Repointing

[imroberts]

I have a 1930's red brick house which is in need of repointing...

It looks like someone has touched it up prior to me owning the house but this is only a few mm deep, hasn't stuck properly, and regularly drops out. I'm looking to grind out the cement to a decent depth and repoint completely.

At the moment I'm proposing buying something like the following:
- http://www.screwfix.com/p/mortar-rake-8-x-40mm/31307
- http://www.screwfix.com/p/roughneck-brick-mortar-gun/67965

Are the mortar rake attachments for angle grinders good enough and easy enough to use for a DIY job? I see they come in 40mm lengths (and also 100mm for removing bricks completely) but I'm guessing I don't want to grind out that much cement? I was thinking probably 10-20mm (depending on how deep I have to go to reach cement that's still solid?

What cement mix should I go for? I presume I'll need to add some plasticiser if I'm using a mortar gun like the above? I'm expecting a bit of trial and error to get an appropriate mix for gunning, but want to make sure I'm starting in the right direction!

 

[vinn]

Rake out to 18mm to 22mm depth. Use an angle grinder to disc out the body of the pointing and then the "mortar rake" to clean it up.
Practice on an out of the way bit of brickwork.

Pointing guns are a no-go as far as I'm concerned.
They take forever to fill, and de-clog to keep clean for operating.
Frustration drives the operator to weaken the mix so that it will flow. Weak mixes will craze crack.
But maybe you might have a better experience with one?

 

[Doggit]

You can often pick up cheap diamond discs in Aldi when they're on sale, and they work beautifully for the initial rake out prior to using the mortar rake, and if you run a black line round the disk, you'll know how far to cut in. But if you can get the mix right for the mortar gun, then they're damn quick to use, and you get less staining on the brickwork. The problem is not in the 5:1 mix, but in the water content; if it hasn't been mixed well in with an electric mixer, then the water gets pushed out first, and the remaining cement is to thick to come out of the nozzle.

 

[stuart45]

What style of pointing is it? eg weather struck and cut, round tooled etc.

 

[stuart45]

What type of pointing is it? eg weather struck and cut, round tooled etc.

 

[theprinceofdarkness]

How old is the house?, decent cement pointing lasts for 50+ years. Lime pointing even longer, if its falling out , I reckon that the brickwork is moving about. If for what ever reason the pointing is falling out then an old 6mmm wood chisel is all you need to hook the stuff out. Disc cutter cover everything in dust and can cause havoc if you slip with it.
As said make sure your mix is really well done, Don't use a mixer, it will producer too much. A bucketfull will keep you amused for an hour or so. You must soak and soak the wall again, just give it 5 mins for the surface to dry off a bit before repointing. I always use a "6mm Striking iron" to finish off the pointing. A SMALL hawk is always useful = why carrry 5 kG when 1 kG will give you busy for 10 mins.
Frank