Painting rendering exterior wall

loulou41

Pl can any painter offer some advice. The back of my 2 bed Victorian house needs painting. The rending has cracked in some places and the paint flake off. I understand the cracks needs to be cut and then fill. I have read that there is now a paint that will last a long time. Can anybody offer some advice on this pl, also how much should I budget, it a small terraced house and only the back needs doing? Thanks

nickj_2

all the loose paint needs to be scrapped off ,if there's any mould this needs to be washed off with a fungicide , it may need sealing with either a stabilizing solution if it's powdery and then painting
you could go for something like dulux weathershield, or sandtex or bedec extra flex (good if rendering is prone to cracking)

it's going to cost around £40ish for the paint ,you might need 2 depending on area to be covered , plus any other bits and pieces , ask at your local trade suppliers rather than a diy shed

nobulljusttruth

IF the paint is coming off around the cracks, then damp is getting in.

Knock the render around the crack and again in none cracked places and see if it sounds hollow.

No point painting it if the render is letting moisture in as you will be doing it again next year. Consider a knock off and repair of the bad parts.

WATER BASED ACRYLIC paints are available from places like Decor8 in Bury. They do deliveries. £80 for 20 ltrs but it will keep and last a lot longer than DIY store products. Van be painted on or sprayed.

cyclonebri1

If you want something to last look up resin based systems, we did my SIL's large detached house in this about 5 years ago, still perfect but then it should be, the paint cost alone was £1200.:eek::eek::eek:

I did a semi I lived in some time back, it took 9 large cans to give it 1 generous coat, to give you some idea of coverage, but it was very rough roughcast.;)

1st_and_last

If render is cracked, but still stuck well, the cracks should be v'd out using a chisel or the sharp edge of a trowel. Use a filler that is more flexible than the render - not cement (acrylic caulk is fine for small cracks less than 1/8 inch) and smooth off. Scrape flaking areas and wash down with a hose and stiff brush. Antifungicide if growth is observed. Don't hack any blown areas away. If you need to do this you must have some prior experience. If not, call a bloke with a van and some tools. :beer:

If you need to use ladders then hook any buckets of water/fungicide on a rung with an "S" hook. Please be aware that heavy trade ladders are best for this kind of shenanigans, using a lightweight domestic ladder will be unstable, especially if it's a long one. Always have someone handy to foot the ladder for you.

If the surface is previously painted and adhered well, then a primer stabilizing coat won't be needed. Don't thin down any paint more than 10% (about a pint per 5 ltr tin) as this will compromise the performance of the resin. You will only need to thin the paint in cold conditions when the consistency is thicker.

Avoid power washing as there is a risk of high pressure jetting the water into the cracks and trapping water behind the render. Lots of people a too trigger happy and don't use the correct methods to wash down safely/effectively.

Apply the first/second coat from top to bottom/ right to left cutting in with brushes and rollering large areas. 2 coats applied in he same day on a good day. Special expensive paint brushes are not really needed for masonry paint and the film is thick enough to be forgiving when applied with any old pure bristle brush. Make sure it is pure bristle and not plastic. An old decorators trick is to tie an elastic band around the handle end of the bristles to stop them fraying out and spoiling the cut ins.:money:

Remember that no plastic paint will remain "maintenance free" despite the claims of any manufacturer. Even paints certified by the B.B.A will only perform to the stated lifespan when applied to a sound masonry surface. "Sound masonry surface" means -

1) Clean un-weathered masonry (basically new)
2) Virgin surface (unpainted)
3) No damp patches

A good test is to use a strip of masking tape. If the tape sticks well to the surface and no dust or debris is stuck to it when removed - the paint will stick well too.:j

Quality trade masonry acrylic paint wont cost any more than £30 / 5 liters . You will Probably need 10 liters and maybe have some left over for touch ins. Using solvent based has it's advantages, such as quick drying time, but even the water based ones dry in about 30 mins in good conditions, so you'd have be caught very short with the weather. Use solvent based when rain is imminent.

In reality the service life of any good exterior masonry paint is max 15 years. Some companies claim even longer but the most I have ever seen is just short of 20 years. Anyway, after this time the paint will be dull and colourless, so will need repainting again.

Hope this helps. It's my first ever post on MSE. I'll catch everyone on the rendering/painting threads soon no doubt :grouphug:

cyclonebri1

1st_and_last wrote: »

Hope this helps. It's my first ever post on MSE. I'll catch everyone on the rendering/painting threads soon no doubt :grouphug:

I take it you have some professional input here so I have a question.
When we did the job I mentioned in my earlier post above, my SIL was adamant he wanted to use the best/longest lasting/fade resistant coverings available. We went for a resin based system from 1 of the major players, can't recall right now but it could have been weathershield 365 or similar?
I asked here for advice as I hadn't used it. I got no real feedback other than it was very expensive, what are your views on the stuff?

As said it looks great, but after this short length of time it should do regardless of paint type.
My only comment is that it is hellishly messy and every you put it in ot roll it with need binning after;)

1st_and_last

cyclonebri1 wrote: »

I take it you have some professional input here so I have a question.
When we did the job I mentioned in my earlier post above, my SIL was adamant he wanted to use the best/longest lasting/fade resistant coverings available. We went for a resin based system from 1 of the major players, can't recall right now but it could have been weathershield 365 or similar?
I asked here for advice as I hadn't used it. I got no real feedback other than it was very expensive, what are your views on the stuff?

As said it looks great, but after this short length of time it should do regardless of paint type.
My only comment is that it is hellishly messy and every you put it in ot roll it with need binning after;)

They are great products but are smelly and hard to clean up after application. Rollers covered with oil based resin are best put in a container with a shallow pool of terps substitute or similar to clean and stop them from going hard. Cleaning this stuff of by hand in a sink or otherwise is not a good idea as the VOC levels are damaging to the environment. I usually end up with a container of paint "sludge" which is horrible stuff and has to be disposed of by using small hazardous waste disposal.

As far as I can tell these oil type paints are starting to be phased out, but they are obviously still readily available to the general public. For a long time these products have been acclaimed as the better alternative to water based in terms of durability etc.. The fact is that paint manufacturers are making better water based products which will eventually become the only ones in use.

"B.B.A" certification is a good sign that the paint has been through a proper testing procedure and will perform well.

Other coatings manufacturers might describe their coatings as having a "proof of performance" reliability of 20 years or more. This is all well and good, but in my opinion is only the case in exceptional circumstances. As I said before, the longest I have ever seen an oil based coating stay on is just short of 20 years. 95% had stuck on solid and could have gone on for another 10 years perhaps. It was a 1960's brick cavity built and s/c rendered bungalow. It was however a very faded coating and had virtually no "decorative" appeal. The good thing was that it was still a "protective coating". :beer:

Some marketing/sales companies push these type products and make some wild claims to get inflated sales. I did some quick calculations and i'm fairly sure that you could get your house .... wait for it..... 24k GOLD PLATED for the same money. _pale_ True story :rotfl:

cyclonebri1

Thanks for that. Your advice should be very helpful to many on here, welcome.