Lime pointing

[Roz]

Anyone got any close up photos of their lime pointing - preferably on stone, that they can show me so I can see what I am aspiring to? I started yesterday and think it looks pretty messy, but am following guidance online. I realise it's a skill, but not one I think we can afford to outsource. Tips please!

[Onoff]

Got any photos (even of your screw ups ? ). I'm on the brink of  doing some flint panels using lime mortar.

[Roz]

17 minutes ago, Onoff said:

Got any photos (even of your screw ups ? ). I'm on the brink of  doing some flint panels using lime mortar.

??? go easy ? I bought ready mixed stuff from Cornish lime. We are going to take a needle gun to the face of the granite later, as it’s got an ugly concrete wash over it 

[Onoff]

11 minutes ago, Roz said:

??? go easy ? I bought ready mixed stuff from Cornish lime. We are going to take a needle gun to the face of the granite later, as it’s got an ugly concrete wash over it 

 

Bits look alright to me. I wonder if you could Disclean the stones and not affect the lime mortar?

[Cpd]

You could try and brush it back a bit with a stiff brush before the mortar sets to expose a bit more of the stone, this will also help to get rid of any snots and give a consistent finish, but it looks good for a first attempt. 

[Roz]

1 hour ago, Cpd said:

You could try and brush it back a bit with a stiff brush before the mortar sets to expose a bit more of the stone, this will also help to get rid of any snots and give a consistent finish, but it looks good for a first attempt. 

I did do this, but 24 hours and 30 hours afterwards it was still too wet, but 48 hours after I think maybe it was too dry. I'll try to catch it in between next time and maybe I'll get a smoother finish!

 

Thanks a lot  Maybe I'll get better as I go!

[Roz]

1 hour ago, Onoff said:

 

Bits look alright to me. I wonder if you could Disclean the stones and not affect the lime mortar?

 I hadnt heard of this before!

[Onoff]

Looks like white vinegar and water is the first thing to try before Disvlean which is muriatic aka hydrochloric acid:

 

[Brickie]

If it stiffens up after a few days & is past workable you can always liven it up with a splash of water. 

For pointing I now use a grout bag (Screwfix next day or Amazon for the great but dear Marshalltown ones.) 

With the bags (& indeed the pointing guns) you have to treat it like plastering in terms of mixing & cleaning i.e. a mixing drill in a Gorilla bucket to keep any stray stones etc out of it. Keeping the mixing equipment,buckets & mortar boards free from even the tiniest debris is essential. 
if all that sounds like a PITA,the payback from using a bag against hand application is huge. 
Good luck!

[mm289]

Some pics below of lime pointing on flint panels and brick. This was using a NHL 3.5 mix, good for a day or two but after that will go off chemically unlike putty based mixes which you can knock back up again for quite a long time.

 

Have repointed most of the farmhouse taking out cement and also done a lot of brickwork in lime. Knack to it is not putting in too wet so it doesn't drip/run, point up rough then come back a few hours later and push into joints with tools. Then a few more hours/next day bash with a bristle brush on the perps/lines to push in hard and roughen the surface and finally finish with a wire brush just before it sets hard.

 

hTis way you get a nice recessed finish and clean bricks. If we do get runs or overspill we use brick cleaner.

 

TBH we have found mortar guns are no use for us but that might be due to the sand mix being a bit course to match our original mortar. but even when using the expensive guns it just compresses and cakes hard in the gun.

 

old school with mortar board and finger trowel ground down to thickness of gaps between bricks works best for us.

 

Above is based on what I learnt from a old boy who had been doing it most of his life and then what a very skilled team of restoration brickies did that I had in to do the larger areas. Not saying its the only way, just the way we do it.

 

Cheers,

 

MM

 

 

[Brickie]

Yeah,any coarseness in the aggregate makes a gun or bag useless. 
Nice work,btw!

[Onoff]

1 hour ago, Brickie said:

Yeah,any coarseness in the aggregate makes a gun or bag useless. 
Nice work,btw!

 

I actually split a good mortar gun trying to put a sharp sand / cement mix through it. Cracked the barrel. Durgun I think it is. Still in use just heavily bandaged with tape.

[Onoff]

8 hours ago, mm289 said:

This was using a NHL 3.5 mix, good for a day or two but after that will go off chemically unlike putty based mixes which you can knock back up again for quite a long time.

 

NHL? ... hydraulic lime?

 

I want a mix where I can trowel it in then lay / push my flints in then do another course. What do you reckon. This is laying rather than pointing. Cheers.

 

 

[Triassic]

I use a churn brush to knock the lime mortar back into the stones, this also helps get a nice look to the finished wall, any mortar left on the stones tends to weather off over the next couple of years.

[mvincentd]

Ok, this is onto flint blocks and not lime, however he's told me the technique would be same just a different mix for lime.  My choice of nailpointing to make the stone 'pop' is optional.

Someone good would think in terms of doing 6sqm a day.  Put as much muck in as gets you to the middle of the day, then go to the earliest stuff and wire brush, nail point, then soft brush.  (The video is of my upper floor which is using standard yellow sand but white cement, the final photo shows lower floor which is 5 white sand, 1 lime,1 white cement.)

 

[mm289]

10 hours ago, Onoff said:

 

NHL? ... hydraulic lime?

 

I want a mix where I can trowel it in then lay / push my flints in then do another course. What do you reckon. This is laying rather than pointing. Cheers.

 

Yep, hydraulic. Alternative to using lime putty mixed in wioth sand which is what the premix bags are. Very different to hydrated which is what your builders merchant stocks and can't be used in the same way.

 

We use St Astier, Derek March up in Maidstone stocks it or you have Chalkdown Lime over Tenterden way who make their own readymix in all different grades.

 

Either will do for laying and or pointing, the flint in the walls in the pics above are all laid with NHL3.5 as we were using that for the pointing anyway and wanted it all colour matched.

 

Are the brick piers laid in lime? If not watch out for colour match as a lime mortar will look quite different to a cement based one unless you play with the sands.

 

Cheers,

 

MM

[mm289]

11 hours ago, Brickie said:

Yeah,any coarseness in the aggregate makes a gun or bag useless. 
Nice work,btw!

 

Cheers Brickie?

[Onoff]

8 minutes ago, mm289 said:

Yep, hydraulic. Alternative to using lime putty mixed in wioth sand which is what the premix bags are. Very different to hydrated which is what your builders merchant stocks and can't be used in the same way.

 

We use St Astier, Derek March up in Maidstone stocks it or you have Chalkdown Lime over Tenterden way who make their own readymix in all different grades.

 

Either will do for laying and or pointing, the flint in the walls in the pics above are all laid with NHL3.5 as we were using that for the pointing anyway and wanted it all colour matched.

 

Are the brick piers laid in lime? If not watch out for colour match as a lime mortar will look quite different to a cement based one unless you play with the sands.

 

Cheers,

 

MM

 

The bricks are laid with 4:1 builders sand / opc. Was thinking the lime mortar would contrast anyway. Now you've got me thinking that maybe I should try and match the colour:

 

This stuff was what I was going to use, B&Q Tonbridge Wells appear to stock it:

 

https://www.diy.com/departments/blue-circle-hydrated-lime-25kg-bag/35712_BQ.prd?

 

This is the text on the link. Is the 1:1:5 or 6 mix any use for what I want to do do you reckon? Cheers.

 

Blue Circle Hydralime is a hydrated lime used for increased plasticity & cohesiveness in cement, mortars & renders

• Preparation: 1 part Portland cement, 1 part hydralime & 5 to 6 parts sand

Features and Benefits

• Blue Circle Hydralime is a hydrated lime used for increased plasticity & cohesiveness in cement, mortars & renders
• Fine, white, dry powder which lightens and brightens mortars
• A high calcium, non hydraulic, hydrated lime
• Makes floating renders and pointing mortars easier
• Hydralime can be used for traditional nominal mixes for mortars and renders in conjunction with standard Portland based cements or in lime-washes without cement

[mm289]

So two very different types of mortar we are talking about.

 

Lime mortar made with Lime putty or NHL is a natural mortar that sets by reacting with the air, it is what has been used as mortar since roman times etc and is the way houses were built until "modern" times. It "breathes", can flex, lets moisture in and out and is why old houses built in lime don't have DPC's etc normally as the walls can breath (until they are rendered/plastere/painted with modern materials and then become damp infested nightmares?)

 

Modern cement based mortar uses portland cement and is non porous, stronger so fractures rather than flexing and sets chemically. Hydrated lime (not hydraulic) is sometimes added to portland cement based mortars to aid its workability and acts like a plasticiser. This IS NOT lime mortar as a restoration builder would talk about it?

 

So if you have built the pillars in cement based mortar, no probs using the mix you reference above, it is still a cement based mortar, just it is quite different to the mortar I think the OP was asking about when people talk about "lime mortar".

 

HTH

 

Cheers,

 

MM

[Onoff]

9 minutes ago, mm289 said:

So two very different types of mortar we are talking about.

 

Lime mortar made with Lime putty or NHL is a natural mortar that sets by reacting with the air, it is what has been used as mortar since roman times etc and is the way houses were built until "modern" times. It "breathes", can flex, lets moisture in and out and is why old houses built in lime don't have DPC's etc normally as the walls can breath (until they are rendered/plastere/painted with modern materials and then become damp infested nightmares?)

 

Modern cement based mortar uses portland cement and is non porous, stronger so fractures rather than flexing and sets chemically. Hydrated lime (not hydraulic) is sometimes added to portland cement based mortars to aid its workability and acts like a plasticiser. This IS NOT lime mortar as a restoration builder would talk about it?

 

So if you have built the pillars in cement based mortar, no probs using the mix you reference above, it is still a cement based mortar, just it is quite different to the mortar I think the OP was asking about when people talk about "lime mortar".

 

HTH

 

Cheers,

 

MM

 

Thanks. Way back on here someone I'm sure suggested that if I used a cement based mortar it wouldn't breath / flex around the flints. In fact as it set it might shrink away from the flints leaving them to almost rattle in pockets. This in turn could lead to water seeping in between the flint and mortar. Obviously really keen to avoid this. 

 

Does the addition of lime guard against thus or should it be a pure lime mix? As in does the workability and plasticising effort carry on to the "set" mortar?

 

Cheers

[mm289]

The addition of hydrated lime won't help in that regard as the set is still a chemical set based on the use of portland cement. Having said all that, flint is very inert, I am not sure that you would need a mortar that flex'd around the flint - we used lime as it was in keeping with our property but not sure I can see a reason not to use portland cement based mortar......

 

looking at  @mvincentd post, he seemed to imply his flint walls were made with portland cement based mortar?

 

Cheers,

 

MM

 

[Simplysimon]

go to the nearest college which does courses in brickwork and ask the technician for your mortar, a nice xmas present should suffice

[mvincentd]

2 hours ago, mm289 said:

looking at  @mvincentd post, he seemed to imply his flint walls were made with portland cement based mortar?

Yes.

[Onoff]

[scottishjohn]

On 19/11/2019 at 17:23, Roz said:

Anyone got any close up photos of their lime pointing - preferably on stone, that they can show me so I can see what I am aspiring to? I started yesterday and think it looks pretty messy, but am following guidance online. I realise it's a skill, but not one I think we can afford to outsource. Tips please!

Is this the right time of year to be doing lime mortar building ?

Iwas ubde the impression it was a summer job building with lime mortar,due to its drying time