boxed standard plasterer to lime plastering

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henry

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Been thinking today just how much of a difference there is with a spread who is a plasterer useing lime and a boxed standard plasterer, Just how much do you need to know about limes etc to
feel competent at it
 
With limes it's the setting time that make a difference, done a few days with spab and it's a bit more interesting the the bog standard plastering.
 
there is a lot more to learn and it takes understanding and patience...u could bring on a gypsum plasterer to lime top coating and they would adapt to that in a couple of weeks...but it does take a few years to really get a feel for 2 and 3 coat work and vernacular work....there is so much more to think about to achieve a successful result both technically and aesthetically....i'd say the main area that requires more attention is in the thorough mixing of the mortars, inparticular with fat limes which have to worked and in some cases batched out the day before to achieve a workable mix with as little water added as poss...correct keys are critical...adequatley haired mortars are very important inparticular for lath work...the keys or nibs formed at the back must be sufficient to support the following coats and must not be broken by hitting too early or hard trowelling on following coats....u need to be able to identify the right time to go on with each coat where there is a fine line between achieving successfull carbonation (or hardening) throughout or failure where the mortar will dry out but not carbonate leaving a crumbly inferior result...aftercare is also required where u will be back misting down to aid carbonation or insuring good air movement in the room.....and to make matters worse the client is paying DOE!! so they will not be accepting anything other than a top result....love working with lime, brought me to some amazing places in this country and alongside some s**t hot craftsmen..not for everyone but certainly give it a go...:RpS_thumbup:
 
Just as I thought more than meets the eye. I have been filling cracks in ceilings useing fibre lime really nice stuff to work with. Now He wants the ceilings re skimming in lime .
 
u should be ok with skimming fine stuff...ty mawr do the best pre mix or mike wye...about £8 for a bag which will do 3m2...control the suction a tad with a mist spray..its a tight first coat, literally scraping it on, then another tight 1 over that, wait for it to pick up, then scour with a small wooden float with a touch of water to bring the fat up..then trowel this in without adding any further water...it is critical not too over do it with the water and also over trowelling with the steel, as soo many gypsum spreads do which leads to grazing all over the shop...u get it right and the finish is the nuts!!
 
u should be ok with skimming fine stuff...ty mawr do the best pre mix or mike wye...about £8 for a bag which will do 3m2...control the suction a tad with a mist spray..its a tight first coat, literally scraping it on, then another tight 1 over that, wait for it to pick up, then scour with a small wooden float with a touch of water to bring the fat up..then trowel this in without adding any further water...it is critical not too over do it with the water and also over trowelling with the steel, as soo many gypsum spreads do which leads to grazing all over the shop...u get it right and the finish is the nuts!!

I would like to work with you for a few months. Really enjoyed my first hemp lime job this year but I know there is so much to learn with this stuff.
 
Got a job to start in October where I will use DG27 from Mike Wye to apply to boards day before skimming over with their 3/2 lime mix followed by a finer finish.
Got to float and skim walls also with 3/1 haired followed by their finish. High suction control has anyone got any tips?
 
High suction control has anyone got any tips?[/QUOTE]

whatever u do don't control the suction with pva, pva and lime don't mix. You need a certain amount of suction for the lime to go off, it's not setting material so if it's just sitting there with no suction it will crack or not go off at all
 
yes the primer mike wye does is very good, bit pricey tho....just as better off using bondit or wba, same principle...it is dangerous territory lime on plasterboard...lime is hygroscopic, it attracts moisture to its cell spaces then releases it regulating humity in a room...moisture with gypsum over time degrades, especially the diydrate gypsum in plasterboard....hence either go with 1 or the other and explain to the customer the reasons why.......i have in the past matched in a couple of boarded areas...sealed the boards, then used 2 to 1 lime putty gauged with casting plaster....as for suction control, there is nothing i can honestly say that will relate specifically to any 1 application....water and lime is a fine balance...oversoak the sub and u could create bond failure and it will blow, too little and it will crack and it will fail to carbonate....a couple of coats of lime wash will slow suction down without compromising breathability....if your on a high suction background spend time just watching what the suction is doing and bring more guys on to it if need be...u will need to mist as u go...and also be back each day to soak it down.....cracking is common place when working with lime and is what will put off the majority as will the slow drying times...this is what takes years to learn its preperation of the mortars and prep of the sub and your aftercare....closing in fissues and overworking will leave a limewash patchy and can create other problems later down the line, and again your customer is payin doe, so a patchy finish is going to leave u bombarded with questions with very little solution to rectify this...although to be fair, its not a perfectly uniform finish anyway and there are some superb breathable emulsion paints out there now and clay paints!!!......i'd recommend to any novice starting off to have a go with hydraulic lime first....non hydraulic systems and should be left to experienced lime plasterers....

danny, where abouts are you based....i've got a job starting in burford at a stately home called swinbrooke house...was damaged in a fire last april....not confirmed a date with the contractor yet, but its 3 coating on to lath...pm over your details and i'll keep u posted as things develop....yes the hemp lime is a great product, they now do a dry hydraulic mix which gets around the problem of using it in damp rooms and walls where the hemp lime takes forever to go and even grows mould lol....
 
Thanks for that,but what did you mean by one or the other regarding boards?
the chap at mike wye recommended Harling on a slurry of 3/1 unaired as a control for suction after an initial wetting down of the wall.
Also I am using gypsum float and skim to the internal walls but wondered what reaction there may be to the lime walls and ceilings that they meet?
 
yes the slurry coat is a good method of controlling suction too, forgot to add that and key also.....where a gypsum internal meats a lime internal it will crack over time, as with a ceiling line for obvious reasons...if u want something more compatable with the gypsum, then use keen's cement which aint really cement at all its gypsum refired with alum...this goes in to ya lime putty gauged with either fine sand to prevent cracking or marble dust..(which is the stuff mike wye sells i believe for hi quality polished lime top coating)....the result is a far more durable finish than neat lime fine stuff and a lower permeability.
 
keen's or casting plaster will be a lot easier to get ya hands on, prestia fine stuff thru southwestern, about £10 a bag is the best...great stuff to have in ya van anyway for speading up the process of making good...
 
If you're using plumb dot and screed you shouldn't have to worry too much about suction control, all houses were done with this method back in the day. Ask the guru on here his name is essexandy.
 
danny, where abouts are you based....i've got a job starting in burford at a stately home called swinbrooke house...was damaged in a fire last april....not confirmed a date with the contractor yet, but its 3 coating on to lath...pm over your details and i'll keep u posted as things develop....yes the hemp lime is a great product, they now do a dry hydraulic mix which gets around the problem of using it in damp rooms and walls where the hemp lime takes forever to go and even grows mould lol....


I'm near Leeds mate, stupid busy at the moment but would definitely travel to learn this aspect of the trade.

The bond of the hemp putty stops 90% of the cracks I suspect and promotes even shrinkage, so I suspect a load of our mistakes were helped by this.

Mould has been an issue too. With no-one in the house to open windows etc it was left to take hold and they had to wash all the walls down with a very weak bleach solution.

Pretty much all of it was furred up, with some darker mould appearing upstairs where the new lime met some older stuff that had already carbonated last year.

This thread shows some of what we did....http://www.plasterersforum.com/general-discussions-plastering/41737-lime-hemp-plaster.html
 
Good thread that danny need that lime section so these threads are more easy to find,:RpS_biggrin:
 
its certainly not a great solution for damp walls or damp rooms..the hydraulic mix gets around this, but still needs carefull attention...we had a nightmare on a job in buckingham few years back with a firm who decided to try to speed things up with heaters...just baked it and it failed...got over that in the end by gauging hydraulic lime in to the pre mix...compromises breathability they say but i don't think its really that significant with 3.5

was goin to join the skillingtons gang over at lowther castle in penrith on a project there, but not heard back since, mind u thats quit a project and the plastering was way off when i enquired...is that far from leeds
 
How is damp look upon in old buildings jack88 do they chemical inject or use other methods
 
damp is most commonly a problem in old buildings as in most new builds when cements or gypsum plasters or non breathable paints are introduced....either that or the source will be water penetrating through leaking gutters or gaps or cracks in the walls, door or windows.....the approach is to remove the source of the damp and replace with the correct breathable system....be that the plasters, the paints, or repoiting the masonry with lime.....firms still go out and chemically inject dpc's to old property's, just like there are companies who coat and repoint old buildings with cement mortars...these are all quick fix solutions which require little knowledge and are just bone idle approaches to covering over the problems short term......general rule of thumb...natural products, work harmoniously with other natural products and these all work harmoniously with nature....hence why the original systems are still standing 1000's of years down the line...i.e timber frame will move and flex, so does the lime mortar with that.....synthetic materials are produced and processed for speed..time is money...not for longevity...they are a quick fix.....u either work in conservation to restore it to last 100's of years and do it properly or stick to modern applications....when u start introducing modern synthetic systems to old builds...it damages the building fabric
 
Can I add a natural accelerator to my 3/1 haired to speed up the setting time? I know that the Romans had to use this maybe pozolan? What about throwing in the odd shovel ( I mean carefully gauged!!) hydraulic powder?
 
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