I am painting over old paint and there is a bit (ok a whole bunch) of chalking and or peeling paint. Can I just paint over this?

No -

Distance of sprayer to wall determines.....
How dry the paint droplets are when they hit the wall. The more watery a paint is the farther from the wall you may stand. However, the closer you stand the greater the chance you have of causing "runs"
Coverage
Drying
Why doesn't the color on the house seem to match the color chip I used?
A color chosen from a color deck often will not represent the appearance of a color in a specific exterior environment. One potential cause may be due to the frequency of the light striking the surface in both environments such as view of the color deck in a pastel colored florescent lit room (the light striking the sample will have absent the frequencies of natural sunlight and so it will only reflect the portion of the spectrum which is available from the florescent light and not absorbed by the room environment) and view of the exterior surface with substantial landscaping (if there is a full grass lawn with substantial shrubbery much of the light reflecting from the exterior surface will already have much of the red absorbed by the landscaping and the light striking the paint will have an excess of greens in the spectrum much as if a green flood light were applied to the surface


Stain from laurel Oak - In situations where Oak trees have been overhanging a deck area and the little fuzzy balls have fallen onto the deck and then been rained upon, the tannins from the seed balls will in short periods of time stain the deck. - Depending upon the severity of the stain, you may make up a solution of 1/2 pound of trisodiumphosphate (TSP) to 1 gallon of water {this will be a caustic solution similar to bleach and similar cautions should be employed}, apply this solution with a mop, a pump up sprayer, or using a more concentrated solution a pressure washer may be used for application. Following the application the solution should sit on the deck for about 30 minutes and then be washed off. Repeated applications should remove much if not all of the tannin.


Qestion-> I recently painted a deck / house / roof and after 2 or 3 days the paint was still tacky When the surface was washed, all of the paint came off…..?

During periods of very high humidity and frequent rains (Florida will typically have 2 to 6 of these periods a year) paint will not have an opportunity to fully cure. In this case the paint is actually still "wet" and washing indeed washes the paint away just as if the surface had just been painted. During periods as described the coating will indeed cure if left sufficiently undisturbed.

Question-> I just had a retaining wall / concrete slab / poured concrete structure built and I was careful to paint it about a day or two afterwards to get the coating protection on as soon as possible, yet about a week to a month later the paint started to blister and peel.

Concrete and mortar typically takes up to 30 days to get a 90% cure, especially in warm and humid conditions. Concrete cures best in cool and humid conditions. While the lime in the mortar is still active the surface has a very basic (as opposed to acidic) Ph. Paint systems typically bond best to neutral or slightly acidic surfaces. The Ph should at least be below 10 when the coating is applied.

How Can I Get Paint to Stick to Hot Surfaces?
The Potential Problem
Paint adhesion to hot surfaces, especially during summertime hot weather.
The Solution When applying any paint, including both waterborne (so-called "latex") and solvent borne, including alkyd (oil-based), rubber-based, epoxy-based, urethane-based, etc., always make sure the surface to which you are applying the paint or coating is NOT TOO HOT - i.e. the surface should NEVER be 90° F (32.2° C) or hotter. Note: The surface is frequently hotter than the ambient (air) temperature. Why? In order to get good adhesion of any paint or coating to any surface, the surface MUST be (A) rough (like rough, 80-grit, sandpaper) and/or (B) porous (have pores in the surface, like the pores in a piece of wood or lumber). This requires that surfaces be properly prepared, e.g. concrete must be made porous by being etched with acid and sheet metal, such as steel,aluminum, copper, etc., must be scarified or roughened until it has a profile (peaks and valleys) measuring 2 to 3 mils (50.8 to 76.2 microns) from highs to lows; even smooth enamel paint must be roughened with sandpaper. The reason for the rough and/or porous surface is so the paint or coating has something to grab onto to hold itself onto the surface, or to penetrate into and anchor itself to. The bond between a paint/coating and the surface to which it is applied is a mechanical bond - not a chemical bond. When the surface is too hot, i.e. hotter than 90° F, then the paint will dry too fast on the back side of the paint film - the side next to the wall, roof, patio or floor - BEFORE the paint has had a chance to penetrate into the pores of the surface, e.g. the pores in the concrete or macadam surface of a driveway, patio, walkway, tennis court, wall of a swimming pool, or stucco walls on the exterior of a building or the tiles on a roof. This is like pancake batter being put onto a hot griddle, and the bottom side of the pancake that touches the hot griddle cooks much faster than the top side of the pancake. It cooks so fast that in a few seconds you have to flip the pancake so it doesn't burn the bottom side of the pancake. If a paint or coating is put on a hot wall, roof, patio or floor surface, you get the same rapid drying on the back side before the paint has the opportunity to penetrate into the pores, cracks, crevices, or the roughened or abraded surface to which it is applied. The result will be a lack of adhesion to the surface, which will eventually result in bubbling, peeling, flaking and chipping of the paint from the surface HELP! Here's a TIP - If you are applying a "latex" (waterborne) paint, you can cool a hot wall, patio or roof by spraying it with a cool mist of cold water from a garden hose, which generally can lower the surface temperature enough so you can apply the waterborne paint. But be sure there is no liquid water left on the surface when you start applying the paint. Of course, you cannot cool a hot surface with cold water if you are applying a solvent-borne (oil-based, rubber-based, epoxy-based, urethane-based) paint or coating. Another thing you can do is to apply paint on the shady side of a building, not the side that is in the sun. Or, you can erect a canvas tarpaulin to keep the hot sun from hitting a wall by shading the wall. Or, you can paint early in the morning when it is cooler, rather than later in the afternoon when it is too hot to apply paint. BE SMART - DO NOT APPLY ANY PAINT TO HOT SURFACES - YOU WILL CAUSE ADHESION PROBLEMS - AND IT WILL NOT BE THE FAULT OF THE PAINT. Thanks to SOMAY Paint - Miami -