xxfrecklesxx

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

snikpoh

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.

bil

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

Poor and expensive,
Poor and cheap
Good and expensive.

johnnyone

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.

bobd22

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

mondeo

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

johnnyone

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

bil

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?

johnnyone

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.

bil

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?

johnnyone

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.

tony

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.

bil

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

johnnyone

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.

bil

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.