Repointing side wall

danrv

Hi
The mortar in my 3 bed property’s end wall has recessed over the years. It’s exposed to the elements and has worn away to a depth of about 10mm. Seems to be quite sandy when raking out too.
With the garage on the side, I’m able to do the first 2 or 3 metres from the roof. Above that I could use ladders.
I’m using a bolster chisel for raking out but was wondering about other suitable tools as it’s quite hard work. There’s cheap wheeled mortar rakes available and I also have an angle grinder but it has an unusual 10mm spindle size. All rake attachments are 14mm. 
Any ideas welcome.

FreeBear

danrv said: I’m using a bolster chisel for raking out but was wondering about other suitable tools as it’s quite hard work. There’s cheap wheeled mortar rakes available and I also have an angle grinder but it has an unusual 10mm spindle size.

The correct tool is a plugging chisel. If you want to go the powered route, then an air hammer with a modified chisel. Using an angle grinder is both messy and also all too easy to slip and make a mess of the brickwork. If you must use an electric power tool, then an Arbortech with the correct blade is preferable, but at £1K, an expensive option (hire is around £125 per week).

By the sounds of it, you have a lime mortar - It should be easy enough to rake out using hand tools, and should be replaced with a like for like material (i.e. No cement).

grumbler

I like SDS mortar chisel (longer ones are called brick removing tool/chisel)

danrv

FreeBear said:

By the sounds of it, you have a lime mortar - It should be easy enough to rake out using hand tools, and should be replaced with a like for like material (i.e. No cement).

Thanks for the reply.
Just thought it was the wrong mortar mix. Some of it seems quite weak. 
General recommendation seems to be 3 to 1 sand/cement mix with plasticiser for weather exposed wall. 
Have bought some Blue Circle cement, builders sand and some plasticiser. All quite cheap so no problem if incorrect.
Just wondering if cement is ever used in mortar. Whatever I make up, I’d like it to be durable.

theoretica

You get problems if the pointing mix is more durable than the bricks or stone - pointing is easier and cheaper to replace.

danrv

theoretica said:

You get problems if the pointing mix is more durable than the bricks or stone - pointing is easier and cheaper to replace.

Yes.
Hope to use what I’ve bought and add lime. Maybe 1 cement, 1 lime, 6 sand + plasticiser.

FreeBear

danrv said: Just thought it was the wrong mortar mix. Some of it seems quite weak. 
General recommendation seems to be 3 to 1 sand/cement mix with plasticiser for weather exposed wall.

A 3:1 mix is way, way too strong. A 6 parts sand to one of cement will be more than adequate. But if this is an old property built of stone or soft brick and lime mortar, you do not want to be using any cement.

Lime mortars are mixed (typically) 3 parts sharp sand to one part NHL3.5 lime. The Type S (or hydrated) lime you get from most builders merchants or B&Q is no good.

danrv said: Hope to use what I’ve bought and add lime. Maybe 1 cement, 1 lime, 6 sand + plasticiser.

Hydrated or Type S lime will act as a plasticiser. No need to add anything else.

stuart45

This is one of the best tools I've had for raking out softish joints. When you need to grind them out you have to wonder if the wall needed repointing. 
There was a time when surveyors always seemed to call for a repoint and I've done a few where the old was probably just as good as the new.

danrv

FreeBear said:

A 3:1 mix is way, way too strong. A 6 parts sand to one of cement will be more than adequate. But if this is an old property built of stone or soft brick and lime mortar, you do not want to be using any cement.

Lime mortars are mixed (typically) 3 parts sharp sand to one part NHL3.5 lime. The Type S (or hydrated) lime you get from most builders merchants or B&Q is no good.

Hydrated or Type S lime will act as a plasticiser. No need to add anything else.

It’s mid 70’s so not old. Just regular brick so thought I’d be able to get everything from Homebase, B&Q and Screwfix.
I bought builders sand rather than sharp sand as this seems to be what’s normally used.
The mortar used seems to be inconsistent in quality. Most of it comes out very easily on this wall where as on the others, it’s solid.
Garage interior is the same. It’s been done pretty badly so have been patching this up with Prestonett masonry filler.

stuart45

6/1/1 should probably be fine for a 70's house. Make sure it's well damped down. I normally use the mist setting to give it a good soaking.

FreeBear

danrv said: It’s mid 70’s so not old. Just regular brick

The mortar used seems to be inconsistent in quality. Most of it comes out very easily on this wall where as on the others, it’s solid.

OK 70s build - Don't suppose this is a Barret house ?

The major national house builders are not noted for their quality of build... https://www.dailymail.co.uk/news/article-6467195/Hundreds-Britains-new-build-homes-risk-crumbling.html

A little gadget that will help you when it comes to pointing (posted a couple of times before).

https://www.youtube.com/watch?v=811RvqR-ECw

Worth making one, and certainly a lot better than those mortar guns (don't bother buying one, they are cr*p).