This is a picture of the wall of my house:
I need to fix the pointing; I think it's causing water to enter around a window at one point, and it's generally a disaster.
The house is in the UK, built about 1970, and is externally stone (with a cavity with concrete blocks inside). This hard, circular profile, gray cement is what is used to point the whole house. The main part of the house has wide eaves which protect from weather, and generally the pointing looks good, with a good bond between the cement and stone.
We also have an "extension" (or what I think might originally have been a garage) which is a flat roof, no eaves, and features issues like in the picture. The cement has blown off in chunks, and can easily be removed by hand (that which hasn't fallen off on it's own). As you can see, behind is a must weaker looking mortar between the blocks.
I am thinking of using a lime mortar to repoint, and following advice I've found on the internet, would make the pointing slightly recessed, and not a "ribbon" (the picture doesn't show it well, but especially on this bit of the house, it looks like it's been piped on out of a bag!)
Is this sensible? Should I use a lime putty, or a weak hydraulic lime mortar?
What confuses me is that the internet is full of advice about "historic" buildings (of which there are many where I live: Calderdale in West Yorkshire). But our house is not really historic… And also none of the local houses, either very old or rather new, have pointing which looks remotely like my house.
Best Answer
I'm a novice DIYer also from Calderdale. I recently repaired some pointing on a similar type of property. Unfortunately it doesn't match the rest of our pointing but I prefer the look of the result i'd be tempted to repoint the rest of the house.
Rake out the dead pointing, i used a mortar rake disc on mini grinder.
4 sand 1 cement and some plasteciser (in place of lime) from B&Q as quantified on the packaging.
I was advised from a few builders but other than that I probably know as much as you from online forums! :)