Render Repair then Painting

[R-head]

Hello,

My first post of what is bound to be many, many more on a variety of topics. My partner and I have recently purchased a property which originally dates from the mid 1830s, it has been extended 3 times by the looks of it since its inception. Whilst our finances cannot stretch to a whole makeover at present we want to make sure that we can make a steady progress and start to take a few chunks out of all the work that needs doing.

The house exterior has not been overly neglected, just not kept on top of I think due to lack of money and capability of the previous owner. Well having looked around the exterior walls there are numerous areas of blown render, flaking paint and minor cracks. My job over the next few months, before the weather gets too chilly up here in Angus is to, remove that loose render, patch it and have a little repaint, I don't think I will get to do the whole house this year as I'm learning.

Not being new to DIY, I do have some big gaps in my period building fixing up ... can anyone help me out with some advice on patching my render and repainting the rest? Here are a few pictures of some of the types of problems I have encountered:

Now costs are paramount in my mind so patching is going to be the only option, I believe something like a NHL 3.5 lime mortar would be suitable for the patching; would this be a sensible option? There are a few areas a little more exposed which NHL 5 would be more appropriate; corners which have eroded a little. I'm starting on the back/side of the house so by the time I get to the front my skills will be honed, I hope.

Now the painting, there appears to be quiet a few layers of paint in places, much flaking. I'm going to scrape and hand sand (gently?) all the flaking off, give a good going over with fungicide, mainly the bottom 3 feet due to the hard floors causing a lot of rain bounce back onto the walls so they look a little green in places. Again cost is a thing so once everything is dried, including the re-rendered repairs, I have to find a suitable paint to go over whats been there before. I'm looking at being economical so Santex masonry paint may fit the finances, would be nice to have a major re-render and lime wash ... I can dream.

Any advice would be gratefully received

Jim

 

[Lime]

If patching is your only option at present, then do it properly.
What is the render made of?
I'd replace like with like if patching.
You need to remove all loose material prior to filling and don't forget to thoroughly wash out and wet the hole in the render before you fill it to get the best adhesion.
The old paint can be scrapped off much more easily using a heat-gun in most circumstances.
Be prepared for the heat gun to cause some bursting in places... that is not a bad thing because it shows you where the water has got in and would burst in the next hard frost.
Any paint you use will last longer if the preparation is done well.

As for cheapness, I needed some paint for the concrete shed on my allotment.
I used the cheapest emulsion I could find, silk finish 10 litres for £6, at my local Crown decorators although they warned me it would not last and it would wash off.
I put 3 coats on thinly.
That was 3 years ago and it is as good as it was when it was put on.... no wash off, no bubbles or peeling and still the same colour.

 

[MatthewC]

R-head

Welcome to the forum. That's a good set of photos too (the first thing that is always asked for here). One major principle is not to do anything permanent (i.e. irreversible) soon after you purchase, without extensive consideration of the consequences.

I'm guessing that you know your render is lime based, since you are proposing to use NHL. Hence you really want to keep it breathable if you can. Any idea what sort of paint it is? There is a case for re-painting in the same sort of stuff, even if it is not breathable, but beware, someone I know did that with something modern; when he came to do the job properly a few years later, all the old paint came off fairly easily but the newer stuff was still firmly attached! I think Sandtex masonry paint is impervious (and hence not preferred by us purists) but there are water-based (breathable) emulsions available if you do as Lime suggests.

What is the ground surface where you get the splashback on the walls? If there is solid path (concrete?) up to the wall, I would be looking at cutting the edge back by 8-12 inches and putting down some pea gravel or similar (possibly lowering the surface as well if needed). For the drive, my groundworker recommended stuff called "self-compacting gravel" which is about 0-15mm, and it's ideal for this as well.

As for cheapness, I needed some paint for the concrete shed on my allotment.
I used the cheapest emulsion I could find, silk finish ...

For clarity, that was for a concrete shed - I'm sure Lime is not actually recommending using (vinyl?) silk emulsion on what might be lime render?

Matthew

 

[Lime]

...........

As for cheapness, I needed some paint for the concrete shed on my allotment.
I used the cheapest emulsion I could find, silk finish ...

For clarity, that was for a concrete shed - I'm sure Lime is not actually recommending using (vinyl?) silk emulsion on what might be lime render?

Matthew

I thought 3 years for an emulsion out in all weathers was quite good.
I was making the point, perhaps in a circuitous way, that emulsion paints are a lot better than they used to be.
Also expensive paints are not necessarily better than cheap paint in this situation.

When money is tight it is often necessary to spend more money than you wish to in order to get a reasonable life expectancy.
However in this situation of a tired render with blown patches covered in lots of old paint it is unlikely an expensive paint will make the render last any longer than if you used a cheap paint IMO.

 

[R-head]

Thanks for the replies. It looks like the bits of blown render are either lime mortar or cement, obviously patching carried out be different people over time. I will endeavour to replace all with lime, seems the most suitable .... "Lime" I never though of using my heat gun, something I'm off to try on a patch later this week.

MatthewC, I'm not sure of the paint that's on there at present, save for the fact it's not lime wash. As the paint which is on there at present is almost certainly not breathable is there any real point in overcoating, a semi-prepared pre-painted surface, with something breathable? If there is, which I'm not totally convinced about, but open to knowledgeable guidance, does anyone have a recommendation for a breathable emulsion that's competitive on price and for my situation?

Final bit, one of my walls, around 25m in length, has been concreted up to the base, that's where I get a lot of splash up, sounds sensible to cut it back and place a layer of gravel, something which I had planned for the front which is only 1m from the public footpath. These jobs seem to be piling up :shock:

 

[MatthewC]

MatthewC, I'm not sure of the paint that's on there at present, save for the fact it's not lime wash. As the paint which is on there at present is almost certainly not breathable is there any real point in overcoating, a semi-prepared pre-painted surface, with something breathable? If there is, which I'm not totally convinced about, but open to knowledgeable guidance, does anyone have a recommendation for a breathable emulsion that's competitive on price and for my situation?

No, I wasn't suggesting that, I was just talking about painting the bits that you will patch with NHL, and thinking of the day when you DO remove all the old paint from the rest.

On the house internally, I have used Natural Building Technologies (NBT) "Environmental Trade Paint" (it says on the label), pure white emulsion. I don't know if they do anything more suitable for exterior work

 

[TheRoost]

Hi,

Sounds good that you are looking to use sympathetic materials to render.

My experience with Sandtex masonry paint hasn't been good - I used it to paint stone window sills that were previously painted. I prepped the surface properly including keying and degreasing, but the Sandtex paint only lasted about a year before it cracked and started to flake. It dries to a very very thin 'plasticcy' layer. I tried thick coats of the stuff but it still dries to a very very thin film (i.e. microns!) it must have a high water content. I dread to think what it would be like to have to remove Sandtex from a whole house. Just my opinion, others may have different experiences.

Might be better to go for something breathable, or something that at at least erodes slowly by weathering rather than cracking/flaking

Good luck with you project

Andy

 

[steveb]

we used silicate masonry paint - not cheap but breathable and in theory lasts a lifetime with one application. Since the labour cost to apply was >5x the material cost, if it doesn't need repainting every few years then it's a massive saver. Very pleased with the result. Note that you need a special primer too

https://www.celticsustainables.co.uk/earthborn-silicate-masonry-paint/
https://www.celticsustainables.co.uk/earthborn-silicate-primer-clear/

-Steve