To start inspect the surfaces and look for problem areas: peeling paint, blistered paint, checked paint, cracking, mildew, dirt, grease, etc. If there are areas that contain problems find out what caused them. Painting over them will not fix them. For peeling I look for adhesion problems: did the last job get done without the surface being cleaned?, or was oil base put on long ago and now is curling up? For blistering I look for vapor pressure coming from the inside of the house outward: perhaps a leaking water pipe or roof leak?, the coat could be a dark color put on in high heat causing the outside film to dry and trap the water in paint beneath it. I have never seen paint blister in this way other than when I put a torch to it to strip it off but they say it can happen. Paint that has checked is from the difference in expansion between different coats. Oil base will not stretch like latex will so if you put oil over latex after heating and cooling eventually the oil base will crack apart. Satin latex will stretch more than flat (but not enough to cause it to crack) which I like, so it is the only exterior paint I have used for the past 30 years. Mildew is cleaned prior to painting with a mixture of 1 part clorox to 3 parts water. I use a 2 gallon garden sprayer to squirt it on. Leave it or brooming it is even better but dont let it dry out. Rewet it if it does. Then Powerwash it off.
I use an airless sprayer to spray a solution of TSP (trisodiumphosphate) on the walls doing a 10' section at a time and before it dries powerwash it off. Most powerwashers have a syphon tube for applying solutions from a 5 gal. bucket (if there's no airless). The airless wont spray the bleach solution without turning the hose into a lawn sprinkler (small holes develope ruining the airless hose). After finishing with this process the house is free of dirt, mildew, and any loose paint has been discovered. Any areas that need stripping are done with a heat gun and scraper. A heat gun can send sparks into cracks and knot holes in the siding and catch the interior wall space on fire. Caulking all the cracks first and keeping a garden hose on hand are necessary. For chipping, peeling areas I just hand scrape. Use a sharp scrapper and file the edge occasionally to make it work best. After stripping, and or scraping I use a power sander to "feather" the paint edge (smooth it out).
At this point if I haven't caulked already I complete the caulking phase. Every trim moulding, jamb, sill, etc. will be better protected and have a better detailed appearance when caulked. Glossy surfaces like the front door need sanding (I use an orbital w/120g or 180g for finer). Now your ready to coat it. Don't caulk the underside of lap (horizontal) siding as it is necessary for the house to breath through this gap or water vapor will cause pressure to blister and peel the paint off.
Primer
If you have scraped and sanded, have bare wood showing, have a checked surface or any other irregularities, then you will need to prime them. I use waterbased products almost exclusively. Oil base primer will give better penetration and grip and would be preferable in the case of a house that has weathered extremely and has bare wood showing. If you are putting 1 coat of latex on and you need to penetrate bare wood and or glue down chaulking paint, etc. add Flood's emulsabond to the latex. This is emulsified oil made to mix into waterbased products giving some of the advantages of an oil base material. The weathered wood will have deteriorated and would be best rejuvenated with oil based products. In cases like this mix oil base primer with paint thinner for the first coat (10-20 percent thinner) and it will penetrate into the wood better. Now your ready to start with water based primer. I like Zinnzer's BullsEye 123. For areas needing spot prime I spray with 123, if the areas are everywhere I find it better to just coat the whole house. For wood that is splitting Pittsburg Paints makes a great wood stabilizer (clear) called "Permanizer plus" that is excellent ($40/Gal.). I highly recommend it. See links page for resoration and read rogers experiences with it which led to me using it.. After priming comes spackle for dents, knot holes, nail holes. I use a sheetrock knife (6",or 10") to apply spackle on checked paint to fill in the checked areas and sand after leaving a somewhat smooth surface. Whatever the surface looks like before painting it will look like after the paint has dried so fix it first. Bondo can be used to fix winow sills etc. and makes a nice hard, smooth (after sanding (orbital with 36G>80G>120G)) surface.
Paint
At this paint your house is ready for the finish coat or coats. I prefer satin latex. Rain water will wash a house down with gloss, or satin better than flat. Gloss should be sanded (TSP will dull it) to get adhesion and who wants to sand an entire house-satin does not. Satin has more elasticity than flat so less cracking at flexing areas. There are elastomerics that stretch much more than latex and last twice as long but if you use them you are forced to continue using them because latex will crack if applied on top of elastomerics. I also feel most people like to change the look of their house after 7-10 years. If you want a never paint again situation there is vinyl, and aluminum siding. Painting is cheaper in the long run and allows you to completely change your house"s appearance. You can purchase Sherwin Williams Duration lifetime guaranteed paint @ $40/gallon. Glidden also gives the same type of guarantee for $22/Gal.(Endurance ). This small investment (compared to siding) would guarantee free paint for as long as you remain in your current home in the event of peeling, fading etc. The problem is nobody lives in their house for 80 years do they? I did a job on a badly chaulked stucco commercial building that hadn't been painted in 20 years at least, with no primer (I added flood's emulsabond) and 1 coat of Kelly Moore's 1245 (satin latex) in 1987 and it is still doing fine (17 years). On T111 siding you are not going to get long life because the plywood will continue to crack and split. I use PermanizerPlus (primer) on this. I usually spray 1 coat as thick as I can get it and it covers fine. If using a deep base, there is so much clear in them that 2 or more coats is required. If doing an extreme color change going to a deep-base use a tinted primer as the first coat. Usually the paint store will use the same tint formula to add to the white primer and it won't be dark enough. Add lamp black (pigment) untill it is slightly lighter in tone even if it not close in color as the paint won't cover very well otherwise. Do a test patch and judge. Also back roll the primer where necessary, but backrolling deep base colors will not cover as well as just spraying.
The trim work gets done in satin also but I used to use gloss and that is best for smooth old style double hung window casings. I mostly see rough sawn trim around aluminum windows.
As to brands? Any true paint stores mid line paints will be good to work with and give you good life. The box stores are O.K. and even WalMart has their paint made by SherwinWilliams (east of rockies) and McCloskey (west) and I like the satin ($53/5Gal.). There are cheap paints I dont like but my general opinion is on the interior paint doesn't have many requirements while on the outside it sees ultraviolet light, rain, heat,cold, etc. so get a good product (@ $20 or so per Gal.-BenjaminMoore, SherwinWilliams,etc.).
Remember 1 thick coat will work fine (that is all I usually do) but you will get longer life out of 2 (1 can be a primer).
For getting up top on a 2 or 3 strorey building some safety issues and difficulties present themselves. I have always found it fastest to move around the house and work off extention ladders. My favorite for high work is a Type ! (heavyiest duty) 28' aluminum. I have a fall set ( 2 giant steel hooks to attach to a roof overhang, a set of stirups that hold a 20' aluminum plank and a pair of block and tackles to raise and lower the plank) that is used by 2 people, one on each end raising and lowering. I never use it since leaving San Francisco and not seeing any building higher than 2 storeys. There are problems using the extention ladders like a sloping or uneven ground ( I use wood blocks but you can get adjustable extention legs to level things out), parts of the structure (like a porch or garage) jut out making it impossible to lean the ladder up on the 2nd storey wall from the ground. If I can I put the ladder against the house to the side of the obstruction, use a ladder jack (attaches to the rungs making a perch for the plank) and site the plank between the ladder jack and the peak or? possibly another ladder jack on the other side. Two extention ladders with ladder jacks and a plank make a nice platform to work off of if there is considerable prep work needed otherwise its quicker to work off a ladder and move it. I have used extention ladder horizontally as a plank with a sheet of plywood across the rungs in a pinch but try it at a foot off the ground to see if it will feel safe first. Using 2 step ladders and putting a plank through the steps makes a nice stage maybe 3 or 4' higher than ground level which is helpfull a lot of times. A 2by10 or 2by12 (not softwood like redwood) works for 10 or 12' planks. If the ladder is tall and looks shaky, using a rope to tie the bottom towards the house to prevent it slipping out from under you is neccessary also tieing it towards upslope to prevent it sliding downslope. For touch up and hard to reach small areas an extention pole is very usefull. There are cherry pickers to rent that will put you in a lift that will reach 3 storeys or you can rent scaffolding by the week or month.
If you are accident prone or not agile then having someone else do the high work would be best. Be carefull as it is not worth it taking chances and falling from any height. Use type 1 or type 2 ladders as the type 3 homeowners extention ladders will work but they are noticably shakier to work off of.
