The difference between lime putty and natural hydraulic lime

Reasons for choosing to repoint grade two listed buildings using lime putty instead of natural hydraulic lime

[@martandsue]

hello mike, I want to point a old soft stone building , the stone is really soft and wearing away badly in areas, which lime mortar putty do you recommend that's pre mixed, and best on line web site to get it from, thanks martin

[@michaeljamesdesign]

Mike Wye's standard lime putty mix. 900 grams off the back of a tail lift. Cracking quality. Sorry I didn't answer earlier.

[@DimMak2011]

Hi James, I have a property in Hungary I am trying to renovate. They use lime putty, fine sand and cement in their mix for everything, but all the renders fall of the wall and turn back to almost sand dust !and any pointed wall suffer from blown bricks as well. As the lime putty and fine sand is readily avalibe, what would be the best mix for re pointing brick walls and also for the external render which always suffer from thaw/frost at lower leves and eventually pops off the wall. difficult to explain, I am not a pro, and everyone here uses 3;1;1 mix with cememnt, which obviously is not working. winter -10 regulary or more, summer 40deg!. Any help appreciated, no sharp sand only fine sand.

[@MrFlynnytwo]

You should not use cement

[@bamptonbred]

Hi, could i ask what the mortar removal tool is called? you mention it on your website and only being available in Denmark. Thanks

[@michaeljamesdesign]

That particular tool is for brickwork. I tend to use a combination of tools. Some powered, some not. A picking axe off eBay or you local builder's merchant is what you want for soft stone.

[@jamiewatkinson5427]

Question sir, how do you know what type of mortar 2 use on certain bricks. I'm starting a brickpointing business and I want to make sure that I use the correct mortar for the brick I'm working on.

[@michaeljamesdesign]

buy Nigel Copsey's book

[@phoenixj1985]

Information in this video and others have been very helpful in my study of Lime Putty that I have recently started working with for the first time. LP is an underrated and misunderstood building material with almost miraculous 'self healing' properties. There are numerous reasons why Lime Putty is used, some are described in this video. Due to its softness, the putty will erode faster than the surrounding stone (the stone can erode leaving a hole surrounded by eg 'Portland' cement). Putty is easier to maintain than cement. Putty does not damage the surrounding stone. Primary reason. Putty is fluid, flexible and self healing, therefore with old houses that may have some degree of movement. Cement may cause greater damage to the stone work in this occurance. The putty acts as sacrificial pawns of this movement and becomes cracked. Smaller cracks may self heal. Larger cracks can easily be re pointed without damaging stone. What I dont understand is why so much putty? The stone work is now barely visible. I understand the need for good adhesion, but this looks OTT surely?

[@michaeljamesdesign]

You'd have to ask the original builder why they used such small pieces of stone.

[@phoenixj1985]

Thanks for the reply. If the cottage was originally built in that manner, it would make sense that after re-pointing, it appears this way. Thanks again for your info, really interested in this type of craft and gain as much knowledge as possible. It is only recently I started working with Lime and was fascinated to hear of its history and unique properties.

[@rogerscottcathey]

wouldnt the surplus just be sacrificial leaving enough when sloughed?

[@saren6538]

Nice info but that’s straight out of a book

[@YouSillyLittleBoy]

Hi, would you happen to know if new builds in stone can use lime morter or do building regs prevent this?

[@michaeljamesdesign]

Building regs do not prevent this. After all, why should they?

[@boradaff]

Could you please share the mix you are using for rendering the plinth area? Thanks in advance!

[@michaeljamesdesign]

I didn't do the plinth, sorry.

[@matthunt2128]

Hi. I have to repoint an old Portuguese stone building and have chosen to use a lime putty mix. What mix ratios would you recommend? Thank you

[@michaeljamesdesign]

Haven't used lime putty for pointing for about 8 years now. I only ever use it for top coat plastering. I found it too much like hard work because it takes so long to go off low down. It's now my opinion that good putty is only really suitable for skimming.

[@dellas7137]

i use lime putty and nhl to repoint buildings i have done on and off for 10 years .i was intrested in how deep you would point ,do you put pieces of stone in deep joints and should the motar be wetter or dryer on use , i belive it should be stiffer so as to avoid shrinkage although me and myvwork colleage differ on these questions

[@michaeljamesdesign]

Hi Derek, I always go as deep as I can. That's always a minimum of 25mm. And I always use pinning stones and tend to work with a stiff mortar when pointing stone. A wet mortar results in decreased mortar strength as it holds the grains apart. This can result in frost damage due to an open structure. Too little water and you'll find cohesion's poor.

[@petergambier]

A rule of thumb for raking out and pointing is that you go back twice the width of the joint but to be honest so long as you've taken out all the loose stuff you should be fine. As you already said, for bigger spaces put in some bits of stone and for deep areas of mortar push in some bits of brick rather than just neat mortar.

[@josephcostello9947]

Hi Mike, as a professional, how much time do you estimate it takes to point a wall like the one in the background of your video. Been doing my foundations at home but finding it painfully slow

[@michaeljamesdesign]

I'm not too sure how foundations are linked to the cottage in the video but if I told you how many square metres I do in a day then that would be telling the world how to price a job. And that's none of their business. Or yours. You'd be better off asking a non-professional. They'd probably give you a realistic timeframe and you'd be working to their speed. Not mine.

[@liamwalters5029]

Joseph Costello about 3 weeks joe !

[@josephcostello9947]

Liam Walters cheers mate

[@cheshstyles]

michaeljamesdesign good answer dont give em the game

[@willclarke5140]

Hi Michael, thanks for the video. Would you recommend a mix of putty and hydraulic lime where some stones are perished but others are not? We have a 16th century cottage in west Oxfordshire, and need to get rid of the horrible cement which has been used over the years. Most of the stone is solid, but some is loose and delaminated. Thank you

[@michaeljamesdesign]

1xNHL2 x 2 sand.

[@willclarke5140]

@@michaeljamesdesign thank you. I was wondering if you sometimes use hydraulic lime mortar for the most part, but then switch to putty where the stone is perished? Is it possible to colour match the putty with the mortar?

[@michaeljamesdesign]

Will Clarke Colour match putty with mortar?

[@willclarke5140]

michaeljamesdesign yes is that possible?

[@michaeljamesdesign]

Will Clarke I think that for your needs KZbin isn’t exactly the ideal teaching forum. I can visit your property and help you through the process and get you to a place where you’re working from a taught knowledge base. Alternatively I can recommend an excellent surveyor who will be able to help you achieve what it looks like you need.

[@robgarner6244]

Hi Michael, what ratio of putty to sand did you use? I use nhl on a regular basis but have only used putty over oak lath when rendering. How long did it take to harden and how course was the sand you used? Rob.

[@michaeljamesdesign]

Hi Rob. I always use a 3:1. Hardening depends on the weather and also where on the property you're working. On a hot day at the top of a building mortar can go off in hours. In winter at the base it can take days. As far as sand is concerned I often use a rough mix of 2 sharp to 1 soft/fine as I believe the larger grains help moisture to pass more easily. They're also harder to weather so the pointing lasts longer.

[@robgarner6244]

+michaeljamesdesign Great, thanks. Very interesting

[@StanOwden]

"soft/fine" would that be regular building sand?

[@michaeljamesdesign]

Nope.

[@sunegroennebaek5283]

Thank you very much for your information. I’m thinking of making a Hempcrete home (lime and hempstraw mixed as a NON-load baring “fluffy cement”) with plaster directly on the interior walls. What would you recommend as environmental friendly and durable plaster. Or do you have any other ideas springing to mind? Very best regards from the Faroe Islands Sune

[@sroberts605]

That sounded so interesting. Did you decide? (without advice :()

[@user-mf2xi2lo8d]

Hiya i have a ramdom question my house is in wales built in the 1920s the bricks are engineering bricks what sort of lime should i use to repoint my house and how do i change the colour can i change the lime to pure white ?? Thank you gor any help

[@michaeljamesdesign]

Try quicklime.

[@extde]

What do you think about artificial hydraulic lime (with controlled properties - you decide how to mix)? Try to use hydrated lime putty and metacaoline mix (6 - 20% is clay content of limestone used for NHL production).

[@michaeljamesdesign]

It doesn't concern me.

[@zeusricochant7357]

Do you apply and finish the lime putty the same way as NHL 3.5. Can you only get that creamy look through mixing your own lime. Thanks

[@michaeljamesdesign]

Same as 3.5 but it's a slightly different animal and no.

[@kuxkiri]

I’m building an extension, out of a mix of Ironstone or Hornton, and some lighter stone, perhaps a Cotswolds building stone. The contractor is building it using modern construction (concrete block, insulation, then faced with stone mentioned above). Would you still suggest a lime mortar for such a job?

[@michaeljamesdesign]

Ultimately you're the specifier so before I answer the question let me ask you what you think as that'll give me an idea of your understanding where natural building materials are concerned. If you have an architect then tell me if he's made a recommendation and also let me know if your contractor has suggested anything. I'm sure he has as choice of material will impact on his profit margin. In sum, where are the three of you coming from?

[@kuxkiri]

@@michaeljamesdesign thank you so much for replying to my questions. My gut (a very non expert gut) tells me I should be using a lime mortar, even though the construction will be modern ie cavity wall with block work, I’d still want to protect the natural exterior stone from the hard cement. Most of the cottage was redeveloped in the 70s and not sure exactly what mortar was used, but I’d hope it’s lime. Therefore I’m thinking it would be a bad idea to go cement for the extension. Architect hasn’t made any suggestions (I have now just dropped him an email to ask), and I suspect the builders would want to use a cement based mortar...

[@michaeljamesdesign]

@@kuxkiri If your architect can't come up with anything sensible - and very few of them can - then I offer sensible consultation rates.

[@kuxkiri]

@@michaeljamesdesign Brilliant, I’ll see what he comes back with. One of the contractors came back and said he’d recommend a cement and lime mix (half and half) That doesn’t sound right to me...

[@kuxkiri]

Architect specified Lime Mortar :)

[@jeansouthworth312]

When you get a tub of ready mixed lime putty. Do you pour off the protective layer of water off or mix it in

[@michaeljamesdesign]

Well Jean, now that's a question. Firstly I don't tend to use tubs as I prefer to order by the ton. But if I did then I'd get rid of the water because it's of no use. It shouldn't really be there and it's not really protective. IMHO it's the supplier making you think you get more for your money. If they got rid of it they'd have to top up with product and they don't want to do that because it costs 'em.

[@jeansouthworth312]

Thank you

[@michaeljamesdesign]

Depends on how wet you want it.

[@mtlicq]

@@jeansouthworth312 Jean, you had the right idea: That water IS a protective layer because a good lime putty in a pail with the protective layer of water, is most likely a very good quality calcitic lime that sets with exposure to carbon-dioxide, also known as air-lime, that doesn't set by contact with water. Being in a pail and already mixed with water, significant time before you use it, is a good thing, i.e.- allowing it to age many months, even a few years, makes it better, more workable, and more freeze-thaw resistant.

[@daos3300]

so what are the differences between nhl and putty, other than that putty is 'softer'? what do they look like before use? how are they mixed? what do they contain?

[@michaeljamesdesign]

www.amazon.co.uk/Hot-Mixed-Lime-Traditional-Mortars-ebook/dp/B07NHF221C

[@Pavlo_S.V.]

Hello wanted to ask, in your opinion is possible to use cement (for better setting) with hydrated lime and sand (0,5:1:5 ratio) for rendering a brick wall layed with lime mortar, as it is quite difficult to find hydraulic lime in our region? Or even small amounts of cement will trap moisture, make wall unbreathable and ruin the bricks? Kind regards

[@michaeljamesdesign]

Where are you and is it an exterior wall?

[@Pavlo_S.V.]

@@michaeljamesdesign Hi, I am from Ukraine (north west part), with pretty hot summer up to 26-28°C and usually harsh winter below 10-15°C for at least 2 month, the humidity is relatively high. It is an exterior wall.

[@michaeljamesdesign]

Use fresh lime hydrate and 3 sand. Once you open a bag then you must use all of it. Don't go back to an open bag a few days later because it will be inert. You can plaster, render, point and build with lime hydrate. It's not as good as quicklime but it serves the same purpose and has a much higher free lime content than any NHL. But leave it sitting around (particularly if the bag is open) for long enough and you'll be in trouble.

[@WallaceRoseVincent]

Do you think that nhl 3.5 would be good for an Adobe structure? Thanks in advance!

[@michaeljamesdesign]

Nope.

[@WallaceRoseVincent]

@@michaeljamesdesign Why? Will it dissolve the adobe brick?

[@michaeljamesdesign]

@@WallaceRoseVincent It's too hard. You need a much softer approach. Best off with quicklime.

[@chrissmith841]

Hi, I have recently had a company look at my house that does lime pointing in the Cotswolds and was told they usually recommend a NHL 2 over 3.5 for old Cotswolds stone cottages I don't know what your opinion is of this

[@michaeljamesdesign]

I have extensive knowledge concerning this but it's not really for the comment a youtube comment section. If you let me know the brands they've recommended it would help.

[@alexthomson7465]

Hello Michael, I wonder if you could help me? I have a property which is in France where Lime is used in most buildings, however I have never used it. There is an interior stone wall which has 2 windows however the lime render all around the inside is cracked and needs replacing. Could you advise on how I mix it please? Thankyou. Alex

[@michaeljamesdesign]

1:3 Alex

[@alexthomson7465]

@@michaeljamesdesign thankyou for your reply. Is that 1 lime 3 sand? Also, is it nhl3. 5 I use ? Thankyou

[@michaeljamesdesign]

@@alexthomson7465 The binder is always specified first. And if you want to use 3.5 then it's completely up to you.

[@alexthomson7465]

@@michaeljamesdesign thankyou for your help. I appreciate it Very much

[@peterfcoyle9127]

Will NHL 2 or 3.5 dissipate water in the same way as lime putty?

[@michaeljamesdesign]

NHL2 will be better if that's your only objective.

[@zaidhussain3658]

should i use hydralic lime or lime putty on back garden wall the mortar is grey in some parts most off it has fallen out plus some of the sones of fallen off the area iim in is blackburn lancashire

[@LiamGrubby]

For a garden wall just use a natural hydraulic lime. If it's an igneous stone wall or beside the sea then use an NHL 5

[@LiamGrubby]

Please look up how to apply it. It will fail and fall out of not done correctly

[@zaidhussain3658]

thanks

[@michaeljamesdesign]

Well Zaid from Blackburn, you can use whatever you want!

[@tkjazzer]

Dear Mike, Thank you for posting content on lime. I am new to this. I live in Detroit, Michigan, USA. I seek a lime supplier or a way to make it on location. Do you have any recommendations? I may have to get freshly made type S hydrated lime as lime putty isn't sold in tubs here. Any tips on how to keep curious kids away from the area? I wouldn't be able to live with myself if one went blind. Thank you so much. TK

[@michaeljamesdesign]

You probably won't get lime putty or NHL where you are and if you did it'd be horrendously expensive. Get some lime hydrate. It must be fresh. Run it to a putty the night before or use it straight from the bag. 1:2 would be good. Use your common sense when it comes to children.

[@tkjazzer]

@@michaeljamesdesign thank you Mike. If the 1929 building has some Portland in the mortar, is there any harm in raking out an inch and putting hydrated type s and sand only mortar in when I repoint?

[@michaeljamesdesign]

@@tkjazzer What's type S?

[@michaeljamesdesign]

@@tkjazzer Yup, that's lime hydrate. We rarely use it in the UK as anything which has been sitting around for too long will have carbonated to the point where it won't set so it's often just used as a plasticiser for cement mortar. So use your lime hydrate and sand but if you want you mortar with a lot of fat then run it to a putty the night before.

[@wezlockley7363]

Hi do you use damp hessian after repointing?

[@michaeljamesdesign]

Depends on the weather Wez me old son.

[@phoenixj1985]

The putty needs to dry slowly in order to prevent cracking occurring. Misting and covering with damp hessian is advisable on dry days

[@aliahmed-rp8by]

How did you mix the lime mortar is it 1 lime and 3 sand.

[@michaeljamesdesign]

Yep, 1:3. Mixed in a drum.

[@tkjazzer]

Where do i get / make lime putty near Detroit, MI, USA and what can I do to make it safer around kids when repointing?

[@michaeljamesdesign]

Try this: "Hi Mike, sorry to bother you. I live in the U.S. (Detroit actually) and was wondering if you could recommend a supplier of lime putty or a method of home manufacture. Many thanks and all the best tkjazzer." Buddy, I guarantee you'll get a response.

[@michaeljamesdesign]

@@dperry428 We're used to good manners in the UK. A little politeness and a modicum of respect go a long way when it comes to asking for free advice. As you may one day discover.

[@michaeljamesdesign]

@@dperry428 You may be 77 but you're a very bad mannered septuagenarian and by the look of it quite an unhappy keyboard warrior. Everyone wants free advice like they're entitled to it. And they're not!

[@wesbravo8251]

Lol MaNnERs in the YewKayy hahahaha

[@nizarahdragon3973]

I live in the USA so no listed building but I'm not a fan of concrete so looking for something that is not wood

[@jeztickles4361]

Would you say 4:1:1 is wrong for lime mortar mix?

[@michaeljamesdesign]

Do you mean 1 x cement, 1 x lime, 4 x sand?

[@jeztickles4361]

@@michaeljamesdesign yes indeed

[@michaeljamesdesign]

@@jeztickles4361 OK, 1:1:4 is a cement mortar mix. Not lime mortar.

[@kookia213]

It was 7 years ago but i would still try to ask a question. Where I live, they sell NHL 3.5. In regards to breathable, is NHL 3.5 good for allowing moisture (raising dump) to evaporate, in comparison to lime putty. or they are quite the same (in a way that i can use either)?

[@michaeljamesdesign]

You can't really use lime putty in damp areas so a good high free lime content NHL2 would be fine.

[@kookia213]

@@michaeljamesdesign thank you. About nhl2, how do i know how much is the "high free lime content"?. What should i look for on the label? (I am buying in Portugal so will try to match a similar text)

[@michaeljamesdesign]

Saint Astier NHL2 @@kookia213

[@ingevansand9180]

And what about hydrated lime please?

[@debcrook9086]

Do you use lime putty for pointing around the windows, or burnt sand mastic? If lime, what mix ratio . Thanks

[@gdfggggg]

Hi, great video. I have to repoint a Victorian house and was wondering what is correct material to use. The old joints are crumbling and look original to me. The stone is in good shape. The interior of the house has been rendered in sand and cement (probably with waterproofer) so I wanted to ensure the breathability of the exterior was maintained as to not create damp on the inside and ensure the longevity of the walls. The stone is some kind of hard limestone. Many thanks.

[@michaeljamesdesign]

I can't say unless I see it. Sorry.

[@keithlittle293]

Hello sir Could you tell me how to just make the normal white lime mortar that was used with the with the red imperial brick???

[@michaeljamesdesign]

1 x Calbux quickime, 4 sand.

[@keithlittle293]

@@michaeljamesdesign no cement?

[@keithlittle293]

Calbux is cement I guess?

[@michaeljamesdesign]

@@keithlittle293 NONE

[@michaeljamesdesign]

@@keithlittle293 If you want exactly the same mortar as was used to build them then it's as I said: 1 x Calbux quicklime, 4 sand.

[@dellas7137]

also what is the lowest temperature for lime pointing

[@michaeljamesdesign]

Just don't do it when it's freezing.

[@phoenixj1985]

5C

[@MrChrisf633]

Hi Mike I live in the norfolk fens I have a room that backs on to the rear of my fire place after trying the fire we found smoke coming out of the plaster board we took the plaster board off and found the the lime motor in some places had fallen away and smoke enters the room I want to sort this out myself what mix should I use? The brick is soft and very old.

[@michaeljamesdesign]

3:1

[@DrobbinsMpharm]

Good Evening, Mike! I'm really hoping that you can provide some advice, because nobody else seems to be able to! We have bought an old stone smallholding, which has spent the last 30-40 years under 4 inches of concrete. When we bought it, the walls were sopping wet inside and out. We have just finished removing the last of the cement render. The stone behind seems reasonably soft - not sandstone, but some form of sedimentary rock. The binder is a common earth mortar. Since removing the render, I believe the house is beginning to dry, but it's a little early to tell. I don't know whether or not to use a lime putty as you have described here, or a NH2 to heavily point the stonework. The building is south facing, on top of a hill and is rather exposed to wind and rain (South Wales). Do you think NH2 would offer any benefit over Lime putty in this instance, or vice versa? Many thanks in advance. Dan.

[@drewbowler]

Did you get a reply?

[@DrobbinsMpharm]

Good evening, Mike! We fallow your videos closely and have finally completed pointing our old farmhouse after listening to your advice. It took us 14 months (full time work, new baby and working around blazing sunshine and thundery showers) but we've finished and are thrilled with the outcome. It's a little rough in places but I think I nailed the pointing technique the time I finished. The one little bug I have with, is that it's very light (lafarge NHL with sharp sand). Is there any means of toning it down now that it's dry? Can I make a dilute solution of mortar stain and spray it over the stonework, or is this a rescipe for diaster? Many thanks, Dan

[@kjpw147]

@@DrobbinsMpharm you could probably use a like wash on it to paint the joints while maintaining the breath ability

[@peadaroloughlin3270]

@@kjpw147 yes and maybe use an earth pigment to tint the lime wash and match the stone better.

[@everymust]

So, what's the difference between them? and, natural hydraulic lime means Hyrated lime?in Korea, Hydrated lime has been used for thousands of years.

[@michaeljamesdesign]

It's used in the UK too but it has to be fresh.

[@Scribe3168]

Can you use lemons instead of limes?

[@michaeljamesdesign]

To date empirical evidence from both the SPAB and Historic England has proved contradictory. It’s a hypothesis to which many academics and masons are currently applying themselves. It’s hoped that after sufficient PhD research that there’ll be enough data from personal endeavours and meta analysis to bring more clarity. For the moment the scientific bodies are recommending limes.

[@Scribe3168]

@@michaeljamesdesign yeah. I just tried using lemons. It doesn’t work. Limes it is!

[@giri7464]

I am not getting this lime.. I just get lime to colour walls How can i use for this white colour..

[@michaeljamesdesign]

Add quicklime to water.

[@douellette985]

Would not, in era of original construction, this exterior wall have some type of rendering or plaster, however you locally name it? Strikes me this vulnerable stone would be better severed by such a coating, violating the currently prevailing tastes as it might do.

[@michaeljamesdesign]

Historical photos suggest not.

[@joshtargo6834]

The stone is probably just fine in the weather. Stone is quite durable.

[@DenianArcoleo]

Beautiful result. Please can you set out your lime putty mix in detail? Thanks.

[@michaeljamesdesign]

Denian Arcoleo. I cant dude. I guard my recipes. Like Coca Cola.

[@Miki-rc1ml]

@@michaeljamesdesign asshole

[@barrieparker200]

I'm unsure any mason or pointer would give up a mix to be honest, it all depends on the stone or brick, each mix is different... you need sand aswell as grit in the mix, the sand helps to bind the mix whilst the aggregate in the grit gives it bulk and gives strength. A mix I use on one job maybe completely different to my next one, the colour of the final mortar will be set by the sands used within the mix. Red building sand with a red sharp sand will give a different finished product to say sherborn yellow sand with some waddington river sand for aggregate. Also the amounts of lime and type of lime used, putty, calbux 90, or NHL's 2, 3.5 and 5 also have an impact, as does the brand of limes. Saint astiers lime is brighter than say tarmac NHLs, there is so much to take into account before just diving in and having a go at your own property. Techniques for pointing depending on the situation, tools used, how it needs to be finished using brushes, how far back you will rake the joints, are they wide joints, are they fine joints, what is the final result both aesthetically and technically your looking for.. learn as much as possible through reading and try to understand the product why we use it, what are its benefits, downfalls and traps to watch for. I dont think for one moment james was trying to be funny about not giving a mix away. Hard work and years of learning and experience go into the job when you earn your living from it, one piece of advice on one video may give you personally the wrong result, suddenly a bad comment could see his work dry up... 👍👍

[@unassailable6138]

@@barrieparker200 He is selfish.

[@Iazzaboyce]

That tile sill under the window should have been done better. It should be 7 whole tiles and fitted into the stonework each side. Also the angle is way too shallow, as water will easily be blown underneath the window causing damp to the wall and rot to the window frame. I should replace it with a piece of slate tomorrow.

[@michaeljamesdesign]

Yep, you're absolutely right. And there was some rotten stone under the cill to support your prediction.

[@chinhvannguyen1685]

Hi, can I putty wall from cement, Lime and polymer latex, tks very much

[@michaeljamesdesign]

I'd answer that if I could understand it.

[@davidinger4150]

It might be an old building but the stone work is rough with its about 50 / stone and mortar !

[@michaeljamesdesign]

Just an old cottage David. It used to be a cobbler's workshop.

[@robkovacs2100]

A question, please :- I have a house in Shropshire on a hill. The south-west facting brickwork is hit hard by strong winds and horizontal rain for prolonged periods in the winter. The brickwork extension was built in 1974/75 and has never been re-pointed. The perpendicular joints were never (originally) mortared properly and are leaking. I am going to re-point the brickwork. There is no sign of brickwork spalling. The bricks look very good. I need a re-pointing mortar that is fairly weather-proof, and also breathable, as the cavity wall has let in a lot of damp and I need this to dry out over time. I am also repairing the cavity insulation (from the inner skin !). What mixture ratio of cement, lime and sand should I use for re-pointing? Also, what "type" of lime should I use (hydrated, hydraulic, NHL2, NHL3.5 or NHL5)? What type of sand (builders/sharp/washed). T.I.A.

[@michaeljamesdesign]

The first thing you need to deal with is the fact that you never combine cement with any kind of lime unless you're using lime hydrate as a plasticiser for your cement mortar because you want a more workable mortar for building or rendering.

[@robkovacs2100]

@@michaeljamesdesign Thanks for the quick reply. Is the term that you used ... "lime hydrate" ... just another term for "hydrated lime" (not the NHL stuff)? I wanted to add "lime" to make the pointing mortar more workable, adhere better and make it less brittle, as I have seen that the cement/sand mortar that was used to build the extension does seem to be cracking up and coming out in hard, lumpy bits. The bricks seem to be holding up perfectly, but the mortar is definitely deteriorating from the harsh weather here. What mixture components and ratios should I use for a pointing mixture for harsh weather, hard bricks and cement/sand "original building" mortar? T.I.A.

[@michaeljamesdesign]

@@robkovacs2100Lime hydrate is hydrated lime. There's a lot of failing 70s mortar around nowadays. Builders then used washing up liquid to make the mortar more workable and this is the result. Builders are often found to be mixing different components based on no empirical evidence what so ever. I use 1 cement, 1 lime hydrate, 4 building sand and 2 sharp when laying bricks or repointing non-heritage. You could go 1:1:5 if you wanted harder.

[@strummer6642]

You don't need to be an expert in lime mortar etc. just get a time served brickie, he will know what to do.

[@michaeljamesdesign]

Of course he will. They all do.

[@raolhooley]

this was supposed to be about the diff bet lime putty and hydrolic lime? oh well..guess it wasnt..lol

[@michaeljamesdesign]

Sorry grant, it was badly titled. One of these days I'll change it.

[@monkeybeatz5372]

You should not be using NHL for this purpose and Lime putty is only good for internal work, even then its debatable. I am a stonemason and have spent much time researching and reading old textbooks to find out how lime mortars where really made. Just a bit of friendly advise here but if you do your research you will find out that NHLs have only been around since the mid 1800's and as for lime putties, well really they were only used for fine plaster work internally. They were never used externally as they are simply not rich enough in Lime to be durable enough. This leaves one true method to make lime mortars which not only is durable and has superior workability, but will be a proper match to the existing mortar ;-)

[@gary24752]

What would that mix be?

[@monkeybeatz5372]

Hot Mixed Lime, it is how it was done for centuries. Putty has not place for external work and only minimal use internally. Lime mortars need to be binder rich, lime putty mortars are not binder rich at all. If you analyse older lime mortars you will quickly see that there is a lot of binder present. Some thing like 2:3 or even 1:1 that is why they were so durable even though they may feel soft to touch. I am a Stonemason and have been using Hot Mixed Lime for a few years now and it is a superior mortar. @@gary24752

[@michaeljamesdesign]

@@monkeybeatz5372 You must've read Gerard Lynch's paper: The myth is in the mix.

[@Littlelamb2023]

grow a ponytail, wear a waist jacket and a flat cap, then you can charge twice as much haha

[@michaeljamesdesign]

Alternatively you can measure up incorrectly, underestimate the amount of work involved, deal with breakdowns, staffing issues, challenging clients and bad weather only to discover that it's your accountant who hasn't grown a pony tail and doesn't wear a waistcoat who is the one who's charging too much. Ha ha.

[@Littlelamb2023]

@@michaeljamesdesign im only messing fella you know that right?

[@michaeljamesdesign]

@@Littlelamb2023 Of course you are. Haha.

[@Littlelamb2023]

@@michaeljamesdesign is that sarcasm?

[@michaeljamesdesign]

@@Littlelamb2023 Well there doesn't seem to be anything else to do around here. You only seem to be interested in my hair and what I have to wear so there's not much point in talking about lime repointing. But if hair and clothes is all you want to talk about then I'll happily indulge you. That's sarcasm.