Options for stepped flashing mortar removal.

[epsilonGreedy]

Not sure if the correct term is "mortar raking", "mortar routing" or "mortar chasing"?

 

Anyhow yesterday I started raking out multiple one brick long slots in my facing brickwork to accommodate the 25mm inserts in stepped lead flashing. Because the roof pitch is 30 degrees the length of each slot is longer than a typical higher pitch roof. The mortar is just one year old and the white cement creates a surprisingly strong/hard mortar for a 5:1 mix so chiseling out the mortar is not an option.

 

I started using a proper masonry cutter disk in my 4" angle grinder but soon realised I need to buy a thicker mortar raking disk like one of these:

https://www.screwfix.com/p/erbauer-masonry-stone-diamond-mortar-rake-115-x-22-23mm/85668

 

That screwfix example is 6.4mm thick which should help create cleaner cuts I hope.

 

And so onto my question. Given the radius of a cutting disk each slot has a long shallow tail which will be awkward to fill with mortar once the stepped flashing is fitted. I would like a cleaner end stop at each end of a raked slot and I am wondering if something like this angle grinder bit will help? My idea is to rake out 80% of each slot with a conventional raking disk and then tidy up the ends with a bit like this:

 

https://www.screwfix.com/p/mortar-rake-8-x-40mm/31307

 

 

 

[markc]

Taking out the bulk with a diamond disk is the fastest and easiest, the raking bit you show is great for cleaning out the ends and verticals

[epsilonGreedy]

I can report both items above worked out very well raking nice clean 25mm slots for the stepped flashing. Some of the slots look a bit fat, I might try the smaller 4mm raking disk for the next phase of the job.

 

The spiky bit shown above was very useful for squaring up the slot ends and for creating a uniform depth which was achieved by running the spiky bit up and down the slot. 

 

One tip I can pass on is ink the drill bit above 25mm to provide a visual depth guide.