Technical Information
For the inquisitive at heart here is some basic information that you should know about for the painting of your home!
Mildew
What is it?
In layman's terms, mildew is a spore that is carried in the air. There are many kinds of mildew and they all have different characteristics. Generally mildew is black or grayish green "dust" on the surface. To the untrained eye, it will look like dust or dirt. Upon closer inspection, it appears to be formed in little clusters or patterns. Mildew likes warmth and moisture and because it is a living organism, it grows under specific conditions. Because of higher humidity and mild temperatures, mildew is very common on the Central Coast.
Where is it?
Interior:
Mildew is usually found in bathrooms because of the warmth and moisture content. Another place is on the walls and ceilings of closets where there is not a lot of circulation. Mildew can also be found on walls behind pictures or furniture. Another common area is under wallpaper particularly in bathrooms. Mildew will grow and discolor the paper. If this is the case then the paper must be removed and the mildew treated.
Exterior:
The most common area on the outside where mildew grows is with the dust under the eaves. It can also be found on the north side of the houses and other places that get limited sun or air circulation. Certain types of coatings are also susceptible to mildew so it is possible that mildew can grow on the whole house.
What Can Be Done?
The cardinal rule is that mildew must be killed before covering it with paint. Whether inside or outside it must be killed first. It must be treated (we use a bleach solution) rather than simply attempting to wash it off. Because, even though the washed surface may appear clean, if a treatment is not used, the mildew will grow back. If the mildew is painted over then a serious condition may occur where the mildew grows back under the new paint job. This only gets worse until all the paint is removed from the affected areas. It is much better to simply kill it all first before painting.
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Wallpaper Removal
What to remove?
Contrary to popular belief wallpaper does not always have to be removed. If the existing paper is clean, in good shape, and both the edges and seems are glued tight, then it is probably ok to place paper over it. However, if the paper has a heavy texture then it may need to come off. Also, if the existing paper is dark then it may show through the new paper.
If painting is desired then it is recommended, as a matter of principal, to attempt to remove the wallpaper. If it does not come off easily the it can be primed and patched to resemble a typical wall and then painted.
If the wall is in bad condition then, after priming, the wall can be re-textured to match the other walls in the room, and then painted.
How Do You Remove Wall Paper?
There is no hard or fast rule to remove wallpaper, since there are many types of paper and glue. Other factors include how may layers of wallpaper are on the wall and for how long. Also, even what was done to the wall before the paper was installed, will affect how the paper will come off.
In concept, if you can get to the glue and then you can use a commercial concentrate remover like "DIFF" that will break down the glue and the paper will come off easily. The trick is getting the glue wet enough to dissolve. The best method is to pull off what comes off easily and then use very course sandpaper to scratch what is left. Then when the all is soaked with the "DIFF" then it will reach enough of the glue and dissolve it. Remember that all the glue must be off before painting. If needed, dry glue can be primed and then painted.
How Much Will it Cost?
Having the wallpaper professionally removed is very pricey. The main reason for this is the fact that no one knows how easily it will come off. If a bid is desired then it will have to be high enough to cover any unforeseen problems. The most common way that we quote a price is by giving a dollar amount based on an allowance of a certain number of man/hours. We arrive at the amount based upon our experience and an on site inspection of the wallpaper and the existing wall.
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FLOATING
INTERIOR:
Floating on the interior is a technique used to smooth out textured or damaged walls in order to either retexture or hang wallpaper. Generally a sheet rock compound is used for this and is applied with broad blades to skim over the all to produce a smooth finish.
Although every precaution will be taken, the fine dust from the sanding of the patching material almost always floats through the house to some degree. This can easily be dusted off.
EXTERIOR:
Floating on the exterior is a process used to help the appearance of wood trim or siding following the prep work.
After the existing weathered surfaces are prepped by scraping, sanding and priming, the surface is usually very uneven. The more coats of paint on the surface that have to be scraped, the worse the surface looks when it is done.
Floating the surface with an exterior spackle or even automotive "bondo" will smooth out the rough surfaces and help the new paint job look even better. Using a semi-gloss paint amplifies the problem so using a flat paint would be better on a badly weathered surface.
The floating of a surface generally does not add to the performance of the paint job. It really is just for the look of the finished paint job.
Because this process is time consuming and more costly then just scraping, sanding and priming, it usually is submitted as an option to the standard paint proposal. Floating sometimes is used only on high visibility areas such as entry ways and courtyards. Because it is costly and since it really doesn't affect the performance of the paint job, some of the other sides of the house don't have to be floated.
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Elastomeric
What is it?
Elastomeric is a relatively new product that has become available in all of the major paint stores in recent years. It is a type of paint that is similar to caulking because of its thickness and since upon drying, it retains its elastic properties. It also comes in the same colors as paints. Also, elastomeric has already been proven to be effective in it's water proofing and protective qualities. For this reason, architects have been recommending it on many of their jobs for both commercial and government buildings.
How is it used?
When regular paints dry they shrink and over time they become brittle. Any small cracks that are in exterior plywood or stucco will reappear soon after painting. This opening allows water to enter the crack. As the wood alternately swells and then dries out, the water that does enter the plywood will eventually destroy the glue and then wood will literally come apart. Elastomeric paint, on the other hand will "bridge" the hairline cracks by stretching when they open up. Because of this elasticity, it is very effective in waterproofing exterior plywood and stucco surfaces.
Another application is the patching of textured wood trim boards. Because of the texture of the wood, other patching materials can't be used. When used, they will smooth out the wood and therefore ruin the existing texture. Using an elastomeric patching compound with a brush will both seal the cracks and also retain the beauty of the existing texture of the wood.
How much is the cost?
Applying elastomeric rather than paint is more expensive than paint for the following reasons:
1. The material is more expensive per gallon than other paints.
2. It takes more gallons of the material because of how thick it is.
3. It takes more labor and larger spray equipment to apply the thicker product.
You will find the results both in the looks and the added protection to be well worth the cost.
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RUST
What is it?
Rust is the break down of metal that is caused by the chemical reaction between water and ferrous metal. Rust will continue to "grow" even if the "infected" metal is coated over with paint. High levels of humidity in the air such as we have here on the Central Coast will cause rust to grow even underneath already painted surfaces. The closer to the ocean, the worse it gets since the salty air aids in speeding up the process. As the rust is allowed to grow, it expands and ruins not only the metal it is growing on but also the surrounding surfaces.
Where is it?
For the painter, rusty nail heads seem to be the most common occurrence of rust. The appearance of rusty nails ranges from a slight discoloration under the surface to ugly "festering" on the surface. Without completely removing the nail the rust will be back. Other typical areas that are susceptible to rust are electrical boxes, roof flashing, and stucco corners where a metal edging is used under the stucco. Inferior building materials are the primary cause of rust.
What can be done?
1. Standard procedure includes not only wire brushing and spot priming. This will not hold back a rust problem, only delay it.
2. Completely removing all rust by wire brushing or sandblasting, then priming with a rust inhibitor primer topped with high quality paints.
3. Removing as much flaking rust as possible and then apply a "neutralizer" that chemically changes the rust back into "metal." Then prime and paint for protection.
4. There are some primers that are designed to go directly over existing rust and will "neutralize" and prime the rust in one application. By following it up with an epoxy-based system, you can provide the best protection from rust.
5. Start with "non-rusting" high quality coated metal products during initial construction or even replace existing rusting metal with the better products. This is the best cure.back to top
Moisture
Moisture Problems
Moisture has a tendency to move through wood and other products as the surface heats up and cools off. Typically, when bubbles and blistering are localized in certain areas and are reoccurring, then there is a moisture problem nearby. Moisture can be caused by a shower on the other side of the wall that leaks or doesn't have proper ventilation, or a kitchen that has a slow leak behind the sink in the wall.
Even a roof leak or a faulty dryer vent can put moisture behind a wall, causing the paint to blister. Or, it simply can occur due to very high levels of humidity inside a house without proper ventilation. This is usually not a problem unless it is excessive and there is no way for the moisture to escape. When the sun comes the excess moisture may be drawn through the paint film on the outside.
The cause must be determined and fixed in order to keep the paint from blistering. Unless the problem is taken care of, even stripping all the paint off and starting all over will not keep the paint from blistering and bubbling.
Horizontal Surfaces
Horizontal surfaces such as decking, concrete or windowsills will often peel within a short period of time. This is because moisture has a way of getting under the surfaces and when the sun comes out it will warm up and draw the moisture through the surface and "pop off" the paint. This is very difficult to cure and most likely these problem areas will need regular maintenance.
What can be done ?
The cause must be found and fixed in order to completely guarantee that the moisture will not continue to ruin the paint job. Even when the water problem is fixed, moisture still will be trapped inside the wall. Enough time must be allowed for the wall to dry out before any finish painting can be done. If the exact problem cannot be found, such as just very high levels of humidity in the house, then the wood siding can be vented. One way is by installing small vents in the surface or even in small wedges placed under the laps joints to open them up enough to allow the moisture to come out instead of popping the paint.
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Peeling Paint
Paint Peeling down to paint
This usually is the previous painter's fault. Either the previous painter did not prepare the surface properly or he used the wrong kind of paint.
Paint Peeling Down to Wood
This is the original primer coming off the wood and not the fault of the last painter. What happens to older wooden homes is the surfaces on the building that get exposure to sunlight become hot. This causes a lot of expansion and contraction of the wood. The expanding and contracting, year after year, will eventually cause the original primer to separate from the wood. There is nothing you can do to stop this from happening on wood and is very common on houses that are over 30 years.
The south side of the house gets the most sun exposure so this is the first side to usually peel. The wood protected from the sun by the overhang will not be peeling as badly. The east and west sides of the house will peel less and usually the north side (with the least sun exposure) will not peel at all. Darker colors on a house will speed up the separation of the primer (peeling) from the wood because the dark colors absorb more of the sun's rays and thus get hotter. White paint will last the longest. Once the peeling process starts, it will continue as long as the original primer is on the house.
What can be done?
There are two ways to work with the problem:
1. The first is to strip off the original primer. This is labor intensive and therefore expensive. If the front of your home faces south, then it is the front of the house that will look bad when the paint starts peeling. In this case you may have a higher motivation to strip off the original primer.
2. The second approach is to scrape and or sand the peeling paint to a tight surface, spot prime the bare wood, and then paint all of the area. This will do nothing for the areas that will eventually peel, and the peeling will occur in the other areas that have not yet peeled. This is a lot less expensive at first but there will be continual maintenance to do later. Most people will do some maintenance touch up painting after about a year or two. If the peeling is on the back or a less visible side of the house, it is more cost effective to just scrape, spot prime, and paint.