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Thanks for your comment. In this demonstration, lime putty mortar was used. We usually mix this at a ratio to 3:1, which is 3 parts sharp sand to 1 part lime putty, by volume. The additive is a pozzolan, to accelerate the setting process and give the mortar some early strength. The specific product has changed since this video was produced, but is the same form of material - metakaolin. Where a pozzolan is being used we tend to gauge this into the mortar at a ratio between 6:1 and 8:1 by volume (mortar : pozzolan). When NHL is used this also is often at a similar mix ratio, although there can be variations for specific jobs, and we would not usually add pozzolan. If you are looking at a particular job and would like some advice please don't hesitate to get in touch.

Hi Sam, the video refers to "Metastar" which is a pozzolan we used to supply. This has now been superseded by Argical M1000 - details here: www.mikewye.co.uk/product/argical-pozzolan/

Hi! It's a mix of lime putty and washed sharp sand sand 3:1

Hi,thanks for the reply. It's to same mix as the scratch coat? Would you recommend adding some finer sand into the top coat for a finer finish? Thanks

The product is made by Secil and called Isovit E-Cork

@@MikeWyeLtd thanks

The Lime mortars are 3 parts washed sharp sand to one part lime putty by volume. A pozzolan is also added at around 8 parts mortar to one pozzolan

@@MikeWyeLtd Thank you!

Sorry for the delay in replying. Are you doing a full internal lime plaster build-up with a harl coat, scratch coat, float coat, and skim, or is this an external render application? If so, what stage are you at now? If the coats are applied "green-on-green" then the previous coat shouldn't have dried out so much that it's very thirsty like you are experiencing. As the last coat you applied was done many months ago then you may benefit from another harl coat (assuming you are at the float coat stage). I'll presume that this is an external application given that you've asked about the addition of a pozzolan. We should safely be clear of the risk of frost now so early spring is a great time for render applications to give plenty of time for carbonation and strength gain before the winter. With that in mind, and given that you have very thirsty walls, I wouldn't go any more than 1:8 pozzolan to lime render by volume. There may even be a case to reduce this to 1:10 provided that the area isn't particularly exposed or vulnerable. I hope this helps but feel free to give us a call on 01409 281644 if you would like to discuss. Best of luck with the project! Ryan @ Mike Wye

Thanks for your comment. It sound like your neighbour was applying a limewash or "sheltercoat" to the wall. Limewash is a suspension of lime in water, and sheltercoats are often similar perhaps with the addition of some finer stone dust/powder. Our limewash is a mix of lime putty with water, which we have found to be robust and reliable over the years.

@@MikeWyeLtd I appreciate the reply it's been a few days and we had some rain come through I noticed for the most part it's still in place but some of it did wash away. We don't get a lot of rain here in the summertime but I think eventually I'll just use regular outdoor paint on my garden wall. someday.

Hi Andrew, thank you. We tend to use a sand with grit 4mm - 0 but I would think that the holm sand should be fine

Hi Drew, that should be fine but with NHL we would recommend three parts sand to one NHL by volume. A 1:1 mix would be too strong and brittle.

@@MikeWyeLtd yes thanks Mike I did wonder. It just states, 1 to 1 on the back of the bag for "earth retaining walls" 😂 should I use SHARP sand?

@@Hew.Jarsol Yes, we tend to use a well graded sharp sand (0 - 4mm)

@@MikeWyeLtd Thanks Mike I'll try it

Hello Jellybear, thanks for your comment. There is no exact timing as material behaviour can vary in different sites. However, Tadelakt should have achieved a good level of strength after four weeks, so in water exposure areas (showers etc) we would try to leave it for that length of time (or longer) if possible.

so we need an alternative bathroom for 4weeks..?@@MikeWyeLtd

Hi there, Professor, thanks for your comment. This is purely a training/demonstration wall we built at our premises many years ago, and it had no DPC. You are correct to identify this as a potential issue in "real World" work, where we would always be conscious of such features and avoiding the creation of moisture bridges. Good observation 👍

Hi Chloe, thanks for your comment. Limewash can be used internally, onto lime plaster surfaces. Alternatives which are useful for internal work (including bathrooms) are Lime Paint from Kreidezeit, and Silicate Masonry Paint.

We are planning some new videos this year, so hopefully we will come up with something useful for you. Thanks for watching

Hi David, you can use synthetic fibres for the scratch coat as long as they are alkali resistant. You can use a grit primer (www.mikewye.co.uk/product/baumit-premium-primer/) on plasterboard and then use a lime finishing plaster. I hope this helps.

Thank you Mike .@@MikeWyeLtd

Hello. A 6:1:1 mix (sand:cement:hydrated lime) is a relatively common mix in the UK but we still consider this to be a weak concrete mix rather than a lime mix. I understand that it may be difficult to source hydraulic lime or lime putty where you are, so a mix like this will be a better option if you have no other option. Despite some information out there, concrete mixes do offer some breathability and have hygroscopic properties than can help to wick moisture away from the fabric of the building - it's just much lower than lime by comparison. As a general rule, the stronger the mix the less vapour permeable it will be. So choosing a weaker mix is always best. It is also possible to "re-hydrate" a hydrated lime by soaking it and creating a putty. However this putty as a binder is generally considered inferior to a fully matured lime putty and definitely not comparable to a hydraulic lime. If you do have to use a mix containing cement and are concerned about breathability, then the use of a breathable paint finish will help the render to work as efficiently as possible. Our recommendation would be a silicate paint which can be applied to both lime renders and cement renders, and is highly breathable and durable. I hope this helps.

Hi Fred, we do two finishing plasters, Heritage (3:2) 3 x parts kiln dried sand to 1 x lime putty. Regency (1:1) Marble dust : Lime Putty

Yes you can, you would then need to use a casein or vega primer before the Tadelakt system

@@MikeWyeLtd or can i do it without cement? just straightly go to tadelakt first layer?thanks

Our tadelakt system is only a few mm thick, you would need to render a brick wall first, to form a flat base@@raiwismatara2398

@@MikeWyeLtd thanks for the advice

@@MikeWyeLtd why i need to use casein?what is the purpose?thank you

It's a plasterers small tool or pointing spatula

gotcha, thx buddy! I need one. ;)

Hi Rosko, basically it is being overworked while too wet. This will happen with most plasters. If you get any blisters, leave that area to dry back, this should get rid of any small ones. Bigger blisters, you will need to remove and redo.

We use a washed sharp sand 4 mm - 0 mm. Thank you

The stone is an essential part of the water repellency. Due to it's small size it compresses and brings the aggregate together and burnishes the surface

Hi Terry, yes it is slaked lime putty mortar

Hello, Lime render can be repurposed into an aggregate but you would then have to add more lime as a binder. I don't think the silicate paint would have any detrimental effect on this aggregate. They are environmentally friendly in production.

@@MikeWyeLtd many thanks for the reply. First time I've heard about the silicate paints. I quite liked the idea of lime washes, but was worried that they wouldn't or wouldn't much fend off the rain. Will investigate more into the silicate paints.

@@mrdespondency6598 Lime washes normally contain a small amount of linseed oil for water repellency but silicate paints seem to shed more water than they absorb

@@MikeWyeLtd how breathable is linseed in/on lime? I see it's used on earthen floors. Spoke to my Mum yesterday and some cowboys had been around to 'waterproof' her house. Her brick wall was south facing and I can't imagine had any problems drying out. I now have horrible thoughts that she will have a non-breathable wall. But as with lots of Mums/people, there was no telling her.

@@mrdespondency6598 It's a very small percentage of the limewash so still allows for vapour permeability. If the have 'tanked' the wall of your mum's house, it is normally only the bottom few feet. I wouldn't worry too much.

Hi Antoinette, it depends on a few factors but a ball park is 1-2 hours

It's sand (the same sand as used in the mortar). Thanks for watching!

Hi Kasim, you can but you would need to use the Claytec yellow Primer first

Methods certainly do change, but if we keep the traditional practices alive it will be good news for our historic buildings.

And quality is lower.

Hi Alexander, thank you for the kind comment. Best of luck with your project!

It is a ceramic burnishing stone www.mikewye.co.uk/product/tadelakt-polishing-stone/

Hi Hazel, plaster coats are typically around 3 mm

@@MikeWyeLtd sorry i mean for the whole thing, from the wall to finish, including the mortar etc.

@@hazellewis6995 Hi Hazel, onto a solid wall typically, 12-15 mm haired scratch coat, 8-10 mm unhaired float coat and then a 2-3 mm skim

Hi Rizwan, unfortunately we no longer sell these products. Our alternatives are www.mikewye.co.uk/product-category/tadelakt-polished-plasters/

The video was given to us by our supplier and shows application of the boards for demonstration purposes only

@@MikeWyeLtd I understand. At the same time, this method of attachment does not seem to be correct. I could be wrong, but doubt it. Could you ask the supplier what the correct process is? I am curious what they will say: without support at the bottom, and no mechanical attachments to the wall but only glue, they whole installation could fall apart. Cracks, detachment, breaks.

@@vdoundakov Hi Viktor, With the cork facade board, no mechanical fixings are needed with the adhesive. The cork is very light. The standard cork insulation panels would have mechanical fixings and base rails, as they have the weight of render on also. There is a note under the video about mechanical fixings.

Hi Emese, thank you for your comment. Is it possible that you can email us sales@mikewye.co.uk? It will be easier to attach drawings etc.

Hello, Thank you for your kind comments. We don't deal with hot lime mixes. Our mixes are three parts sand to one part lime putty by volume. The sand is a washed pit sand (4 mm - 0mm)

Thank you for your kind comments. Our mixes are one part lime putty to three parts sand by volume. This is a traditional mix that air dries and carbonates. The lime that your builders are referring to would be hydrated lime (a dessicated lime putty) that is used as a plasticiser in cement mixes. For a compromise you could use NHL (natural hydraulic lime) at the same 3:1 by volume ratio. This is very common in Europe and easily accessible. The NHL is a dry powder that will give a chemical set with water rather than air-drying. It's a bit of a compromise. Water and protection from direct sun are the main ways to control drying. Our mortars and plasters differ slightly in mix ratios but essentially it is the aggregate size that makes the difference.

@@MikeWyeLtd thank you so much for you quick get back, much appreciated. Hydraulic lime, that’s the one! They still want to add cement to that though which is annoying, 1 lime to 1 cement then sand.. as they say it will be super soft and any little bang will make a mark on the wall. As for the controlling of drying time, I’m slightly worried about this as they they will do it when it’s warmer and Portuguese sun is HOT whatever the tone of warmer months.. so I’m worrying it might dry out too quickly. Should I spray it every day or something to help it along? Thank you so much again x

@@leafside A 3:1 mix of NHL3.5 and sand shouldn't be too soft, the lime putty renders are softer than these and still take a fair bit of abuse. Yes regular damping down will be beneficial.

@@MikeWyeLtd thank you, will put that to them x