Is there a difference between interior and exterior paint?
This may be a question you have asked yourself when deciding on what paint to buy when painting. Do you need to buy different paints? Is there a difference, and if so, what is it?
Exterior paint has a completely different purpose than the paint used inside. The exterior paint is supposed to resist all sorts of exposures like weather and humidity. There can be temperature changes that will make the walls expand and contract, to which the paint needs to adjust to, as otherwise it will crack.
Exterior paint is also designed to dry as quickly as possible and different environments to allow exterior wall painting to be done, not only when the weather is good. However, this also means that to allow of this, the compounds in the exterior paint will have to be different to the ones in the interior paint.
Does that mean it is possible to use interior paint for exterior painting?
It is possible, however not recommended. If you love the colour you have used for your interior, it is more likely that you can get that same colour at a store especially made for exterior painting. Reasons to why interior paint is not as useful is because it simply isn’t made to resist all those exposures.
Interior paint is usually much thinner, which means it will take many coats to even apply a relatively thin layer of it on the outside. What may be enough to cover patches in the living room, may not look as good on the outside of your home. Finally, the problem with this paint is that is doesn’t dry in cold or moist weathers, which means that it will get dirty very quickly.
Does that mean it makes sense to use exterior paint for interior painting?
If exterior paint is resistant to humidity, it seems to make sense to paint your bathroom with it, but the truth is you shouldn’t. Not only that it is not meant for that purpose and will simply not look good, but it is also quite health damaging. Exterior paint that is supposed to last through weather exposures and a good amount of years has certain compounds that create fumes.
While being meant to use outside exposed to the air, exterior paint in the interior exposes fumes due to poor ventilation and trigger respiratory problems as asthma, cause headaches and even nausea. Apart from that, exterior paint is not made to be open to daily use and is unprotected against chemicals like stain removers or detergents.
So, if you are facing mould problems due to humidity, which is often the case in London, try airing more if weather allows it. If not, it is always possible to use a humidity absorber device. They are small and usually cheap and absorb the humidity out of the air to prevent mould spreading.
Whether doing interior or exterior painting, the colours and paints you chose is what you will live with for years. On top of that, the painting process itself and the preparation process can be quite labourious, especially if it needs to be redone.
It is always best to ask for advice first and our painters and decorators are always there for consultation.