Repointing a (lot of) garden wall: angle grinder?

[Peter Kemp]

Folks,

In the autumn, I removed several decades' growth of ivy from a garden wall. Not surprisingly, this has revealed badly-damaged mortar in several places, so major re-pointing is required. The wall was built in the mid-1930s, using a lime mortar, so I will be using that for the re-pointing.

Unfortunately the wall is quite long, so there will be a considerable amount of raking out to be done. I seem to have three choices:

a) Pay someone to do it.

b) Get a lump hammer, a chisel and wave farewell to a large chunk of the summer.

c) Have a play with an angle grinder...

Realistically, option (a) isn't going to happen so it's (b) or (c).

Any experiences (good or bad) to share about using an angle grinder for this sort of work? Any suggestions about a sensible price to pay, features it should have and tips/techniques?

Many thanks, Peter

[Anna Kettle]

Plenty of good news :-) You are making too much work for yourself

If it is lime mortar then you shouldnt need to use an angle grinder, which is just as well because it is difficult to use one without damaging the bricks Find or make something which can be used to rake out any loose mortar, leave in situ any mortar that is still doing the job Then point the bits which need it ONLY the bits that need it

This sort of pointing job looks much better if it is done on an as and when basis because a complete repoint looks horrible for ages, whereas patch repairs seem to fit in or mellow much more quickly for some reason. It must be an eye/brain thing I think

When someone is being paid to do the job, then they will often want to repoint the whole lot, because they dont want to be called back by an upset client because 'another bit has failed'. When you are doing the work yourself that is not an issue, so do the bad bits now and if you have to have another go in a few years time then so be it

Anna

[Owain]

also do gun injected mortar on the Grand Designs French manor house.

[Adrian C]

d) Multimaster type thing? or SDS chisel?

[Jules]

I've noticed that - I think my head expects houses to look a bit 'distressed' and random, and that's why I can't stand new builds - they just look too clean and clinical, somehow. The more 'aged' the better, so long as it's not outright falling down.

[The Medway Handyman]

I've used a 4" angle grinder with a cheap diamond disc to remove old pointing. With care it can be done with incredible precision. It creates s*1t loads of dust though.

Current bargain buy seems to be the Site (made by Makita) @ £22!

've got one & its a good piece of kit.

[Tim Watts]

On Wed, 20 Jan 2010 20:07:02 +0000, "The Medway Handyman" wibbled:

There is an angle grinder attachment that works a bit like a router bit - might be slightly more controllable? Might be even better if the angle grinder had variable speed.

This is what I was thinking of:

've not used them - and I'm watching with interest as my front wall needs a bit of remedial...

Cheers

Tim

[Cicero]

================================================

Consider using a mortar pick / rake:

people seem to use this two-handed, dragging with the handle whilst guiding one end of the metal head with the other hand. It's quite easy to manage once you've tried it.

If the old mortar requires the use of a hammer and chisel then it probably doesn't need to come out.

Cic.

[js.b1]

It is lime, you want a rake, not a grinder.

Piece of 2x4 with M10x75 through it and two handles like a scythe, if it doesn't work you can always use it to cut through the ice the previous car driver will have judiciously polished to a lens grade surface on that off camber road junction in the forthcoming 2010-the- ice-age winter.

[Andrew Gabriel]

Use the proper tool...

the mortar doesn't come out easily with this, it doesn't need repointing. Use the nail to limit depth to about 1/4" into the pointing (and certainly no more than 1/2" - that's no longer repointing). When you've raked out a joint, finish off by running the tool along with the nail pressing against the brick edge to make sure it's clear to take new mortar. Be careful not to let it jump out and scratch the brick surface though, particularly if you have soft facing bricks (unlikely in a garden wall with lime mortar which is still standing).

You'll need some nails to use. IME, large masonary pins last well in the tool, but you break the odd one whilst fitting it in. Ordinarly nails are easier to install, but wear very quickly in use.

Wrong tool. You don't want a power tool for this.

[Stuart Noble]

Hope for a long hot summer and regard it as therapy.

[Tim Watts]

On Thu, 21 Jan 2010 10:49:25 +0000, Stuart Noble wibbled:

All seems very sensible advice. We I look at my pointing, my first though is "oh no, so much wall, 100's of yards to cut out and redo."

If I look again at the dodgy bits, it's probably only 1/5 or 1/4 of the total pointing.

Next question - anyone got any tips on colour matching new to old pointing? I've seen some old patchups which are obviously "wrong" - very grey compared to a fairly yellowy older pointing. Dod the old have too little cement, or perhaps had some lime in lieu of some cement? The newer stuff seems very cement heavy.

[NT]

You only need to repoint the bits that scrape out with a nail or screwdriver. Pulling more out risks damaging the bricks, leading eventually to their destruction.

NT

[safety]

Dear Peter Much commonsense earlier said I agree only to do that needed I disagree about depth - rake out same depth as width or a few mmm more not more than 20 mm max Where there is a large patch all gone but for minor areas it is best to rake out so it is consistently "founded"

Get a sand analysis done together with the ratio of sand to lime and use similar sand even tho you have to mix and match experiment with a few batches (new pointing will look much much whiter for some years but look at the texture

Read Mortars Plasters and Renders in conservation by John Ashurst (RIP) but ignore his recommendation to put in a bit of cement (he recanted)

I have a copy if you want to buy

Carefully match the finish (brush stipple/smooth/ whatever

Keep covered from rain and wet for a month or so

chris

[Stuart Noble]

A little alarmist perhaps. I've done plenty of this sort of stuff and never had a brick subsequently degrade. Obviously a case for lime mortar by the sound of it, although how you get a thin layer sitting on the edge to survive the first rainfall I don't know. I think you'd have to rake out a bit deeper than you suggest.

[Andy Dingley]

Agreed on both of those.

How do you feel about mortar rake chisels on SDS drills?

(Personally I favour a). We have a stonemason living opposite, and his prices are very reasonable)

[NT]

NT

[Clint Sharp]

In message , Peter Kemp writes

Guy who did our house used one to remove the horizontal mortar and a chisel for the verticals, nice job apart from the couple of places he slipped.

[Peter Kemp]

All,

Your pointers to the appropriate tools and materials - and suggestions on how to target only what's really necessary - mean that (b) now looks far less intimidating than it first appeared.

Thank you everyone. I greatly appreciate your feedback.

Peter

[Adrian C]

I'm supprised the 2010 candidate for the Angle Grinder successor - the Pressure Washer - didn't make an showing in this thread!