Lime plaster and Lime insulated plaster- internal solid brick wall

[mh12]

Following on from a similar thread. I will be ordering pallet of St Austier NHL 2 lime and want to make good use of it.

Can you please advise on the ratios required to make lime plaster.

Will be using NHL 2 product and I suspect will require Yellow building sand. Have I missed any other ingredients?

Also insulated lime plaster came into mind. If I was to add hemp or cork to the above lime plaster mix to make insulated lime plaster.

Does anyone have any experience on the thickness of plaster application required to solid 9 inch brick to infer sufficient insulation properties say on par say with adding about 50mm of flexible woodfibre material?

As always, many thanks and extremely grateful

 

[aockenden]

Also insulated lime plaster came into mind. If I was to add hemp or cork to the above lime plaster mix to make insulated lime plaster.

Does anyone have any experience on the thickness of plaster application required to solid 9 inch brick to infer sufficient insulation properties say on par say with adding about 50mm of flexible woodfibre material?

Insulating plasters will never have the same insulation values as a pure insulation board material. If you wanted to get the same insulation value as 50mm of woodfibre using cork+hemp+lime plasters you'd probably need 70+mm of insulating plasters which is pretty nuts. And keep in mind, you'd have to build up that in 2 cm layers with a good few weeks between each layer (to avoid molding or it peeling off the wall due to the sheer weight of wet sticky plaster), so you'd be looking at 3 - 4 coats of the stuff before you can even skim it. Trust me when I tell you, 2 coats is plenty of drudgery already.

In our house, we shoot for a total thickness of 4 cm of insulating hemp+cork+lime plaster, applied in 2 coats of 2 cm with at least a month in between each layer. We use non-hydraulic lime though, so if you were using an NHL 2 instead you might cut down your between-coat waiting times to a week or two.

In this video, they retrofit a cold stone-walled house to the level of a passivhaus standard with a cork + lime insulating plaster IWI approach. They had to build up the plaster to a massive 10 cm (4 coats of 25 mm). They used a spray-gun machine thing.

 

[mh12]

aockenden, many thanks.

Have got couple of thoughts in mind and will post tonight. Have a very early start today, lots of pressure from the brickie, supply issues etc etc.

Feeling the heat but enjoying the ride.

Think I'm evolving into a pre-builder