I have an old brick and stucco home in the southern US (roughly 200 years old). In the rural south, older homes like this aren’t as common as the northeast, so there’s not much knowledge about properly preserving these old places where I am. Videos like this are invaluable to me, and I’m sure many others. My house has had concrete products used to repoint, or even stucco, much of it in the last 50 to 70 years, and that’s done some damage. The damage is not irreparable, but it just goes to show that the art and science of these old structures has been lost to time in many areas like mine. Videos like this are a HUGE help to me to know how to better preserve my old place. Thank your for sharing your knowledge and sending your video out into the world!
Thank you for a comprehensive explanation. I've got some decorative brickwork to do in an 1880 town house and to be honest to the property, I'm doing it in lime, the bricks are soft handmades so Portland cement would be way too strong even with a weak mix. So thank you. 😊
You are spot on. I have learned a few more details with this video. Thank you. But, DON'T put your arm in a revolving mixer! It would do a number on your elbow and shoulder if it grabs and twists your arm. John C. Bielik Bethel, Missouri. USA
@@michaeljamesdesign thats what i heard about nhl bring stronger than people assume And i find after knocking it up after gone off a bit that its greatly improved workability
Nice explanation, we are using NHL5 ( we are adding reinforcing fibres for binding strength) and topping off with NHL3.5 for internal walls. Our requirements are slightly different as we are renovating a cave house, that had been dug in sedimentary rocks. We are using crushed marble sand as our medium as its easier to get hold of in the area that we live.
@@michaeljamesdesign yes it is a little harder than we would like, unfortunately the 3.5 was not quite strong enough and cracked then separated in places. The other cave we must renovate is more stable on the walls, so plan to use either 3.5 or cal hidraulica, which we believe is hydrolic lime mixed with white marble sand 0-2mm. Any thoughts would be most welcome, if you have the time.
Jonathan mentioned galletting stones or small flint pushed into the mortar as you go to prevent cracking. I tried it and I have no cracking issues whatsoever. Could use pea shingle, chipped brick or stone you have locally but the harder the better. the bigger the joint the bigger the size of the galleting stone
@ michael Birchall .... I agree 100% with what you say. I find the way people mix so confusing. Mixing by weight, as done here, makes the most sense to me. The only caveat being how wet the sand might be, but that's probably miniscule in weight so irrelevant.
I'm following your method for repointing the interior of an 1890s brick and stone foundation. Like you note in this video, there's a big difference between sand and lime by volume. I've done mixes both by volume and weight, when done by weight, It ends up being 2.25 containers to 3 masons sand (The sand I have is probably a little wet, which adds to the weight). I saw mentioned in another article to use as little lime as possible and should calculate the "void space ratio" of the sand you use. It would seem your use of pebbles on your deep mortar joints would support this theory. Any thoughts on this?
Lime putty mixed mortar is more breathable than NHL mixed mortar. There are no clay particles in a standard lime putty mix, as in a hydrated lime mix. A lime putty mix won't cure as hard as an NHL mix of mortar. In my own work, I'd tend to use a lime putty mix for actual construction of a masonry unit, or lime plastering. I'd steer clear of any cut or tuck pointing when using lime mortar. Dressed mortar may look the part but water sits on the joints in the structure and the time taken for water to get to the ground is drastically increased. Thats just my personal opinion, Jonathan.
Hey man, so i want to build a stone house using local granite and would like to use lime mortar. What NHL lime would you use for this. Or would you do a hot mix with quicklime. I'll be apprenticing this year. Lots to learn
Great video, we are doing a full new-build with handmade clay bricks. Please help me with the questions below: 1. Do you recommend NHL 5 or 3.5 for mortar bed and pointing? 2. We are after a buff colour mortar, so using yellow building sand with lime, what ratio do you suggest? 3. Can we use mortar colour dye (like Bostik Cementone Cement & Mortar Dye) when using lime? 4. Do you recommend using any white cement in the mix for the mortar bed? Keep up the good work! Please reply.
Thanks buddy. For the actual construction side of using lime mortar, I would encourage you to use a lime putty as the binding agent. We only used an NHL 5 on this property, due to the exposed aspect. If you are in a sheltered site, an NHL 3.5 would be more than sufficient for the strength of the cured mortar. When using colouring additives, I would steer well clear of commercial dyes and colourings. They are made from synthetic constituents. These will have an impact on the functionality and breathability of the lime mortar. When colouring the lime mortars, you could experiment with some different coloured sands, or stick with natural pigments. Oxide based pigments work best with lime mortar. The ratio of aggregates to binder in the mortar will depend entirely on the substrate that you are bonding with the mortar, weather exposure, surface temperature of the finished structure and various other aspects. Never use any cement of any sort in a lime mortar as it removes the breathability and fuctionality of the lime mortar. Hope this helps? Hope this helps?
hello bit help please ,customer asked me to repoint existing house i think built 1950s.Existing many bricks cracked vertically in middle of bricks which i find abit odd.The existing mortar looks like hydraulic lime which looks like mixed with greyish bits added and hard as cement ..My question is some of the building is not being repointed so i have to match existing,which sand can i use would it be washed sharp sand .Thanks malcolm Devon
Great video. I would think that measuring cement by weight would produce the same problem. I thought that's why it's all worked out in parts rather then in weight, so 1 part could be a spoon a bucket or a skip, as long as the sand and lime are all measured with the same item. 3:1 = 3 buckets sand and 1 (same) bucket lime. it even states this on the back of most lime and cement bags. But I'm not a builder. Great to see you gauging it out properly though, I cringe when I see people using shovels to measure, surely that's not consistent!
See page 29 regarding weighing - 'Measuring by volume can be inaccurate as this does not take account of the variations in RBD of different binders, which can affect binder:aggregate ratios. '
@@michaeljamesdesign I was thinking more at a feasible cost. Current price is $24 for 90lbs binder, plus driving fees, I'm just lucky the have metakaolin locally also.
@@michaeljamesdesign Yeah, there is a lot of love for hempcrete here and a many companies pushing it as the new thing with relaxed US hemp regulation. When the binder is pushing $90+ a 40lb bag delivered it really makes it not feasible for people. It's also very difficult to find good information on the various types of lime and what can be used as a binder. I'll do some videos on my path with metakaolin and hopefully it will open up some options for people in different locations.
Many thanks for this info. Could you help with some info on lime pointing internally? I have some inside walls to do on a 1830s Yorkshire gritstone building. Should I use NHL 3.5 and with what type of sand and aggregate and in what ratio? Also for large voids should I fill with larger stones and a bit of mortar and then let it go off a bit before pointing over the top?
Hi Seb, pointing internally is exactly the same process as external pointing. I use the same mix ratio as external pointing on random stone. On internal brickwork, depending on what the client's specification is, I tend to leave out the granite dust and use an extra sand to make up a 3:1 mix ratio. This results in a brighter coloured mortar that contrasts better against brick. This is my personal choice and obviously you could adjust the constituents of the mortar to your own preference. If you were to backpoint large voids, I would be tempted to leave the backpointing to carbonify for a few days, before the application of mortar. Keep in mind that the carbonification process is optimised at mortar depths of 25mm or less. Hope this helps?
Would love to hear elaboration about how lime allows moisture to wick through vs cement. In the states seems like portland is the standard i often here other countries say cement is a mistake and US always saying lime washes away. So confusing
I think the theory behind it, is that cement bonds the aggregate chemically into a solid, impeneterable structure. The cement bonds are so strong that the mortar won't allow for any form of movement, or expansion in the mortar bed/pointing. Lime mortar acts more like a cushion than a bonding agent. Mortar, ideally shouldn't bond the substrate. The mason should work towards making the stonework "hold" for want of a better word, itself together. Giving the structure strength, Instead of relying on the strength of the mortar to do so. Thats only my thoughts on it. I may be wrong.. Well mixed lime mortar won't wash out of the works. Just returned from a trip to the west coast of Scotland. Saw some 1000 year old, habitable, structures on an island. The lime mortars used, still look to be perfoming their job dutifully.
Great videos, very informative. Would you recommend mixing in a fine white mortar sand with the sharp sand to give a lighter finish? If so, what ratio do you suggest? I'm planning to use NHL 3.5 with a sharp washed sand. Any info appreciated, I'm new to this.
Hi there. Many thanks for the comment. I'd steer clear of any fine sand in your mix. There are several colours of lime that can affect the finish colour of mortar. You can find chalk white coloured lime or pure white. The chalk white gives the finish an off white colour. You can use various colours and kinds of sand in test mortar patches on the wall to see what finish colour your project will have.
@@dportercontracting9974 Thank you for your reply, much appreciated. Damn I've now got 250kg of white fine sand if anyone is looking to buy some, haha! This weekend made my first mix to back point the wall I've virtually had to rebuild from bottom up, it's 200yr old. I've learnt everything I needed to know from watching your informative videos, without them I wouldn't have had any aggregate or sharp sand (all I bought originally was lime 3.5 and white sand). How long do you recommend leaving the wall after back pointing to finishing it with a lime render coat? TIA
hello again,i think this house they used granite dust as the picture i took of the hse looks same when in your vid you used the churn brush on the wall to expose the motar between the stone.
Great educational videos. What mortar mix would you recommend for pointing up a granite property in Aberdeen? 1 part 3.5 nhl + 3 parts sharp sand? If you're ever short of work, head north. You'll have job for life re-pointing this city 😏
Thanks Smell my cheese. It completely depends on what kind of weather your property experiences, what aspect faces the sun, etc. You should get a decent mix with a 2.5 to 3: 1 sand to lime ratio. I'm guessing Aberdeen will be like most places now, cemented over the lime?
@@dportercontracting9974 Thanks for getting back to me👍. It's a south facing wall so I guess will have more temperature variances but less rain? I actually have a tub of lime putty and the old mortar is just sand now so in some places it's like 3" deep. Can I do it in 2 stages? An inch or so initially with larger aggregate then the final finished pointing in a few weeks when I have time? Yeah, we have a total mix up here. Patchwork white lime pointing and plenty of cemented for sure!
@@RockStockStar Sure thing to doing it in stages. If you back point the wall then it would be ideal to let it partially cure before you apply the finish pointing. I've a video on pointing a granite house up on Mull which would be a similar background to your property that you might get some help from.
Portland should be used when solid brick or stone is the main wall. Lime mix must be used to allow the wall to breath and move in the way it does. A small amount of prtland added is sometimes used to mke the lime mix a 67% hardness . I like your use of granite dust. Nice one .
Thanks for your input. We don't use cementitious mortars as it stops the breathability of the wall and stops that active flow of moisture from the living space outwards. The harder the mortar, the more chance there is of cracks forming in it, allowing moisture ingress and damp forming . A lime based mortar acts as a cushion for the substrate, rather than a solid, fixture.
Great video, what ratio of sharp sand & NHL would you use of for repointing a standard brick 70's house please? I'm still trying to get my head around not needing cement lol, Thanks
Hi matey, thanks for the props! If you go for a 2.5 to 3:1 ratio of sharp sand to lime, you won't go far wrong. Itll look ace when ypu have lime pointed the original brickwork!
@@mondayschild3493 The local builders merchants is where I source my grit sand. Some call it "River sand." That will be a sharp enough aggregate to use in your mix.
@@dportercontracting9974 OK thanks,i did a 3 to 1 mix with sharp sand and NHL5 when i cut some bricks out of a wall and replaced them i could not get the lime mix to stick to the brick, it was a case of forcing the mix into the joints to try and create a bond. I have some more to do i thinking of using 2 parts soft building sand and 1 sharp. The bricks were damp so this wasn't the cause of it. Can sharp sand be too sharp? as it just says "sharp sand" on the bag.
just about to start a pointing job on a brick house. I see the original pointing has specks of black - assuming char - any idea what this is for and whether I should add to the mix? makes for quite a nice effect and I have made some char this year that I could grind and add.
Hi Sophie, The black specks could be coal dust or mica. Depending on how faffy about the mix you want to be, you could send a sample of your original.mix off to the Scottish Lime Centre. They will do you a microscopic evaluation of the contents of your lime and mix up a batch of like for like mortar to match your original mortar. I expect that the black content of the mortar will be black ash. If the project is in the north of England, then there used to be bins on the end of most northern streets that the fire ash went into. The municipality then collected these coal, ash bins and the contents went into making lime mortar on local building sites. It makes for a very hard lime mortar when mixed right.
@@dportercontracting9974 thanks - this is in the South West near Glastonbury. Lots of mining around here so could have been coal dust as you say. I wondered about how it affected the property of the mix so might try a small sample and see what it looks like.
You can use regular hydrated lime from the builder merchants but it will give you a weaker mortar upon final set. If you go to your local builders merchants and ask for a NHL 3.5, they will happily order you a bag or two in. The extra 10er a bag will be well worth the money.
Various components of the mix will add colour or tone to a mix. NHL lime has clays in it which will add a darker or more grey colour to the cured mortar. Lime putty use, produces a brighter, whiter finish to the cured mortar. Various colours of sand are available, depending on where in the country you are. Each sand produces a different tone or colour to the mortar.
Hi the video show you out 2 buckets of sand and 1 bucket of granit dust. The video says 4 to 1. Can viewers assume you added an additional bucket of sand that is not shown in the video. Thanks.
Further to my comment below I looked at the data sheet for the Tarmac Limelite NHL 3.5 that I'm using and on it it states "mortar mix proportions by volume" . So clearly weight or volume can be correct, you just need to check the data sheet.
@@michaeljamesdesign sorry is this not your page Thought it was as you're answering the questions I just checked as well its by volume with secil not weight
The reason it's that horrible grey colour is because Secil is from argillaceous limestone which is high in clay. That's why it's cheap in comparison to other decent brands. Traces of gypsum have also been found in it. The Secil quarry used to mine gypsum. NHL5 has very little free lime and is too hard even for chimneys. Your work is good but you need to up your game where your materials are concerned.
@@dportercontracting9974 It's a statement of fact Mr Porter. Roundtower NHL5 has a free lime content of nearly 25% whereas Secil NHL5 contains only 15%. So that's an 85% impurity content. I'm trying to persuade contractors to be more discerning where NHL is concerned as a lot of it is piss poor and sets really hard over time. Ideally you want to be looking at 40% available lime. There's not much difference in the price and you can use superior products to help you win better customers and more well paid work. Jus sayin
@@michaeljamesdesign Hi. I cant seem to source Roundtower locally. Could you recommend some other good hydraulic lime brands. Just Ionic and Hanson from our local builders merchants. Thanks
@@JR-yl2rm Speak to Declan and Chalk Down Lime. Tell him about your project and that I've recommended you give him a call and that you want a decent NHL. He'll look after you.
It's nothing to do with repointing which he's very good at, I'm just interested in why he chose that style. The problem with society today is that nobody can make a simple comment without somebody trying to put a nasty slant on the comment. By the tone of your question, I believe that you may be one of those people. His hairstyle does matter, especially to him, otherwise he wouldn't have gone to a lot of trouble to get that look. It's like the racist thing. It's gotten so far out of hand. It is destroying free speech. People nowadays have to be so careful about what words they choose before they speak. A sick society is being created by a minority.
@@johnchampion7819 I admire your slippery ability to manipulate my reply into the inaugural negative I wasn’t remotely negative. Your question was which is likely why the chap with locks didn’t respond
@@Southpoint2019 Give the lad time to respond, he's probably busy repointing. I wasn't trying to lecture you. Your comment raises the question as to why you made it.
I've been wandering round the wilderness of wild Scotland for the last 10 days. No signal, nor the want or inkling to go online bud... What was your question?
I was wondering if you could do a video yourself? Show us all how its done.. I do suppose that if you were a master then you would do your own work so you wouldn’t take anyone to court, hey!