Do I need to apply primer and undercoat when repainting?

confused_landlord

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

ormus

if the paint has come off down to bare wood in places, then you should prime those places.
undercoat all the wood, then final top coat.
if the paintwork is reasonable then a light sanding down, and gloss is ok.

LJM

i would also say prime before paint it makes for a better finsih and its protected a bit then too

BillScarab

I would only prime it where it is down to bare wood. I'd probably then use a self undercoating gloss. If the existing paint is sound you cna just rub it down and it then acts as a primer and undercoat for a new coat of gloss.

totalsolutions

Look at it like this, Primer is the base material and acts like a glue for the undercoat. Undercoat is the colour you finally will see, and gloss is the transparent hard top coat giving it the shine.

artha

totalsolutions wrote: »

Look at it like this, Primer is the base material and acts like a glue for the undercoat. Undercoat is the colour you finally will see, and gloss is the transparent hard top coat giving it the shine.

Not quite true in my opinion. Primers are intended to penetrate the substrate and provide a stable surface for whatever is applied over the top. Undercoat is the potential weak link in the system and is basically a high opacity cover coat to save on using two coats of more expensive gloss but long term flexibilty is compromised by using undercoat. Use of undercoat is a practice peculiar to the UK. If I were doing an exterior repaint using the same colour I would omit the undercoat and apply two coats of primer followed by two of gloss/satin finish. On interiors I might use undercoat to save time