Painting: Is there a difference between exterior and interior paint?
This is probably a question many of us have asked ourselves when deciding on what paint to buy when painting. Is it necessary to buy different paints? Is there actually a difference, and if so, what is it?
Our painters and decorators do both: interior and exterior painting, so we know the differences. Here is a list…
The purpose for painting
The difference may seem an obvious one but is important to explain. 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 quick 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 made 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.
The purpose of interior paint on the other hand, is for aesthetic reasons but also for daily use and cleaning.
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 mostly likely that you can get that same colour at a store especially made for exterior painting. If you can’t find it, our painters and decorators offer colour consultation services and are trained in the latest painting techniques, which means they mix and blend colours until they find the one you are looking for.
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. Lastly, the problem with this paint is that is doesn’t dry in cold or moist weathers, which means that it will get dirty and unaesthetic 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.
What to do if exterior paint was used for interior painting
If you read this post, recently after having painted your interior walls with exterior painting, don’t worry! You can always paint over the other paint. However, firstly you have to prepare the walls, by removing the previous layer of exterior paint on your walls, so that the fumes will not keep passing through the freshly used interior paint.
If you are unsure of how to do this or you are worried of doing something wrong, our painters and decorators are available as soon as the next day!
Final notes on exterior and interior painting…
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 hasslesome, 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. Our customer service responds to inquiries within two hours and are years of experience have prepared us to answer almost any question regarding painting, whether exterior or interior and are ready to help with the process.