Water based Vs Oil based paint on Weatherboards

We are in the middle of a reno/extension, I was speaking to a couple of different paint shop guys who have given me conflicting advice on the type of paint and primer combinations for baltic pine weatherboards so I thought I would pose the question here.

I need comments and opinions on the best combination to give a good and long lasting finish on new weatherboards and how to prepare old, flaky and chalky weatherboards on the rest of the house.

I was planning to prime the new boards with oil based primer, pink or white then apply 2 coats of Solaguard. Same with old reused boards after a good sanding.

As for the rest of the house, sand to remove flaky paint and promote adhesion, wash and apply 2 coats of Solaguard.

Now one guy said this is good and the other said a water based primer is better with a water based paint and oil based primer with oil based paint, but he had a definate preference for water based saying it will remain flexible for longer and won't show signs of cracking as the timber dries out and ages.

Also, to add to the confusion, the Solaguard can says No primer needed for new timber.

My options are,

1. oil primer + oil top coat

2. water primer + Solaguard

3. oil primer + Solaguard

4. No primer, just Solaguard

5. The most logical suggestion from you guys.

Thanks in advance, and Merry Christmas to all.

I'm a fan of Penetrol.

In this case, I'd suggest (assuming the new boards are dry), sealing these with a mix of 75% Dulux oilbase sealer-binder and 25% Penetrol. The old boards need a thorough sanding, dusting off - even maybe washing and a few days to dry out again. Then give these ones a full coat of Penetrol, followed by a coat of undoctored Dulux sealer-binder when the Penetrol is just touch-dry (say, next day).

Let the whole lot dry a week or more, Sika up any defects, and lay on your acrylic of choice (two coats, most brands and colours). Shouldn't need any sanding or funny treatments then unless it's really hot (add Floetrol).

Regards, Adam.

So that is option 3 with lots of detail.

That's great, thanks Adam

I have used Penetrol to treat lightly rusted metal, and to make gloss enamel flow better, awsome results.

Option 3 and what Adam said is right on the money. Weatherboard Queenslander here - get about 12 years out a repaint. However, the house is painted a very pale cream colour. Darker colours will clap out sooner.

The oil based primers seal in linctus & sapwood better than acryclic primers.

One thing I would add - let the primer dry for at least a week - preferably two

Regards
Colin Howkins
Graceville Qld

well the first question is DO you want a high gloss finish ( enamel ) or a low gloss finish ( acrylic )

Enamel system, pink prime or white primer any bare timber patches or spots, putty any holes etc, then 1 coat of 3/4 tinted general purpose undercoat, then 2 topcoats light sand between coatings..


Acrylic system, acrylic primer to bare timbers ( even if the can says no primer needed ) then 2 coatings of top coat.

as for wattyl solagard, do as its written on the back of the can, and you will have no problems..i like the satin finish myself, we always brush on the first coating then airless spray the last ( uses more paint , but gives a nice finish, some of the houses we do can take up to 2 months to paint.

as for Penetrol. its a good product on the right surface. we did our own test and with acrylic we like GB alot better but only use it for the first coating...

you cannot sand acrylics ...never use it on timber windows-enamel system only as enamel is easy to sand

Preparation always has to be done well

Wow, 2 months, I know mine will take longer than that but it's just me and the Mrs and it won't stop raining long enough to get going. I don't want a high gloss finish on the weatherboards but I used gloss Solaguard on the fascias and it is more satin than gloss. I like the water washup but I am not 100% sold on promises of the advertising.

Why has no one marketed a spray on wax to protect the house paint like we wax our cars?

Good advice, thanks to all.