My parents house was roughcast cladding, painted numerous times with acrylic after washing the walls and it lasted for years. Our first house was that fibro planking material, only ever washed and painted with acrylic and lasted for years. Now we have a weatherboard house, in very good nick, has been waterblasted and yet here I am, spending weeks sanding it down because "that is what you do" why ?
happychappy50,
Jan 28, 3:29am
It is because the old paint can often be flaky & that surface in order to hold a new coating needs to be “roughed up†so the new paint can stick.
harrislucinda,
Jan 28, 3:30am
yes agree just like any surface
trad,
Jan 28, 3:41am
I just use a wire brush on my timber window frames (and the stucco walls). Has worked well for years.
rak1,
Jan 28, 3:47am
But what if the old paint is in good condition, not flaky. I have never seen anyone sand a fibro clad house. I'm just trying to see the logic in this. I fully understand what you are saying happychappy and agree entirely, its just, well, how is it that other surfaces appear to get away with it and weatherboard doesn't. Maybe I'm just grumpy because my life seems to spent sanding this bloody house :-)
omamari,
Jan 28, 3:50am
If you have waterblasted and the paint is sound you do not need to sand. After waterblasting there should be no powdery paint on the surface, You only need to sand the paint if it flaking
trad,
Jan 28, 3:52am
If no flaky paint, I think the sanding is just to get a smooth finish,
I do not like water blasting house walls - stucco or weatherboard - it will find any slight cracks or holes or gaps between weather boards and then in goes the water under pressure. The reason we are painting is to prevent water ingress.
gabbysnana,
Jan 28, 4:04am
for real? You need a rough surface for adhesion. Otherwise the paint will hiss or slough off.
rbd,
Jan 28, 11:48am
My last weatherboard house was painted just before I bought it. They didn't strip the paint and it started bubbling and flaking off within 12 months. The 1969 (I assume it was the original) primer was turning to a pinky chalk and the top coats were falling off in big flakes.
Ended up stripping to bare boards, only way to do it properly. Old enamel coats were like rock and the new layers on top turned to sticky toffee when heated. My painter hated that job, worst he'd ever done he said.
91zero,
Jan 29, 6:59am
If it's in good nick, it should still have a quick sand to "rough up" the surface to provide a better surface for the new paint to adhere to. You don't have to go to town sanding it back, just a decent skim over the top.
vivienney,
Feb 8, 12:52pm
Agree with the above. Sand lightly - its enough to bond old and new paint tightly.
boby11,
Dec 28, 9:01am
Sanding directly onto old Fibro board on the outside of houses releases asbestos into the air
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