Any Questions?

With regards to movement joints in an insulated render system – these are required where there is a change in the substrate types that leads to shear movement such as masonry to timber or concrete to SFS or where on a structure the deflection exceeds L/360 or 15mm (whichever is greater). Otherwise, the insulated render system itself does not require movement joints unless the substrate requires one to be present through the whole wall section to the outside face, determined by the project structural engineer or unless it is a brick slip finish being applied to the EWI system.

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In certain climatic conditions algae spores will settle onto any surface and begin to spread, walls with protection from the sun such as trees and shrubs will assist in this process as it allows extended periods of holding moisture in the air to support the algae’s growth. SPS Envirowall can provide special wash cleaners such as Antimoss to clean the algae from your walls.

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A U-value is a thermal calculation where all the wall components and their thickness, including air layers (cavities) and fixings are assessed using their individual Lambda/Chi values (thermal conductivity) which when calculated gives a figure called a U -value. This can’t be carried out without all wall components and their thicknesses. An insulation boards individual thermal performance on its own will not predict a U value without all the other components, to arrive at the insulation boards required thickness to achieve a specified U value.

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Topcoats with an LRV less than 20 should not be used on EWI systems, as this puts undue thermal stress on the EWI system by absorbing a larger level of UV light. This causes the insulation system to overheat and therefore it experiences a greater degree of expansion/contraction. As a result it would expose the finish to the risk of cracking.

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Most clients opt for render with a grain size (usually 1.5mm) as this throws minor shadows across its surface deflecting any slight imperfections in the EWI system.

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Yes, the primer gives a controlled suction to ensure the topcoat sets properly without it drying too quickly due to the basecoat prematurely drawing water content from the topcoat. Also, the colour matching primer offers more depth of colour by blocking out the colour of the basecoat.

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Vapour permeable insulation such as mineral wool requires the render also to be vapour permeable – this is usually a silicone or mineral render.

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External Wall Insulation is an increasingly common solution for improving a buildings thermal performance, both in new-build and refurbishment projects.

For example a traditional solid brick property may have a U value in the range of 1.5 – 2 W/m²K. However adding as little as 60mm of External Wall Insulation (EWI) to the external face of the property could achieve a U value of 0.29 W/m²K which means your house could be up to 6 times more thermally efficient than without insulation, saving you of money on your heating bills.

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The classification system defined in BS EN 13501-1 is the primary recognised standard which applies to external wall insulations systems. All our EWI systems conform to the stringent UK fire regulations, both below and above the regulatory height of 11m.

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There is no reason that you will need to leave your home when having an external wall insulation system installed. EWI is applied to the outside walls so there is minimal disruption and it should not be necessary to vacate the property whilst EWI is installed. Although it can be a little noisy due to the requirement of drilling of the walls. The installers have no requirement to enter your property unless it is related to a boiler flue installation.

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In the majority of cases planning permission is not required. However, you should always check with your local authority planning department before starting works.

As EWI covers the whole of the outside of your property, it is likely to change its appearance and you should ask your local authority planning department whether planning permission is required to install EWI.

Planning permission is not required and is acceptable under permitted development if the final wall covering reflects that of the existing building. i.e. if the existing is a dry dash finish, the new finish should be dry dash. If the new finish varies from that on the existing building, then it is likely planning permission is required.

Planning permission is generally required if the property is within a conservation area or a designated area such as the green belt or countryside.

In a local conservation area, the decision will depend upon the planning constraints of the particular conservation area. Your local authority planning department will be able to advise on any special requirements, particularly relating to the necessary appearance of the finished works. There are a range of finishes which can be used to emulate the surrounding properties and samples can be provided to satisfy local authorities.

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The EWI systems are versatile in their ability to be applied to a majority of substrate types. The systems can be applied to masonry or sheathing boards with a simple switch of a fixing type. Pre-determined pull-out testing offers the systems flexibility to be specified across most construction types.

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Using a mild detergent with warm water and a soft brush is the best way to clean your render finishes, pressure washers can be too aggressive and damage render coatings. Algae can grow on EWI systems should the conditions be suitable but can be cleaned off with our Antimoss cleaner but traffic film and airborne dirt ingrained onto the render finish may not be removable over time. If this is the case after being cleaned, you can overpaint certain types of our textured finishes with our Silicone paint. As with any maintenance regime, the longer you leave it the more staining can remain permanent.

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We offer differing warranties depending on what system and schemes you are operating with, this can range from 2 to 25 years. It is important to note that a warranty has to be applied for pre-contract start, is subject to approval and is only for the materials and not workmanship or application.

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• It reduces heat loss and subsequently your energy bills
• Reduces/eliminates draughts with an immediate thermal sense of warmth
• No requirement to move out while being installed
• This type of system does not reduce internal floor area
• It gives you the “Tea cosy” effect  as external walls to contribute to thermal mass
• Along with weatherproofing it helps with sound resistance too
• It extends the lifetime of the existing walls
• It reduces condensation on internal walls (ventilation is important)

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• Consideration is needed for ventilation to avoid issues with condensation, which could lead to damp problems, ventilation is key to eliminate any potential risks.
• Potential to obtain planning permission if changing the appearance of your home. May not be suitable for listed buildings or those in Conservation Areas.
• External wall insulation will increase the wall depth, which by default increases the depth of the reveals around windows, eaves and requirement for extensions of existing sills.

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Wall System 1/Wall System 2 – Grey EPS/Phenolic or Mineral wool

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Wall system 1 – Direct to Sheathing Board

Wall system 1 – Applied to masonry.

TS Rail system onto SFS or Timber frame.

CS1 Cavity System onto SFS.

CS2 Cavity System onto SFS.

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Wall System 1 – Mineral Wool onto Masonry

Wall system 1 – EPS and Phenolic Insulation onto masonry

TS Rail System onto SFS

TS Rail – Timber Frame

Wall System 2 – Grey EPS Insulation

Wall System 1 – Mineral Wool onto SFS Sheathing board

Wall system 1 – Flexible Brick Slips onto Masonry.

These systems are covered with a BBA or a KIWA BDA certificate.

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In cavity wall construction, the cavity will (almost certainly) be ventilated through open brick grilles and the open top of the cavity. This means that heat from the house penetrating the internal skin into the cavity will be exhausted into the atmosphere by that ventilation before it gets to the insulation. It requires these zones to be attended to in order to maximise the efficiency of the External wall insulation system.

If cavity-fill insulation fails by being saturated with water, it will require attention, possibly even being removed prior to any decision on applying EWI.

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In the first instance you should always make contact with the specialist contractor that completed the works, they are responsible for any remedial works that may need to take place.

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Building Regulations (Part L1B) sets energy efficiency requirements where more than 50% of an external wall (or more than 25% of the overall building envelope is being renovated). You will need to add insulation to improve the thermal performance of the whole of that individual thermal element. The thermal performance of an existing dwelling wall when insulated must have a new U value of 0.30 W/m²K.

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The EWI systems, when installed and maintained in accordance with the Certificate holder’s recommendations and the terms of our Certificates, will remain effective for at least 30 years. The durability can be extended to 60-years by using different fixing arrangements and by following a planned inspection and an effective maintenance schedule.

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We have a wide range of finishes and hundreds of colours in our range, from clay/ flexible brick slips and brick effect render, all able to maintain a classic brick appearance. Our render systems can be tinted to match a large range of RAL or NCS colour or more traditional aggregate spar multi mix colour combinations.

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Specialist fixings which require water sealing are available to fix items of varying weight to the EWI system after it is installed. Standard Rawlplug and screws are not suitable, as the system is classed as none structural and advice should be sought for applying hanging baskets, lights, alarms, satellite dishes etc. to the system.

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Any appliance requiring a flue or an air supply must be accommodated for in the detailing of the EWI system. Mineral wool is applied around flues for fire resistance and air vents are installed through the system to supply a continuous air supply to a burning appliance. These should also never be blocked or covered over during or after the installation. Boiler Flue extension kits may be installed to extend the length of the flue through the EWI system.

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No we don’t install the systems that we supply. However, We have an extensive network of approved and recommended installers so we may be able to help you locate an approved installer specific to your area, see our branch website details to contact for a local installer.

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The most popular overall thickness is 100mm which comprises of 90mm insulation board and 6-10mm of basecoat and render. However, insulation boards can vary from 20mm to over 150mm, so the systems overall thickness may be variable.

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