Paint.. Exterior
 

Im going to be painting the outside of my house, any remmondations on which paint to buy and avoid?...

there is one by Pinay, that I can get here, 49€ for 25kg anyone tried it?.....

wanting a colour, yellowy/cream, not white...

cheers Jen :)

Re: Paint.. Exterior
 

Really depends what you want to spend. Monto do a vast range with various lengths of guarantees.

I need to paint my house some time but can't afford it just yet unless I follow your thread and find a GOOD and CHEAP paint.

Re: Paint.. Exterior
 

Usually like so many things, paint comes in three quality categories.

Poor and expensive,
Poor and cheap
Good and expensive.

Re: Paint.. Exterior
 

If you have older house use a paint that 'breathes'. If you make the exterior walls impermeable you may create problems internally as any damp has no escape to the outside.

Re: Paint.. Exterior
 

Are you able to recommend a breathable paint as most seem to be plastico?

Re: Paint.. Exterior
 

Sandtex is available over here but usually only white - but you can easily colour it with a tint.

:thumbup::thumbup::thumbup:

Re: Paint.. Exterior
 

Sorry I cannot recommend a particular brand. Traditionally a simple lime wash was used. Now there are many products. Most paint manufacturers produce breathable/microporous/permeable paints.

The Sandtex website may be helpful to help you establish what type of paint is suitable. eg Sandtex Intergrasil is mineral based

http://www.sandtextrade.co.uk/Produc...sFinishes.aspx

Re: Paint.. Exterior
 

OK, here's a question.

Everyone says use a breatheable paint. To me, that conjures up the image of groundwater moving up the wall, evaporating out and leaving salts. These should then start the spalling process whereby the outer layers of the plaster fragment and expand, much the same as the way iron rusts.

If tho you use plasticated paint, and stop the evaporation, then isn't that a good thing? Is there something I've missed here? Is there some worse than spalling that would be triggered by a wall that has a degree of dampness?

Re: Paint.. Exterior
 

It is not just a case of rising damp and depends on the construction of the house. In many older properties lime mortars were used. Lime mortars should not be 'sealed in' with plastic paint or any other impervious materials. They need to breath to allow the water vapour they attract in varying atmospheric conditions to find a way out. If you seal the outside you may have problems not only on the outside but also internally as that is the way the water may travel to escape. Sealing both sides leaves the water nowhere to go and it ends up pushing off the sealed coatings.

Re: Paint.. Exterior
 

Well, if the wall is sealed, then atmospheric water is irrelevant, surely?

Also, I can see that there will be a level of damp in a sealed wall, but is that worse than fluctuating levels of damp that pump salts into the wall?

Re: Paint.. Exterior
 

I would agree with you if you were talking about a tanked wall. Paint may seal to a large extent but cannot be relied upon as a vapour barrier and is of insufficient to retain the moisture that may also include condensation that forms within components and not just on the surface.

Re: Paint.. Exterior
 

I think webber make breathable paint,

I have worked as a builder here for quite a while and because of the general lack of damp courses it is important to let rising damp escape, that is why most new builds tend to be rendered with a breathable mono cap.

I had a probem with the lower exterior paint work flaking and the render behind turning to dust, on my old finca, I fitted some rustic stone up to 800mm
so the damp can escape from the unpainted mortar joints.

It seemed to work ok but the morter has crumbled a bit with time, but its better than flaking paint.

Re: Paint.. Exterior
 

Bear with me here. Isn't painting the wall with plastic paint similar to tanking it?

Re: Paint.. Exterior
 

No. Tanking could be a variety of materials, such as asphalt, sika render, that have been developed for that purpose.
Paint cannot hold back the pressure of the water looking to escape losing its adhesion to the sub-base and being pushed off by the pressure of the water.

Re: Paint.. Exterior
 

Right. Check if I have this right.

The problem isn't the moisture in the wall, because if it were the moisture, then tanking wouldn't help, because the wall behind the tanking is wet, OK?

You are looking at a pressurised system. I agree that if water were being pushed up the wall, it would push the paint off. Tanking is effectively a coat of paint that can't be pushed off, which is why tanking has to be so tough.

Where is the pressure coming from in a Spanish wall with no dampcourse? Surely water isn't being pushed up the wall, it's being SUCKED up. ie there's a low pressure inside the wall?

So, isn't breathable paint actually making the problem worse?

I've been using plasticised paint on my walls for a while now, and I've never had any peel off yet. The old, breathing paint? That pops and peels like a mad thing.

Re: Paint.. Exterior
 

How old is your house and what is the construction?

Re: Paint.. Exterior
 

45 years, solid wall standard Spanish construction.

I'd be grateful if you could clear this up for me. The world and his wife tell me that I need breathable paint, but it is starting to sound more and more counterintuitive.

I'm not saying you are wrong, I'm just saying that it seems to me that the problems experienced by myself and others seem like efflorescent spalling, where the walls wick up ground water which contains salts in solution. In winter, this 'salty' water wicks up the wall, and the water evaporates thru the breathable layer, leaving salts to build up in the plaster. Summer comes, and the walls dry as the water table drops. The salts crystallise out and as they form crystals these expand and fragment the plaster making it 'spall'.

Surely the solution to the problem is to repair the plaster and seal the surface, inside and out? n effect, 'tanking' it.

I notice the the previous poster covered his wall with cladding, but still reported what sounds like salt spalling in the mortar between the cladding.

Re: Paint.. Exterior
 

From my experience if you paint over a wall with rising damp what, normally happens is- after time the paint blisters, then a hole apears and the render behind the paint falls out in the form of sandy dust.

One job I done a room had a continuous damp problem on, I hacked off the render, painted the brickwork with rubber roofing paint aprox 1m up and re rendered

That solved the damp on the inside, but now the owner has noticed that the paint on the out side is now degrading as the damp is trying to find a way to escape.

So that tells me it is best to let the wall breath to let the damp out,
so I will probably have to stone clad the out side or re render with monocap
1m up

If you go to your local builders merchant you can get a webber catalouge which gives examples of damp and products to make good.

Re: Paint.. Exterior
 

Hmmm. What it doesn't tell me is how exactly breathable paint prevents efflorescent/salt spalling?

It also tells me that once you painted a NON BREATHING paint onto the inside, it cured the problem on the inside, and the problem appeared on the outside, where the paint may well have been damaged, or breatheable. See What I mean?

You have just said that painting on waterproof, non breathing paint DID cure the problem.

The external degragation may have started BEFORE there was a damp related problem.

Do you see what I'm trying to say here?

Re: Paint.. Exterior
 

hi I can only report what I have seen from my personal experiance of working here for 8 years

the previous job I was talking about I had painted the outside of the house about a year befor with a good quality plastic exterior paint, and up to the point that I damp proofed the interior it was in good condition as the damp had been escaping into the inside of the house causing damage.

I have seen a lot of damp problems here in Spain and it is not an easy thing to fix, as most walls are made from hollow bricks or blocks making it almost imposible to inject a damp course

I am glad to here your house has no damp I think it is a case of luck here !!

All I can say is if the plastic paint works ok for you carry on using it

But I know FOR SURE in some cases it is no good

Cheers Tony

Re: Paint.. Exterior
 

Tony, I have exactly that problem. The ground water has been wicking up into the walls for the last 45 years, evaporating out thru the breathing paint and leaving the salts behind. Every time the walls dry out a bit, the salts crystallise and shatter the plaster. So far this has only happened where the old paint is, and not where I have scraped the old paint off and put on the plastic.

I'm just trying to look at this logically here. I would be grateful if you (or anyone else) can point out if and where my chain of logic is faulty.

1. The problem is caused by salts drying out in the wall.
2. You can't remove the salts, neither can you install a damp course to stop
more coming in.
3. Tanking the walls would work. Therefore it isn't the moisture causing the
problem, it's the drying out that does it.
4. If you prep the wall so the paint can adhere properly then plastic paint is
like tanking on a small scale.
5. The wall will remain damp internally, but that won't actually cause a
problem, it will prevent it.

I just hear everyone repeating the litany 'Must Have Breatheable Paint!' and I'm starting to question this.

I'd appreciate your input please.

Re: Paint.. Exterior
 

Hi Bil

Yes the damage normally starts up a way where the damp drys out then spreads downwards

I have tryed making good the damage and re painting ( with various products and paints) but after time the problem always comes back

I have evan in the past skimmed with water proof swiming pool adhesive

but even with time that holes and dust falls out from behind

As I said before the only thing that I have found to work so far is to hack off paint with roofing paint and re render ( but even doing that it would still be possible for the water to wick up above the level of the roofing paint and escape at a higher level) although I have not had that problem as the water is escaping from the out side.

If you have found a paint that holds the water in the wall that is great, but as up to now I have not.

All the best Tony

Re: Paint.. Exterior
 

So if you are holding the water in the wall what is happening to the wall itself. Surely the water being held in is doing some form of damage?

Rosemary

Re: Paint.. Exterior
 

No, that's the point. It isn't the water that does the damage. It's the salt it brings up. Even that wouldn't matter were it not for the fact that the water evaporates, and more takes its place bringing yet more salt.

Water will wick up quite a distance, but if everything is tanked.....

Re: Paint.. Exterior
 

Tony, so what you are saying is that as long as the paint holds, and as long as you paint the whole surface, it will work.

Now for the second point.

Do you agree that a breatheable paint will actually make things worse as it will allow the water to escape, causing more to wick up and deposit yet more salt?

Re: Paint.. Exterior
 

HI bil

Yes if the paint works the damp can not escape into the room

IF you can find a paint that will stay long term on a damp wall a guess it would be better than a breathable render or paint that deposits salt, but I have yet to find one , if you could recomend a paint that would be great .

Any way can we talk about something else now, how about solar water heaters !
I like talking about them!

Did you know a vacuum tube can boil water in less than three hours, in the spanish sun !

Tony

Re: Paint.. Exterior
 

So I'm right, and all the calls for a breatheable paint are shite, because the breatheable paint will make it worse. Plus, a plastic paint will either stop the problem or make it less bad.

I'd say that was two - nil for plastic paint!

As for solar water. To be honest, that's not impressive. I can melt lead in less than 3 minutes with sunlight, and using far simpler technology.

Re: Paint.. Exterior
 

Hey bil

Do you think the world will end in 2012?

if so who cares about the paint !! unless it only stays on for 3 months !!

But seriously good luck to you if your idea of paint only works.

maybe we should ask other people how they have overcome damp

I AM ONLY INTERESTED IN FINDING A GOOD SOLUTION, not getting one up on you or anybody else

If I can promote a good solution that works to my clients thats good for me and them !!

Cheers Tony

ps did you use a magnifying glass to melt the lead ?

Re: Paint.. Exterior
 

Tony, I'm not trying to start a fight here. I just want to know where the truth of the matter is.

For a long time now the 'let it breathe' claims have been niggling at me, and I wanted to see whether my thoughts on the subject were correct.

In future, I will simply be doing as I have in the past. I shall remove the loose, seal the plaster with a thin solution of plastic paint, fill and paint over that. I suspect that all the cases of paint failing are down to inadequate preparation, incorrect application, or using paint that allows moisture thru.

Painting is a pain in the arse job, and I don't want to have to do it every couple of years, let alone every year!

Ten out of ten on the magnifying glass. I don't wish to be negative about solar power, but what a lot of people fail to realise is that there are only so many kilowatts per hour falling on a sq metre that is perfectly aligned to the sun. In short, a fixed one, will only work at max strength for a comparatively brief period in the middle of the day, and for the rest of the sunlight hours it operates on average at half strength.

Plus, it's all down to size of catchment area relative to water volume.

For me there's an additional problem. I have two bathrooms and a kitchen all so separated from each other that a single system would have a huge time run for the hot water to reach the taps, with corresponding waste each time the tap is used.

Re: Paint.. Exterior
 

HI Bil,

Because the building game is poor at the moment, I have been working in solar water heating ( got to feed the family some how !!)

The type of unit i deal with is vacuum tube compact indirct units

ie the tank is joined directly to the collector as one unit, the tubes contain water which is heated by the sun, as the water is heated it rises up the tube and then into the hiighest part of the tank, as it cools it goes back to the lowest point of the tube, and so that contiues( thermo syphon )

the water in the tank is not used directly, it heats a copper coil heat exchanger, and that is what you pass your mains water through to get hot water.

I have tested the system on my own home befor going into buissiness and it works very well , I get about 80 to 90% of my yearly hot water free.

Vacuum tubes are not so sensative to positioning as they have a tubuler surface the sun tracks around them as it moves

A good way of installation is to pre heat ie send the cold water up to the swh then feed the return back into a normal elactrical cylinder ,

that way the cylinder will only cut in if the weather is poor, it also makes the system automatic, and less problems with running off loads of water befor the hot gets to the tap.

Tony

Re: Paint.. Exterior
 

[QUOTE=bil;9434283]So I'm right, and all the calls for a breatheable paint are shite, because the breatheable paint will make it worse. Plus, a plastic paint will either stop the problem or make it less bad.

No you are not right you just think you are.

Re: Paint.. Exterior
 

It's a great idea, but as I say positioning will take a chunk. Imagine a horizontal tube bed on the equator. At sunrise and sunset, you will get heat ONLY on the equivalent of the diameter of the tube on that side.

Then over the course of the morning that amount will increase until at midday precisely the whole bed will be operating at 100%. It then decreases.

So if we are using 10 tubes all of, say, 3 inches diam, then you will get three inches at sunrise and sunset, 30 at midday, so you will be getting a little more than 15, on average. In other words to get an average of 1 sq metre, you need two.

What's the KWH per sq metre at midday?

Re: Paint.. Exterior
 

[QUOTE=johnnyone;9434532]Excellent. Prove it please.

Oh yeah, I mean PROOF, demonstrable concepts rather than repeating the old mantra.

Re: Paint.. Exterior
 

Lemmee help.

1. The wall wicks up water.
2. The water contains salt.
3. As the water evaporates it leaves salt behind.
4. If the wall dries out, salt crystals form.
5. These crystals expand as they grow.
6. This pushes apart the plasterwork so that it crumbles.
7. A breatheable paint will not stop this process, it will facilitate it.
8. To stop this process we need to stop the flow of water.
9. We cannot easily block the flow at source with a damp course.
10. Tanking walls is a recognised way of curing such problems.
11. Plastic paint is equivalent to a thin tanking layer.
12. The water in the wall is not under pressure. It is sucked up.


So, taking all that into consideration, if you prepare the wall properly, and seal it with a plasticised paint, what will happen?

1. The water will wick up into the wall until it is in equilibrium.
2. The salts will dissolve and stay in solution.
3. This will prevent any further spalling.

What can go wrong?

1. If the paint is breached, then water will be able to evaporate out.
2. This will create localised spalling leading to the 'dustification' of the
plaster immediatly behind that point.

This is precisely what Tony describes.

So, we'll allow you the courtesy that your previous post was based on sound knowledge where you will be able to defeat one or more of the points I have made above.

You can do that, can't you?

Re: Paint.. Exterior
 

The Frigiliana weather station (amateur) generally paks at about 925 w per sqm as it has today (full sun)

Re: Paint.. Exterior
 

[QUOTE=bil;9434544]Bil plastic paint does not stick to damp walls. Perhaps you have been using permeable paint all this time without realising it.

Re: Paint.. Exterior
 

Call it a kilo then per hour. To get an average of a kilo an hour two sq metres, plus you have to allow for the fact that you don't get 100% conversion. 12 hours a day, call it 10 to allow for other bits, and two sw metres will grab you about 10 kilowatt hours.

A 2K kettle boils a litre in 3 mins, so a 1K would take 6, that's 10 litres an hour. So by my reckoning, 2sq metre would give 100 litres of boiling water a day.

That about right? or have my dismal maths let me down again?

Re: Paint.. Exterior
 

[QUOTE=johnnyone;9434597]No man, it say plasticised on de tin! Of course, I cheat by painting when the weather is dry. I find painting wet walls dam' tedious, don't you?

So, am I right? Can you break the chain of logic, or were you basing your comment on the fact that you thought me dumb enough to paint in the rain?

;)

PS, does breatheable paint stick to wet walls?

Re: Paint.. Exterior
 

When the weather is halfway decent my 2sq panel gets the water too hot to use.

Re: Paint.. Exterior
 

OH NO NOT THE PAINT AGAIN !!!

MY 160 litre swh can bring the water to boliing on a sunny day ( I have a video on you tube )

so if you think of that in terms of boiling a 2 l kettle you would have to put it on 80 times !!!! how much electric would that use day arter day !!

IT SAVES LOADS OF ENERGY !!

ANYWAY BACK TO PAINT

I have got a load of old car engine oil if i mix it with diesel do you think it would be any good to paint my timber fence with ??