Paint keeps flaking on render

happyhero

Hi I live in a mock Tudor style house and the paint on the render does not seem to last very long, ie after painting it lasts 2 years if I am lucky sometimes it flakes in less than a year. A few years ago not having much ready cash I had someone paint it for me who I new was not the most thorough of people but he was cheap and I was around to keep an eye that the job was at least complete and tidy. To be fair I did point out a couple of problem areas for flaking and he did seem to improve these areas, basically they flake much less now. I asked him about what he did and he just said he used a stabiliser. He said there were different stabilisers and that he used one which you put into the paint, as opposed to something you paint on before hand.

Before this I had painted the render with Sandtex exterior masonary paint which looked lovely obviously at the beginning but some of it did flake off less than 2 years later. I then tried using exterior unibond first in a test area to try and seal the walls but to my amazment this did not seem to help at all. I asked about this afterwards and was told doing this was not a good idea as it would seal moisture in the render and thus cause the paint to flake.

Since this I have been Googling the problem and found that my render could be lime render although the dates do not agree. I read that they used lime render in the late 1800's and my house was built in 1933. Also I do not think my house was built or decorated in an unusual way as it is in a group of about 12 houses all built and looking almost identical. My point is, it does not look like someone tried to be different and build it with Lime render in the 1930's unless they decided do that to all 12 of them which I suppose is possible.

Anyway from Google and Forums I read to check this it said you should rub your finger on an exposed bit and see if you end up with a white finger, well I did this and I do so does this mean I have Lime render?

I also looked up what you should do with Lime render and one solution is to use a Lime based paint or whitewash as it appears they call it but this feels like an awkward route to go down, i.e. I'd rather use a well trusted paint, Lime paint seems harder to find and quality is harder to be sure of. Also how long would it last, and where to get it etc.

So my questions are

Does it sound like I have Lime Render?

Is there a long lasting solution I can paint on, so that I can use popular paints, I dont mind paying a little extra for something that works?

Am I better offer using a Lime Paint and if so why?

Any advice or help appreciated.

happyhero

help pretty please

prowla

(I first read that as "Paint keeps flaking on reindeer"!)

Happy-Days_3

If it is chalky when you run hands on it, it all needs a going over with a stabilising solution first. Maybe give it a couple of coats.

Also, be sure it is all clean - stiff brush, anything loose removed.

If the wall is clean, render sound an stabilised, shoul be ok when painted.

renovation_man

If a previous owner has sealed the render, then the new paint would just sit on top as a skin and would not take long to wash off.

If the surface is porus then put on a couple of thinned down coats so it soaks into the render and then apply a standard coat.

An alternative is to clean off as best possible then apply a stablising solution and then coat with paint containing priorlite which is waterproof.

A matter of trial and error

happyhero

Happy-Days wrote: »

If it is chalky when you run hands on it, it all needs a going over with a stabilising solution first. Maybe give it a couple of coats.

Also, be sure it is all clean - stiff brush, anything loose removed.

If the wall is clean, render sound an stabilised, shoul be ok when painted.

Hi Happy-Days thanks for the reply, but I have some questions now I have read that lime is supposed to breathe and not be sealed but I am all for the idea that I could use some modern coating so that I don't have to bother with fancy lime washes etc, so do you think the stabilising solution would achieve this and last say 5 years plus, i.e. I am concerned about sealing the render if it is lime render?

Also with stabilising solution, what is the preferred method, ie do you just paint all the render for good measure before painting with paint or do you only really use it on the bad areas?

iamcornholio

I think that it would be unlikely to have lime render from the 1930's - especially for a group of properties. Rubbing a finger is not really a good test unless you know precisely how to interpret what you see

Does this paint flake all over or just at certain points? Is it one particular elevation or all sides?

Do other properties suffer this too?

Once flaked, how does the paint peel or appear on the wall - a picture would help

Does just the paint peel and leave a smooth hard render surface, or is there part of the render stuck to the back of the peeling paint?

happyhero

how do you add an image, I looked about the forum but cant find out how?

iamcornholio

Post the image to an online host - eg https://www.imageshack.us and insert the link

nickj_2

water based paints will not stick to unibond , it tells you this on the tin
you cannot use lime based paints over sandtex type paints .
there are no stabilizers that you put in the paint, your painter was having you on
you need to make sure that all flaking paint is removed ,
the surface must be clean , you can use a fungicide solution to get rid of any green mould etc any cracks etc need to be made good ,
then if the surface is chalky it needs to be sealed with a stabilizing solution
and only then can you put some paint on , if you can get hold of it , try bedec exterior masonry paint - very good at not flaking or peeling

happyhero

Ok hopefully I got this right, here are some images. It does happen to the other properties as well, some worse than others, so obviously you have to wonder what was used on their walls. Also it happens mainly on the fronts which are the damper side (we get sun in the morning in the front but the back is really a sun catcher). The front faces NNE or NE if you want to keep it simple.

http://imageshack.us/photo/my-images/3/imag1196.jpg/
http://imageshack.us/photo/my-images/100/imag1191.jpg/
http://imageshack.us/photo/my-images/268/imag1190u.jpg/
http://imageshack.us/photo/my-images/35/imag1192q.jpg/