Duration over oil

[Unregistered-Sam]

I have an older home with an oil-based exterior paint. The home was last painted over 5 years ago and is in fairly decent shape, except for the most exposed areas. I am having a professional painter do the work. He recommended Sherman Williams Duration and indicated that he has had good success in painting directly over existing oil without a primer. When I went to my local SW store to color match the existing oil, the clerk “officially” recommended hitting it with primer first. Is this just the standard SW company line to avoid potential hassle later, or is my painter off the mark?

[Unregistered-Homewrecker]

The Sherwin Williams web site has an extensive section specifically on Duration paint and their recomendations. I suggest you read that and make your decision based on the manufacturers standards not on the painters or the guy at the store.

[Faron79]

“Professional” painters know how to put on paint well (usually!), BUT there are segments in any profession who don’t know the “why’s” about doing tasks.
For starters…
1) I hope the surface is being cleaned with a house cleaner…pressure-washer hopefully! You HAVE to get off the dirt, etc. before painting over it.
2) Primers DO need to be used! ESPECIALLY on exteriors! Good primers are “resin-rich”, meaning they stick to surfaces better than paint itself. Paint & primer might look the same when you shake them up, but similarities end there. In turn, paint sticks to new primer better than to a 5+ tr. old surface!
3) Primers give an “even drying surface” to new layers of paint. Over the years, some walls/paints can develope “dry spots” that aren’t that visible until new paint goes on. Without priming, the paint will absorb slightly differently in those areas, therefore affecting the SHEEN of the paint slightly. These areas will appear “duller” than others. NOT the result I’d want after spending $$ to paint MY house. The higher the sheen of paint, the more sensitive it is to unevenly absorbing substrates.
4) To summarize, the “Ideal” paint job needs to go on a CLEAN, SANDED, DRY, & PRIMED substrate. THEN 2 coats of the paint color. Some colors, like burgundies/reds, MUST have a gray primer under them, with (often) 3 coats of color.
5) OIL primers are fine under Latex topcoats. Many painters like that. The Oils stick slightly better, while the latex paints have more “flex” in the film.
Hope this helps!
Faron

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