Don't worry about things like lead piping, old plumbing installations etc-you'll be ripping these out anyway, presumably. You're main area of concern should be the structure of the house- i.e. the foundations, walls and roof. If you are unfamiliar with building or what to look for you should really get a competent friend or builder to have a walk around with you. Obvious flaws will be readily visible to someone in the know, once you've got past the first stage you can consider engaging an architect or engineer to give a more thorough, professional opinion. I'd be looking for serious cracking in the walls, around window and door opes etc. anything larger than 1.5mm needs further investigation. Is the roof sound? Rotten timbers are easily spotted, go up into the roof space (bring a step ladder, camera and a torch with you) and examine the rafter where they meet the wall plate. Is the old water tank leaking? Has it caused damage to ceiling below? Look at the chimney stack in the attic, any evidence of smoke penetration? Are timbers sound, dry and do they smell ok (neutral). Wet rot is not a major worry but dry rot is. Look for evidence of settlement in the walls, are doors out of square, hard to close? Can windows be opened easily? Is the area prone to flooding (Cork is a particular risk, isn't it?) Has the house ever been flooded, will it be possible to get buildings insurance? Ask the agent all these questions- he may not want or be able to answer all your queries but he can't lie to you either. Once you given the place a basic look over then you should get a structural survey done, good luck.