Help! Rusty roof slates...

[Simon Chalk]

9 years ago we replaced the roof slates on our 1930s property. We are about to have a loft conversion and when the scaffolding went up this week I was concerned to find that the many of the roof slates are now showing visible signs of rust. The roofing contractor used Sigma 38 slates (allegedly) and were guaranteed against defective workmanship/materials for 30 years.

Rusting is widespread and some of the slates seem to be delaminating as a result. Should I get the roofing company back or is the rusting natural/cosmetic and not likely to affect the longevitiy of the slates?

Any advice from experienced roofers would be greatly appreciated.

 

[datarebal]

If the slate had the T1 certification then it should not be staining. it can rust but not stain.
All Slates have mineral inclusions (Pyrites) not all rust.

Tbh they do not look like a Siga to me but I could be wrong.

30 years product guarantee tells me is lower grade. It is a bit late now but SIG will issue a site specific guarantee.

Call the Roofing company who should know where they got the slate. In which case they can get the rep round to look.

However, there is a possibility they maybe Standards (STD on the pallet) in which case as long as holes do not form to cause a leak then they are performing.

Basically, you need to be identify exactly the slate.
The roofer will know

Things do go wrong, Ive seen genuine Siga 39 rust and stain . They have T1 S1 W1 cert... so yours may well be a Siga, but i'm not familiar with 38s ..never seen one

Basically go back to the roofing company and ask they to contact the supplier its not a workmanship issue

This might help http://www.sigaslate.co.uk/faqs/will-siga-slates-rust-discolour/

 

[^woody^]

I recall a report a good few years back regarding Spanish slates doing this very thing and not suitable for the UK climate .... but they were cheap.

30 years is nothing in the slate world.

 

[catlad]

Yes not fit for purpose in my opinion! We have the best quality slate in the world and we import inferior slate from Brazil, China, and Spain. Moving heavy rocks from one part of the globe to another has massive polluting implications as well as the fact that you find out in a relatively short time that they are rubbish.

 

[datarebal]

Re Spanish slate, the very best are sorted long before UK gets a share.

The best go direct to France and Germany .

I would not write all off.. just the ones that fail to meet standards. Ssq have some good reading.

But! We all know the very best are just up the road in Wales and mustn't forget Cumbria... Canada produce good too

 

[catlad]

We are not gaining anything by bringing rocks from another part of the globe.

 

[datarebal]

I hear what you say ..
Diamonds, opal, Rubi's etc etc
Cars from the far East ...
A monster has been created and now needs feeding

Unfortunately the average person could not afford to pay £3500 plus per ton for say a green Westmoreland (18 M2)
Or even £4:00 plus for a Welsh slate.

The problem here is people buying a product that they no little about.
And it comes back to bite them
A slate is not just a slate

There are situations around the world that call for a slate with rusting pyrites
To create an arty look... Generally not in the UK though .. intentionally.
I think the original poster is unlikely to get much joy

 

[^woody^]

We are not gaining anything by bringing rocks from another part of the globe.

I did my front path with some nice cheap stone from India.

 

[foxhole]

I did my front path with some nice cheap stone from India.

Me too

 

[datarebal]

I have a siga 39 roof. And slate path which I believe is from Spain too..

I guess the chances of me going to heaven are buggered

 

[Simon Chalk]

Thanks for the replies, especially @datarebal, before the thread went a little off topic. The local roofing company 'Quality 1st' (LOL!) has now folded, so basically all I have is the original quote/receipt from them to specify that they were Siga slates that were installed. I have called Siga who have committed to get a Rep to come round and take a look so thanks for that suggestion. I have no idea how they will go about establishing the origin of the slates and if whether they are Siga or not. Anyway it looks like we spent £11k on a new roof that isn't going to last much more than a decade. I feel pretty aggrieved about this and am gutted I hadn't noticed the issue from street-level earlier.

As part of our loft conversion I estimate around 40% of the existing pitched roof will disappear to make way for the dormers and hip to gable, so basically will have to make a decision on how to remediate this problem on the remaining areas of the tiled roof. I will not be investing in slate again and will probably opt for a man made alternative that will survive the test of time.

 

[datarebal]

well i hope, if its theirs they help out, if you are lucky they may supply replacements. doubt labour.
Slate a first class material we use many tens of thousands every year from Wales, Spain, Northern England and Canada. problems are rare.

ive seen many problems with man made alternatives after not many years. I believe Catlad recently stripped a roof with failed man mades on
so that will not make you safe.

there is some good useful info in the posts above, will certainly help you avoid the mines..

good luck with the rep

Quality 1st.... ive seen that name. where were they from?

 

[Simon Chalk]

@datarebal Quality 1st were a Ringwood based roofing firm - the website is still up but all phone numbers have been taken out of service. I notice you are Hampshire-based so are in the same region as us (Bournemouth).

 

[SFK]

@datarebal
Company details are here:
https://beta.companieshouse.gov.uk/company/10025915
SFK

 

[datarebal]

Ahhh