Render problems and render cracking

Chartered Surveyors and Rendered walls

We are Independent Chartered Surveyors and Structural Engineers who take great pride in our work and are very proud of the high standards we achieve. As well as Building Surveys, also known as Structural Surveys, if you want to know what the property is worth we can also offer Independent Valuations, Engineers Reports, Specific Defects Reports and Homebuyers Reports. This article is on rendered walls but we have many years of experience and knowledge on many things property related. Please free phone us on 0800 298 5424.

What is render? Over the years we have used render in buildings to protect our buildings and decorate them. At a glance render from hundreds of years ago looks similar to render that we use today however it is very different in its material properties and how it should be used.
	Cracking to render

Render as protection

Render offers protection to a building, many years ago it was used to protect a timber structure and more recently we would argue that it is being used to allow us to use cheaper materials underneath such as blockwork rather than brickwork or stonework. Render then provides protection against the elements of the weather over the different seasons.

Different types of render and render problems

There are many different types of finishes of renders which we will consider in this article.

Older style render; what is it made of?

In years gone by render has been used as a decoration to depict scenes or to create patterns which were quite impressive and relatively common. Essex is known for decorative render patterns although we do find these across the country. Norfolk and Suffolk are well known for renders finished in a pink or yellow. We have heard rumours, and we are not sure if this is true, that the pink came from a mix of blood and the yellow came from a mix with saffron.

Decorative render to the panel just below the box bay window

Lime rendering in action	You can see what is known as the scratch coat to the right hand side which is applied before the final coat	Close up of finished render (there is still some work needed to be carried out to the roof)

What is render hiding as well as protecting?

Behind the render coat is often a timber frame which can be affected with woodworm, wet rot and even dry rot.

What is behind the render coat?	Render can be hiding all sorts of problems in an old property such as in this photo woodworm and wet rot to the timber frame

Modern render

Over the years, particularly since the War years, render started to change with cement being used in the render mix and the modern applied renders such as pebbledash render. Also pre-formed render panels were being used. We recently spoke to a plasterer who had used a mix where the colour was impregnated all the way through the render meaning in theory you would never have to paint the render again!

Decorative render

Modern render or Cement render

A modern cement render is much harder than an older lime render and works well on more modern properties that do not move very much. However unfortunately it is often used on older properties where you can get the differential movement between the two properties which can cause hairline cracking.

We would always recommend filling hairline cracks as quickly as possible.

Older style render

Older style render is often known as pargetting and can be a mixture of lime, ox hair and other locally available materials.

Stucco render

Stucco render is a system of rendering where it is finished to look like stonework.

Cement Stucco render – you can tell it is cement from the colour and you can also see the pattern staining below the window.	A hard cement render of Stucco blocks next to pink pebbledash render

Pebbledash/Peashingle render Pebbledash/Peashingle render has a texture to its surface and there are arguments abound whether smooth or textured surfaces are better for render. Pebbledash/Peashingle render can be unpainted or painted.
	Peashingle render

If you look closely this relatively new window has been put in place with a different texture of pebbles around the window compared with the original pebbledash.

Peashingle coming away	Peashingle badly repaired where there is a crack beneath that has been hidden	An area where Peashingle has been better repaired but still stands out where there is cracking beneath it.

What is render hiding?

In some cases render is applied to hide defects; this may be a cynical Chartered Surveyors' view but over the years we have come across many defective properties which have had defects hidden by the render and in some cases carried out time and time again.

If render was hiding wall tie failure we would expect to see horizontal cracking.

Should you worry when you are buying the only house in the road rendered?	You can see the tie bar to the right hand side centre of the photo this render could be hiding all sorts of cracking beneath it

Render painted to sell

This can also relate to hidden or latent defects where the render has been painted when the property is to be sold. We come across this a surprising number of times and could blame all the property television programmes that recommend you present your house in as good a way as possible.

Please see our articles on property television programme reviews such as

Cowboy Builders

DIY SOS

Location, Location, Location

Country House Rescue

The newly painted render does make it very hard to see where the problems once were.

Cracking to render

This can be in two forms:-

Cracking to render can be caused by the structure beneath and the cracking can be in the render.

Cracking to render caused by the structure beneath.

This is known as structural cracking and this is where the problems in the property are so bad that even though it has been rendered over the cracking resurfaces.
	A property with problems, these cracks are structural!

Hairline cracking to render

For many reasons this can range from differential movement in the property where materials have expanded and contracted at different speeds to hairline cracking where there are window openings and other structural openings. It can be as simple as the render mix being too hard and it has cracked as it has dried.
	Crack brought about by expansion and contraction of the building.

Pen indicates hairline cracking

Quality of workmanship

One of the most important things with render, regardless of whether it is an old or modern render, is to understand how to detail a property. Over the years an experienced Chartered Surveyor will very quickly assess the quality of rendering; we often base this on the quality of the detailing.

Render detailing

Window drip detail

A window drip detail is to keep rainwater away from the window and can often be seen on buildings with render.

	Window without drip detail

Very shallow drip detail on window	Drip detail on window

Bell mouth detail A bell-mouth is a curve at the base of a wall which throws the water away from the structure therefore preventing dampness.

Poor quality bell mouth detail to the base of the wall	Bell mouth detail to the base of the wall

Bell mouth detail to the base of the wall	This bell mouth detail to the flat roof we will not go into in this article but we would prefer to see lead flashing

Maintenance of render

Render where it is used externally is subject to attack from the weather and as such does need maintenance. You can often find there is a protective coat of paint applied to the render which does weather over the years and needs to be re-painted with the correct type of paint.

How often should I redecorate render?

This depends on many factors such as the location and the exposure of the render together with how well it was originally applied to the wall as well as the detailing to the render which allows the water to run off it so it does not cause problems elsewhere.

A very general answer would be every four to five years but for example we have managed a property that is right next to the road and ideally it should be redecorated every few years.

Mould in render Green mould is often visible to render and sometimes black mould which is a sure sign of dampness.
	Green mould to render

We hope you have enjoyed this article and would like to refer you to other articles on our website that we feel may be of interest to you;

Windows how to look at a window and understand if you have problems with the window

Windows and the Great Fire of London

Buying a house

Building Surveys or Structural Surveys?

Cheap Building Surveys or being wrongly advised by your Building Surveyors

Independent Chartered Surveyors

If you truly do want an independent expert opinion from a chartered surveyor, and many of us are also chartered builders, with regard to surveys, building surveys, structural reports, engineers reports, specific defects reports, structural surveys, home buyers report, valuations, mortgages, mortgage companies, or any other property matters please contact 0800 298 5424 for a chartered surveyor to give you a call back.

Commercial Property

If you have a commercial property, whether it is freehold or leasehold then sooner or later you may get involved with dilapidation claims. You may wish to look at our Dilapidations Website at www.DilapsHelp.com and for Disputes go to ourDisputes Help site www.DisputesHelp.com .

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