Cost of re-slating an old cottage

Would anybody have a rough idea how much it would cost to re-slate the roof on an old cottage.

The cottage is over 100 years old and has two bedrooms upstairs which are essentially in the attic space. Presently there are blue bangor slates on the roof which we want to retain, but every now and then a slate slips and has to be put back in place. Some of the slats the slates are nailed onto are rotted and also the nails have rusted. Considering the age of the cottage they have lasted very well !

realy depends on how many slates are on roof then add a quarter again to the total for breakages and damage also will need to source old ridge tiles as its very difficult to remove the old ones without breaking due to quality of cement used at time slates should be no more than 1.50 euro each and caps about 6-7 euro then labour costs which at present are in your control

Many thanks for your opinion. Will start looking for old slates and ridge tiles before I go any further !

It is hard for anybody to price it until they strip the roof & examine the timbers underneath , if the slates were slipping the battens are possibly rotten & will need replacing then it will have to get some type of felt or protex. If the joists aren't damaged they may reuse them , if they have to change them they will probably cast a ring beam & recut the whole roof. I did a similar job on a cottage I own about 4 years ago. 30 ft long x 20 ft wide the roofing materials came in around 5000.00 not to mention the labour ( used tegral thruetone slates because too many of the origional slates either broke or were hollow when they were stripped off. )