on its own merit and installed accordingly.

nearly 11 years in and no issues..

[Thorfun]

If it’s that much more to install on slates have you considered stripping the roof in the area where the panels will go and putting an in-roof system in? Won’t be cheap but will give a very nice finish.