SuperTherm Topcoat is a dry, ready-mixed finishing plaster designed for use as a topcoat over SuperTherm Insulating Plaster.
Key Features
- Mix Ratio: Only available as a 1:2 mix ratio
- Binder: Lhoist CL90 non-hydraulic lime and pozzolan blend
- Aggregate: 2mm down silica sand
Usage
- This topcoat is suitable for finishing SuperTherm; it should have a mesh embedded and would ideally be applied in two passes, with the mesh in the first pass.
- This can be floated, sponged or trowelled as a finish.
- This product will work on many other mineral backgrounds with some suction; however, it is incompatible with gypsum skim, plasterboard, or wood fibre boards.
Do not use this product below 5°C, do not use this product if freezing conditions are predicted within the following few weeks (including wind chill); we have designed other products which are more appropriate for cold weather work, please contact us for more information. Do not use this product in temperatures above 25°C.
Technical Information
Coverage Rate
- After mixing, a 25kg bag will produce approximately 15 litres of plaster. This will cover 2.5m2 at 6mm thickness.
Benefits
- Designed to be compatible with SuperTherm
- Slower drying; better curing
- Quality-controlled production
- Consistency of mix ratio and working additions
Colour and Texture
- This product is completely natural in colour, giving a light yellowy cream finish.
- No pigments are used in this product.
- Please note that, as sands are natural, there may be some colour variation.
- While variances are slight, for applications where colour is important, such as unpainted render, we strongly advise that each elevation is completed using render from the same batch.
Preparation
We would expect appropriate preparation in accordance with best practice, where the surface is clean, free of dust and other debris.
- Where necessary, the background should be adequately dampened to promote adhesion/bond with the host surface.
- Dense, impervious backgrounds/materials are unlikely to be very absorbent and require little to no dampening, whereas more absorbent backgrounds/materials require adequate dampening to prevent rapid drying.
Application onto SuperTherm
- The substrate should have been cured for the specified time before the topcoat is applied.
- The first pass of plaster should be applied in a two-pass, one-coat type application with a mesh embedded in the middle: butter up the wall, press in the mesh, then immediately overcoat. Leave a light scratch in it to take the second coat.
- Keep the first coat damp and allow it to stiffen for 5-7 days before application of the second coat.
It is possible to undertake this application on Supertherm in only a one-coat type pass, however the likelihood of the mesh grinning through in places is significantly higher, so we do not recommend it unless you have experience working with this product.
Mixing
- A 25kg bag of plaster will require 4.5 to 5.5 litres of clean potable water.
- The water addition will vary depending on the application and the desired consistency/workability of the plaster.
- Always avoid making the mix too wet, as this can promote shrinkage, especially at higher thicknesses.
As a dry mixed material, some settlement or separation may occur in the bag during transit. When mixing part bags, it is especially important that the dry contents are thoroughly blended prior to mixing with water.
Best Practice/Advised Mixing: First, add 80% of the total water to the mixer, then add the dry plaster, and turn the mixer on. Allow to mix until the water is thoroughly distributed, then add additional water to achieve the desired consistency.
Mixing Time: Mix for a minimum of 5 minutes, but for no longer than 10 minutes when using a Belle mixer. For a whisk: mix for no less than 1 minute and no more than 4 minutes.
Quenching: Like most lime mortars, this blend will benefit from quenching; allow the mortar to stand for 10 to 20 minutes after mixing, before use. Whilst this is not mandatory, you may find the plaster stiffens a bit if used straight out of the mixer; it may need a splash more water, remixing, or just knocking back up again after 20 minutes.
Once water has been added, this mortar has an open time of at least 16 hours. Longer in colder weather.
Application
Areas of Use: This topcoat is suitable for use on Supertherm and most masonry backgrounds with some suction; for application onto tanking, please consult us first, as special application methods may be required. Render carrier boards, such as Savolit, are also suitable substrates; however, fine-fibred wood wool or wood fibre insulation boards are not appropriate. For any other render carriers, please contact us for more details on suitability.
Coats: The thickness of the coats should be limited to 6mm per pass.
Application: This product should be treated as most lime plasters; after application, it should be kept damp and mist-sprayed for at least 1 week.
Packaging
This product is supplied in 25Kg polythene lined paper bags, palletised for shipping and handling. The packaging is a mixed material and should be recycled accordingly.
- Pallets contain 40 bags as standard at 25Kg each, we can supply these as up to 50 bags on request if there is suitable allowance for offloading at the delivery site such as a forklift.
Storage
This product should be stored in dry conditions, in unopened bags, and kept clear of the ground. Always protect bags from water and damp. Reseal the part bags after opening if any unused product remains.
Use within 6 months of the manufacturing date (provided on each bag).
Safety & Liability Notice
- Lime mortar is alkaline and can cause skin burns, eye injuries, and respiratory irritation.
- Avoid contact with skin and eyes, and do not inhale dust.
- Wear appropriate protective gear, including gloves, eye protection, and a mask.
- Ensure proper ventilation and keep the product out of reach of children.
By purchasing this product, the user agrees to handle, store, and dispose of it safely. The manufacturer and supplier are not responsible for any injury, loss, or damage resulting from misuse or failure to follow safety instructions and regulations.
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