Is three coat work using nhl always necessary

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FreeD

FreeD

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If your background is relatively flat, is it necessary to do 3 coat work e.g scat, scratch then float coat...(nhl render)

Is it ok to just do a scat then 1 coat of nhl lime render then finish coat? or even if there is already a key just one coat of nhl render at 15mm then finish coat?
 
I would only apply 3 coats if you need too.the only reason to put 3/4 coats on the wall is to straighten it up.so yes why not
 
Two nhl render coats and one coat of putty finish is what I usually do.tbh even if the substrate is flat I'd still do that as it will be stronger than just one render coat.:RpS_thumbup:
 
kgreigh said:
Two nhl render coats and one coat of putty finish is what I usually do.tbh even if the substrate is flat I'd still do that as it will be stronger than just one render coat.:RpS_thumbup:
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Would you count a scat coat as a render coat? My concerns were also about strength...

also do you finish your lime putty the same day? I've always done it the next day as it's been to wet...I've used nhl finish before but found it didn't set quick enough to finish the same day and was hard the next morning...

Is there a quick setting nhl that can be finished the same day? what about this st austier eco mortar r50?

(this is all internal works)
 
Aaron if you want any more diassan or whatever it's called let us know there's still some bags at the yard and their probably out of date so don't tell the customer but you could have them mucho cheapo
 
FreeD said:
Would you count a scat coat as a render coat? My concerns were also about strength...

also do you finish your lime putty the same day? I've always done it the next day as it's been to wet...I've used nhl finish before but found it didn't set quick enough to finish the same day and was hard the next morning...

Is there a quick setting nhl that can be finished the same day? what about this st austier eco mortar r50?

(this is all internal works)
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three coat work doesn't usually include a spatter coat,like s&c and an sbr slurry,I have at times left it till the next day a sponge will liven it up a bit. I'm not sure on the Eco mortar as I've not used it.:RpS_thumbup:
 
spunky said:
Aaron if you want any more diassan or whatever it's called let us know there's still some bags at the yard and their probably out of date so don't tell the customer but you could have them mucho cheapo
Click to expand...

Thanks Dave, pricing up some at the mo so I'll be in touch, hows it going still working for the same company? What work you doing at the moment?
 
still on for the same firm mate were mainly tacking dabbing or rendering, rates have gone up at last works gone mental I think the good days are back
 
kgreigh said:
three coat work doesn't usually include a spatter coat,like s&c and an sbr slurry,I have at times left it till the next day a sponge will liven it up a bit. I'm not sure on the Eco mortar as I've not used it.:RpS_thumbup:
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Just wondered as I read something recently about some older buildings having only one coat of lime render...

The R50 looks goods although over an nhl backing coat you have to put mesh between coats...setting time 2 to 4 hours, think I might give it a try.

 
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spunky said:
still on for the same firm mate were mainly tacking dabbing or rendering, rates have gone up at last works gone mental I think the good days are back
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Yep hope its here to stay...I've noticed alot more spreads around recently. Have you heard of APS? any good? their work looks quality.

Have to hook up for a pint sometime, never see Bod on here...you still in touch with him? See Jordan occasionally.
 
Aps no never I spoke to bod a while ago he's busy doing his own stuff and he said he needed to take blokes on
up for a beer were doing loads of work in bath I'll catch you one day when we're in bristol
 
FreeD said:
Just wondered as I read something recently about some older buildings having only one coat of lime render...

The R50 looks goods although over an nhl backing coat you have to put mesh between coats...setting time 2 to 4 hours, think I might give it a try.

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Yes it was more popular on farm buildings or more basic buildings where the plaster is used just as a basic covering of the masonry and undulations are as standard.:RpS_thumbup:
 
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kgreigh said:
Yes it was more popular on farm buildings or more basic buildings where the plaster is used just as a basic covering of the masonry and undulations are as standard.:RpS_thumbup:
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That's exactly what I read....lol
 
spunky said:
Aps no never I spoke to bod a while ago he's busy doing his own stuff and he said he needed to take blokes on
up for a beer were doing loads of work in bath I'll catch you one day when we're in bristol
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I see bods brother around all the time, never spoke to him though, seen a job they did recently next to APC workwear looked quality.

Is bod working with his brother? what's his company name?
 
FreeD said:
That's exactly what I read....lol
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I'm not surprised lol,it's the truth,you think when you go into old pubs etc an there it just a basic lime render between the beams trying to replicate that basic wavey look.:RpS_thumbup:
 
FreeD said:
I see bods brother around all the time, never spoke to him though, seen a job they did recently next to APC workwear looked quality.

Is bod working with his brother? what's his company name?
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Fark knows mate
 
Hi guys, first time on here. My background is lime plasters and mortars, manufacture, technical and sales. Not applying, you really wouldn't want that.
Three coat work is a Victorian way of plastering to achieve flat, straight polished walls.
Your scat coat should be a gritty sharp, screeding type sand, mixed strong, 2:3, 2 being NHL 3.5, the strong mix offsets the thin nature of the coat. The 2nd coat is the important bit that dictates your finish. Basically your finish coat is ideally a completely consistent thickness, 2 or 3mm depending on the sand used. So all your straightening must be in place.
St.Astier R100 and R50 are best used as bridging coats over backgrounds that don't suit lime. Full details on Natural Hydraulic Lime Mortar Plasters and Renders from St.Astier, product data will give you all the tech info required. You'll also find a huge amount of info on sands, mix ratios and some ready made specs for various backgrounds.
Failing that, Warmcote is a lightweight, insulated lime plaster or render, it's taken me seven years to design (slow worker), goes on pretty much anything, any thickness, can be sprayed on, straightened and polished inside a week.
 
Hi guys. This is my first contribution to TPF, so by way of introduction, my background is lime mortars and plasters, design, manufacture and sales. Not applying, you really don't want that.
The mistake most people, especially architects, make is to have a specification and try to make the building fit around it. There are an infinite amount of variations to what can be achieved with lime, but that's because there are an infinite number of variations in mix, different strength limes, different sands (v important), mix ratios and additives.
The two questions you need to ask before you start are, What am I going on to? What do I want it to look like?
What am I going on to dictates your first coat, What do I want it to look like gives you your finish material. The bit in between joins the two and does any straightening required.
Natural Hydraulic Lime Mortar Plasters and Renders from St.Astier has more technical info on lime, sands and mixes than anything else online.
The R50 and R100 are basically bridging coats for getting lime onto difficult backgrounds such as paint, cement, concrete, tiles etc.
A mesh should only be necessary when there is potential for background movement or your bridging over different materials.
Or for an easy life, I've spent seven years (slow worker) perfecting Warmcote, a lightweight breathable, insulated render / plaster, can be sprayed, polished, patterned, will go on pretty much anything at whatever thickness.
Cheers
 
FutureLime said:
Hi guys. This is my first contribution to TPF, so by way of introduction, my background is lime mortars and plasters, design, manufacture and sales. Not applying, you really don't want that.
The mistake most people, especially architects, make is to have a specification and try to make the building fit around it. There are an infinite amount of variations to what can be achieved with lime, but that's because there are an infinite number of variations in mix, different strength limes, different sands (v important), mix ratios and additives.
The two questions you need to ask before you start are, What am I going on to? What do I want it to look like?
What am I going on to dictates your first coat, What do I want it to look like gives you your finish material. The bit in between joins the two and does any straightening required.
Natural Hydraulic Lime Mortar Plasters and Renders from St.Astier has more technical info on lime, sands and mixes than anything else online.
The R50 and R100 are basically bridging coats for getting lime onto difficult backgrounds such as paint, cement, concrete, tiles etc.
A mesh should only be necessary when there is potential for background movement or your bridging over different materials.
Or for an easy life, I've spent seven years (slow worker) perfecting Warmcote, a lightweight breathable, insulated render / plaster, can be sprayed, polished, patterned, will go on pretty much anything at whatever thickness.
Cheers
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Sounds like the perfect product can it be used externally? it meets part L at what thickness? and what is the insulating material in it?

I used Eco Cork recently very lightweight and nice to work with, can't be sprayed though, and I was a little concerned about impact resistance.
 
Hi FreeD
Warmcote was originally intended as an external plaster for 'difficult to insulate' buildings. Down in East Anglia the traditional way to build was heavy oak timber framing. Generally that is 4-6" of either wood or clay and straw infill. Most people want to expose the frame, usually internally, so that writes off internal insulation. To add much thickness to the exterior would spoil the look of the building (wonky) and probably fall foul of conservation. So the intention was, if you can only get 30-50mm of render, might as well make it count. A lot of external plaster here is decorated, either pricked or combed, there is also heavy relief pargetting. All of which can easily be done.
My tests so far give Warmcote a Lambda of about 0.12, though I wasn't happy with the test biscuits, so should see an improvement. I think the Ecocork comes in at 0.1.
The U value is the measurement for the whole wall system from the external face to internal. be it clay, brick or Thermalite blocks, with plaster,
 
Sorry, pressed send.
Warmcote is mineral based with fibre reinforcement. The spray we have used is a Sablon, hand held hopper. Normally it has to be powered by a single-tool trailer mounted compressor, but because the mix is so lightweight, it'll go through the spray easily with a £150 workshop compressor. So the whole spray kit will cost less than £600 and fit in the boot.
 
The Sablon spray and the Refina one on Jack88's post are identical, as long as you can blank off two of the air jets to run it through the single nozzle.
 
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