MINERAL PLASTER TECHNOLOGY
Frequently
Asked Questions
Please feel free to contact us if you have any questions that aren't covered below. We also have free USB drives available to Architects and tradesmen. These include all of our Technical Manuals, detail drawings (in various file formats) and BRANZ Appraisals.
What Substrates Can We Plaster Over?
AAC Panel (Autoclaved Aerated Concrete) (Aka ALC Panel – Autoclaved Lightweight Concrete)
Mineral Plaster Technology’s BRANZ Appraised PETRAPANEL® system starts with a substrate of 50mm or 75mm thick AAC panels with our three layer reinforced plaster system, consisting of BONDCOAT with a layer of fibreglass reinforcing mesh embedded into it, followed by a SKIMCOAT and a finishing render of either FLOATCOAT or ADOBECOAT, depending on the finish sought.
Polystyrene (EIFS, EPS or XPS)
Mineral Plaster Technology’s BRANZ Appraised Meshclad system starts with an H-grade polystyrene substrate of either 40mm, 50mm, 60mm, or 75mm thickness, then applies our three layer reinforced plaster system, consisting of BONDCOAT with a layer of fibreglass reinforcing mesh embedded into it, followed by a SKIMCOAT and a finishing render of either FLOATCOAT or ADOBECOAT, depending on the finish sought.
Brick, Block and Masonry
Mineral Plaster Technology’s Masonry Render System, STONECLAD, can be applied over brick, block and masonry. It is applied in coats from 5mm up to 30mm thick and can be layered up to 200mm thick (if you need to straighten walls for example).
Fibre Cement Board
Mineral Plaster Technology’s BRANZ Appraised Fibreclad system starts with a 9mm thick James Hardie Monotek fibre cement board with rebated edges. We then apply a 70mm wide layer of fibreglass reinforcing mesh into a layer of BONDCOAT at the rebated joints, before applying our three layer reinforced plaster system, consisting of BONDCOAT with a layer of fibreglass reinforcing mesh embedded into it, followed by a SKIMCOAT and a finishing render of either FLOATCOAT or ADOBECOAT, depending on the finish sought.
Other Substrates
We have a continuing research and development strategy that identifies and appraises new systems for entry into the NZ and Pacific markets. If you have another substrate in mind and want to know if we can apply our plaster system over it, give us a call. Our Technical Team will advise whether we can help you.
Are Mineral Plaster Technology Systems BRANZ Appraised?
YES, three of them are. The others don’t need appraising, because they don’t form part of the weathertight envelope of a building; they are merely a decorative finish (i.e. Stoneclad and Liteclad).
BRANZ APPRAISALS
BRANZ Appraisal No. 466 (2016) MPT Fibreclad System – Recessed Fibre Cement Sheet System.
BRANZ Appraisal No. 445 (2016) MPT Meshclad System – EIFS Exterior Insulation and Finishing System.
BRANZ Appraisal No. 1111 (2020) - MPT Petrapanel® AAC Cladding System – Autoclaved Aerated Concrete System.
BRANZ Appraisals are not required for the Stonecoat or Litecoat systems over brick, block and masonry, as they are considered nothing more than a decorative surface.
How do Mineral Plaster Technology systems perform?
We guarantee our products for 15 years*. The Mineral Plaster Technology brand has been producing high-quality plaster renders in New Zealand since 2001. Our Technical Manager designed the first cavity system introduced into New Zealand. Our reputation for weathertightness is impeccable.
Our systems are fully compliant with the New Zealand Building Code for use as external cladding systems on buildings within the 3604 wind zones up to and including Extra High (ULS); Acceptable Solution E2/VM1 (Weathertightness) with a risk score of 0 to 20 calculated in accordance with E2/AS1, Table 2.
Our mineral plasters do not contain any isocyanates or acrylics. We go to great lengths to ensure that our plasters provide exceptional weather-tightness but remain vapour permeable, so they won’t contribute to wall cavities sweating.
Our plaster products are made from natural ingredients, ensuring that your investment in your home is also an investment in the future of our beautiful planet. They have been independently and invasively tested and appraised by BRANZ, giving you assurance that our plaster systems are of the highest quality.
They are well-suited to New Zealand’s high UV environment, in that they have no acrylics, which can break down over time when exposed to UV light.
What Type of Warranty and Guarantee?*
When your plasterwork has been completed, you will be given a Care Form which will explain what you should do to look after your plasterwork. Your applicator may also arrange for you to receive a warranty on the paint finish from your paint manufacturer. You may also receive a Producer Statement (PS3) from your applicator when the job has been completed. This includes a 15-year warranty on the products that make up the plaster system (from us) and a 5-year workmanship warranty (from your applicator).
Are the MPT Approved Applicators LBP Registered?
LBPs (Licensed Building Practitioners) are used to apply each of the BRANZ Appraised cladding systems (PETRAPANEL®, MESHCLAD and FIBRECLAD) and the LITECLAD system when applied over fibre cement board. Most of our Approved Applicators are LBP registered. Those who are not registered are restricted to working with our STONECOAT or LITECOAT systems over brick, block and masonry. An LBP licence is not required for those systems.
What is the minimum light reflectance value for paint on MPT plaster systems?
The LRV (Light Reflectance Value) is a minimum of 40% on your finish colour of paint. This minimises heat build-up, which can lead to differential expansion of substrates which may cause plasterwork to crack or delaminate.
Are Mineral Plaster Technology renders made from natural products?
Yes. We do not use any acrylics or isocyanates in our plaster renders. The products used are all naturally occurring or are extracts from naturally occurring products. We do not use any petro-chemicals in our plaster renders. The lack of these acrylics and petro-chemicals enhances the vapour-permeability of our plaster systems, extending the life of the plaster system and leading to a drier wall cavity and a healthier home.
Are there wind zone limitations?
Under New Zealand Standard 3604 and the New Zealand Building Code Acceptable Solution E2/AS1.
The wind zone on the PETRAPANEL® System is up to extra high @ fixing centres of 300mm on the vertical
The wind zone on the EIFS (Meshclad) System is up to extra high @ fixing centres on the horizonal of 200mm and the vertical of 150mm.
The wind zone on the Fibreclad System is up to very high @ fixing centres of 200mm.
The wind zones for the Stoneclad system are dependant on the wind zones for the brick, block or masonry systems it is applied to.
What is the maximum framing timber moisture content for MPT plaster systems?
The maximum moisture content of external timber framing is set by most territorial authorities at 20% at the time of cladding.
How often are control joints required in the plaster systems?
Fibreclad
Vertical control joints at maximum 5.4 metre centres.
Horizontal control joints at maximum 5.4 metre centres.
Meshclad (EIFS)
Vertical control joints at maximum 20 metre centres.
Horizontal control joints at maximum 6 metre centres.
Inter–story drainage junctions at 2 stories or 7 metres.
PETRAPANEL®
Vertical control joints at maximum 8 metre centres.
Horizontal control joints at maximum 6 metre centres.
Inter–story drainage junctions at 2 stories or 7 metres.
Is there a preferred substrate temperature when rendering MPT plasters?
Yes, the substrate temperature must be within the range of + 5°C to + 30°C. This will ensure proper curing of the plaster system to its full strength and prevent potential damage to the substrate.
When painting, what should I be using and how often?
Your Applicator will initially apply two coats of high build or two coats of elastomeric paint over the efflorescence-blocking (lime stop) primer in accordance with the manufacturer’s specifications. We do not recommend changing the paint type used when re-coating at a later time.
If re-coating with high build paint, apply two coats every 7-8 years in accordance with the manufacturer’s specifications. If re-coating with elastomeric paint, apply two coats every 10 Years in accordance with the manufacturer’s specifications. The paint manufacturers' specifications take precedence over these guidelines.
Are the plaster systems reinforced?
Yes, we use an alkali-resistant fibreglass reinforcing mesh across the entire face of each substrate. This is embedded into the BONDCOAT layer of the plaster systems. BONDCOAT has been formulated as a glue coat under European standards. We also specify a second layer of reinforcing mesh at some junctions and at corners of apertures. Our mesh used in domestic and light commercial situations has a nominal aperture size of 4mm to 5mm square and weighs about 160g/m2. Some of our plaster renders also contain natural chopped fibre to further increase the tensile and flexural strength of our plaster systems.
What type of flashings do we use around doors and windows etc?
We provide proprietary universal (one size fits all) uPVC flashings for the window sills, jambs and heads. The sill and jamb flashings lock into left and right-hand corner soakers to provide a high-quality weathertight junction. Each flashing is glued to the substrate to prevent movement and delamination.
Each of these flashings is available in standard or pre-meshed options. We recommend the pre-meshed flashings which lock the flashing to the reinforcing mesh on the wall, contributing to a continuous layer of mesh at all stress points around windows and doors.
Mineral Plaster vs Acrylic Plaster
Mineral Plaster Technology:
Increased breathability (vapour permeability) keeps wall cavities drier and healthier.
Natural, sustainable, raw materials.
Environmentally friendly at end-of-life.
Can be used internally and externally.
Provides a strong, long-lasting, well-insulated, economical and weather-tight cladding solution.
Mineral renders cure through mineral reactivity, so can cure more reliably in colder conditions than acrylic renders
Acrylic Plaster:
Acrylic renders use acrylics, which are a type of petro-chemical plastic in their blends. This can lead to structural breakdown over time when exposed to UV light, and reduces vapour-permeability, which can increase the risk of sweating in the wall cavity.
Can also be used on interior or exterior surfaces.
May require curing additives to assist with curing in colder conditions
Can we Fix to Steel Framing?
Yes. The steel framing must meet the New Zealand Building Code requirements.
Minimum framing specification is ‘C’ Section Studs and Nogs of overall section size (minimum) of 75mm web and 32mm flange.
The steel thickness must be a minimum of 0.55mm.
Do we have an insulating mineral plaster?
Mineral Plaster Techology’s LITECOAT render contains a dimensionally stable lightweight natural mineral filler that captures thousands of tiny air pockets within the render. It can be applied by trowel or pump up to 10mm thick per layer and to an overall thickness of up to 30mm. It is typically applied over a 4.5mm fibre cement board but can be applied over other substrates, such as brick, block and masonry pre-cast.
* Please see our terms and conditions for full warranty details.
MPT
Plaster
Systems
