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What do we need to do about cracked render?

When we bought our house six years ago the surveyor noted it had been poorly rendered. Over the past couple of years I've notice more cracks appear in the surface across the house. Can these be repaired or do we need to replace the render? How much is a job like that likely to cost (2 storey, semi detached double fronted house approx 12 meters wide) - ballpark figures would be helpful - I don't even know if it's hundreds or thousands! Also as slightly stupid question but is render coloured? the house is a cream colour and it doesn't look like it's been painted as there is no flaking - or could it be some alternative coating has been used (it's smooth not rough) Thanks for any advice you can offer.

7 Answers from MyBuilder Plasterers

Best Answer

Cement based render is non porous, so many walls that allow moisture through from the cavity or interior will always pop, within a few years. Better to use lime based systems that are breathable. Decopierre or K Rend, for example.Lifespan is indefinate and being self coloured, don.t need painting. Sand and cement is cheap, but add painting and replacement and they are a short term answer. Think old wattle and daub buildings , lime is gooood.


Answered 23rd Feb 2011

You have been given some good information by,Bayley Property Sevices & N Louth Plastering, I would take all render of as, if you patched it, it would always show no matter how good the plasterer is.
I would use a SBR slurry and paint on wall prior to applying the scratch coat.
Done one similar to this not long ago, 2days hacking of, 2&1 gang rendering 3days, 3 coats masonry paint cost approx £2300
The scaffold was £360 but varies in different areas.
There are coloured renders as stated by above, usually come in bags more expensive than sand/cement.
Note, I have known some renderers using these materials, who havent been trained,one in particular done a complete housing site, which has failed, he has now lost his buisiness and house.
Get at least 3 prices, there are some good renderers about.


Answered 21st Feb 2011

sand & cement will crack in time no matter what ,£55.00 per meter k REND is what you need.


Answered 28th Feb 2011

monaqutick i think that what it call a lot of new builds have it on and when it cracks water gets in to it and then you get a problem do not have it bogged up by some one say thay will fill it in the colour dose not trun out the same as whats there you end up whit a shad lighter or darker if its a new build go back to the builder


Answered 3rd Mar 2011

The render on your house has cracked due to a number of reasons, it could of been done in poor weather, or not enough mechanical key.
In my experience you can take of the damaged parts and patch in, but personally I would take it all off and start again, making sure that a good key is achieved in the scratch coat (1st coat of render).
Also this scratch coat should contain a waterproofing in it too.
As for colored render, yes this is possible but only in darker colors and it is hard to get a consistent color. If you are after color render you could have it done in K-rend or monochouche these are a re pre mixed render similar to plaster and can be in applied in either by hand or by machine.
Personally sand cement render with a touch of lime added is as good as anything its cheaper but you will need to paint it after say with a sandtex paint which is micro porous, this lets the wall breathe thus stopping it from cracking and allowing movement hence why we add lime. As for price your looking at an average of about £16 to £20 per sq meter


Answered 21st Feb 2011


There are a few things to look for,

Are the cracks all joined together?
when u tap the render where it is cracked does it sound hollow?
Is it soft ? Crumbling?

If the answer to the above is yes then it will probably need to be removed as it is not adhered to the substrate (background)

This is due to a number of things

The background was not prepared properly ie not dampened down, no PVA applied, mortar joints not raked out etc,

It was applied in too warm a condition so it dried to quickly or applied in too cold condition and the frost effected the curing and subsequently caused the cement to fail and hence has no strength.

The topping coat is a stronger mix than the scratch coat which means the base coat willl be able to flex, expand more than the top coat and again cause the top coat to crack and come away from the wall,

The mix altogether is to weak,

If it is old render and seems solid it could be just cracks from movement off the property over the years but if the surveyer has stated it is a poor job I doubt this to be the case.

To hack off the old render, prepare the background, re render and apply paint or a finishing coat including scaffolding and removal of waste you are going to be looking at £2500 plus as a guestimate.

There are new polymer through colour renders that are out on the market that are normally applied in one coat which are pre coloured and once they have been floated and has set is the finished product they are normally applied with plastic coloured angle and stop beads to match the colour of the render

hope this helps


Tom Lyon


Answered 21st Feb 2011

If its constructed from thermalite or white durox blocks I would apply stainless steel lath as well .


Answered 21st Feb 2011

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