Is there a boring room in your house? You can bring it to life by changing a wall, and we're not just talking about the usual paneling or wallpaper.

One of the simpliest is the photo mural, sold in rolls like wallpaper. It might be an outdoor scene, a cityscape, or fireworks. At any wallpaper store you will probably find several books full murals.

Photo murals start around $100, and are easy to apply. A way to get a mural effect for a lot less money is to create you own by stippling paint onto the wall with flowers, leaves and so on. This calls for a bit of skill and talent, but it's not as hard as you might think. And if you have some leftover paint lying around, it won't cost a thing.

Start by selecting vegetation and flowers with good distinct forms. You will be dipping these in paint and using them like rubber stamps to apply the paint to the wall. A sturdy flower like a zinnia or daisy will work well. So will ferns.

You can rough sketch your design on a piece of paper before you start, or just wing it and see what happens. You'll be using latex paint (oil paint ruins the flowers and leaves too quickly) so if you don't like what you've done, you can wipe it off before it dries.

To stipple with flowers, dip them until the "stamping" sides of the petals are covered. Blot once on a sheet of paper or paper towel, then press against the wall. You will be able to make two or more prints before dipping again.

Use a different technique with ferns and other leaves. Brush or roll a thick layer of paint onto a board or a sheet of aluminum foil. Press the fern or leaf onto this bed of wet paint, then remove it and press it against the wall. Use two or more shades of green to give the mural greater depth.

Using this stippling technique you can bring a wall to life by highlighting a relatively small area. You might create a little garden in a corner where two walls come together, or at the head of a bed.

Supergraphics are another surefire way to liven up a room. Some paint stores sell kits to help you design and apply them, or you can work from scratch. Supergraphics are not as simple as they may seem, so it's best to draw your ideas to scale on paper before you attack the wall.

Once you have an idea, transfer it to the wall. If you have a steady hand you can pencil the outlines of the design on the wall, then apply the paint freehand. If you are a bit shakey, masking tape will help. But don't use tape unless the paint is already on your wall is sound. Removing the tape may also remove the paint beneath it.

Tip: Whenever you remove masking tape, be sure to pull it back against itself, not straight out from the wall. Pulling straight out increases your chances of removing paint with the tape. Q: My husband built a wall dividing one large room in our home into two smaller ones. He used gypsum board, but can't seem to do a smooth job of taping the seams. He has tried smoothing them out but they still look bad, especially in the afternoon when the sun shines on them. How can we solve this problem? My husband doesn't think he can do much better on the joints. A: You could paint the wall with texture paint. It's a very thick paint -- almost a putty -- that you spread on with a trowel or stiff brush. Once it is on, you can texture it in a variety of patterns using a stiff brush or whisk broom, or by patting it with a sponge. A swirl is fairly easy. The texture will hide the uneveness of the taping job, but there are some drawbacks.

Once you texturize the wall, it will be very difficult to "untexturize" it at a future date. Also, a textured wall is difficult to keep clean, and is not a good idea for a child's room.

Other solutions would be to put paneling up over the drywall, or hire a professional.

But I believe your husband should be able to smooth out what he has done. The first step would be to rip off any tape that has bubbles under it. Then retape the bare spots. Use premixed wallboard compound.

After the newly-taped areas have dried, apply a thin coat over all the joints. Use a very wide trowel for this job. A 10-incher is about right. It has to be that wide to bridge across the seam. That thin coat should smooth things up a great deal. If not, trowel on another skim coat and let it dry. That should really smooth out those seams. A little light sanding with 120 paper on a sanding block can knock off any high spots or bumbs, but don't overdo this or you may scuff up the paper facing of the gypsum board, or the tape itself. Q: About two years ago, I had my front lawn taken out and concrete poured and colored green. Now the concrete has faded. Is there any paint or stain that I can use to recolor the surface? A: Yes, but as a first step get in touch with the concrete company that did your work. They may have a treatment to solve your problem. For example, a coat of concrete wax or sealer may bring the old color back, depending on how the concrete was colored in the first place. If not, they may be able to recommend a compatible stain.

If they can't help, you have two choices: concrete stain or paint. A good floor and deck paint formulated for use on concrete would probalbly be best. Stains tend to fade rather quickly and often come off on your shoes. The best types are meant for concrete less than a year old, and on yours might not give a good, deep, even color. Q: I have shopped all over and can't find any of the solar screening you described some time ago. Can you tell me who makes it and where I can buy it in my area? A: Solar screening is made by a number of the major screen makers. I am surprised you and other readers are having trouble finding it, especially in your part of the country. Probably the most universal source would be Sears. yIt is listed in the Sears Home Improvement Catalog under the name of Comfort Shade Screen. You can also get more information by writing the Screen Manufacturers Association, 410 N. Michigan Avenue, Chicago 60611. Q: I am about ready to repaint my house, but I am unsure about how to do it. The paint salesman at my local store tells me I should start with a coat of oil-base primer, then use latex paint over that. I thought primers were for use on bare wood, . . and I also thought it was best to use latex over latex, or oil over oil. What do you advise? A: According to studies made at the Forest Products Labs, your paint salesman is probably right. A good alkyd primer is formulated to stick to "problem" surfaces (and that includes chalky paints) much better than an ordinary latex. Still, you might be able to skip the primer if your existing paint is in good condition. You can check it with a simple test:

Clean a section of your house with detergent, water and a brush as you normally would before painting. Then brush on a test patch of the paint you plan to use on your home. Let it dry for at least 24 hours, longer in cool or humid weather.

Then apply a strip of adhesive tape -- the white cloth type -- and rub it down firmly. Grab one end and pull it quickly off the house at right angles to the siding as shown in the sketch. If no paint comes off with your tape, there is no need to prime. But if paint peels off, follow your salesman's advice, and brush on a coat of alkyd primer.

When that is dry, apply your latex topcoat. Incidentally, the Forest Products Labs tests show that if you apply two coats of latex over the primer, your paint job can last up to 10 years. That's a long time, and well worth the extra effort. Q: We have a large and uneven flagstone entryway in our home that we would like to remove. How can we do this without causing damage to the cement floor below? A: This sounds like a job for a good mason. Even assuming you could remove the flagstone yourself, you would still have to repave the area the covered with new concrete. I would suggest you have a professional mason handle both jobs.

If you want to try it yourself, rent a jackhammer. Some renatal shops have small electric models that would be ideal for the job. Use the hammer carefully, to avoid breaking the subfloor. The trick is to start at an edge and use the hammer at an angle to chip the flagstone loose. Do not direct the force of the hammer straight down onto the floor.