Re-pointing old stonework

[robgraham]

What is the correct material for re-pointing a random rubble stone walled property? The stone is a mixture of sandstone and a basaltic rock (whin).

Thanks Rob

[Dave Liquorice]

Ideally whatever the existing mortar is. Which may well be a lime mortar. You can use a cement based mortar but that is brittle and won't flex and move with the building like a lime mortar does. Also if using a cement base mortar make it fairly weak or it will be harder than the stone and thus the stone will weather faster than it leaving raised joints.

[meow2222]

Lime mortar. 3 sand to 1 lime. Its very slow setting though, so don't rake out too much of the wall until earlier work has set. Also don't apply it when frost is imminent.

Use of cement on stone often results in it pulling away the surface of the stone when it eventually fails.

NT

[robgraham]

Thanks guys. This came from our rather stupid semi-detached neighbour employing what looks like an unemployed building worker to strip off perfectly good flush pointing and repoint with recessed pointing, which is atypical of farm cottages in this area of Scotland.

Anyone any idea of the what Party Wall regulations apply in Scotland as the work involved has crossed the boundary line ?

Rob

[stuart noble]

I thought the whole idea was that only the surface of the mortar sets. If the interior doesn't set, so much the better