The PIC round my old Devon house (no dpc - it's cobb on stone footings) is a decade old and is neglected, but doesn't bother me from an aesthetic point of view. It's on a slight slope, so water drains away quite well even considering the stamped finish. But with the more stormy rain patterns we seem to be getting, I am a bit concerned about some settlement cracks in the PIC that may well be letting surface water seep towards the house where I'd rather it didn't.
So I'm looking to make the PIC more storm-proof by sealing the cracks. All I can think of is to (very carefully!) angle-grind the cracks until they are about 5 mm deep and wide, and then fill with a mortar mix. Is this a sensible approach, bearing in mind there's about 2-3 metres of crack in all? If so, any suggestions about mixes and additives? I'm much more concerned about sealing the surface than the cosmetic issues, although obviously I'll make it all as neat as I can!
Grinding is the right thing to do, but make sure you blowout the crack before you apply the sealant, i would also be going 10mm deep, instead of using grout which will blowout if there is any expansion over summer, use a polyurea sealant or a similar flexible sealer. You can dress the surface of the sealant with coloured sand to make it less noticeable.
