Float and Set - NHL 3.5

[spotpush]

Also, please don’t use 3.5. Way way too hard and severe for this.

2 at a push is still very severe, if you must, the St Astier is the most consistent NHL

But without knowing the broader context of the building and issues, environment etc it’s hard to comment. But an NHL for plastering, especially inside isn’t advisable.

You're right, damm! I've just AI'ed it, but it's too late I've order 6*25kg of NHL3.5 and 18*25kg of Sharp sand for the scratch coat.

Anything I can do with the NHL3.5, higher mix ration 1:5 for example? What's the best way to store it? And how long will it last?

 

[spotpush]

You say "2 at a push", what would you suggest then? What did they use in 1880/1890's?

 

[stuart45]

It's not the same volume.
A pure air lime is more suitable for interior plastering.

 

[spotpush]

Also, please don’t use 3.5. Way way too hard and severe for this.

2 at a push is still very severe, if you must, the St Astier is the most consistent NHL

But without knowing the broader context of the building and issues, environment etc it’s hard to comment. But an NHL for plastering, especially inside isn’t advisable.

Why isn't NHL advisable for plastering internally? The house is Victorian 1880-90 semi

 

[spotpush]

It's not the same volume.

Ok but when i knock it up it will be. If it's not a simple 1:3 kg ratio then I'll have to buy more sand...

 

[stuart45]

Why isn't NHL advisable for plastering internally? The house is Victorian 1880-90 semi

NHL3.5 is similar to a 1/1/6 lime/cement/sand mix in strength and breathability.

 

[spotpush]

NHL3.5 is similar to a 1/1/6 lime/cement/sand mix in strength and breathability.

Which is probably not what i'm after.

 

[Stevers]

Anything I can do with the NHL3.5, higher mix ration 1:5 for example? What's the best way to store it? And how long will it last?

I store mine in the plastic tubs that fertiliser comes in. The sort of tubs with 20% extra are a nice size and you have a fighting chance of squeezing 25kg into two of those. Never had a problem using NHL stored that way.

You say "2 at a push", what would you suggest then? What did they use in 1880/1890's?

Hot lime mixed in a hole in the ground would have been contaminated with sub soil that was potentially pozzolanic - how convenient!

Why isn't NHL advisable for plastering internally? The house is Victorian 1880-90 semi

Well I used NHL3.5 on my basement Chimney breast and yes I can't bang a picture hook nail into it, but whether that is the 50/50 Mendip stone dust/sand that I used or the NHL 3.5 is something I'd need to experiment with. If I did it again I'd cut the NHL3.5 with Hydrated lime 50/50. The actual repair, rendering and plastering with NHL3.5 was fuss free, and in an extremely dodgy situation (damp and heavy salts) it is performing brilliantly. However this is a very solid stone house (built in 1879) on bedrock with no signs of any movement, seasonal or otherwise - very different from a timber framed house!

 

[spotpush]

I'm starting to think that my assumption of using Natural Hydraulic Lime 2/3.5/5 when renovating my old Victorian house is incorrect. I've already been down the Non-Hydraulic Lime/Non-Hydrated Lime (why they can't have different names for these things is beyond me) route and dismissed them for reason i forget.....

 

[stuart45]

NHL2 is roughly a 1/2/9 mix. What you want if it's an old solid brick wall is a pure, well matured lime. NHL is more for external work, such as pointing in exposed areas.

 

[spotpush]

I'm looking to plaster a bedroom

NHL2 is roughly a 1/2/9 mix. What you want if it's an old solid brick wall is a pure, well matured lime. NHL is more for external work, such as pointing in exposed areas.

"a pure, well matured lime" such as? It's a solid brick (handmade) house

 

[stuart45]

I'm looking to plaster a bedroom

"a pure, well matured lime" such as? It's a solid brick (handmade) house

Lime Putty, Lime Putty Mortar Mix, Lime Putty Filler

Lime putty is the main binder for mortars, plasters, stone repairs, limewash and shelter coats. It relies on carbonating over a period of time

www.limebase.co.uk

 

[spotpush]

I store mine in the plastic tubs that fertiliser comes in. The sort of tubs with 20% extra are a nice size and you have a fighting chance of squeezing 25kg into two of those. Never had a problem using NHL stored that way.

Hot lime mixed in a hole in the ground would have been contaminated with sub soil that was potentially pozzolanic - how convenient!

Well I used NHL3.5 on my basement Chimney breast and yes I can't bang a picture hook nail into it, but whether that is the 50/50 Mendip stone dust/sand that I used or the NHL 3.5 is something I'd need to experiment with. If I did it again I'd cut the NHL3.5 with Hydrated lime 50/50. The actual repair, rendering and plastering with NHL3.5 was fuss free, and in an extremely dodgy situation (damp and heavy salts) it is performing brilliantly. However this is a very solid stone house (built in 1879) on bedrock with no signs of any movement, seasonal or otherwise - very different from a timber framed house!

I was think more in the bags them come in. I don't have fertiliser tubs

 

[spotpush]

Lime Putty, Lime Putty Mortar Mix, Lime Putty Filler

Lime putty is the main binder for mortars, plasters, stone repairs, limewash and shelter coats. It relies on carbonating over a period of time

www.limebase.co.uk

Anything more commercially available?

 

[stuart45]

Anything more commercially available?

Do you mean like your local builders merchants? They normally only stock NHL3.5, as this is generally the most popular with builders. It's a bit of a compromise between using cement mortar and lime mortar. Keeps customers happy thinking it's a proper lime mortar/plaster, but is similar to cement mortar for the builder to use.

 

[spotpush]

Ok. So I'm now thinking i need non-hydraulic lime in the form of lime putty for the scratch, float and finishing coats. If that's correct how do I knock up lime putty myself?

 

[stuart45]

You can buy it ready mixed in tubs. You can get base and finish. Base is a coarser aggregate.

 

[Kearn]

The calculation's above are based on weight. But, forgive me if this is a stupid question, isn't 25kg of Lime the same weight/volume as 25kg of Sand? What am I missing here.

It’s the same weight, it’s not the same volume.

Call up your lime supplier with the areas etc and they’ll let you know ratio and amount of sand, and type required. Which you can then source locally….

 

[Kearn]

You can buy it ready mixed in tubs. You can get base and finish. Base is a coarser aggregate.

Given the gist of this thread, I’d very much recommend pre-mixed.

You don’t need to go 3 coat, but really depends on the application, finish required, substrate and aesthetic desire, not to mention skills and time allocated.

I default to Eden Hotlime Nosterfield 4mm for lots of my plastering, as it’s very forgiving to work with and requires less tending due to the large aggregate size. However, it’s more of a challenge to get a smooth trowelled finish for the same reason, but feasible with some skill and patience. The other huge benefit to me, is that you can do two passes of 4mm in one go, giving and 8mm depth straight away. This obviously may not be thick enough for your needs, but for my applications as pure finishing, it’s been very helpful to just have to plaster each panel the once. Even if you’re going thicker and want a finishing top coat, this is great for scratch and float.

Suggest you probably have a detailed chat with someone from the major suspects who you’ll be purchasing from.

Not sure for all, but Eden also supply ton dumpy bags of pre mix, massively more cost effective. Although they also supply in 20kg plastic resealable tubs, which again are very useful, I like some of the others who ship in fragile plastic bags.

 

[spotpush]

It’s the same weight, it’s not the same volume.

Call up your lime supplier with the areas etc and they’ll let you know ratio and amount of sand, and type required. Which you can then source locally….

ok, when mixing i'll uses the same volume and purchase more sand if needed