Do I need to apply primer and undercoat when repainting?

badhairday · Posted: Wed May 19, 2010 10:13 am

I'm having the external woodwork on my house repainted (the window frames, front door etc) as the paint is currently peeling and I dont want it to be damaged from the elements.

I had been under the impression that it would be best to apply primer and undercoat as well, but my painter is adamant that 2 coats of gloss is sufficient.

I'd be interested to hear what you professional painters think of this, as my painter is more of a 'handyman'.

Thanks in advance

Robbie uk · Posted: Wed May 19, 2010 8:27 pm

If the paint is peeling then two coats of gloss wont help. All woodwork should be thoroughly sanded down and any raw or exposed wood needs a coat of primer. This will protect it from the elements and also allow the undercoat to adhere to it and not soak in. This then will be rubbed down. A second undercoat may be applied if the first has not covered too well. After that a very light sanding and a dust off and a coat of gloss. Some people like two coats of gloss but that is not always neccessary.

badhairday · Posted: Thu May 20, 2010 6:28 am

Robbie uk wrote:

If the paint is peeling then two coats of gloss wont help. All woodwork should be thoroughly sanded down and any raw or exposed wood needs a coat of primer. This will protect it from the elements and also allow the undercoat to adhere to it and not soak in. This then will be rubbed down. A second undercoat may be applied if the first has not covered too well. After that a very light sanding and a dust off and a coat of gloss. Some people like two coats of gloss but that is not always neccessary.

Thanks for your response Rob. So I have 2 more questions:
1) If after sanding down there is no exposed wood, am I to understand that gloss might be sufficient?
2) Is gloss important? Can I just apply a black undercoat and leave it at that?

joe-90 · Posted: Thu May 20, 2010 8:17 am

Robbie is spot on.

Robbie uk · Posted: Thu May 20, 2010 6:59 pm

As the woodwork is outside i wouldnt really just gloss onto the sanded surface. It just wouldnt last long enough. The undercoat will also help the new gloss to adhere and help protect the timber for longer.
The glos is inportant becuase it is a finishing coat that protects everything. The undercoat does not have the additives and chemicals that the gloss does to protect the surface and would otherwise soon peel off.