When a building’s exterior is rendered, there are some common problems that are likely to occur.
These include fading, cracks, mould, and leaks.
Learn more about these issues, and how to fix them.
The Common causes of render defects
Building render cracks are common on external walls.
They are caused by a number of different factors, including weathering and structural movement.
While they can be cosmetic, they can also be quite serious, and can cost the typical homeowner a lot of money if not fixed at the early stages.
They may need to be repaired or replaced, and could eventually cause structural problems.
The main causes of exterior render defects include:
Moisture behind the render, which can penetrate through the wall.
This can cause penetrating damp which can result in timber decay, stained plaster and mould.
Rising damp can have a major impact on the structure of a building, causing bulging and bulged walls, floorboards and skirting boards to warp, and even rotting.
Surveyors can identify signs of rising damp and recommend the best solution.
Inadequate preparation before a rendering job can contribute to issues with the surface.
It is often necessary to clean the wall of dust and dirt before applying the render.
This can help to slow the drying process.
The application of two coats of render is standard.
The strength of the first coat varies with the type of brick and stone used. It is important to allow the wall to dry properly before applying the second coat.
Avoiding renders that are not breathable
For the optimum performance, it is a good idea to choose renders that are breathable.
This will prevent damp problems from arising in the building envelope.
Water is a significant cause of damage to buildings.
It can be introduced by wind-driven rain or moisture that is trapped underneath render.
If the wall is not waterproof, the resulting damp can lead to discolouration and damage.
Another way to avoid the dreaded damp is to clean and maintain the render. Keeping it clean will help to reduce the risk of dampness, and will also avoid any organic growth.
There are a variety of different types of render. Some are more flexible than others, so make sure you choose the correct one for your needs.
Some renders are designed with breathability in mind, such as silicone. This will prevent the build-up of fungus and algae. In addition, it will provide a highly durable finish.
There are other types of render that are less breathable, and will allow the moisture to soak in over time. This means that your wall will need to be treated with a waterproof exterior coating.
Repairing persistent render problems
One of the most enjoyable aspects of owning or managing a house is the opportunity to improve it, and in some cases, add value to it.
However, if you are in a pinch, it is often easier to call in the pros. Rendering, for example, is not as easy as it sounds and even the most keen and experienced DIY’er can make a right pigs ear of rendering if they have no training or experience in applying render.
Fortunately, repairing persistent render problems is not as hard as it sounds for a professional rendering company.
Whether it is a case of neglect or a lack of time and resources, you can get a quick fix if you choose wisely.
Of course, the best way to ensure that the job is done right is to hire the best people to do the job. Try and get recommendations from work colleagues or family.
Luckily, there are many qualified contractors in your area, all of which are licensed and insured. Whether you are in need of a free estimate or a full-blown renovation, the best bet is to find one that suits your needs.
You will not only be able to tackle your exterior rendering problem in no time at all, but you will also save a ton of money in the process.
RAL or British Standard (BS) colour
It’s not a good idea to leave render in its bare form, unpainted. In addition, who wants to live in a dull, grey house?
If you are planning on re-rendering your exterior walls, you may be wondering about the use of RAL or British Standard colour. These are colour specifications that were originally created for camouflage and signalling. They have been used in industry and construction for many years and remain in use today.
For these purposes, a RAL or British Standard colour has a number assigned to it, which can be applied to the central colour location. This number is one of the criteria of product quality. It is a way to ensure that the paint is correct and has been tested.
Despite these requirements, a variety of paint suppliers use different names for the same colours.
Some of these names are approved by RAL, but others have a less than perfect reputation. This makes it difficult to distinguish the genuine colour product from those that do not conform to RAL.
The colour of a product is a major criterion of product quality. For this reason, RAL has a system for providing colour samples. To obtain these samples, a contract is made between a manufacturer and the supplier. In addition, the agreement includes a guarantee that the colour will be produced according to specifications.
Can render be applied over existing rendering?
In general, no it can’t. If you attempt this, in most cases, the render just won’t stick to the wall, will crack and fall off. It is usually best to remove the old render before applying a new 2 coat render however the exception is a product that we use, namely Wethertex AX1 pliolite one coat render.
It has a lifespan of over 40 years and is ideal for making good a house with rough render, maybe one that has been patch repaired numerous times, and for homes with poor render but render that has not blown (come away from the wall)
“Boasting long-life, through-coloured protection, proven to work for up to 45 years AX1 will create a beautiful, durable finish that ensures the property is finished with the highest quality wall coating on the market. In addition to it’s longevity, AX1 Pliolite Thin Coat Render is a flexible, waterproof and breathable render specially developed to provide the highest quality protection” Source:wethertex.co.uk
To see this product in action, we used in recently on a job we did on an old fisherman’s cottage in South East Cornwall, which you can see here.
TIP: If you click the image above you can learn more about this rendering and wall coating job we did.
What should I look for to ascertain if the render on my house needs replacing?
The most obvious sign would be cracks in the walls.
Cracks can be tiny, hairline cracks or larger ones, the latter being the most concerning.
The first thing you should do is tap the wall with a chisel.
If the render is good it should produce a ringing sound, but if the rendering is bad, blown, meaning the coating of render has come away form the bricks behind it, the chisel will make a dull, hollow sound.
For the musically minded, a typical tuning fork also does the same job.
Also if the wall is bulging outwards, this can be a very bad sign and you need to contact a wall coating company to come out and take a look.
Another sign is damp on the interior walls, which often comes from bad render on the outside.
Should I get the wall patch repaired or completely re-rendered?
Again this is solely a decision to be made based on a survey of the wall and what sort of condition it is in.
Patch repairs are difficult to match in to existing render, and can show through masonry paint when painted over, however a textured exterior wall coating, like the one we offer, is much thicker and is good for hiding repairs such as this, especially if its a wall that gets direct sunlight.
The render on the outside walls of your home serves an important function and should be kept in good condition throughout your time living in your house.
Keeping your rendered walls in good condition can be achieved by a NEVER PAINT AGAIN wall coating, which is guaranteed for 20 years to offer superior protection from all the aspects of the weather that can bring harm to your render, such as cold, snow, frost, damp, pollution and so on.
To get a quote to have your rendering fixed and protected, give us a call today, on 0800 970 4928