ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Help and Advice on How To Render Internal & External Walls

Updated on December 4, 2015

Help and advice on rendering internal and external walls by a qualified plasterer and renderer.

What is Render & why use it ?

Render is a measured mixture of water, sand, and cement. Render is applied similar to plaster, but has a more durable and longer lasting finish.

The mixture remains hard for many years and helps protect the buildings structure from the elements.

Internal render is usually used when there has been a damp problem. Normal plaster or plaster boards may rot and begin to crumble quite quickly if the damp continues to perforate the external brick or block work.

Internal rendering permits a solid inner skin on the damp walls which is mainly impervious to moisture from outside.

The render can be skimmed over with plaster afterwards to create a perfectly even finish which is more moisture resistant.


How To Mix Render

Correct measurements are the key to a durable and long lasting render. The same as most mortar mixes, the mixture is three measurements of sand to one measurement of cement. 3 to 1.

Use a bucket, spade, or other large measuring implement to ensure correct quantities are used. Local qualified plasterers or renders will mix render in the same way.


Mix Consistency

A simple method of mixing all types of plaster, mortar or render is the drill attachment mixing implement. Cheap enough to keep in the garage for when ever it is needed. Simply fit into a drill and begin whisking.

Mixing in a cement mixer will take most of the labor out of the job in hand, or even hire someone to mix on your behalf. If using a mixer, turn the machine on, add some water, then add the 3 to 1 mix.

Add PVA to the water and stir well prior to adding sand or cement. This will act as a waterproof barrier within the set render.

The mixture needs to be seen 'folding' whilst the mixer is turning. This means not to stiff, but wet enough to spread without falling all over the floor.



IMPORTANT

Whether rendering inside or outside, ensure that the render remains above the damp proof course (DPC)

With external render, ensure a bell cast bead is placed on the wall JUST above the DPC.

Internal render can stop just above where the skirting board will be.

Most render is applied to a height of 1100mm above floor level.


Wall Preparation

Help with rendering begins with preparing the wall to be rendered. Remove any loose pieces and locate the piece most protruding from the wall.

This protruding piece is called the highest piece and and will be the shallowest part of the rendered wall.

Coat the entire wall with a 50/50 mix of PVA Bonding Agent and water. This will help with suction and remove more dust and particles. Allow the PVA mix to go tacky before applying any render.


Scratch Coat

The scratch coat is the first layer of render to be placed on the wall. This is typically up to 10 mm thick. Once the render has been applied to the wall, use a straight edge (about 1.8 - 2 m long) to smooth over the render.

Use the straight edge both vertically and horizontally. Gently scrape off the lumps and mounds of render protruding out. This should leave a more or less flat wall. Now scratch it.

The scratching will give a 'key' or 'biting point' for the top layer of internal or external render. Always scratch horizontally, this helps prevent any moisture from forming at the bottom of the wall.

Scratcher for Render or Plaster

Top Coat

The top coat of render is usually about 5 mm thick. This coat is simply to cover over the scratch coat and leave a smooth finish. Use a long level to ensure that the wall is straight both vertically and horizontally.

Rubbing Up

Rubbing up render means using a plastic float in circular motions to leave a sandstone effect. Whilst this is being done, any small dents can be filled in with moist render mix.

The render is to wet to rub up, if when rubbing up the render is being dragged. On hot days, only render small areas and then rub up before applying render to another part of the wall.

Skimming Over Render

Using finishing plaster, it is possible to skim over render. Apply a liberal coat of PVA onto the render, then skim over with plaster.

Questions

We can answer questions if you have problems or queries on rendering or plastering. Please leave comments or questions in the comments box at the foot of the page.

How to 'Dot & Dab' Plasterboard

How To Skim A Wall Using Plaster

How to plasterboard a ceiling.

Comments

    0 of 8192 characters used
    Post Comment

    • billericky profile imageAUTHOR

      billericky 

      3 years ago from Plymouth

      The moisture will still penetrate from the outside wall, no matter if you use bondcrete or not. You may consider rendering the outside first., this will help prevent moisture entering the inside. Please note the word 'prevent' and not 'stop' moisture from entering. The builder was correct in my eyes of his assumption.

    • profile image

      Grace 

      3 years ago

      We have single brick garage wall that had to be fixed by the builder. The bricks are completely different in look and texture and we want to render the inside of the garage wall.

      The builders say it can't be done because it's a single course, but can the wall be rendered with a layer of Bondcrete underneath or will the moisture penetrate and will the render fall off.

    • billericky profile imageAUTHOR

      billericky 

      3 years ago from Plymouth

      Called a 'dubbing out' coat. The render should be thick enough to just cover over the pebble-dash. Do not leave a smooth finish. Once applied, scratch the finished surface to create a key for the finishing layer.

    • profile image

      Darren 

      3 years ago

      Hi

      What thickness should the render be to skim over pebble dash?

      Thanks again

    • billericky profile imageAUTHOR

      billericky 

      3 years ago from Plymouth

      You can skim over the pebble-dash. Brush on a mixture of PVA / water at a 50% mix ratio onto the pebble dash. Allow to go tacky. Then skim over with a 3 sand to one cement mixture. In the render mix, add a water proofer for protection against the elements.

    • profile image

      Darren 

      3 years ago

      Hi,

      I have fine pebble dashed render on outside if house. Can I skim over this or do I have to remove it first?

      If skim, what should I use?

      Many thanks

    • billericky profile imageAUTHOR

      billericky 

      4 years ago from Plymouth

      Browning can be used, but if the area is prone to damp, then quite soon the browning will begin to fall off. The bonding and browning can both be used once the sand and cement render has been applied. The render will act as a moisture barrier, whereas the browning or bonding will not.

    • profile image

      Pm 

      4 years ago

      I have an interior wall to render which is on the outside of the house.

      Does this wall have to done in sand and cement or can it be done in car lite bonding or browning.

    • billericky profile imageAUTHOR

      billericky 

      4 years ago from Plymouth

      The bell cast should be above the damp proof course (DPC) by approximately 1cm to 1 inch or thereabouts.

    • profile image

      Sally 

      4 years ago

      Should the bottom of the bell cast be above the damp proof course, If so by how much? Many Thanks

    • billericky profile imageAUTHOR

      billericky 

      5 years ago from Plymouth

      Yes you can drill into a rendered wall, just like a normal wall

    • profile image

      Desleigh 

      5 years ago

      can we drill into a render finished wall...we need to install a door jamb to prevent swing doors blowing in the wind.

    • billericky profile imageAUTHOR

      billericky 

      5 years ago from Plymouth

      You can skim over the internal render as soon as it is dry, and after a week, I am assuming that it is.

      You will need to add a PVA mixture over the render and old plaster prior to skimming over, without the PVA the new plaster may begin to crack and fall off.

      No special type of plaster is required, simple multi-finish is suitable.

    • profile image

      Begum 

      5 years ago

      Hi I have had DPC in my old victorian terraced house. I've hacked off a lot off the old plaster and recently had someone come in to render all the walls up to the old plaster.

      Its been over a week since it has been rendered, my question is; when can we skim over and do we need to pva the rendered walls before we skim? and lastly do we need to use special type of plaster to skim the walls?

    • Armchair Builder profile image

      Michael Luckado 

      6 years ago from Hawaii

      Like the look. I've never heard the term render. Where are you located?

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)