Beware of working with renders and treated wood.

The use of timber cladding and elaborate wood detailing in new builds and refurbs seems to be on the increase in a big way. When wood is skillfully used in a contemporary design along with a great looking render such as those by K Rend or Parex the results can be stunning.

Unfortunately, in a lot of cases this stunning look may only be temporary as one key problem seems to be getting overlooked time and time again if the regular calls our Mendrend technical team receive are any indication.


A lot of the pressure treated timber on the market appears to be treated with a substance that is not completely water proof so when the timber gets wet the wood stain is then dragged down the wall which then pentetrates deep into any surface that is porous such as your normal cementitious render. The results can be devasting and extremely difficult to correct. We strongly advise if you are considering the use of treated wood in the design of you build that you check with your wood supplier that the treaments used in its production are completely stable in the presence of water or consider the use of an additional wood seal that makes the timber completely impervious to water.

Please call our technical team if you need any advice with the rectification of this issue.

Why choose our 2 year crack free guarantee?

We've specialised in repairing renders for many years now from the design and development to on-site application of our specially designed patented Mendrend range of products we have been focused on customer service as a core driver of our business.

During our time as render repair specialists prior to our focus on the supplying of materials we quickly realised that there is a key grey area when its comes to render applicators and the manufacturers warranties that are provided when renders are correctly applied. This grey area is building settlement; if a building settles (The vast majority don't but any building can.) and cracks after render is applied it tends to be the applicator who is blamed when in fact its absolutely no ones fault the issue has occurred. The applicator may then call the manufacturer in to see if the issue is covered under the warranty only to be correctly told that settlement is not covered under their standard warranty terms. This would be the case for pretty much any render system sold on the market today. 

This usually results in the applicator / builder / customer going round in circles trying to solve problem and one of them ends up having to pay to correct the issue depending on who loses the argument! 

Our no quibble crack free guarantee provided when we supply render systems is designed to solve this age old problem. We have teams of technicians who operate nationwide assisting customers and resolving disputes daily. I'll be frank we don't aim to be the absolute cheapest render supplier out there, I'll leave that to the guys who cannot provide their customers with assistance or have no idea what they are selling.  We aim to provide low competitive prices whilst providing help when needed.

We invite all our applicators to offer this guarantee to their customers and maybe offer a cheaper price without this guarantee if a cheaper supplier is available and let the customer themselves decide.

We invite all our customers looking to have their own properties rendered to strongly consider our industry leading backup service for what tends to be a small addition to the price of having the works done.

Those who have ended up actually needing repairs done have found our service to be invaluable. A simple crack which normally could have been a problem to fix suddenly becomes a simple phonecall. This service is currently implemented on large housebuilder sites such as Taylor Wimpey, Arncliffe Homes and Cyden Homes with great success.

If you have any questions about how you can provide your customers with better service please contact us.  

Working with thin coat renders in the winter

It's started.

The phone has rang a couple of times this week with customers a little flabbergasted that the thin coat render they applied a few days ago has washed off in the last rain shower with a slightly accusatory tone in their voice.

All I will say on this matter is that there is nothing wrong with the material when this happens, and its not unusual for customers to start flagging this issue up at this time of the year, as its the same every year. The simple fact is that some thin coat renders perform better in cold and damp conditions than others and each job needs planning accordingly.

Traditional thin coat resin based bucket renders generally depend on good air drying conditions as there's no curing process with these. If the air is constantly cold and damp they struggle to dry if not protected and can hang around for days only for a rain shower then take them off the wall in a hair curlingly frustrating fashion. They will dry in cold (5c+) air if the air is dry and crisp and the background is dry, but it may still need a good 24 hours before it is considered safe from the weather. Be careful with these at this time of year, a weather shielded scaffold and a space heater goes a long way to alleviating some of the problems cold damp weather may bring with these types of renders. 

The new mineral thin coat renders such as K Rend Mineral TC perform better in colder conditions with less risk of washing off because they cure and are much less dependent on good air drying conditions to harden. They still need to be applied on a dry background, but a bit of fog or moisture in the air won't prevent them from going off completely and drying times will be measured in hours rather than days. Temperatures still need to be a minimum of 5c on a rising thermometer. This is an excellent winter alternative to a traditional thin coat render if you have a job that needs to be done!

If you have any questions or need advice, please contact us!

What are the Benefits of Using Render?

We have briefly mentioned in previous blog articles some of the benefits and reasons you might want use an external render system, but it is worth further elaborating on these points and more as to why rendering an external wall is beneficial to a property.

Improve the external appearance of a property

There’s no denying that applying a render system to an old, tired-looking building will transform its appearance – making it look modern and more visually appealing.  Local authorities will often use render when renovating their properties for this reason.

This aesthetic improvement can be beneficial in multiple ways – if you live in the property - it makes your home look nice. If you looking at selling a property, it can make it look more visually appealing to potential buyers. 

From a wide range of colours, to a huge selection of textures and finishes, there are a wealth of possibilities available when rendering a house.

Increase the thermal efficiency of walls

Some renders – like the K Rend Silicone Thin Coat range – can be used as part of an External Wall Insulation System. While most render systems themselves are not classed as insulating (though they do provide a small amount of innate insulation), when used as part of an EWI system they can help increase the thermal efficiency of walls and reduce heating bills – not to mention the other benefits featured in this article.


External walls that are in a poor condition can lead to the ingress of water and external debris which will worsen if left untreated. The use of a render system on an external wall forming a barrier, protecting a building from the elements. These renders incorporate water repellent technology, protecting against water whilst still allowing the substrate to breathe.

If you need help with applying render or you would like to know more about the benefits of render, contact our experts today.

Achieving The Right Texture Finish

Render systems are available in all sorts of colours, styles, finishes and textures and whilst they all vastly improve the appearance of a building, their suitability and appropriateness vary from factors such as the building substrate to planning regulations of the local authority.

What types of render texture finishes are possible?

Each manufacturer has renders with different finishes, and the look you wish to achieve will influence the render system used.

Textured, Smooth, Scraped and even more unique finishes such as brick effects or ashlar detailing are achieved via a combination of the application method and the finishing tool used.

How are different texture finishes achieved?

Standard renders usually have 3 categories of finishes - scraped, smoothed and textured – each with their own subtle variances. For example, Parex Monorex can be scraped to achieve a fine or medium finish. 

Scraped texture finishes are achieved by scraping the render with a scraping tool before the render has set hard whereas using a trowel or float will result in a smooth-looking finish.

Applying the render using a spray machine will give a far more pronounced texture finish, similar to tyrolean and roughcast.

There are also more technical and specialist finishes such as pebble dash where an aggregate is thrown onto a wet receiver; and brick or ashlar effects, where a pattern is cut into wet render to give it the appearance of real brickwork. 

Guidance on choosing the best texture finish

For advice on achieving the right texture finish, or if you would like guidance on choosing a texture finish, contact our experts who are always ready to help.

Applying K Rend – Why It Is Important To Follow Manufacturer Guidelines

The result of a well-applied render system is a fantastic looking finish, designed to give old and tired-looking exteriors a new lease of life.

However, this is only true if the chosen render system - such as K Rend - is applied correctly. Incorrect application can result in the failure of the render system, requiring it be replaced. One of the main factors of a poor quality K Rend render system is due to the applicator not having sufficient knowledge of how to apply K Rend.

Always Follow Manufacturer Guidelines

Rendering an exterior surface is a technical task but its payoffs are well worth it – a fantastic looking exterior finish with additional benefits such as weatherproofing and improving the visual appearance of a tired, old building.

People may be put off using products such as k rend insulated render systems due to the horror stories that have come about due to applications performed incorrectly either from lack of experience or failure to follow manufacturer guidelines. If applied correctly, problems like the infamous Curse of "Halo Ring" can be easily avoided.

Different Methods Yield Different Results

The application of k render systems affects their appearance, both in how it is applied and how it is scraped – just take a look at our blog post on Why You Should Always Provide a Customer Test Panel. In order to achieve the best results, it is essential that the render is applied in accordance with the official K Rend instructions.

Use an Expert for Expert Results

Our qualified technicians are experts in applying K Rend and can help rectify any mistakes or issues that occurred during a previous poor application. Contact us today for help and advice on k rend application.

Why You Should Always Provide a Customer Test Panel

One thing some applicators are better at than others is providing their customers with sample test panels of a finished render product as it can cause big problems with customers who are expecting their render to look exactly like it does in the brochure or even worse on their computer monitors!

The two render samples shown in the above picture are made from exactly the same render from the same bag. The sample on the right was simply scraped much earlier during the drying process than the render sample on the left and the difference that can make on the outcome of the final colour of all cementitious renders can be quite profound. It is for this reason we strongly recommend that you complete customer samples so you can test and verify the colour with them before ordering any materials 

It is very common for applicators to scrape renders early, therefore the colours achieved on site could possibly be much stronger than the colours of manufacturer provided samples which are made in a laboratory under ideal circumstances. It should be noted that all manufacturers of cementitious render products would deem this to be normal behaviour of the product.

We are happy to provide assistance with this, please feel free to contact us!

Fissures in Render and How to Fix Them

As we have written about before, large cracks in render can be an indication of a major problem in the substrate. However, smaller and much less serious fissures can also appear. These fissures tend to be a lot smaller than cracks (around 0.1-3mm in width) 

Origins of fissures in render

Like cracks, fissures can occur due to movement from the building or the substrate the render has been applied to. Whereas large cracks tend to be an indication of a more severe issue, minor fissures usually occur due to minor inconsequential movement in the substrate.

What to do if you find fissures in render

It goes without saying, but you should always seek the advice of a professional before attempting any repairs. Determining the origin of the fissure is essential to ensure that there are no recurring instances of the problem. It is also advisable to wait for a period of at least 6 months to make sure that all fissures in the render system have stabilised.

Repairing fissures in render

Our patented Mendrend Flexible Fissure repair system is specifically designed to repair fissures in render from leading manufacturers and is supplied in a range of colours intended to match render manufacturer colour ranges. We also provide a comprehensive support service for this product. 

Rendit offers expert help and advice on repairing fissures in render – contact us today to find out more


Applying Render in Adverse Weather Conditions

Most render systems are best applied in optimal weather conditions – ideally between 5oC and 35oC, with no rain, wind or snow. However, some projects may have to be undertaken in less-than-ideal conditions either due to time or budget constraints, so it is vital that the risks and challenges of applying render in adverse weather conditions are fully understood. 

Know your conditions

It goes without saying that before you begin the application process of any render, you should read and fully understand the application instructions supplied by the manufacturer.

The type of render system being applied is another factor to consider. Dry dash systems are more resilient to wet and cold weather than their silicone counterparts.

It is also advisable to check the weather forecast for your planned application dates – try to avoid any days with excessive rain, wind, heat or cold. Extreme weather conditions can severely affect the both the application and drying / curing times of the render. 

Simple Solutions

In hot weather, do not apply render on walls which are exposed to direct sunlight. Instead, start on an adjacent wall in the shade and follow the sun around the building. This method allows you to work in sunny weather, whilst avoiding any curing issues direct sunshine may cause.

Certain weather conditions will slow the curing process down – usually due to colder temperatures (less than 5oC) or high humidity (90% and higher). If this is the case, then the render will retain moisture for a longer period of time and if sustained will become more susceptible to damage from trapped moisture so it is essential that the render system is protected during this stage.

Ask an expert 

At Rendit, we offer a 2-year crack free guarantee on our Render Systems, so if you need any help applying your render contact Rendit today!

“Do we really need to two pass with K Rend and Parex?”

“Do we really need to two pass?” was a question I got asked by a customer a couple of weeks ago, the question was then followed by the statement “We’ve never had to before!”

The answer to this question, as I explained to my customer is yes, when you aren’t applying render over a basecoat and for a number of pretty big reasons.

Firstly, the biggest reason is science. There has been a huge paradigm shift in all industries to green and environmental thinking. There’s been massive pressure applied to all manufacturers from above to focus on carbon saving on every aspect of their business and this has had a huge impact in product development labs everywhere. Everyone in the building industry is thinking cheaper, lighter, stronger, less energy for everything whether it be bricks, blocks, plasters, mortars and renders. I think for the render industry it’s had a great effect. From a render applicators point of view, today as I type this I honestly think that if you could buy a bag of render from any of the larger manufacturers and you would have a great product to apply. Gone are the days of the huge heavy trailer diesel powered mud-slinging pumps which could only be afforded by the busiest of applicators. These days due to these modern advancements you can buy a tiny Ritmo, plug it in and start firing a buttery, light and fluffy dream of a render at a wall 3 floors up in about 30 minutes. Applicators are positively spoilt in this day and age!

The push for green advancements does have a minor downside, especially when we look at the concrete blocks available on today’s market, the push for cheaper, lighter and stronger does mean essentially that there’s more air in them, which in turn means more suction, or variable suction. Too much suction on a render that’s applied to thick on the first pass could result in accelerated drying backwards as the moisture is drawn quickly into the background and there’s potential for random splits occurring in the skin of the render due to the pressure of this pull. Whilst this won’t happen all the time, the risk of it happening is quite high and it is one of the reasons most renders are manufacturer specified, including those from K Rend and Parex to be applied in two passes. The first pass takes the initial suction hit and quickly pulls in which then protects the second pass from too much background pull. Most still suggest a primer such as K Rend R10 or Parex Micro Gobetis on very lightweight blocks though as the suction on those things can be huge. Dense blocks need priming also but that’s because there’s not enough suction for the render to create its bond, but that’s for another article!

The other main reason for two passes being specified during render application ties somewhat to the reason above. The proliferation of modern light, fluffy and extremely easy to apply renders compared to the heavy unwieldy renders that were around not so long ago has left applicators spoilt in these days of Facebook, Twitter, forums and social media. Applicators who have a bad day applying a product that they can’t get on with are quick to tell their mates or anyone else who reads their social media accounts, which in turn can be shared many thousands of times in applicators circles very quickly. So whilst science is making these products go green, at the same time science has to pretty much create a render product that essentially puts itself on the wall compared to the renders that were around just over a decade ago relatively speaking.

An amazing feat when you think about it which all of the large manufacturers have pretty much nailed in my opinion. There’s been pain getting to where we are today, but today as I type this we are in a very good place with application quality of modern renders!

The only downside to a light and fluffy easy to apply render, is that in most of the country they have to a finished depth of a minimum of 15mm thick (20-25mm in some areas.) to pass water absorption criteria set them by building regulations, but they simply don’t have the structural strength during the initial application from the spray to be applied at that depth in one pass without the risk of sliding down the wall and risking horizontal splits or tears as it sags under its own weight. You may not even see these happening until the scraping process at which at that point of no return they reveal themselves as random horizontal cracking across the wall.  Our technicians can fix this if need be, but it needs a fair bit of work.

Best to be avoided if at all possible.

My customer ignored my advice.

We’re on site to sort his problems in a few weeks, he doesn’t get paid by his customer until we’ve done it…………..

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