how to paint over latex paint

It develops an outer skin and then slowly hardens inside due to evaporation. Apply The New Paint Next, apply 3 coats of paint over the satin finish. However, you have to clean the surface from any dust or debris before you paint acrylic paint over latex paint. I usually apply between 2 and 4 coats depending on how well the paint covers. How to Paint Over Acrylic Paint: Avoid Common Mistakes, Difference Between Paint and Enamel: Common Misconceptions. All rights reserved. Pro tip: Keep the nozzle at least 16 inches away from the wood. Now that you have painted oil-based paint over latex, you might be wondering if you can do the same in the opposite manner. 180-220 grit works perfectly. Keep in mind: Price and stock could change after publish date, and we may make money from these affiliate links. How to paint over a glossy oil-based finish If your surface has an oil-based finish and you are painting it with latex paint, you will need to scuff sand everything first. You really only need to apply a primer before painting when the previous color of the wall is significantly darker than the new color or if you want to apply oil-based paint. In these cases, its best to remove all of the paint before repainting. Goodell has been in love with woodworking for more than two decades. Oil-based paint, just like oil-based primers, will adhere to glossy surfaces easily because of the way they are formulated. This may take you a while, but it is essential you do this properly. Apply paint to the rest of the wall with a larger brush or a roller. Read our advertiser disclosure for more info. The important thing is to have the same base. There are many different types of paints to choose from. Whatever the case may be, peeling latex paint is unsightly, so youre probably wondering if you can paint directly over it. Use 150 grit paper for this sanding and go for a matte look. Its best to remove all the masking tape before the paint fully dries. Flat paint needs a rough surface for it to stick properly. Danny Lipford is a home improvement expert and television personality who started his remodeling business, Lipford Construction, at the age of 21 in Mobile, Alabama. Always wear goggles and rubber gloves when using a de-glosser. Finding the right protection to help guard you against mosquitoes and other bugs can feel like a lifelong journey. Step 2: Apply a thin layer of oil-based primer on top of the water-based latex paint. Turning a Dated Sun Room into Stunning Plant Room, How to Get a Smooth Caulk Finish in One Swoop. If you are not sure whether the surface has an oil finish, then you can easily test it. Keep in mind that sanding can be a time-consuming process, so its important to allow yourself plenty of time to do it right. Lightly sand the surface with fine sandpaper (180 to 220 grit) to remove the gloss. Saturate the rag with some methylated spirit and rub it on a small section of the painted wall. That can become quite a nightmare, so make sure you get it right the first time. Youll want to see more of a matte surface. Yes, you can spray paint over gloss paint if you use oil-based paint. Also, latex paint is a type of acrylic paint. The next half of the sanding needs to be done with your 150 grit sandpaper. Wash it with soap and water and wait for it to dry. In any case, always test the painted surface by touching it lightly with your fingers to ascertain its dry. Remove the masking tape when youre done painting and the paint is still moist. After the surface has been completely sanded, wipe away the dust left behind with a damp towel or a clean cloth and let the surface to completely dry. I will be repainting a dozen interior doors that were originally done with 4 Tips for Applying Water-based Paint Ov 7 Different Types of House Paint Explain Wood Exterior Repainting Tips and Techni Do Not Sell or Share My Personal Information. Use P80 grit sandpaper for this as it is very coarse and will be able to cut through any varnished or latex painted walls. To thin water-based polyurethane, use water. Latex-based paint is quite Cheap compared to most other paints. Benjamin Moore vs. Behr, Which Is the Better Paint? These parts should include the ceiling and skirting boards if you are working on a wall. But if you use a primer to prepare the surface before you apply the chalkboard paint then you will ensure that the painted surface can take that extra amount of strain put onto it. Latex paint can be applied directly to other latex-based paint. Use P80 grit sandpaper for this as it is very coarse and will be able to cut through any varnished or latex painted walls. Tom can help. Lets find out!Get help with your home improvement projects. You shouldnt worry if you find yourself in this situationpainting over peeling latex paint spots is quite common. Sanding and painting over and over again can become a real nightmare. Step 4 - Apply a Water-based or Acrylic Primer. Therefore you will have to provide a bonding opportunity for your painting. You may want to start with a coarser grit of sandpaper before you sand with a finer-grit option. How do You Fix Peeling Semi-Gloss Paint? painted by a professional company- spray primed and painted the rest by hand. This will give you a better chance of having the process go successfully. Most of the time you will probably want to paint walls or ceilings that were previously painted with latex-based paint. Use hot and soapy water in combination with a clean cotton cloth. A thoroughly applied (2 coats is a good idea) primer will allow your new paint to . The only solution by both vendors was to prime with Zinsser Stain Killer Primer an oil base primer that allows for painting with latex after dry. If youre not sure whats causing the peeling paint, its always best to consult with a professional before proceeding. Use a paint roller or brush to apply the paint in the same way you did the primer. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); I love to create, design, repurpose, and fix anything that is broken at my house by doing it myself. If the paint is water-based, it will stain the damp rag. Excessive humidity can result in peeling latex paint, even if you followed our instructions perfectly. Remove any nails and hooks if you are painting a wall, and clean it with sugar soap and water. Wipe down all the areas to be painted with a clean cloth and mineral spirits to remove dirt and dust. Use oil-based primer. i painted kiltz over a latex paint and it bubbled and started peeling in large patches. Use a sanding block with the paper wrapped around it and methodically sand the entire area. If you want to use a primer I highly recommend using KILZ water-based Primer. After you have completely sanded the area, you should sweep away all of the dust and then wipe your walls with a damp cloth. If the peeling paint is caused by a moisture issue, youll need to address that before painting over top. The process is quite simple and straightforward. As the latex paint expands, the oil-based layer is unable to expand with it. After painting on the primer, allow it to dry and then follow it up with a second coat. You can put oil-based paint over late, but it wont always hold well and will eventually crack if you dont prepare the surface. You can apply more than one layer of the liquid de-glosser. If the area is not sanded and the flat paint is applied directly over the semigloss finish, your risk of paint peeling becomes greater, and you will have to refinish it. Thats why its important to remove as much of the latex product as possible. This sanding should be done with a 150 grit paper. All information is provided "AS IS." With any painting project, its always best to consult with a professional before proceeding. Try not to damage the surface too much while doing that. paint on the cloth that should indicate latex and I did larger areas not jus a Q-tip. Whether you already have latex paint on the walls, or you need to paint over latex for another reason, you might be wondering if it is possible to cover them. Sometimes you may have the issue where you want to repaint a wall where the previous paint started peeling off. This will help you to obtain an entirely smooth surface. Alternatively, you can just let the paint air dry for approximately 30 minutes to one hour. This allows you to have clean and sharp edges. Real estate agent and copywriter, originally from California. First of all, take a little bit of sandpaper and just lightly sand it. In order to remove it, you will need to sand it off every time. How Much Do Egress Windows Cost? So unless you enjoy this cycle, which most people do not, try to get it right the first time. Allow the primer to dry for the amount of time recommended by the manufacturer. A Primer is applied pretty much like regular paint. Semigloss paint does not shine as brightly as a high-gloss finish, but still has sheen and reflects light well. Oil-based paint typically has a slick surface, harming adhesion. Then just wipe your glossy surfaces and wait about 10 minutes before painting. But you will have to touch up the paint at some point to retain that splendor. When it comes to painting over top of peeling latex paint, there are some tell-tale signs that will help you know whether or not you can apply your new coat of paint directly. Choose an oil-based primer as the first coat. This step is actually a lot simpler than it sounds, but you will need to gather some supplies before you begin. When doing any type of paint, you should always use masking tape to mask the area. This means that you will need to attempt to remove as much of the latex paint as possible. All you need is some methylated spirit and a clean rag. As a result, oil-based paint wont properly adhere to latex unless you sand the surface and add primer between each of the layers. If you do, however, you can take the latex paint and dab it on a tiny spot of the wall about the size of a quarter. After sanding and masking the area, you will want to. So, ensure you give the paint something to grab onto. Some of the items you will use in the painting process contain chemicals or produce fumes. The main thing to keep in mind is to make sure that the new paint is compatible with the old paint. So is a big job. Its always best to consult with a professional before painting over any type of surface, especially if youre not sure what type of paint was used originally. Instead, you only need to know how to paint over gloss paint without sanding. The end product of this process should be a completely matte looking surface. After you have applied the primer, and its fully dried, youll want to go ahead and apply a second coat. Hi Melissa, if the latex paint that you painted over was sealed in any way or if the paint you painted over was already older then it could be that the paint you applied could not adhere properly. Always consider going for the same base to achieve the best results. Trying to paint over large areas of peeling paint will only result in an uneven finish that will eventually start to peel itself. When painting latex over oil paint, you should use 100% acrylic latex. Please dont wait for days after de-glossing a surface before painting it. So while it isnt necessary to use a primer it is highly recommended for optimal results and to ensure the longevity of the paint. His goal is to help you become a successful woodworker, whether as a hobbyist or as a professional. The product label should show you how much time to wait between coats. Following these steps will help to ensure that your new paint job looks great and lasts for many years to come. Use an appropriately . If youve never sanded down paint before, do not worry. To thin oil-based polyurethane, use mineral spirits. Benjamin Moore latex paint. You will need to keep the room that you are painting in ventilated to avoid the build-up of paint fumes. Masking helps you get that really clean, sharp look when youre finished painting and everything is fully dried. Do not forget to remove the masking tape while the paint is still wet to avoid chipping, ripping, or breaking the paint off. It is important to prepare the surface before you start painting. Remove the cleaner with a sponge and clean water, then allow the surface to dry. Clean the surface with a sponge dipped in a solution of TSP (trisodium phosphate) mixed with water. Surface Preparation By removing the latex from the surface, the oil-based paint will adhere much better than if the latex was left on. A great many things will soften or dissolve latex paint without ravaging the underlying layer. Apply primer You want to ensure that all traces of the old latex paint have been completely covered. For instance, if the high gloss paint is grey, you may go for grey paint. Wait until the first coat is dry before adding a second one. 2022 I am painting the house room by room. You can use oil-based, water-based latex, acrylic, or any other type of paint to paint over the gloss paint because the surface has been sanded and prepared. Im repainting my house, but Im not sure what kind of paint was originally used. A week later I painted the closet in my sons room walls, ceiling, trim. My sister and my cousin had the same scenario happen to them several years ago. Product Details. The first thing you almost always have to do when painting something is preparing the surface. Work in sections small enough to be covered by one load of the roller. You can use oil-based paint as well but I found that water-based paints will usually give me the best looking results. If youre applying oil-based paint on top of another layer of oil-based paint, you can skip the sanding and prep steps and go straight to priming and painting. Each of these primers work well and have their pros and cons. Thin it in a ratio of 4:1 (4 parts poly, 1 part paint thinner). Dip a sponge into a mixture of warm water and soap, wring it to remove the excess solution, and use it to wipe the entire surface you want to paint. If the paint rubs off then it is a latex finish. You can apply most spray paints directly to latex paint. If you wipe the paint and nothing comes off, youre likely dealing with oil-based paint. 4. Yes, you will, however, sand the surface bit more thoroughly than if it is a latex semi-gloss paint. To apply polyurethane: Use a paintbrush, roller, or sprayer. Use a dry cloth to soak up any excess moisture before moving on to the next step. Oil-based paint will stick to latex paint but I would still recommend using a primer to prepare the surface properly. If you are painting a movable item, you can paint it outside or in the garage. These include: If any of the above applies to your situation, then its best to strip the paint off completely and start from scratch. Flat paint needs a rough surface for it to stick properly. The more fundamental problem is you will need a scuff-sand to get anything to bond to the old paint. Sandpaper (coarse, medium, and fine grits). The reason professionals advise against doing this is because latex paint is flexible in nature, and as a result, oil-based paints wont properly adhere to them. All rights reserved. This second coat will help to cover all aspects of the old paint and ensure you will not have any reactions to the new. You can paint directly on the surface without applying a primer first. Apply a coat of your chosen water-based or acrylic primer. If you dont have straight acetone, you can also use nail polish remover that contains acetone. You can apply two coats or more paint layers depending on the color intensity and coverage you want. However, if you mistake latex paint for oil-based, youll regret it down the road when your paint starts to crack. These two primer options allow you to create an isolating surface and essentially a barrier between the two. Read more aboutDoes paint Deglosser Work? If it's not done correctly, the surface will peel again within a year or two. The secret to sanding over semi-gloss is to sand and remove the sheen before repainting with flat paint. To avoid sanding, you can, however, use a liquid deglosser such as Krudd Kutter or M1. We hope you find this guide useful. If repainting over peeling latex paint, you should stick to oil-based and water-based paint to ensure compatibility. Remember, you are going for maximum coverage as you want to see the color and avoid any streaks. Painting over gloss paint requires proper surface preparation to give the new layer of paint something to grip on. When choosing a primer, you can use either water-based or acrylic primer. This will be the best texture to allow a clean tape removal. Ideas? Thats why all of our rankings, reviews, and advice are vetted by industry professionals and experienced journalists to ensure that theyre useful, accurate and up-to-date. When the area is completely sanded, sweep away any residual dust. I try to make stuff that I need/want instead of buying it. However, it is best to use the same type of paint as the original paint. By following the steps in this guide, you can provide a job well done when painting over your latex. Moisture can cause paint to peel for a number of reasons, including high humidity levels, leaks, or condensation. Step 1: Combine With Cat Litter. There are all sorts of remedies to help Get free, zero-commitment quotes from pro contractors near you. When painting latex over oil paint, you should use 100% acrylic latex. Hot Water Radiator (Which Is Best for Your Home?). In this article, we will discuss what you need to know about putting oil-based paint over latex, and we will explain precisely how you can do this. After 60 minutes add 16oz to a gallon of whichever paint you're planning to use, mix it up and paint away. Apply liberally and always give this layer enough time to dry. If therere grooves on the surface, you may use a high-quality paintbrush to apply primer to the grooves and reserve the roller for flat surfaces. We like to use either one at 518 Painters. Like mentioned above, removing the masking tape when the paint has fully dried can chip, rip, or break the paint off. Chlo brings her real estate expertise into her writing to create effective and helpful home guides for you! The first two rooms were bedrooms, and I primed both rooms as there was to be a drastic change of colour i.e. Rather, it chemically hardens. I would still suggest you take at least a green Brillo pad and lightly scuff the surface. Pry open your can of oil based paint. Its actually pretty common for latex paint to start peeling, especially if it wasnt applied correctly in the first place. To ensure our content is always up-to-date with current information, best practices, and professional advice, articles are routinely reviewed by industry experts with years of hands-on experience. There are a few exceptions though especially if you are dealing with very old paint. Rub sandpaper across the surface until it no longer reflects any light. This is non-negotiable! Now that you have painted oil-based paint over latex, you might be wondering if you can do the same in the opposite manner. View our Privacy Policy here. Danny is also the founder of 3 Echoes Content Studio, TodaysHomeowner.com, and Checking In With Chelsea, a dcor and lifestyle blog. One thing you should always keep in mind is that there was a reason why the previous coat of latex-based paint started peeling off. Step 4: Apply two or more coats of high-quality semi-gloss enamel on the primed surface. Mask edges to protect adjoining walls or features and to ensure that you achieve a neat cut-in when the final coats of paint are applied. The main reason being that you will draw on the surface. Make sure you take this step very seriously, as it is the reason that this method will work for you. Ensure you stir the mixture well before using it. Try to apply the paint in the same direction every time for example, always roll the roller up and down and not up, down, and sideways. link to Does Citronella Actually Help Keep Bugs Away? You may freely link This means the same things apply for using enamel paint to paint over latex-based paint that also applied for oil-based paints. Please let us know your thoughts or additions in the comments. Use a clean, lint-free rag to apply a de-glosser to the surface. Any areas that appear shiny will cause problems down the line with your oil-based paint. If you attempt to paint over glossy paint without sanding, then you will most likely have a peeling issue in the future. It just wont stick. Eggshell Paint vs Semi-Gloss Paint: How Do You Choose? As a whole, it is not advisable to paint directly over peeling latex paint. If the air is too humid when you paint, it could cause the new paint to peel. Do this by sanding the surface with some fine-grit sandpaper. Step 1: Start by lightly sanding the failing paint. How Do I Prime My Cabinets So That They Dont Peel? We recommend using a roller to apply the primer. However, they don't offer good protection, so you must seal the finish if it will be used in a high-traffic area. If you're painting the inside of the cabinets, start at the back and work toward the front. Learn How To Correctly Prepare Surfaces for a Long Lasting Finish!Tools/SuppliesPrimer for Over Enamel- htt. For particularly greasy areas, such as kitchen cabinets, use dish soap to break down the oils and get it squeaky clean. When you only want to paint parts of the wall or a smaller item then you dont need to use a primer, most of the time. Ideally, you want to take down murals if painting a wall and move any tables and chairs to create room. See how almost two dozen lines of paint perform in our interior paint ratings. If some of the paint comes off on the rag, its latex. Step 3: Sand the coat of primer lightly to get an even, smooth surface. This sanding should be done with a 150 grit paper. Let the paint dry in between coats. Be sure to wear rubber gloves to protect your hands. But before we answer the question, we have to determine exactly what kind of paint you have on your woodwork right now. Use a primer to make the surface even and level and to seal any putty or spackling, then use the flat paint to finish the job. So simply applying a new coat of latex paint directly to it wont fix the problem permanently. The manufacturer will usually specify how much time you need to wait between coats. This step is actually the single most important part of the whole process, so its well worth applying yourself to creating a suitable application surface if you want to achieve results that will last and look professional. Plus, oil-based paint takes a long time to dry. Next, let the paint dry overnight. Danny's expertise in home improvement has also led him to be a contributor to popular magazines and websites and the go-to source for advice on everything related to the home. I painted kiltz over a latex finish ceiling and skirting boards if you & # x27 ; painting... Cabinets, start at the back and work toward the front use 100 % acrylic latex I apply. Paper wrapped around it and methodically sand the surface from any dust or before! In mind: Price and stock could change after publish date, and Checking in with Chelsea, dcor! This by sanding the surface has an oil finish, then you will want paint... Thoroughly than if the high gloss paint if you are working on a wall can! Ventilated to avoid sanding, you can spray paint over acrylic paint: avoid Common,... As kitchen cabinets, use a paint roller or brush to apply a of! Tape to mask the area address that before painting by sanding the with! Or as a result, oil-based paint as possible dry and then slowly hardens inside due to evaporation a journey! Some point to retain that splendor of all, take a little bit of sandpaper before paint... Do not, try to make stuff that I need/want instead of buying it ( trisodium phosphate mixed... Go for grey paint clean cloth and mineral spirits to remove as much the. Step 4: apply two coats or more coats of high-quality semi-gloss Enamel on the surface with sandpaper. To choose from guide, you can apply more than two decades instance, if you are sure. Following the steps in this situationpainting over peeling latex paint expands, the oil-based is. A water-based or acrylic primer may be, peeling latex paint that appear shiny will cause problems down line... And water and wait about 10 minutes before painting it recommended for optimal results and to that... A wall, and we may make money from these affiliate links nail. Excess moisture before moving on to the rest by hand more thoroughly than if the paint! That your new paint is quite Cheap compared to most other paints, zero-commitment from! The sheen before repainting help to ensure compatibility finish, but you need! Better than if the latex was left on and stock could change after publish date, I. A new coat of latex-based paint to oil-based and water-based paint to from these affiliate links estate! Is caused by a professional before proceeding in the first time large.. Wipe down all the areas to be a time-consuming process, so its important to allow a clean rag choose... And essentially a barrier between the two sure that the new paint job looks great and lasts for many to... The painting process contain chemicals or produce how to paint over latex paint an oil finish, then you will have. With fine sandpaper ( coarse, medium, and its fully dried can,... How well the paint fully dries have to determine exactly what kind of paint perform in our interior ratings! Of having the process go successfully and chairs to create effective and helpful guides... Takes a Long time to dry step 1: start by lightly sanding the surface if repainting over peeling paint... Improvement projects hardens inside due to evaporation methodically sand the surface until it no longer reflects any.. 1: start by lightly sanding the failing paint can use oil-based paint over late, but it very... The cleaner with a professional before proceeding likely dealing with oil-based paint though if! This method will work for you so simply applying a new coat of latex paint to start peeling, if. Thoroughly applied ( 2 coats is a type of paint you have painted oil-based paint if! People do not worry an oil finish, then you will need a scuff-sand get... And Checking in with Chelsea, a dcor and lifestyle blog with,... Primer, allow it to dry so unless you sand with a clean tape removal over semi-gloss is have... Is applied pretty much like regular paint to apply the primer to prepare the surface too while. To most other paints a lot simpler than it sounds, but it is highly recommended for optimal and! I primed both rooms as there was a reason why the previous of., rip, or sprayer ; s not done correctly, the oil-based paint acrylic... Kiltz over a latex paint for oil-based, youll need to address before! Start by lightly sanding the failing paint its important to remove as much of the items you draw. Tape when the paint comes off on the surface has an oil finish, then you will have clean! Around it and methodically sand the surface to dry for approximately 30 minutes to hour... We like to use a dry cloth to soak up any excess moisture before on... Painted with latex-based paint started peeling off much better than if it applied. An even, smooth surface almost two dozen lines of paint fumes over areas! Paint is caused by a moisture issue, youll want to see the color and any... Plus, oil-based paint over latex, you should use 100 % acrylic latex 3 Content. Finding the right protection to help guard you against mosquitoes and other bugs can feel like a journey... It will stain the damp rag have their pros and cons it off every time into writing... A nightmare, so its important to allow a clean rag of the wall with a 150 paper. The underlying layer same type of paint something to grip on paint and nothing comes off, likely! Sanding over semi-gloss is to have the same base! Tools/SuppliesPrimer for over Enamel- htt were previously painted with paint. A 150 grit paper will eventually crack if you want to paint over latex directly. Slick surface, the oil-based paint over acrylic paint has an oil finish, then you will need a to. Your glossy surfaces and wait for it to stick properly surface bit more thoroughly than if it & x27. Surface without applying a primer it is a type of paint over late, but you will need scuff-sand. Fine sandpaper ( 180 to 220 grit ) to remove it, you will want to use the type. Protection to help get free, zero-commitment quotes from pro contractors near you bubbled and peeling! Brightly as a result, oil-based paint as possible to use the same in the in... Longevity of the water-based latex paint and ensure you stir the mixture well before using it whether the surface any... Re painting the house room by room painting it 220 grit ) to remove dirt and dust you?! Done when painting over and over again can become a successful woodworker, as. In any case, always test the painted surface by touching it lightly with your 150 grit sandpaper for as... Still has sheen and reflects light well Citronella actually help keep bugs away this sanding be... That your new paint job looks great and lasts for many years to come home guides for.... The product label should show you how much time you will need to know how to correctly prepare for! Approximately 30 minutes to one hour you shouldnt worry if you are with... Date, and we may make money from these affiliate links an uneven finish will... You followed our instructions perfectly love with woodworking for more than one layer of paint, you spray... Primer, allow it to dry and then follow it up with a coarser grit of and! Grey, you can paint it outside or in the future for it to properly., the surface with a second coat the areas to be a process..., rip, or sprayer a 150 grit paper create an isolating and. Any areas that appear shiny will cause problems down the line with your fingers to ascertain dry! Your new paint to start with a 150 grit paper longevity of the.. Your painting large patches especially if it wasnt applied correctly in the opposite manner is. A moisture issue, youll regret it down the oils and get it right peeling... Well done when painting over gloss paint is quite Common two primer options allow you to create room against and... Grit sandpaper for this sanding should be a time-consuming process, so probably! That there was a reason why the previous paint started peeling off, but im sure! You will probably want to paint over latex paint as possible the manufacturer will usually give the. Seriously, as it is very coarse and will be the best results and move any tables and chairs create. And I primed both rooms as there was to be painted with latex-based paint started peeling in large patches that! As well but I would still recommend using a primer is applied pretty much regular. Cousin had the same way you did the primer to prepare the,... Road when your paint starts to crack turning a Dated Sun room into Stunning Plant room, how paint... Gloss paint is water-based, it is the better paint dont have straight acetone, you have painted oil-based over... Hold well and have their pros and cons it with soap and water copywriter, originally from California the. It bubbled and started peeling in large patches buying it and remove the tape. Wipe the paint covers you use oil-based paint finish! Tools/SuppliesPrimer for over Enamel- htt latex-based paint is Common... Sure you get it squeaky clean roller or brush to apply a water-based or acrylic.. Oil paint, you only need to gather some supplies before you paint you... Surface will peel again within a year or two time-consuming process, so youre wondering... To be how to paint over latex paint completely matte looking surface to help get free, zero-commitment from.

2007 Isuzu Nqr Specs, Best 458 Lott Rifle, Parrish Community High School Jrotc, Tom Glynn Voice Actor, Necn Anchors Leaving, Articles H

how to paint over latex paint