1905 slate roof - Does it require felting?

[snooky]

Hi... needed some advice and I'm sure this forum has the answer!

Just had a surveyor who has noted that in the older part of our house which dates to 1905, there is no felt under the slate roof.

As far as I'm aware, this is quite normal for this period of house, and since the house has been in the family since it was built, we have no recorded evidence that it EVER leaked....

Should we now consider felting it or use some other spray on membrane or just leave as is?

Thanks

p.s. sorry - I posted this in the Dublin section - but it's a general architectural question rather than being specific to Dublin, so I am reposting it here....

[DOC]

Honestly....leave as is. If it has never leaked, don't try and fix what's not broken. Someday the roof will leak and/or the slate will have to be replaced. When that day arrives, then install roofing felt.

[teak]

But maybe felting would be a sensible precaution given the consequential costs of any leaks that may arise.

[snooky]

Thx for your views . Hmm.. well the cost of felting /re-roofing isn't cheap I would have thought, and the original tiles may get broken during the process (they are def welsh slate I think.. )

The thing I don't understand is, it must be a pretty common problem in loads of pre-1930's stock, surely they're not all going around re-roofing when the buildings have not shown any sign of leakage?

[DOC]

Slate will definitley get broken during the re-roofing process, that's why I'd suggest wait until it has to be re-roofed. If it were me, I would have somebody check the nails/fixings and if they are o.k., then I would leave alone.

If you ocassionaly monitor roof/look out for leaks, any leak caught in a reasonable time should cause no lasting or permanent damage.

[PVC King]

Sounds like it might possibly be an instance of arse covering; far too many pi claims flying about these days.

[Paul Clerkin]

I wouldn't touch it unless it's broken

[onq]

Hi... needed some advice and I'm sure this forum has the answer!

Just had a surveyor who has noted that in the older part of our house which dates to 1905, there is no felt under the slate roof.

As far as I'm aware, this is quite normal for this period of house, and since the house has been in the family since it was built, we have no recorded evidence that it EVER leaked....

Should we now consider felting it or use some other spray on membrane or just leave as is?

Thanks

p.s. sorry - I posted this in the Dublin section - but it's a general architectural question rather than being specific to Dublin, so I am reposting it here....

There is no easy way to felt this roof.

The existing slates will most likely be brittle after ten and a half decades of weathering, wetting and exposure to freezing winter skies.

Even new slates will suffer a high rate of breakage on removal from a roof.
I've helped carefully hand-remove 300 x 600mm slates from the roof of the Garda Depot in the Phoenix Park and they were thick and strong, and we still lost 10% or more.

Then there are the battens and roof timbers which are typically quite minimal for the imposed load - more cracking and breaking when you break the nails and remove them.

Personally I would leave well enough alone, but get someone to check the roof over who knows about such things.

I would respectfully suggest you get a Grade 1 conservation architect who knows the house type and take some professional advice, or failing that talk to someone like David Slattery whose office used to be down near Ashtons on Clonskeagh Road.

ONQ

[goneill]

Why on earth would you need a Grade 1 Conservation Architect to advise on this? Any competent architect (even a non RIAI one) should be able to help and would probably advise not to touch it. I can't believe that ONQ, of all people would specify RIAI requirements for a simple job, and then overstate the skills required.

[onq]

I learnt a long time ago to stick to what I'm good at and to go out of my way to offer the best advice I can to people.
If you read my post I gave my own advice first, sprinkled with observations based on personal experience.

Then I suggested a second opinion from people who are likely to be more competent than I.
A grade 1 conservation architect or David Slattery outrank me on conservation.

If I had given advice that was inadequate I would understand your comments.
To complain because I promoted a high standard of advice seems perverse.

I don't post here to run down competent Members of the Institute.
I decry an Act that suggests MRIAI is the minimum standard.

ONQ.

[Devin]

David Slattery? Conservation? Lol ......... Conservation is frankly not the first thing that springs to mind when David Slattery is mentioned ....

[onq]

Really Devin?

Is your humour getting the better of you, or do you just not know who he is?

http://www.sisk150.com/sitemedia/book/07_Craftsmanship.pdf

http://www.epa.ie/licences/lic_eDMS/090151b280168c3b.pdf

http://www.gui.ie/news_detail.asp?id=493&area=1

DAVID SLATTERY – Architect – Historic Buildings Consultant
8, Vergemount, Clonskeagh, Dublin 6, IRELAND.
Phone: 01-2697344 Fax: 01-2604098
David Slattery, Dipl. Arch., F.R.I.A.I.
e-mail: slatcon@iol.ie

I fail to see what you find either amusing or inappropriate in referring to him.

ONQ.

[apelles]

Re; David Slattery see this http://www.archiseek.com/content/showpost.php?p=110262&postcount=7033

[onq]

I put up his contact details for the avoidance of doubt.
There may be other David Slatterys and this could cause confusion.
I should point out that I have no working relationship with David Slattery.
I once had the pleasure of working with him back in 1997/1998 on an office developmnt at the top of Barrow Street.
We had to be especially careful about the abutting end of terrace buildings and he was brought in as an expert in older forms of contruction.
He lived up to his reputation.

ONQ.

[missarchi]

I think I have found the best solution...

Lets tar and feather the roof...

That way the slate will last longer have upgraded insulation/camouflage values...

[Devin]

Onq, as somebody in the biz for some time, I'm surprised you are as unaware as you pretend to be of David Slattery's reputation as a developers' gun for hire. Yes, he has worked on some big conservation projects - as one is manifestly reminded at the end of each report of his - but it's for the 'Darth Vader, Dark Lord of Conservation' persona he is best known in my part of the world.

As you mention Barrow Street (and by way of example), in 2006 David Slattery condemned two interesting stone buildings at the corner of Barrow Street and Ringsend Road on behalf of Versus Ltd. for a redevelopment of the Bolands Milll complex. Dublin City Council, in one of its rare boomtime refusals of a major scheme, said the demolition of these buildings would be seriously injurious to the amenities of the area and contrary to the development plan.

Edit - link: 4616/06 Bolands Mill

[onq]

Onq, as somebody in the biz for some time, I'm surprised you are as unaware as you pretend to be of David Slattery's reputation as a developers' gun for hire. Yes, he has worked on some big conservation projects - as one is manifestly reminded at the end of each report of his - but it's for the 'Darth Vader, Dark Lord of Conservation' persona he is best known in my part of the world.

As you mention Barrow Street (and by way of example), in 2006 David Slattery condemned two interesting stone buildings at the corner of Barrow Street and Ringsend Road on behalf of Versus Ltd. for a redevelopment of the Bolands Milll complex. Dublin City Council, in one of its rare boomtime refusals of a major scheme, said the demolition of these buildings would be seriously injurious to the amenities of the area and contrary to the development plan.

Edit - link: 4616/06 Bolands Mill

(chuckle)

Well Devin,

Thanks for clearing that up.
No, I didn't know about that aspect of how people view him.
The last firm I dealt with was Buchan Kane and Foley - more a hand-over than a collaboration.

At the time both the people in the adjoining property and the developer found Slattery good to deal with.
It was more a case of finding a way to assure them no daamge would be doen to their building than a conservation issue.

In relation to the Bolands Mill Development, I think the old stone building is the old Annex Building.
I'm delighted to see the old Mill wasn't pulled down - there are a lot of interesting older storage buildings in the area.

ONQ.

[CTR]

Interesting. My brother has just bought a c.1880 house in Rathmines and I noted in the survey report that there is no sarking felt in the roof. The architect noted quite a lot of minor slate slippage but it doesn't sound like there's much work needed to repair this. I guess the lack of felt was common practice in those years.

What benefit does felt provide (non-architect here)? I assume it is for waterproofing, support and may even provide a tiny amount of insulation? Was there a particular reason that it wasn't used in these Victorian/Edwardian constructions?