2020 Architect’s ‘Drumnamallaght house’ uses a K-rend finish.

When building a new home, a common question our clients at 2020 Architects ask is what type of render or exterior finish to use.    

The options are simple – plaster finish, paint, dash, smooth concrete finish, dash, or K-rend render.

The growing popularity of K-rend render has led to a surge in colours and textures on offer with over 500 options to choose from.

Following an informative and factual CPD by K-rend, 2020 Architects have devised answers to some of the most common questions our clients ask us.

1. What is K-rend?

It is a coloured coating applied to the walls of buildings.  K-rend is a mineral-based product traditionally processed using limestone. It is delivered on-site pre-bagged.

‘Bucket-mix’

K-rend is now producing organic resin renders (or ‘bucket mix’) which come in over 500 colours.  These are cement free and ready-made on site in paste form.   They are incredibly low maintenance and durable.  The silicone additive provides exceptional water repellency.  The main difference is they contain fewer pores than traditional renders, have no sparkle and provide a smoother finish.

2. What are the main benefits of K-rend render?

The major benefit is that there is no need to paint your house, plus it is quicker than the traditional method of scratch coat, plastering and painting.  The decorative top-coats of K-rend come in hundreds of different colours and finishes to suit everyone’s taste.  Unlike traditional plaster, you don’t have to rely on good weather to apply it.

3. How much does K-rend cost?

K-rend render costs approximately £7/sqm compared to the traditional method of scratch coat, top coat and paint which costs approximately £5/sqm.  The obvious benefit of K-rend is its durability which means you don’t have to repaint your house every 3-5 years, thus this is where the cost-saving comes into effect.

4. How do you prevent algae on K-rend?

Algae inhibitors are contained in all K-rend products – this helps reduce the likelihood of algae forming.  Contrary to popular belief, algae grows in clean air, which is why it is more commonly spotted in coastal towns and villages.

Sunlight and frost kill algae, however Irish weather provides the ideal climate for algae to grow.

K-rend is manufactured to enable vapour to pass through the render, allowing the house to breath and preventing internal condensation.

‘K-pro’ is a product which is applied to finished K-rend renders.  It is a breathable and water repellent product which does not allow water to penetrate.  It keeps K-rend for longer by dramatically reducing the algae.  It seals the surface meaning algae can’t penetrate.

5. What is the recommended preparation for K-rend?

• Allow settlement of new builds – (NSAI standard is a “minimum of one month”)
• Don’t apply K-rend in extreme temperatures (less than -5 or over 35+)
• Don’t apply in heavy rain – this will cause wash off.
• Apply corner beads and mesh to strengthen around windows/openings and places more susceptible to cracks.
• Install all vent pipes, guttering and downpipes before the render goes on.

6. How long will it take for the true K-rend colour to appear on my house?

It takes on month for the real K-rend colour to appear.

7. Can you apply K-rend over existing render?

You can apply K-rend onto unpainted surfaces.  However, if the original render is painted, then the paint MUST either be removed or a barrier created by means of a breathable membrane interface.   K-rend should NOT be applied directly to the surface of paint which is susceptible to flecking.

8. How do I clean K-rend?

To remove dirt, K-rend recommends warm soapy water.  To remove (and prevent) the formation of algae, K-rend recommends you treat the render every 12 months with their specially formulated product ‘Biocide.’  Enter the solution as directed into an Knapsac sprayer, spray and leave for 40 hours.  Lightly spray it off with a power hose.

People make the mistake of power washing K-rend to remove algae.  This is not recommended as it only causes algae to spread by removing the top layer and dispersing it.

9. How often do I need to reapply K-rend?

BBA’s standard is every 30 years.

10.  What is the latest and most popular product currently in the K-rend range?

‘K1’ is the latest product on the market.  It is a thinner aggregate than traditional renders and therefore provides a smoother finish.  This smoother finish means it contains less pores therefore reducing the likelihood of algae.  View all the product ranges at www.k-rend.co.uk/