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?
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.